journal of the association of professional … · on the development of sustainable vlsi...

JOURNAL OF THE

ASSOCIATION OF

PROFESSIONAL ENGINEERS OF TRINIDAD & TOBAGO

Volume 38 • Number 1 (ISSN 1000 7924) • October 2009

Special Issue on Engineering Infrastructure for Sustainable Development

Editorial……………………………………………………………………………….…..2

Advancing the Use of Earth Observation Systems for the Assessment of Sustainable Development …………………………………………………………………………….6

On the Development of Sustainable VLSI Infrastructure for the Caribbean Countries…16

A Dynamic MOPSO Self-Regulating Modulated Power Filter Compensator Scheme for Electric Distribution Networks ……………………………………………………..24

Development of a Shoreline Management Tool for Trinidad ……………..………….…33

Municipal Solid Waste to Energy: Potential for Application in Trinidad and Tobago….42

Natural and Recycled Guanapo Quarzite Aggregates for Ready Mix Concrete ………..50

Laboratory Scale Production of Biodiesel from Used Vegetable Oil …..…………...…57

Investigating Slope Failures Using Electrical Resistivity: Case Studies ……..………...66

Exploring the Link between Ecotourism Activities and Surface Water Quality: Using Water Quality as a Sustainability Indicator ……………..…………………………….76

Market and Economic Assessment of using Methanol for Power Generation in the Caribbean Region ……………….……………………………………………………..88

Call for Papers: Special Issue on Engineering Asset Management: Trend and Challenges. ………….100

Editor: Kit F. Pun

Head Office of the Association: Professional Centre,11-13 Fitz Blackman Drive, P.O. Box 935, Port of Spain, Trinidad and Tobago, West Indies

PRESIDENTS OF THE ASSOCIATION OF PROFESSIONAL ENGINEERS OF TRINIDAD AND TOBAGO

2009-2010 Hannah Wei-Muddeen 1988-1989 Alvin C. Lutchman 2008-2009 Ahmin Z. Baksh 1987-1988 Gerald L. Webb 2007-2008 Vaughn I. Lezama 1986-1987 Cecil I. Chin 2006-2007 Mark D. Francois 1985-1986 Winston H.E. Suite 2005-2006 Geoffrey M. Abdulah 1984-1985 Myron Wing-Sang Chin 2004-2005 Chandrabhan Sharma 1983-1984 Winston M.L. Riley 2003-2004 Winston G. Lewis 1982-1983 J.V. Bowles 2002-2003 Anthony C. Farrell 1981-1982 Richard E.K. Inniss 2001-2002 Clifford G. Murray 1980-1981 Basil M. Pashley 2000-2001 Imtiaz Hosein 1979-1980 Selwyn Lee Young 1999-2000 Winston A. Mellowes 1977-1978 Ignatius D.C. Imbert 1998-1999 Jerry B. Medford 1976-1977 Aldwyn L. Lequay 1997-1998 Francis E. Paul 1975-1976 Harry O. Phelps 1996-1997 Merlyn Ramjohn 1973-1974 Majid Ibrahim 1995-1996 Samuel R. Narinjit 1971-1972 Fenrick R. DeFour 1994-1995 Leopold C. Martin 1969-1970 R.A. Thomas 1993-1994 Clément A.C. Imbert 1967-1968 Kenneth S. Julien

1992-1993 Hollis Charles 1965-1966 Karl Seheult

1991-1992 Emile S. Charles 1963-1964 R.K. Bates

1990-1991 Stephen J.G. Gift 1961-1962 Rupert D. Archibald

1989-1990 Denis R. Singh 1959-1960 Rupert V.S. Aleong

FOUNDATION MEMBERS OF THE

ASSSOCIATION OF PROFESSIONAL ENGINEERS OF TRINIDAD AND TOBAGO IN 1959

Rupert V.S. Aleong (Founding President) Keith I. Allahar Rupert D. Archibald Don D. Ash Rudolph Balgaroo Luther A. Boyce Fenrick R. De Four

Leslie G. Dookie Roderick E. Douglas Luis G. Felipes Kenneth W. Finch Cecil M. Fung Emmanuel J. Guevara A. Majid Ibrahim Richard Inniss

Granville R. Johnston Curtis L.U. Knight Aldwyn Lequay Winston Manson-Hing Basil Pashley Harry O. Phelps Karl F. Seheult Cecil R. St. Hill

Peter F. Walker Errol A. Williams

Note: APETT’s logo was designed by Derek Aleong.

JAPETT; Vol. 38, No.1, October 2009 1

JOURNAL OF THE ASSOCIATION OF PROFESSIONAL ENGINEERS OF TRINIDAD & TOBAGO

Special Issue on Engineering Infrastructure for Sustainable Development

2 APETT President’s Address

4 Editorial

6 Advancing the Use of Earth Observation Systems for the Assessment of Sustainable Development by Raid Al-Tahir, Terri Richardson and Ron Mahabir

16 On the Development of Sustainable VLSI Infrastructure for the Caribbean Countries by Davinder Pal Sharma

24 A Dynamic MOPSO Self-Regulating Modulated Power Filter Compensator Scheme for Electric Distribution Networks by Adel M. Sharaf and Adel A.A. El-Gammal

33 Development of a Shoreline Management Tool for Trinidad by Candice Gray-Bernard and Andrew J. Chadwick

42 Municipal Solid Waste to Energy: Potential for Application in Trinidad and Tobago by Kamel Singh, Solange O. Kelly and Musti K.S. Sastry

50 Natural and Recycled Guanapo Quarzite Aggregates for Ready Mix Concrete by Abrahams Mwasha

57 Laboratory Scale Production of Biodisel from Used Vegetable Oil by Videsh Seecharan, Yamani Ramnath and Rodney R. Jagai

66 Investigating Slope Failures Using Electrical Resistivity: Case Studies by Malcom J. Joab and Martin Andrews

76 Exploring the Link between Ecotourism Activities and Surface Water Quality: Using Water Quality as a Sustainability Indicator by Ken D. Thomas, Joniqua A. Howard, Erlande Omisca and Maya A. Trotz

88 Market and Economic Assessment of using Methanol for Power Generation in the Caribbean Region by Renique J. Murray and Haydn I. Furlonge

Call for Papers: 100 Special Issue on Engineering Asset Management: Trend

and Challenges

Volume 38 • Number 1 (ISSN 1000 7924) • October 2009

Head Office of the Association: Professional Centre,

11-13 Fitz Blackman Drive, P.O. Box 935, Port of Spain,

Trinidad, West Indies

Tel/Fax: 1-868-627-6697 E-mail: [email protected]

Editor-in-Chief: Professor Kit Fai Pun

Industrial Engineering Office Faculty of Engineering

University of the West Indies St Augustine

Trinidad and Tobago West Indies

E-mail: [email protected]

The Journal, JAPETT (ISSN 1000 7924) isa publication of the Association ofProfessional Engineers of Trinidad andTobago. One volume (with 1-2 issues) is published annually in April and/or October,and is circulated to all members of theAssociation, all member institutions of theCouncil of Caribbean EngineeringOrganisations, and to a number of technical libraries within the Republic. Responsibilityfor the contents rest upon the authors and notupon the Association or its members.Individual copies: members first copy of avolume free for members; non-members US$25 per volume. Member copies of journals are for personal use only. Copyrightand Reprint Permissions: Abstracting ispermitted with credit to the source. For othercopying, reprint, or reproduction permission,write to the Head Office of the Association.All rights reserved. Copyright© 2009-2011 by the Association of Professional Engineersof Trinidad and Tobago. Printed in Trinidadand Tobago. Postmaster: Send addresschanges to The Head Office of theAssociation: Professional Centre, 11-13 Fitz Blackman Drive, P.O. Box 935, Port ofSpain, Trinidad, West Indies; Printed inTrinidad and Tobago.

JAPETT; Vol. 38, No.1, October 2009; APETT President’s Address 1

APETT President’s Address

As President of our Engineering Association in the 50th Anniversary Year, it is a distinct honour for me to share with you the significance of this Special Issue of the Journal of the Association of Professional Engineers of Trinidad and

Tobago (APETT). “Engineering Infrastructure for Sustainable

Development” was specifically selected as the theme for this Special 50th Anniversary Issue, as it encapsulates a very poignant message. It focuses the purpose of engineering activity on achieving economic and social development in ways that do not inequitably deplete the earth’s natural resources. The objective of ‘Sustainable Development’ resonates with the Association’s purpose to “safeguard the life, health and welfare of the public” which was recognized in APETT’s Constitution back in 1959, as it now provides the wider contextual framework inclusive of the natural environment and interrelation of all life, which must be considered if we are to truly safeguard public life, health and welfare, while engaged in the practice of engineering.

This Journal goes to print at a time in our history when major national, regional and international events have occurred, that further cement the imperative for sustainable development. In November 2009, APETT participated in the Commonwealth People’s Forum, a pre-event to the Commonwealth Heads of Government Meeting, hosted by Trinidad and Tobago, with the theme of “Partnering for a More Equitable and Sustainable Future”. The forum highlighted key areas for attention if we are to build a sustainable future, such as environmental protection, mitigation of climate change, and innovation – all areas in which engineers must play a role. Also, the importance of civil society bodies (such as APETT) in working with others to promote sustainability was not overlooked.

In December 2009, over 119 world leaders including those from Trinidad and Tobago met in Copenhagen, Denmark at the United Nations Climate Change Conference to address the No.1 global environmental problem of climate change. While no legally binding agreement was reached on

reduction targets for anthropogenic greenhouse gas emissions, the Conference served to emphasize key sustainable development matters such as the need for cleaner technologies, renewable energy sources, and related research and development - areas in which engineers must take a leadership role.

Lastly in January 2010, a 7.0 magnitude earthquake struck the country of Haiti, causing devastation of the capital Port-au-Prince and taking a heavy toll of human life. This tragedy caused deep reflection on means to prevent and mitigate such destruction. It highlighted major areas of engineering relevance such as: engineering infrastructure and related construction materials, physical planning and development, construction codes and standards, disaster preparedness and response systems - all of which engineers have a professional responsibility to ensure are at acceptable standards.

In this 50th Anniversary issue of the Journal, I acknowledge the foresight of the Foundation Members of APETT in 1959. The attainment of this Golden Anniversary is indeed testament to the sterling leadership of Past Presidents and their Executive Councils, and the strong foundation on which APETT was built.

As APETT stands on the threshold of a new decade, the current Executive Council has articulated a Vision where: “APETT will be, and will be seen to be, the premier engineering association in the Region, and the first port of call by policy makers and other stakeholders for engineering-related guidance to shape public policy and legislation. APETT will be a cohesive Engineering Association, driven by a strong, unified, dynamic and innovative membership committed to engineering excellence and ethical conduct in all affairs.”

May God bless our Association – an enduring institution with a noble purpose.

HANNAH WEI-MUDDEEN, FAPETT, R.Eng. B.Sc. M.Sc.(Eng.), M.Sc.(OSH)

President The Association of Professional Engineers

of Trinidad and Tobago, West Indies

JAPETT; Vol. 38, No.1, October 2009; Editorial 3

Editorial

I. From the Editor A. Editor’s Note This issue is one of the twin Special Issues delegated to celebrate the 50th Anniversary of The Association of Professional Engineers of Trinidad and Tobago with the theme on ‘Engineering Infrastructures for Sustainable Development’.

Infrastructure is the stock of basic facilities and capital equipment needed for the functioning of a country or area. At the firms level, organisations may differ in their core business processes, functions, and infrastructure systems but commonly have significant business risks attached to the fabrication, management or use of highly engineered products or environments. For sustainable development, a nation as a whole and organisations of various sectors should stress decision making and management of various infrastructure systems from both technical and managerial points of view.

B. Call for Papers The next issue with another theme on ‘Engineering Asset Management: Trend and Challenges’ (Volume 39 Number 1) will be targeted to publish in April 2010. Engineering asset management (EAM) continues to grow in importance in both public and private sector organisations. It is intended that contributions will provide a better understanding of trends and best EAM practices that meet the diverse needs and challenges in the Caribbean Region and a wider global context. Research and technical papers are invited and an extended submission deadline will be 30th November 2009. The ‘Call for Papers’ appears in this issue. C. Special Issue Proposals Are Always Welcome Proposals for special issues on topics of current interests in engineering, engineering management and related disciplines are always welcome. Please send a brief description of the concept for the issue to the Editor ([email protected]). If the initial response is favourable, the Editor-in-chief will request a specific plan and more detailed information to be used in the final decision about proceeding with the special issue.

II. About This Issue Volume 38 Number 1 of the Journal addresses on the current status and future trends in infrastructure

planning, development and management in the engineering context. It aims to bring together the work of researchers, engineers, scientists, and practitioners, and exchange views on sustainable developments in engineering infrastructure and related areas in the Caribbean region. This issue includes ten research and technical articles. The relevance and usefulness of each paper are summarised below.

R. Al-Tahir, T. Richardson and R. Mahabir, “Advancing the Use of Earth Observation Systems for the Assessment of Sustainable Development”, argue that the gap in data and information can be managed through the adoption of earth observation technology. The paper reports on a developed methodology that involves several critical steps in using multi-spectral imagery including cloud and cloud shadow removal, image classification and image fusion. The results demonstrated the accuracy, flexibility and cost-effectiveness of these technologies for mapping the land cover and producing other environmental measures and indicators that support information for sustainable development in the Caribbean region.

D.P. Sharma, “On the Development of Sustainable VLSI Infrastructure for the Caribbean Countries”, discusses the development of sustainable infrastructure for one of the exponentially growing areas of electronics industry, that is, Very Large Scale Integration (VLSI) design for the Caribbean region. Both technical and general issues related to design of the VLSI Research Unit for Caribbean are explored to tap the Consumer Electronics market, with the help of all campuses of the University of the West Indies, industry and governments.

A.M. Sharaf and A.A.A. El-Gammal, “A Dynamic MOPSO Self-Regulating Modulated Power Filter Compensator Scheme for Electric Distribution Networks”, present a novel Modulated Power Filter and Compensator (MPFC) scheme based on Multi-Objective Particle Swarm Optimisation (MOPSO). The technique is used to find the optimal control settings that control the input control signal to the activation/triggering block of the Sinusoidal Pulse Width Modulation. The MPFC device with the dynamic error driven controller is claimed as a viable solution for voltage stabilisation, power factor correction, power quality, efficient-utilisation, and loss reduction for distribution and utilisation of electric grid systems.

mailto:[email protected]

JAPETT; Vol. 38, No.1, October 2009; Editorial 4

C. Gray-Bernard and A.J. Chadwick, “Development of a Shoreline Management Tool for Trinidad”, develop a Shoreline Management Tool for Trinidad (SMTTT) that uses Geographic Information Systems (GIS), Database and Information Systems (DIS), mapping and other techniques to store and visualise spatial and attribute information on the coastal environment of Trinidad. The SMTTT information pertaining to the coastal environment could be made available to decision makers and other stakeholders and be used as a guide for decision making in policies of shoreline protection.

K. Singh, S.O. Kelly and M.K.S. Sastry, “Municipal Solid Waste to Energy: Potential for Application in Trinidad and Tobago”, compare various technologies for converting Municipal Solid Waste (MSW) to energy, and propose a new Waste-to-Energy (WTE) process based on plasma gasification technology. A cost-benefit analysis of the plants operations is briefly presented. The paper concludes by discussing potentials of the proposed WTE process as a feasible and environmentally favorable solution to the MSW problem in Trinidad and Tobago.

A. Mwasha, “Natural and Recycled Guanapo Quarzite Aggregates for Ready Mix Concrete”, analyses the physico-mechanical properties and micro-structural properties of recycled quartzite aggregates mixed with ordinary Portland cement. The result of this investigation can be used to explain the physical and mechanical behaviour of hardened concrete manufactured using recycled Guanapo Quartzite aggregates. This paper investigates into the sustainable use of recycled/secondary aggregates as a suitable substitute for natural aggregates in construction and other uses.

V. Seecharan, Y. Ramnath and R.R. Jagai, “Laboratory Scale Production of Biodiesel from Used Vegetable Oil”, seek to ascertain whether a generic trans-esterification reaction procedure can be used for different sample types of refined soybean oil in laboratory setting. It was found that the recycled oil had a lower yield than the refined oil when compared to the theoretical yield. In an attempt to identify an alternative energy source that supplements the conventional fuel, this is a pioneer investigation into the laboratory scale of biodiesel production in Trinidad and Tobago.

M.J. Joab and M. Andrews, “Investigating Slope Failures Using Electrical Resistivity: Case Studies”, outline a methodology used to estimate the location of failure surfaces in landslides in clay slopes in Trinidad. As illustrated in case studies, the

use of electrical resistivity provides a quick and cost-effective means of extending the investigation and improving the confidence in the results of the slope stability back analyses. The paper signifies the importance of routine use of electrical resistivity that is unique to the field of geotechnical engineering in Trinidad and Tobago.

K.D. Thomas, J.A. Howard, E. Omisca and M.A. Trotz, “Exploring the Link between Ecotourism Activities and Surface Water Quality: Using Water Quality as a Sustainability Indicator”, present a framework on integrating water quality as an indicator of sustainable management of ecotourism facilities. Research at two field sites, Greencastle in Jamaica and Iwokrama in Guyana, is used to demonstrate the real use of the framework. The paper contends that once proper monitoring of the indicator takes place, longitudinally changes in land use, population and visitation can be used to correlate with the water quality results.

R.J. Murray and H.I. Furlonge, “Market and Economic Assessment of using Methanol for Power Generation in the Caribbean Region”, investigate into the use of methanol as an alternative fuel for power generation. Modifications to existing infrastructure would address the particular fuel properties of methanol in terms of its relatively low heating value, low lubricity and high inflammability. In order to assess the overall economic viability of this alternative fuel, an integrated economic model of the entire methanol to power (MtP) chain is also developed in the paper.

III. Acknowledgements

On behalf of the Association, we gratefully acknowledge all authors who have made this special issue possible with their research work. We greatly appreciate the voluntary contributions and unfailing support that our reviewers give to the Journal. Our reviewer panel is composed of academia, scientists, and practising engineers and professionals from industry and other organisations as listed below:

• Abrahams Mwasha, The University of the West Indies, Trinidad and Tobago

• Adel A.A. El-Gammal, University of Trinidad and Tobago

• Adel M. Sharaf, University of New Brunswick, Canada

• Andrew J. Chadwick, The University of the West Indies

• Chanan Singh Syan, The University of the West Indies

JAPETT; Vol. 38, No.1, October 2009; Editorial

5

• Christopher Osita Anyaeche, University of Ibadan, Nigeria

• Davinder Pal Sharma, The University of the West Indies

• Denver Faron Cheddie, University of Trinidad and Tobago

• Domalapally S. Rao, The University of the West Indies

• Edwin I. Ekwue, The University of the West Indies • Gossett Oliver, University of Technology, Jamaica • Hannah Wei-Muddeen, TCL Group – Corporate,

Trinidad • Harinder Pal Singh Missan, The University of the

West Indies • Haydn I. Furlonge, The University of Trinidad and

Tobago • Kit Fai Pun, The University of the West Indies • Leslie Monplaisir, Wayne State University, USA • Man-Yin R. Yiu, The University of the West Indies • Malcom J. Joab, Geotech Associates Ltd., Trinidad • Martin Andrews, Geotech Associates Ltd., Trinidad • Maya A. Trotz, University of South Florida, USA • Musti K.S. Sastry, The University of the West

Indies • Raid Al-Tahir, The University of the West Indies

• Richard Dawe, The University of the West Indies • Rodney R. Jagai, University of Trinidad and

Tobago • Stephan J.G. Gift, The University of the West

Indies • Sunday A. Oke, University of Lagos, Nigeria • Timothy M. Lewis, The University of the West

Indies

Finally, the views expressed in articles are those of the authors to whom they are credited. This does not necessarily reflect the opinions or policy of the Association.

KIT F. PUN, Editor-in-Chief Faculty of Engineering,

The University of the West Indies, St Augustine, Trinidad and Tobago

West Indies

October 2009

R. Al-Tahir et al.: Advancing the Use of Earth Observation Systems 6

ISSN 1000 7924The Journal of the Association of Professional Engineers of Trinidad and Tobago

Vol.38, No.1, October 2009, pp.6-15

Advancing the Use of Earth Observation Systems for the Assessment of Sustainable Development

Raid Al-TahiraΨ, Terri Richardsonb and Ron Mahabirc

Department of Surveying and Land Information, The University of the West Indies

St Augustine Campus, Trinidad and Tobago, West Indies aE-mail: [email protected] bE-mail: [email protected]

cE-mail: [email protected] Ψ Corresponding Author

(Received 15 May 2009; Revised 17 July 2009; Accepted 1 October 2009) Abstract: Decisions made on the use of land in Trinidad and Tobago, with little considerations to environmental impact or physical constraints, have resulted in physical, socio-economic, and environmental problems. As a result of the country’s economic progress, urbanisation and development are fragmenting natural areas and reducing the viability of the environment to support the population. Spatial information is a crucial component in the characterisation and examination of the spatio-temporal dynamics and the consequences of the interaction between human and the environment. This information is of critical importance in the development of models to predict future trends in land cover change and therein, best land use practices to be implemented. However, the lack of data at appropriate scales has made it difficult to accurately examine the land use/cover patterns in the country. This paper argues that the gap in data and information can be managed through the adoption of earth observation technology. Moreover, it reports on the developed methodology, and highlights key results of examining the use of geo-spatial images in addressing sustainability issues associated with development. The developed methodology involves several critical steps in using multi-spectral imagery including cloud and cloud shadow removal, image classification and image fusion. Additionally, a method for improving classification performance using high resolution imagery is discussed. The results demonstrated the accuracy, flexibility and cost-effectiveness of these technologies for mapping the land cover and producing other environmental measures and indicators. Further, these results confirmed the effectiveness of this technology in establishing the necessary baseline and support information for sustainable development in the Caribbean region. Keywords: Earth Observation Systems, Spectral Image Analysis, Image Segmentation, Sustainable Development 1. Introduction The Earth’s surface has been under constant change throughout the years. These changes have been mainly the result of anthropogenic forces in the environment. Compared to natural factors, humans pose a greater threat due to their inability to sustainably use and manage land. This has transcended into rapidly changing ecosystems largely to meet human’s growing demands for food, freshwater, and timber (WRI, 2005). Over the years, these demands have since increased due to a variety of pressing factors facing nations worldwide, including accelerated population growth,

urbanisation, migration and economic growth. These pressures placed on ecosystems are further exacerbated by issues of climate change, loss of biodiversity, growing water scarcity, and inappropriate technology applications (FAO, 2008).

Specific to Trinidad and Tobago, the country has witnessed remarkable expansion, growth and developmental activities, such as building, road construction, deforestation and many other anthropogenic activities since the country’s first oil boom in the 1940s. This has resulted in increased land utilisation, modification and alterations to the land use/cover over the years.


Thus, a matter of grave concern is the unsustainable patterns of consumption and production that are considered the major causes for the deterioration of the environment. Development cannot survive upon a deteriorating environmental resource base and the environment cannot be protected when growth leaves out the costs of environmental destruction. Consequently, the approach of “sustainable development” has evolved to meet the major needs of the present without endangering subsequent needs and aspirations of future generations allowing for the conservation of nature (Gotlieb, 1996).

To promote sustainability, it has become increasingly important to be able to measure how significantly vulnerable each human, environmental, and economic aspect is to damage and to identify ways of building resilience. As such, there is a need to pinpoint and implement indicators that collectively measure the capacity to meet present and future needs. The purpose of the sustainability indicators is to provide information on the state of human, environmental and economic conditions, the trend of changes in these conditions, and to identify issues that need to be addressed within each of these three pillars of sustainability (Bell and Morse, 2003). The success of any sustainability indicator depends largely on how accurately it measures reality. This depends on the use of current and accurate spatial land information, chiefly, land use and cover.

In contrast, there is a severe shortage of reliable and compatible data sets in the Caribbean region. In the case of Trinidad and Tobago, this has resulted in some of the most critical datasets on the island, including land cover, being over 30 years old (Baban et al., 2004). During all these years, the land use/cover in the country would have undergone extensive change, after that map was produced. Besides being late in its delivery to represent current land, this dataset was also mapped at a scale of 1:150,000, offering a much generalised view of the land cover at the time. The present land cover dataset is not suitable for making sound decisions concerning the present and future use of land resources in the country.

It is therefore necessary to adopt more effective techniques for gathering relevant spatial information to avoid problems associated with sustainable development. This is especially needed as greater land use and land cover changes will occur with the country’s initiative of acquiring first or developed world status by the year 2020. This paper argues that

the gap in data and information can be managed through the adoption of earth observation technology. Remotely sensed geo-spatial images have great potential in overcoming the information void in the country. They are relatively inexpensive and have the ability to provide information crucial to sustainable development.

In this study, earth observation images were used to fill the gap in the knowledge on the state of land use and cover in Trinidad and Tobago. The objective was to undertake a detailed, spatially explicit inventory of local trends in land use and cover changes and to build a time series of land use and cover maps in order to evaluate the changes and to determine the driving forces responsible for these changes. This data could be coupled with other socio-economic and demographic data in an interdisciplinary assortment of scientific methods to investigate the causes and consequences of land use/cover change across a range of spatial and temporal scales.

This paper, additionally, highlights the needs and discusses the means for the extraction of information from high resolution imagery to both support current and ongoing land cover research, and to overcome some of the present problems encountered by traditional use of medium resolution remotely sensed imagery. 2. Land Use, Land Cover and Changes Land use refers to the human activity or economic function associated with a specific piece of land (Lillesand et al., 2004). Examples of land use include agriculture, urban development, grazing, logging, and mining. Land cover, on the other hand, refers to the observed bio-physical cover on the Earth's surface (Meyer, 1995). It includes aspects of the natural environment (such as forests, wetlands, bare soil, and inland water surfaces), as well as human-made features and physical structures (such as, roads and buildings).

The land use/cover pattern of a region is an outcome of natural and socio-economic factors. However, land cover today is altered worldwide primarily by direct human use: agriculture and livestock raising, forest harvesting and management, and urban and suburban construction and development. There are also indirect impacts on land cover from human activities, such as forests and lakes damaged by acid rain from fossil fuel combustion (Meyer, 1995).


The changes in the environment brought in by anthropogenic forces have resulted in an observable pattern in the land use/cover over time. Consequently, reliable spatial and temporal information on land use/cover is critical to sustainable development. Such information serves to monitor changes on land and to understand the dynamics of those changes, leading to better planning and implementation of land use schemes. Furthermore, time series analysis of land use/cover change and the identification of the driving forces responsible for these changes are needed for the sustainable management of natural resources and also for determining the future of land use. 3. Earth Observation Systems (EOS) Observations of the earth from space provide objective information of human utilisation of the landscape. This is advantageous for monitoring and understanding the influence of human activities on natural resource bases over time. The collection of remotely sensed data facilitates the synoptic analyses of Earth-system function. This makes the detection of change possible at local, regional and global scales over time. This information is of critical importance in the development of models to predict future trends in land cover change and therein, best land use practices to be implemented.

Remote sensing of the environment involves measuring electromagnetic radiation reflected from or emitted by the Earth’s surface and relating these measurements to land cover categories or other possible surrogate indicators for environmental health (Al-Tahir et al., 2006). A variety of sensing instruments can be used to measure and record this radiation depending on its wavelength. The most commonly-used sensors are aircraft-borne cameras and multi-spectral sensors mounted on satellites orbiting the Earth. Photogrammetry has often referred to techniques for extracting information from aerial or terrestrial images, while remote sensing deals with processing multi-spectral satellite imagery.

Geo-imaging techniques offer various advantages: extensive coverage, reliable and current data, and cost efficiency. Besides, they provide a unique opportunity to study the impact of land-use changes as a dynamic process across space and time, and provide proactive solutions to environmental spatial issues. In most instances, aerial or satellite imagery provides the most up to date source of data

available, hence, helping to ensure accurate and reliable decisions (Al-Tahir et al., 2006). 3.1 Digital Aerial Cameras The field of photogrammetry is rapidly changing with new technologies and protocols being developed constantly. In a relatively short period of time, the practice of aerial photography and photogrammetry has gone from the analogue to digital with the advent of computing and imaging technology. The main driving motivation in developing digital photogrammetry has been the premise that it would enhance the performance and increase automation and accuracy in extracting geo-spatial information (Al-Tahir and Singhroy, 2008).

One of the most obvious requirements for digital photogrammetry is concerned with the digital images themselves. While these may be obtained by scanning aerial photographs, the emerging trend is the use of digital airborne cameras for direct capturing of digital images. The first commercial digital aerial cameras were presented in 2000; nine companies now manufacture digital aerial cameras. The basic architectures are either to place linear Charge Coupled Device (CCD) arrays in the focal plane (using single lens head) or to use several area CCD chips in several cones (up to 8). A CCD is a silicon integrated circuit that enables the transportation of analog signals (electric charges) through successive stages (capacitors). Based on camera architecture, number of lenses, and intended use and applications, these cameras produce images with a dynamic range of 12 to 16 bits and an image size from 22 to over 100 megapixels (Lemmens, 2008).

The new digital cameras combine photogrammetric positional accuracy with multispectral capabilities for image analysis and interpretation. Capturing of colour or multi-spectral images is achieved through adding a beam-splitter or additional lenses depending on the camera architecture. Coupled with differential GPS and inertial navigation systems (INS), these sensors generate directly georeferenced multispectral image data of any user-defined resolution up to 0.1m ground sampling distance. 3.2 High-Resolution Satellite Remote Sensing Traditionally, the extraction of information from satellite images has depended on multispectral systems, which collect data at several discrete bandwidths within the visible and infrared regions of


the electromagnetic spectrum. As such, remote sensing based data collection has been predominantly founded on using medium resolution satellite imagery. Three platforms are currently in orbit and obtaining data; the US Landsat, the French Spot, and the Indian IRS programs. All three systems have a swath width of 60-180 km and produce multispectral data in the visible, near infrared, and short-wave infrared (SWIR) with a ground resolution of 10 to 30 m. All of these instruments have been built and operated through government-sponsored programs.

Since the late nineties, private satellite corporations started collecting high-resolution remote sensing data. The satellites from GeoEye (Ikonos, launched in 1999; and GeoEye-1, launched in 2008) and Digital Globe (QuickBird, launched in 2001) are already in orbit capturing imagery at up to 0.50m ground resolution. These systems share several common specifications with respect to the spectral (number and range of spectral bands) spatial resolutions as well as orbital details. Besides, the new satellite images are recorded with 11-bit dynamic range extending the pixel values to 2048 grey shades. These new capabilities have made the use of high resolution imagery a much needed resource in a growing number of applications worldwide (Al-Tahir and Singhroy, 2008). 4. EOS in the Assessment of Sustainable

Development Conventional methods of land use/cover mapping are labour intensive, time consuming and are done relatively infrequently. These maps quickly become outdated, particularly in rapidly changing environments, making monitoring and analysing change quite difficult. On the other hand, Earth observations from satellite sensors provide repetitive and spatially explicit measurements of biophysical surface attributes. As such, remote sensing has become an important source for land use/cover change assessment. Recent advances in this technology also suggest that these systems have even greater potential for providing and updating spatial information in a timely and cost-effective manner (Al-Tahir et al., 2006). 4.1 Classification of Multispectral Satellite Images Procedures for mapping land use and cover from satellite images rely heavily on the differences in spectral characteristics of the landscape for separation into land use and cover classes (Lillesand

et al., 2004). Many land cover classification schemes have been developed using moderate resolution images (i.e., 20 to 250 meters ground sampling distance) in the optical and thermal wavelengths. Within this resolution range, imaging sensors smooth out variations across the individual pixels making this approach effective for use in the creation of land cover maps.

After image acquisition, the process for extracting land cover information from multi-spectral images goes through the stages of pre-processing, classification and accuracy assessment before generating the final map. The pre-processing stage is necessary to restore the imagery and rectify errors and discrepancies caused by problems associated with the sensors and the platforms. This task comprises several procedures and algorithms that are often grouped into radiometric and geometric corrections (Lillesand et al., 2004).

The actual extraction of distinct land use and cover categories or classes from satellite imagery is achieved at the stage of image classification. The intent of the classification process is to identify spectral signatures for the various objects on the earth’s surface and to associate each signature with a unique land cover class. Various automated and semi-automated methods of classification do exist, the most common of which classify imagery using per pixel classifiers.

Two main classification schemes exist: supervised and unsupervised classification. The essential difference between both methods lies in whether or not intervention is needed by the image analyst. Supervised classification requires such intervention, and is usually the more accurate method. The image analyst defines on the image training sites that are representative of each desired land cover category. Based on statistical analysis of the training sites, spectral signatures for each land cover category will be defined by the software and used to classify the remaining pixels. Unsupervised classification on the other hand is a fully automated process, by which the image pixels are classified by aggregating them into natural spectral grouping, or clusters (Lillesand et al., 2004).

The final stage of accuracy assessment is to compare the classified imagery against ground truth (field samples). This is an important stage as the success of extracting information from remotely sensed imagery is affected by the complexity of the landscape being observed, selected remotely sensed


data, and image-processing and classification approaches used (Lu and Weng, 2007). 4.2 Extraction of Information from High

Resolution Images Within recent years, there has been increased availability and wide use of high resolution imagery in land applications. High resolution imagery shows object information such as structure, texture and detail clearly, making it ideal for observing object detail changes on the earth surface and for monitoring the extent to which humans have altered the environment (Su and Hu, 2004).

It has been suggested that the application of traditional per pixel classification methods has limited applicability to high spatial resolution data because they cannot fully exploit its content (Hester et al., 2008). This is especially problematic in heterogeneous environments where pixel values are near similar and is in part due to the limited number of spectral information in such imagery (Cots-Folch et al., 2007). Additionally, high resolution imagery can be affected to a great deal by artefacts, such as shadows, making previous approaches to image classification unsuitable for this type of imagery. Image complexity and large data volumes are other general issues associated with the use of high resolution imagery that have been reported (Hester et al., 2008).

One way of increasing classification accuracy with high resolution imagery is by using approaches that utilise the texture in the image. Texture is a repeated variation of intensity and colour that is directly portraying object structure and space arrangement in the image (Su and Hu, 2004). Research incorporating the use of texture measures to improve spectral classification accuracy of land cover has already met positive results (Palubinskas et al., 1995; Franklin et al., 2000; Puissant et al., 2005). A review of some of these approaches has been highlighted in (Cots-Folch et al., 2007). Those strategies targeted towards high resolution imagery include examples presented in De Martino et al. (2004) using a partial classification method in the detection of objects in an urban part of Brazil using 4m Ikonos, and Ettarid et al. (2008) in which an automated method for extracting building from 2.5m Spot and Quickbird imagery for the cities Benir Amir and Rabat in Morocco was used.

Several methods use texture for image segmentation and classification; they differ mainly by the degree of prior information they require and

the way texture measures are applied. Commonly used methods use statistical approaches. These are based on the measurement of the occurrences of each grey level value in a particular neighbourhood (Grey Level Co-occurrence Matrix) (Cots-Folch et al., 2007). Haralick et al. (1973) suggested a set of several features, which can be used to classify texture images; angular second moment, contrast, correlation, sum of squares, inverse difference moment, sum average, sum variance, sum entropy, entropy, difference of variance, difference of entropy, information measure of correlation 1 and information measure of correlation 2. Subgroups of these features have been widely used in research for a wide array of image classification studies.

Other texture-based methods are embedded in other schema such as artificial neural networks (ANNs) and fuzzy classifiers (Shah and Gandhi, 2004; Cots-Folch et al., 2007). The ANN structure is based on the human brain’s biological neural processes. Interrelationships of variables that are correlated in the image symbolically represent the interconnected processing of neurons of the human brain used to develop models. With fuzzy classification, there are no hard boundaries dividing geographic objects. Fuzzy classification methods assign gradual membership of pixels to classes as degrees in [0, 1], giving the flexibility to represent pixels that belong to more than one class. A review of some these applications can be found in Smits and Annoni (1999). 5. Developing the Methodology In its approach to assess the sustainability of the development in Trinidad and Tobago, this study has developed a methodology to quantify and analyse the interaction between natural and urban development in Trinidad and Tobago. As outlined in Figure 1, the methodology’s main thrust is the use of a series of satellite images covering the period from the 1970’s to present. These images were acquired and analysed to depict the nature of land use/cover during different times.

Land cover information would be extracted from these images and combined with other available environmental, demographic, and economical data in order to define a set of mainly spatially-based sustainability indicators. A specific set of indicators; namely land use and settlement patterns, vegetation cover, loss cover, and fragmentation of land and habitat are purposely chosen because they can be extracted and updated, directly or indirectly, using

R. Al-Tahir et al.: Advancing the Use of Earth Observation Systems

11

5.1 Multi-spectral Classification geo-imaging techniques (Richardson and Al Tahir, 2008). The island of Tobago was chosen as a pilot study for

the implementation of this methodology. The findings of this pilot are hoped to identify and address hurdles and pitfalls in the methodology. The multi-date data used to extract land use/cover information for the island of Tobago consist of four archive remote sensing images; Landsat 5 Thematic Mapper (TM) for the 1991, and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) for the years 2000, 2001 and, 2002. All these images share the same 30m spatial resolution and other spectral and radiometric characteristics. The choice of these images was done on the bases of availability and the low percentage of cloud coverage.

Figure 1. Methodology for Assessing the Sustainability Prior to image processing and classification of

the imagery, extensive field survey was carried out within the study area to identify ground truth data for each land use/cover class sought in the classification. Some of these ground data will be used to create training sites for use in signature generation. This task is then followed by several other tasks. Figure 2 shows the workflow for the development of the land cover map based on multi-spectral data. Some details are also presented in the following sections.

of Development The chosen indicators best represent the

magnitude of land use/cover changes and the threats on the stability and resilience of the ecosystem. It is expected that temporal and spatial analysis of changes in these indicators against land management and physical development policies and practices would provide recommendations into the most appropriate scenario for sustainable development.

Figure 2. Methodology for the Development of the Land Cover Map Using Landsat Imagery

Using the image processing software Idrisi Andes (Clark Labs, Worchester, USA), the Landsat images were first geo-referenced using a total of ten ground control points extracted from the 1:25000 topographic maps of Tobago. Images were then atmospherically corrected, using the dark object subtraction model (Lillesand et al., 2004).

One disadvantage of optical imagery in tropical environments, more specific to the Caribbean and Trinidad and Tobago, is the persistent cloud cover that complicates the processing of satellite imagery.

Pixels represent clouds and their shadows in the scene must first be pinpointed and masked using one approach or another. The method adopted for this research was a semi-automated approach that was put forward by Martinuzzi et al. (2003) and modified by the authors to produce a new cloud and cloud-shadow masking technique. The method involves identifying contaminated pixels and developing a mask using Landsat image values in the blue wavelength (band 1) and in thermal range (band 6.1).


Initially, an unsupervised classification was performed to identify patterns of general spectral categories relating to the land cover. Subsequently, a supervised classification was performed on the Landsat TM and ETM+ images for 1991 and 2002. Training sites selection was guided by the cover types identified during the unsupervised classification and a priori knowledge of the study site. A signature file representing each individual land cover class was created by the software and used to classify the remaining image using the Maximum Likelihood Classification method (Lillesand et al., 2004). These classes included, forest, savannah and agriculture, urban and water (sea).

The final classified image contained large data gaps as a result of the removal of cloud and cloud shadow pixels. These gaps were filled using photo interpretation techniques and knowledge of the study site. This was done using other available higher resolution imagery for Tobago, including 2003 Ikonos imagery (1m resolution colour image) and the 1994 mosaic of panchromatic aerial photographs.

The land cover map is also updated for other features in the image that were not distinguished by the supervised classification process for different reasons (e.g., cloud cover, spatial resolution of images). The land water bodies of the Pigeon Point, Kilgwyn swamp, and Hillsborough dam are examples for such missing features on the final classification output. These features were identified on the high resolution imagery, digitised on-screen, and finally used to update the classified image. Figures 3 and 4 show the completed land cover maps for Tobago for 1991 and 2002, respectively.

An accuracy assessment was performed for the 1991 and 2002 derived land cover maps by comparing these results with reference ground truth data (151 sample sites). The accuracy was derived by means of error matrix (confusion matrix), which calculated the overall accuracy to be 89.4% for the classification of 1991 image, and 88.7% for the classified image of 2002. While they can be slightly improved, these accuracy values were considered appropriate at this stage in the research.

5.2 Non-spectral Image Segmentation In the Caribbean, there are large archives of panchromatic aerial photographs dating back to the middle of the last century. The use of this data will permit access to historical information, critical for any temporal analysis of land cover. Additionally,

aerial photographs do not suffer from cloud cover effects. However, multispectral classification techniques cannot be applied to panchromatic aerial photographs. Based on available literature, there has not been any attempt for an automated approach to mapping and monitoring land cover information in the country from aerial photographs.

Figure 3. The Land Cover Map of Tobago for 1991

Figure 4. The Land Cover Map of Tobago for 2002

At present, the authors have embarked upon a research effort to utilise texture measures for improving the current performance of presently used classification methods in the region. This research is still in its preliminary stages but from an extensive survey of the literature to date a proposed methodology has already been purported based on textural measures from aerial photographs (Figure 5). This approach utilises texture measures derived from the Grey Level Co-occurrence Matrix (GLCM) for various size windows along with varying co-occurrence pixel angles in the image. A supervised classification technique is then used to extract object detail to a resulting land cover map. 6. Conclusion Trinidad and Tobago can be characterised as small islands with fast rates of development.


13

Figure 5. Methodology for Land Cover Mapping Using Image Texture Many of the farmlands, forests, and wetlands have been transformed at unprecedented rates into human settlements. Thus, there is a growing concern about the untenable patterns of urban sprawl, loss of natural vegetation and open space, and a general decline in the health of the environment.

To achieve sustainability, there is a need to measure the changes in land use/cover that have occurred and to predict the impact of future changes in order to identify the factors that cause deterioration of the environment. One significant source of current and reliable geographic information on land use and cover is air and space borne imaging sensors. Images from earth observing systems have an important role to play in maintaining the equilibrium between the sustainable management of natural resources, environmental protection and rapidly increasing population.

It is the view of the authors that the effective use of remote sensing data and a suitable blend with environmental and socio-economic data would help in achieving a local specific prescription to realise sustainable development in the Caribbean region.

The pilot study in Tobago has produced rewarding results and demonstrated the flexibility and cost-effectiveness of these technologies for mapping the land cover. Other environmental measures and indicators can also be derived from this data and augment the analysis.

There are limitations in using satellite images for monitoring land use/cover changes. Firstly, the medium resolution of the imagery impacts on the size of features that can be distinguished in the

image. This may affect the accuracy of image classification and assessment of changes over time. The second limitation is the unavailability of multi-date images of satisfactory quality, especially with respect to a low percentage of cloud cover of the image.

Aerial photographs, as well as high resolution satellite images, most definitely provide a valid alternative. This is especially beneficial since there exist an available achieve of aerial photographs spanning back to the middle of the last century. With this information a more accurate depiction and a larger time span of land cover changes can be studied. However, a robust approach for extracting information in format and scale compatible to those of the satellite images has not yet been developed.

Consequently, the study has embarked on developing a methodology for extracting land use/cover information based on texture and tone in the image rather than the spectral components. The developed methodology is expected to provide a faster approach for updating current and future land cover maps of the country. Other Caribbean islands or other countries with similar settings can also adopt this methodology and expect similar or greater benefits.

References: Al-Tahir, R. and Singhroy, V. (2008), “Mapping

landslides in tropical environment using contemporary geo-imaging technologies” in Baban, S. (ed.). Enduring Geohazards in The Caribbean: Moving from the


Reactive to the Proactive, The University of West Indies Press, Jamaica, Chapter 5, p.81-103

Al-Tahir, R., Baban, S., and Ramlal, B. (2006), “Utilising emerging geo-imaging technologies for the management of tropical coastal environments”, The West Indian Journal of Engineering, Vol.29, No.1, pp.11-21

Baban, S., Ramlal, B., and Al-Tahir, R. (2004), “Issues in information poverty and decision making in the Caribbean region: A way forward”, The West Indian Journal of Engineering, Vol.27, No.1, pp.28-37.

Bell, S. and Morse, S. (2003), Measuring Sustainability; Learning by Doing, London: Earthscan Publications.

Cots-Folch, R., Aitkenhead, M.J. and Martinez-Casasnovas, J.A. (2007), “Mapping land cover from detailed aerial photography data using textural and neural network analysis”, International Journal of Remote Sensing, Vol.28, No.7-8, pp.1625-1642.

De Martino, M., Macchiavello, G. and Serpico, S.B. (2004), “Partially supervised classification of optical high spatial resolution images in urban environment using spectral and textural information”, Proceedings of IEEE International Geoscience and Remote Sensing Symposium, Alaska, Vol.1, pp 80-91

Ettarid, M. Rouchdi, M. and Labouab (2008), “Automatic extraction of buildings from high resolution satellite images”, The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. XXXVII, Part B8. Beijing, pp. 61-66

FAO (2008), Feeding the World Sustainable Management of Natural Resources, Food and Agriculture Organisation, United Nations, Rome; www.fao.org/docrep/010/ai549e/ai549e00.htm

Franklin, S.E, Hall, R.J., Moskal, L.M., Maudie, A.J. and Lavigne, M.B. (1990), “Incorporating texture into classification of forest species composition from airborne multispectral images”, International Journal of Remote Sensing, Vol.21, No.1, pp.61–79.

Gotlieb, Y. (1996), Development, Environment and Global Dysfunction, Towards Sustainable Recovery, Florida: St. Lucie Press.

Haralick, R.M., Shanmugan, K. and Dinstein, I. (1973), “Texture features for image classification”, IEEE Transactions on System, Man and Cybernetics, Vol.3, No.6, pp.610-622.

Hester, D.B., Cakir, H.I., Nelson, S.A.C. and Khorram, S. (2008), “Per-pixel classification of high spatial resolution satellite imagery for urban land-cover mapping”, Photogrammetric Engineering and Remote Sensing, Vol.74, No.4, pp.463-471.

Lemmens, M. (2008), “Digital Aerial Cameras - Product survey”, GIM International, Vol.22, No.4, pp.22-25.

Lillesand, T., Kiefer, R., and Chipman, J. (2004), Remote Sensing and Image Interpretation, 5th edition, New York: John Wiley & Sons.

Lu, D. and Weng, Q. (2007), “A survey of image classification methods and techniques for improving

classification performance”, International Journal of Remote Sensing, Vol.28, No.5, pp.823-870.

Martinuzzi, S., Gould, W. and Ramos, O. (2003), “Cloud and cloud-shadow removal in the creation of a cloud free composite Landsat ETM+ scene in tropical landscapes”, Presented at the National GAP Annual Meeting, Fort Collins, Colorado, USA.

Meyer, W.B. (1995), “Past and present land-use and land-cover in the USA”, Consequences, Vol.1, No.1, pp.24-33.

Palubinskas, G., Lucas, R.M., Foody, G.M. and Curran, P.J. (1995), “An evaluation of fuzzy and texture-based classification approaches for mapping regenerating tropical forest classes from Landsat-TM data”, International Journal of Remote Sensing, Vol.16, No.4, pp.747–759.

Puissant, A., Hirsch, J. and Weber, C. (2005), “The utility of texture to analysis to improve per-pixel classification for high to very high spatial resolution imagery”, International Journal of Remote Sensing, Vol. 26, No.4, pp.733-745.

Richardson T. and Al-Tahir, R. (2008), “Modelling land use and land cover dynamics to assess sustainability in Trinidad and Tobago”, Proceedings of the 10th International Conference for Spatial Data Infrastructure, GSDI Association.Trinidad and Tobago. 15 pages.

Shah, S.K. and Gandhi, V. (2004), “Image classification based on textural features using artificial neural network (ANN)”, Electronics and Telecom Engineering, Vol. 87, pp.72-77.

Smits, C.P. and Annoni, A. (1999), “Updating land-cover maps by using texture information from very high-resolution space-borne imagery”, IEEE Transactions on Geoscience and Remote Sensing, Vol.37, No.3, pp. 1244-1254.

Su, Junying and Hu, Qingwu (2004), “Fast residential area extraction algorithm in high resolution remote sensing image based on texture analysis”, Istanbul, ISPRS. Available from Internet: www.isprs.org/istanbul2004/comm7/papers/214.pdf (Last accessed on July 25, 2008)

WRI (2005), World Resources 2005: The Wealth of the Poor-Managing Ecosystems to Fight Poverty, In collaboration with United Nations Development Programme, United Nations Environment Programme, and World Bank. Washington, DC: World Resources Institute

Biographical Notes: Raid Al-Tahir is the coordinator for the Centre for Caribbean Land and Environmental Appraisal Research (CLEAR), and a Senior Lecturer in Photogrammetry and Remote Sensing in the Department of Surveying and Land Information, at the University of the West Indies, St Augustine, Trinidad and Tobago. He received a BSc in


15

Surveying Engineering from the University of Baghdad (Iraq) in 1980, and MSc and PhD from The Ohio State University (USA) in 1989 and 1995, respectively. His research interests are in the areas of environmental geoinformatics and algorithmic aspects of processing geo-spatial images. Terri Richardson received a BSc in Surveying and Land Information from the University of the West Indies. She is currently a Research Student and a Graduate Research Assistant in the Department of Surveying and Land Information. Her research interests include the use of remote sensing for mapping and assessing the changes in land use and land cover and their relations with sustainable development. She has received in 2008 The Commonwealth Association of Surveying and Land Economy (CASLE) Award for Young Authors. She is a member of the Centre for Caribbean Land and Environmental Appraisal Research (CLEAR), UWI.

Ron Mahabir received his BSc in Computing and Information Systems from the University of London and his MSc Geoinformatics from The University of the West Indies in 2004 and 2008 respectively. He is currently an Assistant Lecturer in the Department of Surveying and Land Information, University of the West Indies, and working towards a PhD degree in Geoinformatics in the same university. He is a member of the Centre for Caribbean Land and Environmental Appraisal Research (CLEAR), University of the West Indies and a member of the International Society for Photogrammetry and Remote Sensing Student Consortium. His current research interests include feature extraction from high resolution imagery, pattern recognition, computer vision, and image analysis.

D.P. Sharma: On the Development of Sustainable VLSI Infrastructure for the Caribbean Countries 16


Vol.38, No.1, October 2009, pp.16-23

On the Development of Sustainable VLSI Infrastructure for the Caribbean Countries

Davinder Pal Sharma

Department of Physics, The University of the West Indies, St Augustine Campus, Trinidad and Tobago, West Indies

E-mail: [email protected]

(Received 1 May 2009; Revised 2 August 2009; Accepted 19 September 2009) Abstract: Tremendous growth has been observed worldwide in the electronics industry during the last two decades but Caribbean countries like Trinidad and Tobago have not yet paid much attention towards building economy based on this industry. These countries can stimulate their economic growth, jobs or new opportunities and future collaborations among private industry, government and academia through suggestions proposed in the present paper. As a case study, development of sustainable infrastructure for one of the exponentially growing area of electronics industry, that is, Very Large Scale Integration (VLSI) design for the Caribbean region is discussed. Both technical and general issues related to design of the VLSI Research Unit for Caribbean are explored to tap the Consumer Electronics market, with the help of all campuses of the University of the West Indies, industry and government. Keywords: Very Large Scale Integration, Field Programmable Gate Array, Consumer Electronics Products,

Matlab, Simulink, Xilinx Foundation Series Software, Digital Signal Processing 1. Introduction Economy of most of the Caribbean countries depends either on petro-products or tourism. Nobody can cultivate petro-products forever due to limited natural resources and tourism industry may also face downfall due to recession all over the world. It is the demand of time that these countries should look for some other alternatives for their economic sustainability. Electronics industry seems to be a good option due to its tremendous growth rate. Something has been done in the area of telecommunication by just creating basic infrastructure but this has not yet taken the form of an industry. Next alternative, that seems reliable and realizable, is the development of an industry based on VLSI design. India has done excellent work in this area (Kishore, 2007). The VLSI design based industry can tap the entire consumer electronics market, which is growing exponentially day-by-day.

Consumer electronic products include applications ranging from household devices like washing machines, VCD/DVD players, cell phones to office equipments like fax machine, printer, surveillance, automation and control devices. Signal processing techniques or algorithms are used almost

in all these consumer electronics products. The most common approach to the implementation of digital signal processing (DSP) algorithms was digital signal processors, which had brought revolutions in the market in 80s. Nowadays, this approach is not the first choice of the application developer due to large development time involved in it (Parhi, 1999). People are now looking for the technology using which any application can be developed within few days. Application Specific Integrated Circuits (ASIC) technology can be the next candidate but its development cycle is also too long. Moreover development process is very costly. Clean room facility and fabrication unit of billions of dollars are required. Field Programmable Gate Array (FPGA) can be used to alleviate digital signal processing problems with the semi-custom approach. FPGAs are programmable logic devices which bear a significant resemblance to traditional custom gate arrays and may be well suited for the design of consumer electronics products using digital signal processing algorithms (Berkeley Design Technology Inc., 2007). The advantages of DSP on FPGAs are primarily related to the additional flexibility provided by FPGA’s reconfigurability. Not only can


high-performance systems be implemented relatively inexpensively, but also the design and test cycle can be completed rapidly due to the elimination of the integrated circuit fabrication delays. This new approach also allows adapting the functions to account for unforeseen requirements. Other advantages of the FPGA based consumer electronics products include higher sampling rates than that are available from traditional DSP chips, lower costs than an ASIC for moderate volume applications, and more flexibility than the alternate approaches (Baese, 2001).

2. Suitability of VLSI Infrastructure for the

Caribbean This paper proposed development of sustainable infrastructure for FPGA based VLSI design of Consumer Electronics Products within the Caribbean region. There are many reasons for choosing this infrastructural development. First of all consider the financial aspects. Infrastructural requirement for this proposal is not very costly. It just needs a small piece of land, equivalent to Physics Department of St. Augustine campus of the UWI, to establish VLSI Research Unit. As far as research equipments are concerned, we just need few personal computers, networking facilities, some high end software, hardware and basic test equipments along with the general facilities. UWI has three different campuses around the Caribbean region and any of the campus can provide these infrastructural facilities without any difficulty.

The second aspect is human resources, which can be easily managed from various UWI campuses themselves. For this pilot project, skilled faculty members and students from physics, mathematics, computer science and electrical engineering departments will be needed to carry out research and development. A research group can be made easily by gathering like-minded researchers from the UWI. Already a lot of UWI researchers are working towards VLSI, just a common platform like VLSI Research Unit is needed.

The third aspect is the utility or benefits of the proposal. Any digital application, particularly related to consumer products, can be realised on FPGAs (Cofer and Harding, 2005), and trends reveal that consumer electronics products have very big market worldwide. So lot of revenue can be generated through the production of these products and consultancy in this area.

The fourth aspect is sustainability of proposed

development. Any industry can sustain itself for the long period, if it maintains its human resource, supply of raw material, sale of products and the possibility of up gradation. Campuses of the University of the West Indies (UWI) will keep on providing necessary human resources, FPGA or other supporting hardware can be managed for US easily, consumer product related to day-to-day life will be always in demand and as far as up-gradation is concerned, we know that digital systems are always easy to upgrade.

The fifth issue is the training facility in the proposed area. The Mathworks Inc. and Xilinx Inc. have already entered a strategic exclusive alliance and joint development agreement for the system level creation of FPGA–based DSP designs (Hoimberg and Mascarin, 2000). Both companies have their own university training programmes and UWI can avail the benefits of these programmes.

3. Major Objectives Vision here is to develop an internationally accepted incubation centre for excellence in VLSI design within the Caribbean region, which will be recognised for technological contributions, fundamental research as well as development with the help of strong academia-industry participation on a mutually rewarding basis. Mission behind this proposal is to create a sustainable infrastructure for VLSI design with the following goals:

1) To achieve high research impact through active participation of UWI faculty and students,

2) To deliver novel solutions to electronics market (consumer market in specific),

3) To encourage direct industry participation through projects and visitor programmes,

4) To create resource base, design expertise and development tools, and

5) To provide economic strength to the Caribbean as a whole.

The above said mission can be accomplished using three-step strategy i.e. by investing in good education to produce smart people, investing in research and development (R&D) to produce smart ideas and creating the right environment in which smart people can develop smart ideas. 4. Visualisation Figure 1 represents the visualisation of the proposed VLSI Research Unit for sustainable VLSI infrastructure development in the Caribbean region.


First of all, let us have a look on the infrastructural requirements for the proposed research unit.

Figure 1. Visualisation of the proposed VLSI Research Unit

These requirements can be categorised as

follows: 1) Electronic Design and Automation (EDA)

Tools. 2) Configurable Hardware (FPGA). 3) Computing Facilities. 4) Space. 5) Utilities.

EDA or Computer Aided Design (CAD) tools are high end state of art softwares that are integral part of the VLSI design. The specific system simulator to be used is Simulink, which runs within the Matlab programming environment. Matlab is familiar to a large number of engineers and scientists, and as part of an open programming environment, provides an ideal platform for DSP system level tool development. The Matlab environment allows the DSP designer to take advantage of using familiar stimulus generation in addition to output data analysis tools. Various toolboxes and block sets of Matlab will be needed for this proposal (Pratap, 2005).

The second required EDA tool is Xilinx System Generator for Simulink software. Along with the Mathwork’s popular Simulink system-level design tools and the Xilinx CORE Generator & LogiCORE DSP algorithms, this software is the first to bridge the gap between system-level DSP design and FPGA implementation, allowing developer to easily design high-performance DSP applications in Xilinx FPGAs (Vanevenhoven, 2007). In addition to the Simulink tool, there will be requirement of logic synthesis libraries, a hardware macro generator, and place-and-route software collectively known as the Xilinx Foundation Series Software (Dick and Krikorian,

1999). Apart from these, commercial as well as academic licence of few EDA tools from Mentor Graphics, AccelChip and Cadence will also be needed.

The second infrastructural requirement is the configurable hardwares, particularly FPGAs, on which consumer products are to be developed. Xilinx has produced FPGAs that can provide world’s highest-performance programmable DSP solution, having access to millions of gates with Tera MACs per second performance (Hauk, 1998). So FPGAs for consumer applications can be obtained initially from Xilinx and at later stage from other companies like Altera or Atmel. Supporting chips like ADC and DAC etc. can be sourced from Texas Instruments, which also runs university programme. Multilayer PCB development and packaging facility will be needed to produce complete product.

Next infrastructural requirement is establishment of computing facilities. Powerful servers will be needed at VLSI Research Unit (at St. Augustine Campus) as well as nodal research centres (other UWI Campuses) along with workstations. Space for main research unit and other nodal centres is other requirement. Main unit will need more space (St. Augustine Campus has plenty of space for this in new engineering building) where as space equivalent to two normal computer labs will be sufficient for nodal centres. Last infrastructural requirement is utilities like telephone, internet access and basic facilities etc.

UWI faculty has to play very vital role in the proposed development. Almost whole of the responsibility to carry out research and development for this work will be of the faculty members of Physics, Mathematics, Computer Science and Electrical Engineering departments of all the three UWI campuses. Main research unit and nodal centres will be headed by the most experienced faculty member of the field. Various other people apart from the UWI faculty will be part of the proposed unit. These includes permanent staff having expertise in FPGA based VLSI design & EDA tools, visiting experts from industry, students and trainees. Faculty members from other institutes can also be involved in the research group to carry out specific projects and consultancy. Industry experts will also participate in projects, act like consultant, provide necessary training and will keep all the members updated. Students and trainees from all the campuses of UWI, industry and other institutes in Caribbean and worldwide will be

VLSI Research

Unit

Steering Committee

Industry

UWI Faculty

People

Infrastructure


encouraged to be a part of this research unit. Industries like Xilinx, Altera, Atmel, Texas

Instruments, Mentor Graphics, Mathworks and Cadence should be encouraged to participate in this proposal under their university programme. These industries will be chief source of funding for the centre and will provide access to their laboratory resources for specific technology research, project developments, training programmes and student participation. There should be effective representation of industry on the steering committee. Steering committee should be made for proper functioning and for monitoring development of the entire unit. Faculty members and experts from industries nominated by Vice Chancellor of UWI should be the members of steering committee. Committee will oversight all the activities of the entire unit, will liaise with UWI and industry, and will be responsible for charting the long-term growth of the unit. Committee organisation is shown in Figure 2.

Figure 2. Organisation of the Steering Committee

of the Unit

Manufacturing and marketing are the major issues that will be addressed properly for sustainable growth of the unit. As far as manufacturing is concerned, unit has to configure (design) FPGAs provided by Xilinx etc. so as to use them for specific consumer application product. Application codes will be developed through combined effort of UWI faculty, research staff, students and industry experts. Unit head will be responsible for manufacturing of end product (i.e., FPGA chips). Marketing of chips will be done with the help of Marketing and Communication Department of the UWI, Industrial links of the staff and government. Even separate marketing wing of the unit can be established and marketing experts from Economics department of UWI can be involved. It has been observed that general products producing business units located in the university departments generally cannot compete

in the open marketplace but the proposed area requires very skilled manpower so ordinary industry cannot compete with the university based units. Various Indian IITs and US universities are successfully running their VLSI research units. 5. Research Methodology Various consumer electronics applications will be modelled and simulated in the Matlab. After that, Matlab model of application will be converted into any popular Hardware Description Language (HDL) programme using Xilinx System Generator for DSP (Cigan and Lall, 2005). Then using Xilinx ISE Foundation Series software and Mentor Graphic’s Design, Verification & Test package, simulation and synthesis of the HDL model will be done. Finally after verification, consumer application will be implemented on Xilinx based FPGA and design validation will be carried out to check the performance of the designed product (Tanurhan et. al., 2006).

A block diagram of the design flow for modelling and implementation of consumer electronics product is given in Figure 3. The entire design flow is described hereafter, which is applicable to all applications and targets (along with Xilinx FPGA and custom logic devices). Within Simulink, the DSP system designer creates a model of the hardware system as well as test environment in which we have to simulate the model. The system model is capable of operating on real (i.e., double precision, floating point) or integer (i.e., quantized, fixed point binary) data types. When the model is first entered, simulation is typically performed using floating data types to verify that its theoretical performance is as desired. The internal data types are then converted to the bit true representations that will be used in the hardware implementation, and the model is re-simulated to verify its performance with quantized coefficient values and limited data bit widths, which can lead to overflow, saturation and scaling problems. User defined black boxes can also be incorporated in the modelling and elaboration process (Turney et. al., 1999).

The designer can invoke the net lister and the test bench generator as soon as the model get converted to form a realisable system in the FPGA and its performance meets specification. The net lister extracts a hierarchical representation of the model’s structure annotated with all the element parameters and signal data types. A mapper then analyses the elements in the hierarchy and creates a

Steering Committee Industries

Visiting Staff Research Staff and Students

Unit Head

UWI Faculty

Department Heads

VC of UWI

D.P. Sharma: On the Development of Sustainable VLSI Infrastructure for the Caribbean Countries

20

VHDL [VHSIC (Very High Speed Integrated Circuit) HDL] description of the design. Where possible, the mapper uses the Xilinx CORE Generator to make hardware macros for specific design elements. When an element or its parameter

values imply functionality unavailable in CORE Generator, the mapper instantiates a reference to a parameterised, synthesisable entity in a synthesis library or user supplied model.

Figure 3. Design Flow for FPGA-based Consumer Electronics Product Development

Synthesizer Control Design

FPGA (Place & Route)

Core Generation

LogicSimulator

Bit Stream Pass/Fail

EDIF EDIF + Timing

Core Parameters

VHDL

Input System Model Output

Net Lister

Test bench Generator

Mapper

Simulation

Synthesis

Simulation Data

Simulink

Xilinx Foundation Environment

Matlab Environment Library

Test Vectors

Source: Abstracted from Turney et.al. (1999)


The actual hardware entities used have additional inputs and outputs for control signals that are not evident at the level of abstraction used in Simulink. The mapper adds the necessary control ports and connects them up to control logic blocks. Each control logic block is given a default synthesisable behaviour, which may require alteration by a logic designer to achieve a working implementation. This alteration is shown in the flow through Control Design. The test bench generator is an interactive tool that runs in the Matlab environment, in which the designer captures the input stimuli and system outputs of selected simulation run for conversion to test vectors. The generator converts the captured simulation data into VHDL code that will exercise the implemented model and test its outputs against the expected results.

The Xilinx Foundation Series tools are used to synthesise the control logic and those elements for which no hardware macros exist and combine all the pieces into a single fully-realised netlist and place and route the design in an FPGA (Synplicity Inc., (2005). The outputs of this back-end process are a bit-stream file and an EDIF (Electronic Design Interchange Format) structural netlist of the hardware file annotated with timing information, which can be sent to the foundry for mass production after successful device design. This netlist can be simulated with the test vectors produced previously from system simulations to verify the performance of the completed FPGA hardware realisation. 6. Benefits 6.1 To the Caribbean and UWI Mutual benefits to UWI and the Caribbean as a whole upon developing sustainable infrastructure like VLSI Research Unit will be as follows:

1) Due to better infrastructure, researcher of UWI and the Caribbean will able to conduct research with higher impact.

2) Due to higher level of industry interaction, upliftment of research, development, training and review is expected.

3) Caribbean will have accumulating resource base of expertise and intellectual property to generate revenue through consultancy worldwide.

4) Funding for research and development can be managed from alliance industries.

5) UWI will get support for post-graduate research programmes and Caribbean will get

its own skilled manpower in the area of VLSI. 6) With the help of industry, VLSI unit will be

able to produce low cost consumer electronics products for the Caribbean to strengthen its economy.

6.2 To Industry Along with UWI and Caribbean, industries will also get benefited by the proposed development. Major benefits to the industries will be as follows:

1) Industry will get skilled man power in the area of VLSI design, which is the biggest challenge nowadays.

2) Industry will able to work on their Strategic Research Projects driven by faculty attached to the unit through participation of students and industry.

3) Industry can drive their Short-term Development Projects which will provide access to tools and facilities available in the unit to the industry, and industry can involve faculty through consultancy.

4) Training programmes conducted by laboratory staff and/or faculty will reduce the financial burden of industry because now industry will directly get trained manpower and can save millions of dollars.

5) Industries can conduct training programmes for their employees using laboratory facilities of the unit.

7. Current Status VLSI research laboratory has already been established in the Physics Department of UWI’s St. Augustine Campus. Laboratory is equipped with basic EDA tools, FPGA target boards and various test / measurement equipments. Department is going to establish research collaboration with electrical engineering and mathematics departments of its own campus along with physics department of Barbados campus. Very soon Jamaica campus will be involved in this pilot project but there is still a need of bringing physics, mathematics, computer science and electrical engineering departments of all the UWI campuses under a single system administration setup. As far as the industries are concerned, Mathworks, Cadence and Xilinx are already involved somehow with UWI under university programme. Other suggested industries have to be involved in this project.

As far as existing research and development activities in this area are concerned, plenty of faculty


members from St. Augustine campus are involved in so called Electronic Systems Group. This group conducts research and collaborative work in the design of reconfigurable logic systems using the ever-increasing family of static RAM base programmable logic devices such as the FPGA and the Complex Programmable Logic Device (CPLD). Two research projects in the area of “VLSI implementation of DSP algorithms” are also in progress at physics department of the same campus.

St. Augustine campus is currently offering Bachelor of Science (BSc) in Electrical and Computer Engineering programme with electives in Electronic Systems and Master of Applied Science in Electrical and Computer Engineering (MASc) programme with majors in Electronic Systems. Department’s electronic systems programme emphasises analog and digital electronics design using state-of-the-art simulation and CAD tools as well as cutting edge CPLD and FPGA technology. The Department of Physics is also planning to start its Master in Physics (MPhys) programme with major in Digital System Design / VLSI Design. Few students are working here in the area of VLSI design for their MPhil and PhD programmes. 8. Conclusion In this paper, a proposal on the development of sustainable VLSI infrastructure for the Caribbean countries is presented with the objective to make Caribbean a major VLSI design testing and application development destination globally and to catalyse an increase in Caribbean share in the global market through consumer electronics products apart from petro-products. The basic philosophy behind the programme is for the government to play the role of catalyst and infrastructure provider.

The key ingredients of the government inputs for this area are: investing in good education to produce smart people, investing in R&D to produce smart ideas and creating the right environment in which smart people can develop smart ideas. Initial setup cost of the suggested unit will be around USD 0.5 million only and recurring annual expenses can be managed from annual membership from each industry, consultancy and products development. Basic infrastructure and manpower for this proposal can be easily arranged from all the three campuses of the UWI. Funding, training and high-end research facilities can be managed from industrial collaboration. The proposed VLSI infrastructure is sustainable and can boost-up the economy of the

Caribbean region. References: Baese, U.M. (2004), Digital Signal Processing with Field

Programmable Gate Arrays, 2nd Ed., Springer-Verlag, Germany.

Berkeley Design Technology Inc., (2007), “FPGAs for DSP”, 2nd Ed., BDTI Report.

Cigan, E. and Lall, N., (2005), “Integrating Matlab algorithms into FPGA designs”, DSP Magazine, October, pp.37-39.

Cofer R. C. and Harding B., (2005), “Implementing DSP Functions within FPGAs”, Programmable Logic Design Line, (Design Article), available (online): http://www.pldesignline.com

Dick, C. and Krikorian, Y. (1999), “A system-level design approach for FPGA-based DSP implementations”, DSP World, Spring.

Hauck, S. (1998), “The roles of FPGAs in reprogrammable systems”, Proceedings of the IEEE, Vol.86, No.4, April, pp. 615-639

Hauck S. (1998), “The future of reconfigurable systems”, Proceedings of the 5th Canadian conference on Field Programmable Devices, (Keynote Address), Montreal, June

Hoimberg, P. and Mascarin, A. (2002), “The Mathworks and Xilinx take FPGAs into mainstream DSP”, Xcell Journal, Vol.37, pp.14-15.

Kishore, K.L. (2007), “Trends in VLSI technology: rural application perspective”, IETE Technical Review, Vol. 24, No.4, July-August, pp. 243-248.

Parhi, K.K. (1999), VLSI Signal Processing Systems, Wiley Publication, New York.

Pratap, R. (2005), Getting started with Matlab 7: A Quick Introduction for Scientists and Engineers, Oxford University Press, USA.

Synplicity Inc., (2005), “True DSP synthesis for fast, efficient, high performance FPGA implementation”, White Paper.

Tanurhan Y. Dinkevich V., Dharod M. and Syed S. (2006), “ DSP Design Flows in FPGAs – Strategies for Designing DSP Applications for FPGA”, Programmable Logic Design Line, (Design Article), available (online): http://www.pldesignline.com

Turney R. D., Dick C., Parlour D. B. and Hwang J. (1999), “ Modelling and Implementation of DSP FPGA solutions”, International Conference on Signal Processing Applications and Technology (ICSPAT), Orlando, USA, available (online): www.techonline .com

Vanevenhoven, T. (2007), “Using MATLAB to create IP for system generator for DSP”, Xcell Journal, 4th Quarter, pp.24-27

Biographical Notes: Davinder Pal Sharma has done B.Sc. in Electronics

D.P. Sharma: On the Development of Sustainable VLSI Infrastructure for the Caribbean Countries

23

(1997), M.Sc. with specialisation in Microelectronics (1999), and Ph.D. in Communication Signal Processing (2004), all from Guru Nanak Dev University, Amritsar, India. He has about 10 years of teaching and research experience. His area of research includes Digital Signal Processing, Data Communication, and VLSI implementation of DSP Algorithms. He has authored a book on Digital Signal Processing and has more than 20 publications in reputed International/National Journals and Conferences to his credit. Dr. Sharma has designed various courses and research laboratories in the area of

DSP, VLSI, Digital Electronics and Digital System Design. He was Visiting Professor in Guru Nanak Dev University from June 1999 to May 2002. He joined Amritsar College of Enginering and Technology, Amritsar in July 2002 and was Head and Assistant Professor in Electrical and Electronics Engineering Department till August 2008. He is also a member of various professional societies like IEEE, IETE, ISTE, and IE, etc.

A.M. Sharaf and A.A.A. El-Gammal.: A Dynamic MOPSO Self-Regulating Modulated Power Filter Compensator Scheme 24


Vol.38, No.1, October 2009, pp.24-32

A Dynamic MOPSO Self-Regulating Modulated Power Filter Compensator Scheme for Electric Distribution Networks

Adel M. SharafaΨ and Adel A.A. El-Gammalb

Centre for Energy Studies, The University of Trinidad and Tobago, Point Lisas Campus,

Esperanza Road, Brechin Castle, Couva, P.O. Box 957, Trinidad, West Indies aE-mail: [email protected]

bE-mail: [email protected] Ψ Corresponding Author

(Received 19 April 2009; Revised 23 June 2009; Accepted 14 September 2009) Abstract: The paper presents a novel Modulated Power Filter and Compensator (MPFC) scheme for voltage stability, energy conservation, loss reduction, power factor correction, and power quality enhancement for electric distribution systems based on Multi-Objective Particle Swarm Optimisation (MOPSO). The MPFC scheme was developed by the first author to vary the shunt power filter equivalent admittance, modify the reactive power flow to the distribution network. The filter dynamic switching is achieved using two complementary switching pulses generated by a Sinusoidal Pulse Width Modulation (SPWM) strategy and controlled by a tri-loop dynamic controller comprising three regulating time decoupled control loops, a minimum RMS source current dynamic loop, voltage stabilisation loop, and synthesised dynamic power loop. The MOPSO technique is used to find the optimal control settings that control the input control signal to the SPWM activation/ triggering block that minimises the distribution feeder current for reducing feeder losses, bus voltage deviations, and ensure distribution feeder capacity release. Keywords: Modulated Power Filter, Multi-Objective Particle Swarm Optimisation (MOPSO), Distribution

Network, Power Quality, and Green Energy 1. Introduction Fixed and Switched Capacitor Banks are widely used in distribution and utilisation systems for voltage stabilisation and reactive power compensation as well as power/energy reduction, voltage regulation and system capacity release (Sharaf and Kreidi, 2002). The extent of their benefits depends greatly on how the capacitor banks are placed and sized. The problem of how to place capacitors banks on the radial distribution system such that these benefits are fully achieved and/or maximised against the total cost associated with fixed or switched capacitor placement is termed ‘the General Capacitor Placement Problem’. The problem consists of determining the optimal locations to install capacitors, the types and sizes of capacitors to be installed and the dynamic control schemes for the capacitor switching such that an objective function is minimized, while the load constraints and system operational constraints at varying load levels are

satisfied. The voltage regulation problem in distribution and utilisation grid networks is becoming more and more critical as electric utilities operate their grid systems at higher capacities. Increasing network loading results in increasing in active and reactive power feeder losses. An increase in active power loss represents loss in savings to the utility as well as a reduction in feeder energy utilisation, whereas an increase in reactive power loss can cause system voltages to decline, which in turn increases the active power loss and reduces system reliability. Voltage instability may also arise in heavily loaded distribution networks. Initially, an increase in reactive power requirements causes the voltage to decline slowly; however, the AC system may reach an unstable region where a small increment in load may cause a steep decline in the system voltage. Here, as load power is increased, the distribution network is no longer capable of transmitting the needed power to meet the load.


Installing capacitor banks in distribution networks tends to reduce active and reactive power losses, increase feeder utilisation, improve power quality and allow for the installation of more loads on existing distribution systems, thus increasing utility savings.

Several AI-related soft computing techniques, such as Genetic Algorithms (GA) can be used to solve this optimisation problem. GA is an iterative search algorithm based on natural selection and genetic mechanism. However, GA is very fussy; it contains selection, copy, crossover and mutation scenarios and so on. Furthermore, the process of coding and decoding not only impacts precision, but also increases the complexity of the genetic algorithm. Particle swarm optimisation (PSO) is a novel emerging intelligence which was flexible optimisation algorithm proposed in 1995. There are many common characteristics between PSO and GA. First, they are flexible optimisation technologies. Second, they all have strong universal property independent of any gradient information. However, PSO is much simpler than GA, and its operation is more convenient, without selection, copy, and crossover. The proposed use of the novel low modulated /switched power filters and compensators (MPFC) (Sharaf and Chhetri, 2006; Sharaf et. al., 2006, 2007; Sharaf and Ammar, 2008) can be a viable low-cost alternative to ensure supply power quality enhancement, flicker control or electric energy savings. Power filter selection and tuning are crucial for successful harmonic reduction (Sharaf et. al., 2007; Sharaf and Weihua, 2006). The optimal capacitor selection of distribution network capacitors is a challenging problem since it often involves various conflicting objectives and goals. The main objective of the Multi-Objective (MO) problem is finding the set of acceptable (trade-off) Optimal Solutions. This set of accepted solutions is called Pareto front. These acceptable trade-off solutions give more ability to the user to make an informed decision by seeing a wide range of near optimal solutions that are near optimum from an “overall” standpoint. Single Objective (SO) optimisation may ignore this trade-off viewpoint (Ngatchou et. al., 2005; Berizzi et. al., 2001; Coello and Lechuga, 2003), which is crucial. The main advantages of Multi-Objective Particle Swarm Optimisation (MOPSO) method are: It does not require prior knowledge of the relative importance of the objectives, and there is a set of acceptable trade-off near optimal solutions. This set is called Pareto front

(Ngatchou et. al. 2005; Berizzi et. al., 2001; Coello and Lechuga, 2003) or optimality trade-off surfaces. Modulated dynamic type power filters and compensators are switched type filters. Modulated power filters are mainly used to provide measured filtering in addition to avoiding tuning problems associated with the use of passive power filters. The modulated power filter and compensators are controlled by the on-off timing sequence of switching pulses that are generated by the error driven dynamic controller. The novel MPFC device developed by the first author is an effective low-cost energy utilisation and power quality enhancement tool for reducing inrush current transients and load excursions. The novel hybrid MPFC compensator structure comprises a fixed capacitor bank and a modulated SPWM (i.e., Sinusoidal Pulse Width Modulation) switched tuned arm filter. The effect of the MPFC on the supply power quality for three-phase induction motor load under disturbances has been studied. The hybrid modulated power filter and is expected to provide:

• Power factor improvement (at the generator and load sides),

• Potential rise reduction during short circuit as well as safe neutral by eliminating hot grounds,

• Improved damping of transient conditions, and • better energy conservation.

The paper presents a low-cost harmonic mitigation SPWM power filter device to be used under both balanced / unbalanced, normal/fault conditions. The switched power filter is controlled by a dynamic-minimum harmonic ripple controller based on MOPSO technique to adjust the duty-cycle ratio or (ton) time. The degree of reactive compensation is controlled by the duty ratio of the SPWM switching. SPWM switching technique provides switching at frequency much higher than the power line frequency and consequently does not result in any low frequency offending harmonics.

The MPFC is a green plug and FACTS based Device that can reduce Feeder Power Losses and ensure minimal Active and Reactive Voltage drops and enhanced efficient energy utilisation in addition to dynamic Voltage Stabilisation and inrush Transient Excursion Damping. Green Technology is a TERM Coined for all Sustainable, Energy Efficient, Low Impact, Environmentally Safe, Minimal Losses, and Energy Conservation and Management Devices and Systems (Sharaf et. al. 2007).


2. Particle Swarm Optimisation PSO is an evolutionary computation optimisation technique (i.e., a search method based on a natural system) developed by Kennedy and Eberhart (1995) (Shi and Eberhart, 1998, 1999; Eberhart and Shi, 2001). The system initially has a population of random selective solutions. Each potential solution is called a particle. Each particle is given a random velocity and is flown through the problem space. The particles have memory and each particle keeps track of its previous best position (called the Pbest) and its corresponding fitness. There exist a number of Pbest for the respective particles in the swarm and the particle with greatest fitness is called the global best (Gbest) of the swarm. The basic concept of the PSO technique lies in accelerating each particle towards its Pbest and Gbest locations, with a random weighted acceleration at each time step.

The main steps in the particle swarm optimisation algorithm and selection process are described as follows:

(a) Initialise a population of particles with random positions and velocities in d-dimensions of the problem space and fly them.

(b) Evaluate the fitness of each particle in the swarm.

(c) For every iteration, compare each particle’s fitness with its previous best fitness (Pbest) obtained. If the current value is better than Pbest, then set Pbest equal to the current value and the Pbest location equal to the current location in the d-dimensional space.

(d) Compare Pbest of particles with each other and update the swarm global best location with the greatest fitness (Gbest).

(e) Change the velocity and position of the particle according to equations (1) and (2), respectively:

( ) ( )idgd22idid11idid XPrandCXPrandCVV −××+−××+×=ωEq. (1)

ididid VXX += Eq. (2)

Where: Vid and Xid represent the velocity and position of the ith particle with d dimensions, respectively. rand1 and rand2 are two uniform random functions, and ω is the inertia weight, which is chosen beforehand.

(f) Repeat steps (b) to (e) until convergence is reached based on some desired single or multiple criteria.

The PSO search and dynamic total error minimisation algorithm has many parameters and

these are described as follows: ω is called the inertia weight that controls the exploration and exploitation of the search space because it dynamically adjusts velocity. Vmax is the maximum allowable velocity for the particles (i.e. in the case where the velocity of the particle exceeds Vmax, then it is limited to Vmax). Thus, resolution and fitness of search depends on Vmax. If Vmax is too high, then particles will move beyond a good solution. If Vmax is too low, particles will be trapped in local minima. The constants C1 and C2 in (1) and (2), termed as cognition and social components, respectively. These are the acceleration constants which change the velocity of a particle towards Pbest and Gbest (generally, somewhere between Pbest and Gbest). Figure 1 shows the general flow chart of the PSO algorithm based on total error iterative minimum search.

Figure 1. Flow Chart for the SOPSO Minimising Search Algorithm

The most striking difference between PSO and

the other evolutionary algorithms is that PSO chooses the path of cooperation over competition. The other optimisation algorithms commonly use some form of decimation, survival of the fittest. In contrast, the PSO population is stable and individuals are not destroyed or recreated. Individuals are influenced by the best performance

Generation of initialcondition of each agent

Evaluation of searchingpoint of each agent

Modification of each searchingpoint (based on absolute total

error minimization)

Reach maximum iterations

Start

Stop

No

Yes


of their neighbors. Individuals eventually converge on optimal points in the problem domain. In addition, the PSO traditionally does not have genetic operators like crossover between individuals and mutation, and other individuals never substitute particles during the run. So, in PSO all the particles tend to converge to the best solution quickly, comparing with GA.

3. Mutli-objective Particle Swarm Optimisation The following definitions are used in the proposed MO Optimisation search algorithm:

Def. 1 The general MO problem requiring the optimisation of N objectives may be formulated as follows: Minimise

[ ] T

N321 )x(f....,),x(f,)x(f,)x(f)x(Fy rrrrrrrrrrr==

Eq.(3) ( ) M,1,2,j0xgj K

r=≤tosubject Eq.(4)

Where: Eq.(5) [ ] Ω∈=T*

P*2

*1

* x,...,x,xx rrrr

yr is the objective vector, the represent the constraints and is a P-dimensional vector representing the decision variables within a parameter space . The space spanned by the objective vectors is called the objective space. The subspace of the objective vectors satisfying the constraints is called the feasible space.

( )xg irr

*xr

Ω

Def. 2 A decision vector Ω∈1xr is said to dominate the decision vector Ω∈2xr (denoted by 11 xx r

pr ), if

the decision vector 1xr is not worse than 2xr in all objectives and strictly better than 2xr in at least one objective. Def. 3 A decision vector is called Pareto-optimal, if there does not exist another

Ω∈1xr

Ω∈2xr that dominates it. An objective vector is called Pareto-optimal, if the corresponding decision vector is Pareto-optimal. Def. 4 The non-dominated set of the entire feasible search space Ω is the Pareto-optimal set. The Pareto-optimal set in the objective space is called Pareto-optimal front.

In MOPSO, a set of particles are initialised in the decision space at random (Ngatchou et al., 2005; Berizzi et al., 2001; Coello and Lechuga, 2003). For each particle i, a position in the decision space and a velocity are assigned. The particles change their

positions and move towards the so far best-found solutions. The non-dominated solutions from the last generations are kept in the archive. The archive is an external population, in which the so far found non-dominated solutions are kept. Moving towards the optima is done in the calculations of the velocities as follows:

( ) ( )idrd22idpd11idid XPrandCXPrandCVV = ×ω + × × ×+− × − Eq.(6)

Eq.(7) ididid VXX = + Where are randomly chosen from a single

global Pareto archive, ω is the inertia factor influencing the local and global abilities of the algorithm, Vi,d is the velocity of the particle i in the dth dimension, C1 and C2 are weights affecting the cognitive and social factors, respectively. r1 and r2 are two uniform random functions in the range [0 , 1]. According to Equation (7), each particle has to change its position Xi,d towards the position of the two guides Pr,d, Pp,d which must be selected from the updated set of non-dominated solutions stored in the archive. The particles change their positions during generations until a termination criterion is met. Finding a relatively large set of Pareto-optimal trade-off solutions is possible by running the MOPSO for many generations. Figure 2 shows the flow chart of the MOPSO.

P ,P dp,dr,

Update position

EvaluateParticles

Find Global bestthen insert in archive

Update Velocity

Initialize Position,Velocity, and archive

Update the memoryof each particle

archive

Figure 2. Flow Chart of the MOPSO Optimisation Search Algorithm


4. System Description The sample study system comprises three-phase ac utilisation system, short feeder, hybrid load including a motorised load (i.e., 3-phase induction motor), non-linear load, and linear load as shown in Figure 4. The tri-loop error-driven dynamic controller is a novel structure developed by the First Author and used to modulate the power filter compensator. The global error is the summation of the three loop individual errors including voltage stability, current limiting and synthesise dynamic power loops. The global error signal is input to the self tuned variable structure sliding mode controller. The (per-unit) three dimensional-error vector (ev ,eI, ep) governed by the following equations:

Eq.(8)

Eq.(9)

Eq.(10)

The total error et (k) at a time instant:

Eq.(11)

The solid-state switches (S1, S2) are usually (GTO, IGBT/bridge, MOSFET/bridge, SSR, TRIAC) turns “ON” when a gating pulse g(t) is applied by the activation switching circuit as shown in Figure 3.

Figure 3. The gate pulses of the electronic switch SA

Removing the pulse will turn the solid-state switch “OFF”.

Eq.(12) Where: fs/w is switching frequency, and 0<ton<TS/W.

The novel filter and compensator scheme is a low-cost attractive solution for both distribution and utilisation radial circuits, feeding a nonlinear load. Figure 5 depicts the self-tuned variable structure sliding mode controller developed by the First Author for adjusting the switching duty-cycle-ratio (α) based on MOPSO searching technique. The effective reactance of the combined hybrid fixed capacitors and the modulated tuned arm filter depend on the duty cycle and the frequency of the SPWM output which in turn is a function of the self tuned variable structure sliding mode controller output. The output of the SPWM generator is a train of pulses with variable duty cycles and constant frequency. The degree of reactive compensation is dependent on the duty cycle of the generated pulses. This would in turn vary the effective reactance of the hybrid power filter.

The system control voltage has the following form in the time domain:

Eq.(13)

The MOPSO searching algorithm is implemented for tuning the gains (β0, β1) to minimise the system objective functions. The selected objectives functions in this paper are to minimise a stated number of objective functions using PSO algorithm are defined by the following: 1. Minimise the voltage deviations:

Eq.(14)Eq.(15)Eq.(16)

2. Minimise the Distribution Feeder total active power Losses:

Eq.(17)

3. Minimise the Distribution Feeder total reactive power losses:

Eq.(18)

4. Minimise the absolute total error deviations:

Eq.(19)

A.M. Sharaf and A.A.A. El-Gammal.: A Dynamic MOPSO Self-Regulating Modulated Power Filter Compensator Scheme

29

Figure 4. Three-phase Sample Study AC System with the Proposed MPFC

Non Linear Load

T1

138 / 25 KV 5 MVA

AC Utility VSVL

Terminal Bus

Substation

25 / 4.16 KV 5 MVA

T2

Lf

Rf

Cf Cf

Cs10 Km Feeder

SA

SBTri-loop dynamiccontroller for theModulated Power

Filter based onMOPSO

VL

IL

Motorized Load:2 MVA @0.85 PF 1740 rpm , 4.16 KVLL

Linear Load: 1MVA @ 0.8 PF

RLCL

Non Linear Load:RL = RL0+RL1sin2ωotωo = 20 rad/secCL = 200 μF

R/Km = 0.3 ΩX/Km = 0.4 Ω138 KV

MVASC=5 GVAX/R = 10X = 3 Ω,R = 0.3 Ω CS = 30 μF

CF = 200 μFLF = 10 mHRF = 0.5 Ω

V0 Vn

MPFC

Figure 5. Tri-loop Self-tuned Variable Structure Sliding Mode Dynamic Controller for MPFC

In general, to solve this optimality search problem, there are two optimisation techniques based on PSO. These two possible techniques are:

1. Single aggregate Objective Particle Swarm Optimisation (SOPSO), which is explained in Section 2, and

2. Multi-Objective Particle Swarm Optimisation MOPSO, which is explained in Section 3.

The main procedure of the SOPSO is based on deriving a single aggregate objective function using the functional model of the shunt power filter. The weighted single objective function may combine several objective functions using specified or selected weighting factors. The objective function is optimised (either minimised or maximised) using the PSO method to obtain a single global or near optimal

+++

+-

IrefCurrent Limiting Loop

eI

ePet

PSO Tuning Controller

β0, β1 are tuned by the PSO Algorithm to minimize the total error

1Ibase

11 + T0S

+ - γP×

Synthesized Dynamic power loop

11 + T0S

β0γI

11 + T0S

1Vbase

γV+-

Vref

11 + T0S

P

iL

vL

SPWM

Voltage Stabilization Loop

eV

fSW

VC

SA

Ton

Limiter

β1

d/dt

++

11 + T0S

× ++

SB


solution. On the other hand, the main objective of the MO problem is finding the set of acceptable (trade-off) Optimal Solutions. This set of accepted solutions is called Pareto front. These acceptable trade-off multi level solutions give more ability to the user to make an informed decision by seeing a wide range of near optimal selected solutions that are feasible and acceptable from an “overall” standpoint. Single Objective (SO) optimisation may ignore this trade-off viewpoint, which is crucial.

The two main advantages of the proposed MOPSO method are:

1. It does not require a priori knowledge of the relative importance of the objective functions, and

2. It provides a set of acceptable trade-off near optimal solutions. This set is called Pareto front or optimality trade-off surfaces.

5. Digital Simulation Results Matlab-Simulink Software was used to design, test, and validate the effectiveness of the proposed MPFC device and the associated dynamic SPWM controller based on SOPSO and MOPSO search optimisation techniques. Table 1 shows the main objective functions versus the Tuned controller Gains based SOPSO and MOPSO control schemes, SOPSO obtains a single global or near optimal solution based on a single weighted objective function. The weighted single objective function combines several objective functions using specified or selected weighting factors as follows:

44332211 JJJJ function objective weighted αααα +++= Eq.(20)

Where, α1 = 0.25, α2 = 0.25, α3 = 0.25, α4 = 0.25, are selected

weighting factors. J1: Minimise the voltage deviations, J2: Minimise the Distribution Feeder total active

power Losses, J3: Minimise the Distribution Feeder total reactive

power Losses, J4: Minimise the absolute total error deviations.

On the other hand, the MOPSO finds the set of acceptable (trade-off) Optimal Solutions. This set of accepted solutions is called Pareto front, MOPSO obtains six near optimal point as a Pareto front. These acceptable trade-off multi level solutions give more ability to the user to make an informed decision by seeing a wide range of near optimal selected solutions. The digital simulation results are presented for MPFC on the test system using MOPSO searching optimisation algorithm.

Table 2 shows system behavior comparison with and without MPFC based SOPSO and MOPSO optimisation technique, Comparing the dynamic response results of the two study cases, with and without the hybrid modulated power filter compensator, it is quite apparent that the hybrid modulated power filter compensator highly improved the ac system dynamic performance from a general power quality point of view. The effect of the MPFC is noticeable where it highly improved the power factor by reducing the amount of reactive power drawn from the supply, maintaining the system dynamic stability under sudden disturbances and recovering faster from any inrush transient state.

It was found that the MPFC had a great impact on the supply power factor improving it from 0.25 to around 0.92 which is highly desired. Moreover, the load power factor also improved from 0.2 to a value of .85. The simulation results show that the power factor can be effectively improved (from 0.35 to 0.9) when the novel dynamic compensator is used in the unbalanced fault case and from 0.4 to 0.85 in the balanced fault case.

Table 1. Main Objective Functions versus the Tuned controller Gains Based SOPSO and MOPSO Control Scheme

β0 β1

J1 Minimise the

voltage deviations (PU)

J2 Minimise the

Distribution Feeder total active power Losses (PU)

J3 Minimise the Distribution

Feeder total reactive power losses (PU)

J4 Minimise the

absolute total error deviations

SOPSO 0.7498 19.5937 0.0462 0.0612 0.07478 0.21746 0.5108 42.3264 0.019 0.0771 0.0273 0.1273 0.1167 26.3051 0.0422 0.0554 0.07080 0.1024 0.8393 10.2121 0.0233 0.0396 0.0371 0.2788 0.5002 33.6397 0.0517 0.0662 0.0352 0.1398 0.6539 41.9221 0.0514 0.0537 0.0976 0.1597

MOPSO

0.8127 21.0800 0.0360 0.0456 0.0837 0.2323


Table 2. System Behaviour Comparison with and without MPFC Based SOPSO and MOPSO Techniques

Without the MPFC With the MPFC-with SOPSO Technique

With the MPFC-with MOPSO Technique

RMS Voltage (PU) 0.863454 0.93567 0.9634542 Power Factor 0.456798 0.9278645 0.959835 Maximum Transient Voltage – Over/Under Shoot (PU)

0.129756 0.093454 0.092563

Maximum Transient Current – Over/Under Shoot (PU)

0.09826 0.083654 0.073597

RMS Current (PU) 0.674564 0.4787465 0.429875 Active Power Losses (PU) 0.113746 0.0687231 0.0498576

Reactive Power Losses (PU) 0.148575 0.072543 0.598324

In addition, the phase voltage can maintain around 1pu and the transient over-voltages and surge type inrush currents are also damped. By comparing the results of all sample simulation cases, it is concluded that the novel dynamic MPF-Facts device with the SPWM dynamic controller developed by the first author is an attractive low cost and efficient Voltage stabilisation and power factor correction device that also improve power quality and efficient-utilisation of three phase–four wire Residential and Commercial Loads.

6. Conclusion The paper presents the application of MOPSO technique for MPFC device regulated by a dynamic error driven tri-loop Controller for voltage stabilisation of Low Voltage distribution systems. Comparing the dynamic response results of the two study cases, with and without the hybrid modulated power filter compensator, it is quite apparent that the hybrid modulated power filter compensator highly improved the AC system dynamic performance from a general power quality point of view. System losses, system voltages stability, capacity release, and power quality are fully enhanced for distribution networks. The iterative simulation results show the effectiveness of the MOPSO approach with phase voltage maintained around 1pu and the transient over-voltages and surge type inrush currents greatly damped. The novel dynamic MPFC device with the dynamic error driven controller developed is a viable solution for voltage stabilisation, power factor correction, power quality, efficient-utilisation, and loss reduction for distribution and utilisation of electric grid systems.

References Berizzi, A., Innorta, M. and Marannino, P. (2001),

“Multiobjective optimisation techniques applied to modern power systems”, Proceedings of the IEEE Power Engineering Society Winter Meeting, Columbus, Ohio, Vol.3, Jan/Feb, pp.1503-1508

Coello, C.A. and Lechuga, M.S. (2003) “MOPSO: A proposal for multiple objective particle swarm optimisation”, Proceedings of the IEEE World Congress on Computational Intelligence, Washington, DC, USA, Vol.2, May, pp.1051-1056.

Eberhart, R. and Shi, Y. (2001), “Particle swarm optimisation: developments, applications and resources”, Proceedings of the 2001 Congress on Evolutionary Computation, COEX, Seoul, Korea, May, pp. 81-86

Kennedy, J. and Eberhart, R. (1995), “Particle swarm optimisation”, Proceedings of the IEEE International Conference on Neural Networks, Vol.4, Piscataway, NJ, Nov/Dec, pp.1942–1948

Ngatchou, P., Zarei, A. and El-Sharkawi, A. (2005), “Pareto multi objective optimisation”, Proceedings of the 13th International Conference on Intelligent Systems Application to Power Systems, San Francisco, CA, November, pp.84-91

Sharaf, A.M. and Aljankawey, A. (2006), “Voltage stabilisation using a facts modulated power filter”, Proceedings of the International Symposium on Industrial Electronics, Vol.3, Montreal, Quebec, Canada, July, pp.1937-1942

Sharaf, A.M. and Ammar, M. (2008), “A switched power filter compensator scheme for ac motorised electrical loads”; Proceedings of the Electric Power Conference (EPEC 2008), Canada, October, pp.1-6

Sharaf, A.M. and Chhetri, R. (2006), “A novel dynamic capacitor compensator/green plug scheme for 3 Phase-4 wire utilisation loads”, Proceedings of the Canadian Conference on Electrical and Computer Engineering (CCECE 2006), Ottawa Congress Centre, Ottawa,


Canada, May, pp.454-459 Sharaf, A.M. and Kreidi, P. (2002), “Dynamic

compensation using switched/modulated power filters”, Proceedings of the Canadian Conference on Electrical and Computer Engineering (CCECE 2002), Vol.1, Winnipeg, MB, May, pp.230-235

Sharaf, A.M., Aljankawey, A. and Altas, I.H. (2007), “A novel voltage stabilisation control scheme for stand-alone wind energy conversion systems”; Proceedings of the International Conference on Clean Electrical Power (ICCEP '07), Capri, Italy, May, pp.514 -519

Sharaf, A.M., and Wang, W. (2006), “A low-cost voltage stabilisation and power quality enhancement scheme for a small renewable wind energy scheme”, Proceedings of the International Symposium on Industrial Electronics, Vol3, Montreal, Quebec, Canada, July, pp.1949-1953

Sharaf, A.M., Mahasneh, H.A. and Biletskiy, Y. (2007), “A novel power quality enhancement scheme in low voltage distribution system using modulated power filter compensator”; Proceedings of the International Conference on Clean Electrical Power (ICCEP '07), Capri, Italy, May, pp.171-174

Sharaf, A.M., Wang, W. and Altas, I.H. (2007), “A novel modulated power filter compensator for distribution networks with distributed wind energy”, International Journal of Emerging Electric Power Systems, Vol.8, No.3, pp.1-20

Shi, Y. and Eberhart, R. (1998), “Parameter selection in particle swarm optimisation”, Proceedings of the Seventh Annual Conference on Evolutionary Programming, Alaska, May, pp. 591-601

Shi, Y. and Eberhart, R. (1999), “Empirical study of particle swarm optimisation”, Proceedings of the 1999 Congress on Evolutionary Computation, Vol.3, Washington, DC, July, pp.1945-1950

Appendix: AC Utility Parameters:

138 KV, MVASC = 5 GVA , X/R = 10, X = 3 Ω , R = 0.3 Ω

Distribution Feeder parameters: 10 Km Feeder, R/Km=0.3 Ω/Km, X/Km=0.4 Ω/Km

Transformer T1 parameters: 138 / 25 KV, 5 MVA, XT = 6.05 Ω, RT = 1.21 Ω,

Transformer T2 parameters: 25 / 4.16 KV, 5 MVA, XT = 2.15 Ω, RT = 0.81 Ω,

Hybrid Load Parameters: Motorised Load Parameters: 2 MVA @ 0.85 PF Lag, 1740 rpm , 4.16 KV Linear Load Parameters: 1 MVA @ 0.8 PF Lag Non Linear Load model Parameters:

tsinRRR o2

1L0LL ω+= , ωo = 20 rad/sec , CL = 200

µF , RL0 = 0.6 PU , RL1 = 0.3 PU PSO Based Controller:

Search for the optimal controller parameters (β0 , β1) to optimise the selected objective functions, where: 0 ≤ β0 ≤ 1, 0 ≤ β1 ≤ 50 , γI =0.5, γv =1, γp =0.25, To = 10 ms, fsw = 180 Hz.

Unbalanced Fault Condition: The unbalanced fault is single line to ground fault (Phase A, Terminal Bus or Load bus VL) from 0.2 to 0.4 sec

MPFC Parameters: Cs = 30 µF , Cf = 30 µF , Lf = 10 mH , Rf = 0.5 Ω

Biographical Notes: Adel M. Sharaf obtained his B.Sc. degree in Electrical Engineering from Cairo University in 1971. He completed an MSc degree in Electrical engineering in 1976 and PhD degree in 1979 from the University of Manitoba, Canada and was employed by Manitoba Hydro as Special Studies Engineer, responsible for engineering and economic feasibility studies in Electrical Distribution System Planning and Expansion. Dr. Sharaf was selected as NSERC-Canada Research Assistant Professor in 1980 at University of Manitoba. He joined the University of New Brunswick in 1981 an Assistant Professor. Dr. Sharaf was promoted to Associate Professor in 1983 and full professorship in 1987. He has extensive industrial and consulting experience with Electric Utilities in Canada and Abroad. Dr. Sharaf authored and co-authored over 500 scholarly Technical Journal, Referred Conference Papers, and Engineering Reports. He holds a number of US and International Patents (Pending) in electric energy and environmental devices. Dr. Sharaf supervised over 40 Graduate Students (33 MSc and 12 PhD) since 1981. Adel A.A. El-Gammal received his B.Sc. degree in Electrical Power Engineering from Helwan University-EGYPT in 1996. He completed his MSc degree in Electric Drives and Machines Engineering in 2002 and PhD degree in 2007 from the Faculty of Engineering (Helwan University-EGYPT), respectively. Dr. El-Gammal joined the University of Helwan, Egypt as an Assistant Professor in 2007. He has gained industrial and academic experience as well as participated in several technical consultations in Egypt, Dr. El-Gammal joined UTT as Assistant Professor at the Center of Energy Studies. His current research areas include Power Systems and Electro-technology, Renewable/Alternate Energy Systems, Harmonics and Power Quality, Applications of Intelligent Systems, renewable / Green Energy systems and Electric Drives, Application of Power Electronics to Power Systems, and Computer-Based Controllers. He authored and co-authored over 25 papers in scholarly-refereed journals and technical conferences.

C. Gray-Bernard and A.J. Chadwick: Development of a Shoreline Management Tool for Trinidad 33


Vol.38, No.1, October 2009, pp.33-41

Development of a Shoreline Management Tool for Trinidad

Candice Gray-Bernard aΨ and Andrew J. Chadwick b

Department of Civil and Environmental Engineering, The University of the West Indies,

St Augustine Campus, Trinidad and Tobago, West Indies aE-mail: [email protected]

bE-mail: [email protected] Ψ Corresponding Author

(Received 1 May 2009; Revised 3 August 2009; Accepted 28 September 2009) Abstract: Shoreline management is the act of dealing, in a planned manner, with the actual and potential shoreline erosion and its relation to planned or existing development activities on the coast. Within Trinidad the management of the shoreline is disjointed leading to the construction of shore protection solutions that are often (i) functionally inappropriate for the environment in which it is placed and (ii) does not consider the impacts on adjacent beaches. Shoreline Management promotes the concept of the littoral cells whereby the activities within one littoral cell do not impact adjacent cells. Decision support systems and databases have been developed for the use of coastal managers, engineers and even the general public in order to promote a better understanding of the coastal environment leading to sound asset management and informed decision making. The Shoreline Management Tool for Trinidad (SMTTT) is being developed as a vehicle through which science and management can be merged. The SMTTT uses Geographic Information Systems (GIS), Database and Information Systems (DIS), mapping and other techniques to store and visualise spatial and attribute information on the coastal environment of Trinidad. Within the SMTTT, the shoreline has been divided into littoral cells or management units; for which coastal erosion hotspots will be mapped and recommendations for appropriate shore protection policies for the hotspots identified. The SMTTT information pertaining to the coastal environment can be made available to decision makers and other stakeholders and be used as a guide for decision making in policies of shoreline protection. Keywords: Shoreline management, geographic information system, decision making, databases, shore protection,

littoral cells

1. Introduction Shoreline erosion or the gradual retreat of the shoreline can be attributed to a variety of short-term and long-term causes. These causes may be natural and/or anthropogenic, and include but are not limited to strong winds, high waves, high tides, storm and surge conditions, sea level rise and land subsidence. The process of shoreline erosion can have vast consequences on the natural and human and built environment; the loss of private and state-owned properties (e.g. roads, bridges, resorts), death of mangrove and other wetlands due to increased salt water intrusion, the inundation of backshore areas, loss of economic interests (e.g. fishing and tourism) and the loss of valuable historical assets and ecological values (e.g. destruction of benthic communities) are all potential ramifications of

shoreline erosion. Shoreline Management is the act of dealing, in a

planned manner, with the actual and potential shoreline erosion and its relation to planned or existing development activities on the coast (Mangor, 2004). It is a generic approach to the strategic management of the combined hazards of erosion and flooding hazards in coastal areas; the main objective being to select a series of strategic options to be applied within a set time frame or epoch. Recent development in shoreline management looks towards the future evolution of the shoreline; considering longer-term implications (say, 50-100 years) of coastal change.

The aim of Shoreline Management is to provide the basis for the implementation of overall shoreline management policies and strategy for a well-defined


region or sediment cell. This is a section of the coastline in which the physical processes are relatively independent from the processes occurring within an adjacent sediment cell. The extent or boundaries of a sediment cell usually coincides with large estuaries or prominent headlands. It promotes a regional and comprehensive understanding of shoreline dynamics for determining the most appropriate solution or combination of solutions to mitigate the hazards of erosion and flooding. Mangor (2004) presents a model for the selection of the most applicable shore protection policy based on (i) the problem, (ii) type of coast and (iii) exposure of the coast. Shoreline Management guidelines developed and adopted within the United Kingdom (UK) over the past 10 years have grouped strategic options into four categories: (i) advance the line, (ii) hold the line, (iii) managed retreat, and (iv) no intervention (DEFRA, 2001).

Shoreline Management therefore sets out to produce sustainable polices for coastal defence against erosion and flooding of the shoreline. The process must take into account the natural coastal processes and issues relating to the environment and human needs. 2. Shoreline Management Plans Over the last ten (10) years, the first generation of Shoreline Management Plans (SMPs) was developed for over 6,000 kilometres of the coast in England and Wales. These plans set out to:

i) Provide a large-scale assessment of the risks associated with coastal process, and

ii) Present a long-term policy framework to reduce the associated risks to people and the developed, historic and natural environment in a sustainable manner

Government and lead authorities are obligated to ensure that the investment of taxpayer’s money is justified by the benefits delivered. In 2004, the Office of Science and Technology published the Foresight Future Flooding report that took a long-term view of the national flooding and coastal erosion risks within the UK (Foresight, 2004). It was estimated that over GBP800 million per annum was spent on flooding and coastal defences, but even with the defences damages per annum were estimated at GBP1,400 million.

SMPs therefore attempted to use best science to achieve sustainable policies, for example, due to natural coastal process the construction of coastal defences might be unadvisable due to adverse knock-

on effects elsewhere, or the cost of defences compared the assets to be protected may make investments in defences uneconomic.

A review of the strengths and weaknesses of SMPs was conducted by DEFRA and the industry. It was found that although these SMPs were classed as high-level strategic documents, they were based on incomplete datasets of the coastal and natural processes. In 2000, DEFRA commissioned the Futurecoast project which aimed at providing complete datasets of the natural processes along the shoreline of England and Wales, and providing predictions of coastal evolutionary tendencies over the next century.

The second generation of shoreline management plans (SMP2s) is being developed using the revised guidelines (DEFRA, 2006a, b), and is expected to be completed by 2010. One of the main inputs identified is a better understanding of coastal processes, the movement of sediments using the datasets developed under the Futurecoast project.

3. Shoreline Management in Trinidad Cambers (1997) postulates a general trend of erosion on Caribbean beaches. Evidence of erosion can be seen along the eastern and southern coasts of Trinidad. Whilst coastal erosion is a naturally occurring phenomenon, continuing and increasing human interaction with the coast has made this naturally occurring phenomenon into a critical coastal issue. Often without proper guidelines and regulations, human interaction and developments have been pertaining to (i) the setback from the high water line and (ii) the suitability of coastal protection that is required for protection.

Beaches are dynamic, changing their profile and planform in both space and time in response to the natural forcing of waves and currents, sediment supply and removal, the influence of coastal geological features and the influence of coastal defences and ports and harbours. Time scales range from micro (for wave by wave events), through meso (for individual storm events) to macro (for beach evolution over seasons, years and decades. Similarly space scales have a range of micro (for changes at a point) through meso (for example changes of beach profile) to macro (for example changes in planform evolution over large coastal areas) (Reeve et al, 2004).

Factors contributing to erosion can be both natural and anthropogenic, occurring on different time and spatial scales as illustrated in Figure 1.

C. Gray-Bernard and A.J. Chadwick: Development of a Shoreline Management Tool for Trinidad

35

Figure 1. Illustration of temporal and spatial scales of natural and anthropogenic factors contributing to erosion

In response to the coastal erosion, developers have constructed coastal protection structures, most often without considerations of the impact on adjacent beaches or stretches of coastlines or the time and spatial scales at which the erosion is occurring. Additionally, within Trinidad there is not clearly defined regulatory structure or guidelines in place to ensure that coastal developments are environmentally and functionally sound.

Currently, responsibility for management of the coastal resources within Trinidad is disjointed, and in some cases, there is an overlapping of

responsibilities. Table 1 provides a summary of the regulatory agencies in Trinidad and their responsibilities within the framework of shoreline management. In some cases, development on the coast is undertaken without approval or input from the relevant regulatory agency or authority.

In shoreline management, it is imperative that private developers, engineers, designers and decision makers understand the coastal dynamics contributing to the erosion. In order for this understanding to be achieved, there must be readily available access to information and data on the physical environment and coastal processes.

The current data structure in Trinidad and Tobago is one where access to data pertaining to the coast, the physical environment and coastal processes is limited and often restricted. Private property owners and public agencies often construct shore protection structures without due consideration of its suitability for the physical environment in which it is placed; often leading to the functional and structural failure of the structure.

In order to foster proper shoreline management practices in Trinidad, it is imperative that managers, politics, engineers or private property owners be given the appropriate tool by which to implement shoreline management.

Table 1. List of Agencies with Responsibility for the Management of the Coastal Zone in Trinidad Regulatory

Agency/Division Umbrella Ministry Responsibility in the context of Shoreline Management

Land Reclamation Committee

Cabinet Appointed

• To review and approve land reclamation applications • To develop a policy for land reclamation in Trinidad and

Tobago

Institute of Marine Affairs

Ministry of Public Utilities and the Environment

• To conduct fundamental and applied research in marine affairs • To conduct pre and post Construction Monitoring of approved

coastal developments/projects • To provide advice in matters of coastal affairs

Drainage Division

Ministry of Works and Transport

• To approve applications for the design of coastal structures and coastal developments

• To provide solutions for mitigation of coastal erosion • To provide advice in matters of coastal affairs

Environmental Management Authority

Ministry of Public Utilities and the Environment

• To conduct pre and post construction monitoring of approved coastal developments/projects

4. Shoreline Management Support Systems Integrated Coastal Zone Management (ICZM) has been debated and discussed over the past years. It is a process which seeks to link different policies that have an effect on the coast by bringing together stakeholders to inform, support and implement these

policies. Management support systems (MSSs) have been

developed with the aim of providing a framework for integrating sophisticated coastal modelling with coastal management for decision making. Within the context of ICZM shoreline management support


systems offer the potential to improve the understanding of the coastal processes and hazards.

In 1998, the Buffalo District of the US Army Corps of Engineers commissioned the Lower Great Lakes Erosion study. The first year of the study was designated towards the development of a GIS tool housing databases for shoreline classification, recession rates, land use and its trends. The databases were proposed to be the foundation for a shoreline erosion modelling system for the Lower Great Lakes; with recommended uses to address issues related to lake level control and, coastal zone management and site specific designs (Stewart, 1999).

Other such shoreline management support systems and databases include Futurecoast (UK), Texas Coastal Hazard Atlas (USA) and the Gold Coast Beach Management System (Australia). Although developed under different circumstances, the underlying factor contributing to the development of these systems was the need to map and understand the natural coastal processes and to use this information to inform decision making as it pertains to sustainable coastal defence policies. The structure of these systems/databases will be briefly outlined in subsequent sections. 4.1 Futurecoast The main objective of the UK Futurecoast study initiated by the Department of Environment, Food and Rural Affairs (DEFRA) was (i) to improve the understanding of coastal behaviour (building upon information contained within the first round of Shoreline Management Plans (SMPs) for the UK and Wales, (ii) to assess potential future shoreline behaviour under two scenarios – unconstrained (assuming no defences or management practices) and managed (assuming present management practices continue indefinitely) and (iii) to provide a ‘toolbox’ of supporting information that can be applied in future assessment of shoreline behaviour.

Following consultation with potential end-users and the client group, it was concluded that the most useful way to present the study results was via an interactive CD-ROM. There are many advantages in terms of the way data can be accessed and displayed. The interactive CD-ROM allows the user to navigate through both the text and mapped data; there are also links from mapped data to sections of texts. The user is also able to ‘design’ reports. The output of the Futurecoast study therefore took the form of an interactive CD containing (i) thematic studies on

Shoreline Behaviour Change, and (ii) mapped datasets at three default scales of 1:500,000, 1:100,000 and 1:25.000.

The Futurecoast database system involved mapping of the coastal and geomorphological process of entire England and Wales coastline, using this as the basis for predicting coastal evolution over the next 100 years (Barter et al., 2003). Figure 2 shows a screenshot of an application of Futurecoast; Future Shoreline Change for unconstrained conditions from West Wittering to Gilkicker Point in the UK.

The key objective is to allow current coastal processes and past, present and future management decisions to be coupled within a longer-term and wider scale framework; thus, providing a vision for the coast and a scientific basis for considering sustainable strategic management response.

Figure 2. Screenshot of Futurecoast

The data and information contained within the

Futurecoast project will be fed into the second generation SMPs (SMP2s) improving their consistency, quality and reliability. These SMP2s are due to be completed by 2010. The Futurecoast study was therefore aimed at addressing the lack of data on long term shoreline evolution, thereby ensuring that the second round of SMPs are better informed and are therefore able to make strategic coastal management decisions in a longer-term and wider-scale context (Barter et. al, 2004). 4.2. Gold Coast Beach Management System

(GCBMSS) The GCBMSS was developed as a geographic information (GIS) based beach analysis and management system for the Gold Coast City Council. It is an internet-based system that aims to


improve search, access and manipulation of data and information for Gold Coast beach management strategies. Within the context of ICZM the GCBMSS offers the opportunity to improve the understanding of coastal erosion hazards (Pointeau, 2006). Hunt (2008) contends that the GCBMSS can be used as a decision support system through the integration of data management, process simulation and graphical representation of complex coastal environments.

GCBMSS allows beach protection recommendations and applications for predicting episodic beach changes and estimating erosion damage exposure probabilities to be accessed. Five modules make up the system. These are:

1) Beach Survey Data – This is composed of a beach survey database and a data computation module that classifies beach surveys, beach nourishment and dredging data available since the 1960’s from the Gold Coast City Council. Thus, all beach survey data can be quickly found and easily downloaded.

2) CoastED – This is an educational module using different animation to show and explain using a user-friendly interface all over the general coastal processes. This model provides a conceptual model for stakeholders to get basic knowledge of coastal management processes, techniques and technologies. The ultimate aim is to assist users in understanding the main coastal processes and how the beach functions.

3) Planning Strategy for Erosion Impact – Using the beach processes modules SBEACH and BMAP software computations the maximum beach erosion distribution due to sea level rises and storm probabilities can be evaluated; providing coastal managers with the capability of evaluating storm-induced beach erosion scenarios and potential impacts. Coastal managers can therefore adjust coastal defence development strategies.

4) Beach Evolution Modelling – This is a user-friendly mapping interface where the user can select wave and wind parameters to model the coastal dynamics affecting a particular stretch of beach. The tool is intended to be educative. It shows general processes based on a statistical value and aims to model overall coastal processes and their consequences in beach evolution using validated Delft 3D software modules.

5) Beach Nourishment Modelling – This is a user-friendly tool that allows the user to select

different nourishment volumes, deposition area, meteorological climate conditions and duration to determine and visualise processes such as beach nourishment erosion or accretion, sediment flow, sea bed evolution and current magnitudes and velocities using validated Delft 3D software modules. Within this module, a combination of recommendations is made for supporting coastal decision making process. Users are therefore provided with the basic information required for decision making when nourishing a stretch of coastline.

The GCBMSS encompasses the use of Geographic Information System (GIS) and web-based design. An ArcGIS/Delft 3D interface allows the selection of strategic management tools with an integrated spatial visualisation capability. The system therefore offers the potential to improve the understanding of coastal erosion hazards (Pointeau, 2008). 4.3 Texas Coastal Hazard Atlas The Texas Coastal Hazard Atlas was developed in response to the need for technical information by coastal planners and to increase public awareness of coastal processes. The atlas has been developed for the entire Texas coast (Gibeaut, et al. 2003).

The atlas consists of GIS files in ArcView format. The maps may be downloaded from the main website (www.beg.utexas.edu), viewed and customised on a personal computer using ArcView or ArcExplorer. The atlas is also be accessed online using ArcIMS (an internet map server that renders maps at the request of the user). ArcIMS also contains basic GIS tools that allow the user to create new data sets based on spatial relations or to (ii) retrieve existing data sets from the map’s graphical interface. Mapped layers that can be viewed in the Texas Coastal Hazard are outlined in Table 2. 5. Shoreline Management Tool for Trinidad Various technologies, techniques and software have been employed within various systems to develop decision support systems where coastal managers and other end users can readily access information about the coastal environment; thus informing the decision making process. The proposed Shoreline Management Tool for Trinidad is intended to be a starting point where information about the coastal environment of Trinidad can be readily accessed by coastal manager and other end users.


Table 2. Display layers within the Texas Coastal Hazard Atlas

Source: Based on Gibeaut, et al. (2000)

It is not the intention of this research to provide a detail specification as to the end user of the SMTTT but rather to develop the structure of the SMTTT. Notwithstanding this, expected end users of this system can include politicians, engineers, consultants, government agencies and the general public. 5.1 The Structure of SMTTT The SMTTT is being developed using the Shoreline Management and Nearshore Database (SANDS). SANDS is a data capture, monitoring and analysis suite developed particularly for shoreline managers, coastal engineers and environmental scientist. It provides a facility through which input data can be analysed to establish links between forcing and response. It allows data management and decision support through a variety of analytical and visualisation tools. Key uses of SANDS include:

· Coastal Data Storage · Beach and Structure Inspection · Erosion and Accretion Analysis · Tidal Analysis and Prediction · Wind/Wave Extremes Analysis · Sediment Transport Analysis · Wave Transformation

Database systems using the SANDS platform have been developed by organisations and universities, such as the Government of Barbados,

the Civil Engineering Department of the University of Nothingham, UK, and the National Hydraulic Research Institute, Malaysia. Display Layers

A. Bay Erosion B. Cities C. County Boundaries D. Digital Orthophoto Mosaics E. Environmental Sensitivity Index (ESI) Shoreline F. Faulting G. Hurricane Surge and Flooding

G.a.1. Computer Model Surge Data G.a.2. Maximum Surge Lines (Level 1-5) G.a.3. Net Inundation Area (Level 2-5) Hurricanes Beulah and Carla Flood Areas

H. National Wetland Inventory I. Shorelines

I.a.1. Historical Shorelines I.a.2. 2026 Shoreline I.a.3. 2056 Shoreline

J. Net Projected Shoreline Erosion and Accretion (1996-2026)

K. Washover Features K.a.1. Washover Channels and Interdune Drainage K.a.2. Washover Areas

The main features of SANDS are its mapping and diary capabilities that promote sound asset management and information based decision making. The diary capability of SANDS allows data and information to be stored through pre-defined forms/records. These include:

· Beach Profile Inspection – This allows new profile survey records to be stored and old records to be viewed.

· GPS Network Control Station – This allows data relating to control stations to be stored

· Visual Inspection – allows the record of data during walkover surveys.

· Beach Inspection – This allows data from inspections of a length of coastline to be stored. Coastlines can be grouped into Coastal Process Units (CPUs). CPUs are recommended for Shoreline Management (DEFRA, 2001)

· Monthly Rainfall and Wind Records – That allow rainfall and wind records for each month in the year to be stored with the ability of determining average monthly rainfall records over specified periods.

· Structure Inspection – This allows for the storage of data on the condition of any coastal structure. Additionally this form has a built in Action Levels model for predicting dates for undermining and overtopping of a structure by related inspected dip levels to trends in associated beach profiles and structure specific variables; allowing maintenance instructions to be issued.

The mapping capability of SANDS allows data stored in the database to be referenced spatially and overlaid on geo-referenced digital maps or raster images. Most of SANDS functions can be assessed through the map system.

5.2 Database Structure of SMTTT The proposed database structure of the SMTTT is provided in Table 3. The database structure can be further developed to include other spatial elements pertaining to the coastal environment.

Some of the mapped features of the SMTTT are described as follows:

1) Littoral Cells - define closed compartments in terms of sand supply. The boundaries of littoral cells are typically headlands; as


headlands restrict transfers of onshore sediment to offshore movements within individual littoral cells. These internal exchanges are typically described in terms of contributions to or losses from the littoral cell sediment budget. Thus, erosion or accretion along any given segment of shoreline is reflected in the balance of the budget. Within each littoral cell, smaller sub-cells can be identified based on features such as jetties, inlets and rocky outcrops. To date, the coast of Trinidad has been divided and mapped into 32 ‘quasi’ littoral cells based on the limits of headlands along the coastline.

Table 3. Proposed Display Layers within the Shoreline

Management Tool for Trinidad

2) Coastal Hotspots – These are areas where the threat of erosion is high and the continued threat of erosion is predicted. These erosion hotspots along the coast of Trinidad will be identified through a combination of field or reconnaissance surveys and mapping techniques. Spatial and attribute data of the erosion hotspots will be stored in the SMTTT.

3) Coastal Classification - Mangor (2004) defines classification of the physical characteristics of the coast based on (i) the angle of incidence of he prevailing waves, and (ii) the wave exposure for sedimentary coasts. It is the intention of this research to adopt this classification in order to develop recommended shore protection schemes for the identified coastal hotspots.

Five (5) main types of coasts have been defined on the basis of the angle of incidence, α of the prevailing waves and exposure of the coast as

described in Tables 4 and 5, respectively.

Table 4. Description of Wave Approach Conditions Description of Wave Approach Condition

Perpendicular α0 ≈ 0° Nearly Perpendicular 1° ≤ α0 <10° Moderately Oblique 10° < α0 < 50° Very Oblique 50° < α0 ≤ 85° Nearly Coast Parallel α0 > 85°

Table 5. Description of Wave Exposure Conditions Description of Exposure Condition

Protected (P) Hs, 12h/y < 1 m Moderately Exposed (M) 1m < Hs, 12h/y < 3m Exposed (E) Hs, 12h/y > 3m Where Hs, 12h/y represents the “once per year event”

Figure 3 illustrates the wave approach conditions, where α represents the angle of the wave approach with respect to the shoreline. Based on the description of wave approach and wave exposure, the coast is characterised from types 1P to 5E as described in Table 6.

Display Layers

A. Watershed Boundaries B. River Network C. Base Mapping D. Bay Erosion E. Littoral Cells F. Beach Profiles G. Shoreline

G.a.1. Historic Shorelines G.a.2. Future/Predicted Shorelines

H. Coastal Hotspots I. Coastal Classification J. Shore Protection Policies

J.a.1. Existing J.a.2. Recommended

K. Land Use

Shoreline

0º

90º

α

Figure 3. Illustration of Wave Approach Conditions 6. Shore Protection 6.1 Existing Shore Protection Policies (Schemes) Existing shore protection schemes will be mapped (spatial location) and attribute (dimensions, age, owner, and design life etc) data stored using the diary and library capability of SANDS. 6.2 Recommend Shore Protection Policies

(Schemes) Mangor (2004) defines a technique for determining the most appropriate shore protection policy for the coastal problem within the erosion hotspot. The choice of shore protection policy is based on the classification. For example, in the case of a moderately exposed beach with perpendicular wave approach having a combined coastal problem of


erosion and inundation (e.g., flooding), a seawall is recommended as the most appropriate shore protection policy. Recommended shore protection policies and schemes will be proposed for the coastal erosion hotspots based on the method as outlined in Mangor (2004).

Table 6. Coastal classification based on Angle of Incidence and Wave Exposure

Source: Based on Mangor (2004) 7. Conclusion Studies conducted within the UK indicate that although funds are allocated annually to flood and erosion protection, damages from flood and erosion hazards continue to rise. It is therefore imperative that in keeping with the context of sustainability, decisions as to flood and erosion protection are made with a comprehensive understanding of the natural

processes contributing to these hazards. A review of the shoreline management process

within the UK has indicated that the weakness of the first generation Shoreline Management Plans was the lack of complete datasets on the natural and anthropogenic processes along the coast; this lead to the development of complete datasets under the Futurecoast project. Comparative shoreline management databases have been developed with the main aim of promoting sustainable decisions for flood and erosion protection. This provides coastal managers and decision makers with information pertaining to how the coast has behaved and is expected to behave.

Angle of Incidence Coastal

Type (0 = shore normal)

Exposure Main Coastal Characteristics

1P Protected Marshy

1M Moderate

Narrow stable sand beach, barrier island, sand spits

1E

0

Exposed

Wide stable sand beach, barrier island, sand spits

2P Protected Marshy

2M Moderate

Narrow stable sand beach, barrier island, sand spits

2E

1 - 10

Exposed

Wide stable sand beach, barrier island, sand spits

3P Protected Marshy

3M Moderate

Narrow unstable sand/shingle beach, cliff or dunes

3E

10 - 50

Exposed

Wide unstable sand/shingle beach, cliff or dunes

4P Protected Marshy

4M Moderate

Narrow unstable sand/shingle beach, cliff or dunes, salients

4E

50 - 85

Exposed

Wide unstable sand/shingle beach, cliff or dunes, salients

5P Protected Marshy

5M Moderate

Sandy beach, accumulative land forms, spits

5E

85 - 90

Exposed

Sandy beach, accumulative land forms, spits

The ‘Demonstration Programme’ on ICZM commissioned by the European Union during the 1990’s examined the pressures and problems facing the coasts. One of the underlying causes contributing to the biological, physical and human issues facing European coastlines was a lack of vision related to management at the coast. This was based on a very limited understanding of coastal processes and dynamics and with scientific research and data collection isolated from end-users (Atkins, 2004).

The Shoreline Management Tool for Trinidad is an ongoing research project. This is intended to (i) promote a better understanding of the geomorphologic and hydrodynamic forcing factors leading to shoreline change; (ii) to assess the vulnerability and risk of the natural and human and built environment to flooding and erosion; and (iii) to promote information led development of appropriate coastal protection schemes and defence policies and for them to be implemented within a set time frame. The SMTT can also be used for asset management.

To date, the coast of Trinidad has been divided into thirty-two (32) littoral cells (in keeping with DEFRA guidelines) and mapped within the SMTTT. Once fully developed the SMTT can be used to answer questions such as:

· Which areas are most at risk to coastal and flood hazards?

· Where should funds be allocated for the implementation of coastal and flood protection infrastructure?

· What type of asset/infrastructure is suitability for the coastal environment within a littoral cell?

· How often and when should a coastal asset/infrastructure be maintained?

End users of the SMTT can include government/

C. Gray-Bernard and A.J. Chadwick: Development of a Shoreline Management Tool for Trinidad

41

decision makers, consulting engineers and the general populace. References: Atkins (2004), ICZM in the UK: A Stocktake, Queen's

Printer and Controller of HMSO. Barter, P.W.J, Burgess, K.A, Jay, H. and Hosking, A.S.D.

(2004), “Futurecoast: Predicting the future evolution of England and Wales”, Journal of Coastal Conservation, Vol.10, pp.65-71.

Barter, P.W.J, Burgess K.A., Jay, H. and Hosking A.S.D., (2003), “Futurecoast: Predicting the Future Coastal Evolution of England and Wales”, Proceedings of the International Conference on Estuaries and Coasts, Hangzhou, China, November, pp.174-182.

Cambers, G. (1997), “Managing Beach Resources in the Smaller Caribbean Islands”, Papers presented at a UNESCO-University of Puerto Rico Workshop, Coastal region and small island papers, UPR/SGCP-UNESCO, Mayaguez, Puerto Rico, (21-25 October 1996), No.1, pp 3-12

DEFRA (2001), Shoreline Management Plans: A Guide for Coastal Defence Authorities, Department for Environment, Food and Rural Affair

DEFRA (2006a), A Strategy for Promoting an Integrated Approach to Management of Coastal Areas in England, Department of Environment, Food and Rural Affairs, UK.

DEFRA (2006b), Shoreline Management Plan Guidance, Volume 1: Aims and Requirements, available at: www.defra.gov.uk.

Foresight (2004), Foresight Future Flooding Report, Office of Science and Technology, UK, Available at: www.foresight.gov.uk

Gibeaut, J.C., and Tremblay T.A. (2003), Coastal Hazard Atlas of Texas: A Tool for Hurricane Preparedness and Coastal Management: Volume 3, Bureau of Economic Geology, Austin, Texas, available at: www.beg.utexas.edu/coastal/hazard_atlas3.htm

Gibeaut, J.C., White, W.A. and Tremblay T.A. (2000), Coastal Hazard Atlas of Texas: A Tool for Hurricane Preparedness and Coastal Management: Volume 1, Bureau of Economic Geology, Austin, Texas, available at: www.beg.utexas.edu/coastal/hazard_atlas1.htm

Hunt, S., Stuart, G., Red, R., Myendersk, H., and Tomlinson, R.B. (2008), “Managing Coastal Hazards on Australia Gold Coast”, Wallendorf, L., Ewing, L., Jones, C., and Jafe, B. (2008)(Eds.), Solutions to Coastal Disasters, ASCE, pp. 698-712

Mangor, K. (2004), Shoreline Management Guidelines, DHI Water and Environment.

Pointeau R., (2006), “Presentation of the Gold Coast Beach Management Support System”, Presented at

Les journ’es g’omatiques de l’Ouest, Geomatics and Coastal Environment, Brest, France

Pointeau R. (2008), “Coastal Information Network, Gold Coast, Queensland, Australia” Presented at the 7th PIANC-COPEDEC Conference on Coastal and Port Engineering in Developing Countries, Dubai, February.

Reeve D., Chadwick A. and Fleming C. (2004), Coastal Engineering: Processes, Theory and Design Practice, Spon Press, New York, NY.

Stewart, C.J. (1999), “A GIS mapping tool for the presentation and analysis of coastal data along the shorelines of the North American Great Lakes”, Proceedings of the Canadian Coastal Conference, Victoria BC, May 1999: p.487-498.

Biographical Notes: Candice Gray-Bernard is a Civil Engineer currently undertaking research at the University of the West Indies, Civil and Environmental Engineering Department in Shoreline Management. Ms Gray is currently employed with the Ministry of Works and Transport, Drainage Division as a Drainage Engineer. Her interests lie in the fields of Shoreline Management and Watershed and River Basin Management. Ms. Gray has received international training in Shoreline Management, Flood Modelling for Management and Decision Support Systems in River Basin Management. She is currently pursuing for an M.Phil in Civil Engineering, conducting research in the development of a Shoreline Management Tool for Trinidad. Andrew J. Chadwick is the Professor of Coastal Engineering at the University the West Indies and formerly held a similar post at the University of Plymouth UK. He has a substantive publication record, including books, refereed journal papers and international conference papers. Since 1986, his research work has centred on nearshore wave measurements, coastal sediment transport, hydrodynamic and morphodynamic numerical modelling. The emphasis of much of this work has been in evaluating and validating theory and models against field and laboratory data and in identifying key processes to be modelled. He recently led the UK contribution to the European Network for Coastal Research Co-ordination Action (ENCORA) and was the ENCORA themes co-ordinator for all of the EU. He has been a member of the editorial Panel for Maritime Engineering, the review board for the Journal of Hydraulic Research and the EPSRC Peer Review College.

http://www.defra.gov.uk/

http://www.foresight.gov.uk/

http://www.beg.utexas.edu/coastal/hazard_atlas3.htm

http://www.beg.utexas.edu/coastal/hazard_atlas1.htm

K. Singh et al.: Municipal Solid Waste to Energy: Potential for Application in Trinidad and Tobago 42


Vol.38, No.1, October 2009, pp.42-49

Municipal Solid Waste to Energy: An Economic and Environmental Assessment for Application in Trinidad and Tobago

Kamel Singha, Solange O. Kellyb and Musti K.S. Sastry cΨ

a, b The University of Trinidad and Tobago, Pt. Lisas Campus, Esperanza Road,

Brechin Castle, Trinidad and Tobago, West Indies E-mail: [email protected] E-mail: [email protected]

c Department of Electrical and Computer Engineering, The University of West Indies,

St. Augustine Campus, Trinidad and Tobago, West Indies E-mail: [email protected]

Ψ Corresponding Author (Received 15 May 2009; Revised 13 August 2009; Accepted 21 September 2009)

Abstract: Economic and social progress in Trinidad and Tobago has resulted in the tripling of generation of solid waste from 1990 to 2007. It is anticipated that by 2020 the waste generated will exceed 1.4 million tons per annum (tpa). As a small island developing state, the country will be confronted by shortage of land area for setting up new landfills, significant environmental deterioration, negative public health impacts and scarcity of resources for the safe disposal of the waste. This paper presents comparison of various technologies for converting Municipal Solid Waste (MSW) to energy, and proposes a new Waste-to-Energy (WTE) process based on plasma gasification technology. A brief cost- benefit analysis of the plants has been presented from which it is shown that this proposed WTE process is a feasible option and an environmentally favorable solution to the problem of solid waste management in Trinidad and Tobago. Keywords: Municipal Solid Waste, Solid Waste Management, Waste to Energy, Plasma Gasification 1. Introduction Household waste (or domestic waste) with sometimes the addition of commercial wastes collected by a municipality within a given area is known as Municipal Solid Waste (MSW). Disposal of this waste is a challenging task in every part of the world due to the associated health risks and impact on the environment. In Trinidad and Tobago, most of the solid waste collected is disposed of in the country’s three major landfills; the Beetham Landfill which is the largest landfill located on the outskirts of the country’s capital and poses an ecological threat as it is located in a wetland environment; the Forres Park Landfill in Claxton Bay is the only engineered sanitary landfill (i.e., constructed with a leachate collection system which requires extensive maintenance), and the Guanapo Landfill in Arima which has the potential to have a direct negative impact on the underlying aquifer and all the surface water downstream of the site is in close proximity to

many private residences. Figure 1 shows the daily amount of waste taken to each of the landfills in 2007.

Figure 1 shows the daily average amount of solid waste received at Trinidad’s 3 Major Landfills, (SWMCOL, 2007). Approximately, 214,880 tons of solid waste were generated in 1990, increasing to 607,788 tons in 2007 (SWMCOL, 2007). It is anticipated that the Beetham Landfill, which accounts for 55% of the country’s waste, will reach its capacity within the next few years.

Figure 1. Daily Average Amount of Solid Waste at Trinidad’s 3 Major Landfills


The problem of solid waste management (SWM) is now of national importance. Figure 2 shows the waste generated annually. It is estimated that by the year 2020, the country will be generating 1.4 million tons of MSW per year. The GORTT has approved a MSW Management Policy in 2008 (GORTT, 2008). This policy seeks to address strategies for managing waste in a manner that would protect the environment and integrate waste systems, using cost effective measures. It is within this context that a WTE plant is proposed.

Figure 2. Total Estimated Annual Tons

The objective of the paper is to assess the various WTE conversion technologies based on an economic and environmental analysis with the aim of selecting the most appropriate technology. The paper also introduces a novel approach to waste management in Trinidad from collection to conversion to electrical energy. The discussion is divided into 6 sections. The issues related to SWM and related information is provided in Section 1. A detailed composition of waste is presented in Section 2; along with the forecast of the amounts of waste that will be generated in future. Section 3 presents a comparative study of Thermochemical Conversion Technologies that are presently used. The details of the proposed WTE plant for SWM in Trinidad and Tobago are presented in Section 4, along with a brief cost estimation. The socio-economic and environmental benefits are illustrated in Section 5. Overall conclusions are provided in Section 6. 2. Waste Quantification and Characterisation In 1995, SWMCOL conducted a household waste qualification study for the nation’s three major landfills categorises. The study quantified the major

components received (see Table 1).

Table 1. The 1995 Waste Qualification Study for Three Major Landfills

Component Beetham (%)

Forres Park (%)

Guanapo (%)

Total (%)

Plastics 20% 13% 20% 17% Paper 20% 18% 20% 19% Organics 16% 0% 17% 11% Food 10% 39% 11% 21% Glass 10% 8% 6% 9% Metals 10% 8% 10% 9% Textiles 7% 4% 9% 7% Rubber & Leather 5% 2% 7% 4% Fines 0% 2% 0% 1% Yard And Garden 0% 6% 0% 2% Non-Recylables 0% 0% 0% 0% Total 100% 100% 100% 100%

Source: Based on SWMCOL (1995)

Sixty eight percent (68%) of household waste came from primarily four components; paper, plastic, organics and food. Food accounted for 21%, paper 19%, plastics 17% and organics 11%, respectively. Each of the components has some level of recovery. The opinion of subject matter experts interviewed anticipated possible recovery rates based on 1995 total generation figures at the landfills. The highest recovery rate is expected to be glass at 25% because of the existing arrangement between salvagers of the Bottle Vendors Association of the Beetham Estate, SWMCOL and Carib Glassworks Limited (CGL), where SWMCOL purchases the glass from the salvagers and acts as their facilitator for its resale to CGL. Metal recovery is also about 25% because of the ease of retrieval.

Recovery of materials for recycling and composting was estimated at 54.47 tonnes or 11.6% of daily generation, leaving 414.53 tonnes to be converted into useful energy. Based on a characterisation and quantification analysis with the use of handbook data, (Kreith, 2007), the calorific value (CV) of the waste discarded was calculated and found to be 16,150 kJ/kg. With such a high CV potential, there exists an opportunity for the conversion of the waste to much needed useful clean electrical energy generation.

3. Thermochemical Conversion Technologies Incineration and Conventional Gasification are the two proven technologies with energy recovery capabilities that are currently in use for SWM in different parts of the world.


3.1 Incineration Waste incineration has been and continues to be practiced in many countries in order to accomplish disposal in a cost effective manner. A major benefit of incineration is the volume reduction of the original waste by 95~96%, depending on the composition and degree of material recovery such as metals from the ash for recycling. Incineration reduces the necessary volume destined for landfilling significantly, in addition to treatment of certain institutional wastes in niche areas as clinical wastes and certain hazardous wastes where pathogens and toxins can be destroyed by high temperatures (Speight, 2008).

The amount of heat recovered from the incineration process is quite small when compared to other thermochemical conversion technologies. Hence it is not surprising that incineration used in conjunction with steam cycle boilers and turbine generators achieves lower efficiency.

The most publicised concerns about incineration of MSW involve the fear that it produces significant amounts of dioxin and furan emissions. Dioxins and furans are considered by many to be serious health hazards. The concerns over its health effects have been significantly lessened by advances in emission control designs and stringent air pollution rules. Inspite of this incineration for waste disposal and energy production, it remains a controversial topic for waste management (Ojolo and Bamgboye, 2005). 3.2 Conventional Gasification Process Gasification offers more scope for recovering products from waste than incineration. When waste is incinerated the only practical product is energy, whereas the gases, oils and solid char from gasification can not only be used as a fuel but also purified and used as a feedstock for petrochemicals and other applications (Speight, 2008). A process flow for the gasification of MSW is as shown in Figure 3.

The principle behind waste gasification and the production of gaseous fuels is that waste contains carbon and it is this carbon that is converted to gaseous products via gasification chemistry. Thus when waste is fed to a gasifier, water, and volatile matter are released and a char residue is left to react further.

The product gas generally contains large amounts of hydrogen and carbon monoxide and a small amount of methane, as well as carbon dioxide and steam.

Pre-treatment

Figure 3. Process Flow for the Gasification of the Municipal Solid Waste

Source: Abstracted from Speight (2008)

By displacing fossil fuels, gasification can help

(i) meet renewable energy targets, (ii) address concerns of global warming, and (iii) contribute to achieving Kyoto Protocol commitments. Associated with gasification of MSW, the issues include feedstock homogeneity, feedstock heterogeneity, and process scale up that can lead to a number of mechanical problems, shutdowns, sintering and hot spots leading to corrosion and failure of the reactor wall. 3.3 Plasma Gasification Process

One of the increasingly popular types of gasification is Plasma Gasification. Plasma gasification technology has been shown to be the most effective and environmentally friendly method for solid waste treatment and energy utilisation. It is a non-incineration thermal process that uses extremely high temperatures in a partial oxygen environment to decompose completely the input waste material into very simple molecules. The products of the process are a fuel or gas known as synthesis gas and an inert vitreous material known as slag (Stehlı´k, 2009).

Plasma gasification uses an external heat source to gasify the waste, resulting in very little combustion. Almost all of the carbon is converted to fuel. The high operating temperatures allow for the breaking down of all tars, char and dioxins. The exit gas from the reactor is cleaner, and there is no ash at the bottom of the reactor. The waste feed sub-system is used for the treatment of each type of waste in order to meet the inlet requirements of the plasma furnace. For example, for a waste material with high moisture content, a drier will be required. However, a typical feed system consists of a shredder for solid waste size reduction prior to entering the plasma furnace.

The plasma furnace is the central component of the system where gasification and vitrification takes place. Plasma torches are mounted at the bottom of


the reactor, they provide high temperature air (i.e., almost three times higher than traditional combustion temperatures) which allow for the gasification of the waste materials. Figure 4 shows a block diagram of the plasma gasification process. (Mountouris et al., 2006)

The gas produced in the furnace system is referred to as synthesis gas. This gas then enters the synthesis gas cleaning system. Gas cleaning refers to the process of removing acid gases, suspended particulates, heavy metals and moisture from the synthesis gas prior to entering the energy recovery system where power, steam and synthetic fuels can be obtained. Unlike waste incineration, plasma gasification WTE technology has proven to have a benign impact on the environment.

Figure 4. Plasma Gasification Process Source: Abstracted from Mountouris et al. (2006)

A comparative analysis among the three

technologies - conventional gasification, incineration and the plasma gasification process - is summarised in Table 2 (AlterNRG, 2008). From this, it can be seen that plasma gasifications technology for SWM is a superior, environmental-friendly, safe and sustainable solution. 3.4 Existing Plasma Gasification WTE facilities There are a few Plasma gasification WTE facilities existing throughout the world. Some are listed in Table 3. Planning is also being done for the establishment of additional facilities in Canada and new facilities in the US, India, England and Wales. In the Caribbean (with the exception of Jamaica), there has been little attempt at WTE using plasma gasification. The capital cost of such technologies appeared far too high to be considered an appropriate waste management solution.

Table 2. Comparison of Thermochemical Conversion Technologies

Plasma Gasification

Conventional Gasification

Incineration

Gasification of solids by partial oxidation and water-gas shift reaction resulting in high quantities of hydrogen and carbon monoxide.

Gasification of solids by oxidation resulting in high quantities of CO2

Attempts complete combustion of solids resulting in high quantities of environmentally unfriendly gases like CO2 being produced.

Wide range of composition of MSW can be used. Simultaneous feeding of organic and inorganic constituents is allowed.

Operation stability requires control of moisture as and a more homogeneous type of MSW

Operation stability requires control of moisture and heat content.

Vitreous slag produced; slag can be used for making bricks, road bed etc.

Ash produced needs to be landfilled

Ash produced which needs to be landfilled

Can be used with a combined steam and gas cycle or simple cycle gas turbine for achieving high thermal efficiency.

Can be used with a combined steam and gas cycle or simple cycle gas turbine for achieving high thermal efficiency.

Can be used with steam cycle

Table 3. Some of the existing plasma gasification WTE

facilities Year

Commissioned Location Type

2004 3-5 tpd facility Tainan City, Taiwan

Information not available

2002 24 tpd facility in Mihama/Mikata, Japan

District Heating

2003 200-280 tpd pfacility Japan – Eco Valley Waste to Energy Facility

Electricity Generation

1995 Ishkawajima, Japan Electricity Generation

1992 Chicoitimi, Quebec, Canada

Commercial Aluminium Dross Recovery Furnaces

1989 Ohio, USA Commercial Cast Iron Production

Sources: Based on AlterNRG (2008) and Wikipedia (2009) 4. Proposed WTE Plant in T&T Based on the amounts of waste generated in Trinidad and Tobago, a WTE pilot plant rated at 450 tonnes per day (tpd) is proposed and the possibilities of establishing the same are analysed. The proposed location of the plant is the Beetham Landfill, Port-of-Spain due to the fact that it is the largest of the three landfills in the country and fast reaching its limits. It is assumed that this proposed plant will ideally have a 3-shift operation, 7 days per week.

The waste collection model considered in this study includes the purchase of landfill space per

K. Singh et al.: Municipal Solid Waste to Energy: Potential for Application in Trinidad and Tobago

46

tonnage of waste by the waste collector from the WTE plant facility. The charge applied by the WTE facility will be referred to as the “Tippage cost”. The WTE plant operators will be responsible for managing the landfill where the waste will be stored prior to its conversion to energy. Scales would be integrated into an automated record keeping system to record the weight of MSW delivered to the plant. Collections would be done in two 12-hour daily shifts, 6 days per week, while gasification will be continuous, so ample storage of MSW usually 2-3 days (i.e., 1,350 tonnes) is required. MSW can be received in a floor dump type of operation where the recovery process is performed. Remaining MSW can then be loaded onto conveyors that carry the material to a flail mill or trommels where it is then processed. Figure 5 shows the overall process of the proposed WTE model.

Figure 5: Flow diagram of proposed model for WTE

system

4.1 Preliminary Costing A preliminary cost estimate is prepared for the 450 tpd waste to energy plant utilising a combined cycle power generating. Table 4 shows a cost comparison between the three waste conversion technologies: plasma gasification, incineration and conventional gasification technologies.

In determining the plant size, economies of scale are considered. The plant will serve the island; however consideration must be given to haulage cost to Beetham, Port of Spain on overall project economics.

Table 4. Cost Analysis for a 450tpd WTE Pilot Plant Using Plasma Gasification, Incineration and

Conventional Gasification Technologies

Plasma Gasifier Incinerator Conventional Gasifier

Waste capacity (tpd) 450.00 450 450

Unit power potential (MWe) 35.11 12.49 22.11

Calorific value for MSW (MJ/kg) 16.10 16.10 16.10

Calorific value for NG (MJ/m³) 38.00 38 38.00

Total unit price $ 127,528,089.89 $ 103,477,500.00 $ 120,493,800.00

Tippage Cost Scenario #1 $ 5.00 $ 5.00 $ 5.00

Scenario #2 $ 10.00 $ 10.00 $ 10.00

Scenario #3 $ 15.00 $ 15.00 $ 15.00

Scenario #4 $ 20.00 $ 20.00 $ 20.00

Plant operation time (360 days/yr at 24 hr/day) 8640.00 8640.00 8640.00

Total power production (Kwh/yr) 303,370,786.52 107,912,219.18 191,042,630.14

Debt service coefficient 0.1158 0.1158 0.1158

Operating and maintenance factor 0.05 0.05 0.05

Estimated Economic Life (years) 5 5 5

Present value of annual costs over the estimated economic life $ 65,081,039.17 $ 37,719,551.13 $ 61,491,250.47

Present value of annual revenues without tippage cost $ 91,416,538.34 $ 32,517,836.13 $ 57,568,021.37

Average annual net cash inflows without tippage cost $ 26,335,499.17 $ (5,201,715.01) $ (3,923,229.10)

Average annual net cash inflows with tippage cost applied

Scenario 1 - $5.00 $ 30,272,308.16 $ (1,264,906.02) $ 13,579.89

Scenario 2 - $10.00 $ 34,209,117.15 $ 2,671,902.97 $ 3,950,388.88

Scenario 3 - $15.00 $ 38,145,926.14 $ 6,608,711.96 $ 7,887,197.87

Scenario 4 - $20.00 $ 42,082,735.13 $ 10,545,520.95 $ 11,824,006.86


The capital costs for the plasma gasifier, incinerator and conventional gasifier to energy plants have been estimated at USD 127.528 million, USD 103.477 and USD 120.493 million, respectively (all based on supplier prices). Tippage costs are assumed to vary from USD 5.00 to USD 20.00 per ton. The analysis shows that the Plasma Gasifier is the most feasible thermochemical conversion technology. Without the application of the tippage cost, the payback period for the plasma gasifier plant is 5 years (see Table 5), and as the tippage cost increases the plant becomes even more profitable. The small amount of energy produced per unit ton of waste by the incinerator renders it the least attractive option.

Table 5. Payback Period for Each Plant at Selected Tippage Costs

Payback Period for Selected

Scenarios (Years) 5 - - No "tippage cost"

Scenario 3 - $15.00. 3 16 15 Scenario 4 - $20.00 3 10 10

If the waste is not converted to energy, additional storage space (landfills) will have to be sought. Given the rapid rate of increase in waste which is estimated to reach 4,033 tpd by 2020, a new landfill has become necessary. With an estimated rate of USD 179-538 per m2 the cost of just acquiring land space, the size of the Beetham landfill (i.e., 61 hectares) will be approximately USD 109 to 328 million. This cost does not include infrastructure for an engineered sanitary landfill such as liners, leachate and gas collection systems and methane destruction processes. Hence, the conversion of WTE is, economically, a very lucrative option for the management of waste.

5. Socio-Economic and Environmental Benefits In Trinidad and Tobago, the SWM systems especially in the urban areas are challenged to deal with the growing population concentration and lifestyles, which give rise to increasing levels of commercial, industrial and household waste. Such economic and social progress has placed increasing pressure on the natural environment, threatens human health and creates an opportunity for the reoccurrence of communicable diseases. This also calls for an improved understanding of the waste management problem. It is against this backdrop that the strategic intervention of a WTE initiative is

proposed. This will involve government, private sector and community initiatives for the infrastructure and mechanisms for collection, storage, processing, recovery, conversion and distribution of the energy products. Such integrated approach engenders a spirit of entrepreneurship, provides employment, and contributes to the social and economic development of the country.

The benefits for locating the WTE plant at Beetham are as follows: (i) Size: Largest facility comprising 61 hectares, land available for refuse receipt, processing and storage; (ii) Location: 2 km east of the capital Port-of-Spain and close proximity to major urban centers, generators of MSW (including East West Corridor, Diego Martin, and Trincity), accounts for more than 54% of the country’s waste, landfill capacity expected to be exhausted in a few years, unless measures are taken to reduce volumes destined for landfill; (iii) Existing Infrastructure: South of the Beetham Highway, well developed road infrastructure, minimise the impact from increased truck traffic. MSW will be delivered to the plant by truck, minimise queuing; and (iv) Industrial and commercial area (e.g., noise, dust, odor).

Thermal efficiency, in terms of energy recovery for electricity generation from the combustion process, production of fuel gases for energy production (e.g., boilers, heat engines, and fuel cells), synthesis gas for petrochemical manufacture and slag as a value added construction material from the gasification process are the saleable products from WTE plants. The use of MSW as a fuel will result in a reduced demand for natural gas for power generation, thus diverting the natural gas to the area of manufacturing more value-added products (e.g., iron and steel, ammonia, and methanol). Gasification will also yield synthesis gas: the building block for a synthetic fuels industry (e.g., dimethyl ether (DME), Fischer-Tropsch (FT) products, methanol, and ethanol etc), (Sunggyu, 2007).

The proposed plant can be configured to produce an array of energy products in ratios to suit local requirements, thus creating a new industry in the country which potentially can provide employment opportunities in recycling, recovery, maintenance, electricity generation and synthetic fuel manufacture. Plasma gasification over incineration has the added benefit that all of the organic material is fully converted to a fuel quality synthesis gas for use in combustion turbines coupled to electric generators or for chemical production. Plasma Gasification


systems have been reported to be more efficient for energy recovery, in terms of electricity generation. The temperature within the reactor reaches 2,700ºC, at which point molecular dissociation takes place. The pollutants that were contained in the waste such as dioxins, furans as well as pathogens are completely cracked into harmless compounds.

The production of carbon dioxide is also greatly reduced when using Plasma gasifiers. A simple gravimetric combustion analysis using stoichiometric equations was undertaken to estimate CO2 production from the conversion of 450 tpd of MSW from each of the three thermochemical processes. From Table 6, plasma gasification showed the greatest potential for reduced greenhouse gas (GHG) production by having the smallest CO2 emissions. Table 6. CO2 Emissions from the Three Thermo-Chemical

Conversion Technologies Feature Plasma

Gas Conventional

Gas Incineration

CO2 Emission (tpd)

62 188 565

Low CO2 Yes No No Stoichiometric Air

0.33 (sub) 1 1.8 (complete

combustion) Chemical Equations

3C + 2O2 → CO2 + 2CO

3C + 2O2 → CO2 + 2CO

C + O2 → CO2

Moreover, the use of waste for such purposes reduces the impact of methane emitted into the environment when organic waste decomposes in landfills. Plasma gasification saves on GHG, produces more energy and can therefore be considered “more green” than conventional gasification and incineration. 7. Conclusion It is imperative to address the problems of MSW in Trinidad and Tobago with appropriate technologies, as country’s landfills have already exceeded their capacities. From the comparative analysis of WTE technologies, it can be seen that the conversion of WTE using plasma gasification technology is a viable option to the problems facing the management of waste in Trinidad. Although the proposed WTE process may cost high initially, the wide ranging economical, social and environmental benefits far exceed such costs and essentially reduce the country’s carbon footprint. Therefore, this is a sustainable solution to the SWM challenges in

Trinidad and Tobago. Besides, a thermoeconomic analysis of the

proposed WTE process should be undertaken. Such analysis considers both the thermodynamic and economic implications for any energy conversion system. An optimum “green” WTE system can be designed based on a combinational analysis of presented approach and the results of thermoeconomic analysis.

References: AlterNRG (2008), Westinghouse Plasma Corporation,

Pennsylvania, USA. GORTT (2008), “Government of the Republic of Trinidad

and Tobago: New Waste Management Strategies Coming”,http://www.news.gov.tt/index.php?news=349, last accessed May 2009

Kreith, F.D.Y. (2007), Handbook of Energy Efficiency and Renewable Energy. Florida: CRC Press Taylor and Francis Group.

Mountouris, A., Voutsas, E. and Tassios, D. (2006), "Solid waste plasma gasification: equilibrium model." Energy Conversion and Management, Vol.47, No. 13/14, pp 1723-1737.

Ojolo, S. and Bamgboye, A. (2005), "Thermochemical conversion of municipal solid waste to produce fuel and reduce waste", Agricultural Engineering International: the CIGR Ejournal, Vol.VII ( Manuscript EE 05 006), pp.1-8

SWMCOL (1995), Report on Waste Qualification Exercise- Guanapo Landfill Site 1995, Beetham Landfill Site 1995 and Forres Park Landfill Site 1995, Solid Waste Management Company Limited. .

SWMCOL (2007), Site Data 2007 (Unpublished), Solid Waste Management Company Limited

Speight, J.G. (2008), Synthetic Fuels Handbook: Properties, Process and Performance. United States: McGraw-Hill.

Stehlı´k, P. (2009), "Contribution to advances in waste-to-energy technologies", Journal of Cleaner Production, Vol.17, No.10, pp.1-13.

Sunggyu, L.J.G. (2007), Handbook of Alternative Fuel Technology, Florida: CRC Press Taylor & Francis Group.

Wikipedia (2009), “Plasma Arc Waste Disposal”. http://en.wikipedia.org/wiki/Plasma_arc_waste_disposal, last accessed May 2009.

Biographical Notes: Kamel Singh is a Senior Instructor and Program Leader for the Bachelor of Applied Technology and Bachelor of Engineering in Applied Process and Utilities Technology Programs at the University of Trinidad and Tobago. He has eighteen years of industrial experience in the design

http://www.news.gov.tt/index.php?news=349

K. Singh et al.: Municipal Solid Waste to Energy: Potential for Application in Trinidad and Tobago

49

and construction of process plant, pressure vessel, storage tank, pipeline, offshore production facilities, welding engineering, quality control and maintenance management. He was the Fabrication Manager at Carillion Caribbean Limited (CCL) and worked on several construction projects in energy, marine and commercial building sectors. His research interests include - modern energy systems, engineering curricula development and machine design. Solange O. Kelly has fifteen years of postgraduate research and industrial experience in process optimisation, exergy analysis, exergoeconomic analysis, air-conditioning and manufacturing. She worked as a Research Assistant at the University of the West Indies and also at the Technical University of Berlin in the extended areas of energy systems. Her work on splitting

exergy destruction into endogenous and exogenous parts, received the “Best Student Paper Award” by the Advanced Energy Systems Division of the ASME, in 2006. She is presently with University of Trinidad and Tobago as an Assistant Professor Musti K.S. Sastry is presently with the University of West Indies as a Lecturer in Department of Electrical and Computer Engineering and Program Coordinator for Bachelor of Technology Program at the University of Trinidad and Tobago. He is a member of IET, UK and a senior member, IEEE, USA. His research interests include Energy Systems, Electrical Power and Engineering Education

A. Mwasha: Natural and Recycled Guanapo Quarzite Aggregates 50


Vol.38, No.1, October 2009, pp.50-56

Natural and Recycled Guanapo Quarzite Aggregates for Ready Mix Concrete

Abrahams Mwasha

Department of Civil and Environmental Engineering, The University of West Indies

St Augustine Campus, Trinidad and Tobago, West Indies; E-mail: [email protected]

(Received 29 April 2009; Revised 16 June 2009; Accepted 14 September 2009)

Abstract: Quarrying involves the removal of the harder aggregates from the ridges and mounds in the area, while fine aggregates left over are prone to weathering and erosion. This exacerbates the risk of landslides leading to serious environmental problems. Today, aggregates from recycling concrete are gaining importance because it protects natural resources and eliminates the need for disposal by using the readily available concrete as an aggregate source for new concrete or pavement subbase layers. Quality of the products containing recycled aggregates is often the source dependent. Rigorous monitoring and testing can broaden the use of recycled aggregates into applications. In this paper the author will analyse the physico-mechanical properties and micro-structural properties of recycled quartzite aggregates mixed with ordinary Portland cement. The result of this investigation can be used to explain the physical and mechanical behaviour of hardened concrete manufactured using recycled Guanapo Quartzite aggregates. Keywords: aggregates, cement, concrete, construction wastes 1. Introduction It has been confirmed that concrete is not an environmentally friendly material due to its destructive resources-consumption nature and severe environmental impact after its use. Today, Portland Cement Concrete (PCC) remains one of the major construction materials being utilised worldwide occupying 55-80% of concrete volume. Without proper alternative for aggregates in the future, the concrete industry globally will consume 8-12 billion tones annually of natural aggregates after the year 2010 (Mark, 2007). Aggregates which occupy at least three quarters of the volume of concrete play a major role in reducing shrinkage, bleeding and of course enhancing strength for medium and high strength concrete, according to Neville (1996).

In this paper, the compressive strength of cubes using varying grades of Recycled Aggregates (RA) were performed for different grades such as Low strength (LS) having compressive strength values below 30 MPa, Medium Strength (MS) having compressive strength values between 30 and 40, and High strength (HS) having a compressive strength greater than 40 MPa. The compressive strength of all

test cubes were performed according to BS 1881: Part 116 (BSI, 1983c). The manipulation of the water to cement ratio (w/c ratio) for a varied sample of recycled aggregate was conducted by randomly varying the amount of LS, MS and HS. Various w/c ratios (including 0.4, 0.45 and 0.5) were adopted in this work. 2. Quarry Industry in Trinidad and Tobago and

its Ecological Impact The Trinidad and Tobago (T&T) quarry industry comprises fifty-six (56) active quarries of which thirty-eight (38) are sand and gravel quarries. Total production from the quarry sector for year 2002 was approximately 5.3 million cubic meters. Of this production 3.4 million meters were sand and gravel. It is believed that a considerable amount of sand and gravel came from unlicensed quarry operations (Arvind, 2008).

The quarry operations, in Trinidad fall within the northern range of mountains, which are an extension of the Andean Mountains in the South America. This area has primeval tropical rainforests, renowned for their diversity of flora and fauna. Typically, the


rainforest includes over 2 300 plant species with 700 species of orchids, and provides a habitat to over 430 species of birds, 620 species of butterflies, 100 species of mammals, 70 species of amphibians and freshwater fish, and 70 species of reptiles (Shrivastava at el., 2009).

The movement of heavy masses of rocks is likely to destabilise the hill slopes and lead to further sliding of soil and loose masses rolling down the same. Landslides and topographical changes are interrelated with the effects on hydrology and watershed (see Figure 1).

Figure 1. Schematic view of slope instability caused by mining activities

3. Potential for the Use of Recycled Aggregates There is a need to find and supply suitable substitute for natural aggregates as soon as possible. Utilisation of recycled concrete wastes has been taking place for many years i.e. 42 million tonnes of construction and demolition waste (including concrete) was recycled in the United Kingdom (UK) in 2001 that is an increase of 382% since the early 90s. The use of primary aggregates for construction has decreased by 28% from 1989 to 2002. The use of recycled/secondary aggregates for construction has increased by 94% during 1989 to 2002. Though there is impressive increase in the use of recycled concrete in T&T, basically these recycled aggregates are used as fillers in road construction and in low-level applications due to impurities and defects associated with recycled aggregates (Mwasha and Mark, 2008).

According to ACI221R-87 (ACI, 1999), recycling of concrete for aggregates involves breaking, removing, and crushing existing concrete into a material with a specified size and quality. The

processing of demolition waste, so as to convert it into satisfactory aggregate free from contaminants is still being developed and there is no proper standard to be followed.

The strength, physical and chemical properties of natural aggregates depend entirely in the properties of the parent rock. The properties of recycled aggregates depend on both natural aggregates and hardened older cement paste surrounding them. The older cement paste may have a considerable influence on the quality of the concrete, either fresh or in the hardened state. Considering the nature of recycled aggregates, it is difficult to define a good recycled aggregate other than by saying that it is an aggregate from high strength concrete.

4. Methodology Recycled concrete used in this paper was derived from relatively young aged concrete (i.e., one to two years). In this paper, the properties of both fresh and hardened concrete using re-cycled quartzite aggregates from T&T were analysed. Four different tests were performed.

Firstly concrete cubes were manufactured and cured properly to attain 28 days strength. High strength quartzite aggregates and type-1 cement from Trinidad were used. These cubes were tested at varying water cement ratio. After 28 days, the hardened concrete cubes were crushed to determine their compressive strength.

Secondly the crushed blocked were further crushed and sieved. These aggregates were used to manufacture new concrete blocks using the same water/cement ratio (i.e., 0.4, 0.45 and 0.5). After curing for 28 days compressive Strength tests were performed.

Thirdly, mixtures of different aggregates from different water/cement ratios were used to manufacture and test the samples. Fourthly, the physical chemical methods were used to investigate the crushed samples.

5. Materials and Samples 5.1 Portland Cement The Portland cement used in this experiment was manufactured at Trinidad Cement Limited. The composition of typical cement used in this experiment is shown in Table 1. More detailed specification for this cement can be referred to the European Standards ENV 1974 (EN, 1992).


Table 1. The composition of Portland cement was used

<Insert Table 1 about here>

5.2 Water Natural (i.e. ordinary tap water) was used. Natural water in Trinidad is slightly acidic with pH value of 6.5. Portland Cement Concrete can be attacked by liquids with pH value below 6.5. According to Neville (1996), the attack is severe only at a pH below 5.5. It was found that the content of humic and organic acids was at minimum in the water used.

5.3 Natural Quartzite Aggregate in T&T Quartz is a very common mineral and it is a chemical compound of silicon and oxygen known as silicon dioxide (SiO2). According to Akhavan (2009), Quartz is usually classified in two groups

• Macro crystalline – This is the group of quartz that form crystals and has macroscopically crystalline structures.

• Crypto crystalline or microcrystalline – This group does not exhibit any visible crystals and has a dense structure. Quartz in its pure form is colorless but it can

have any colour if it is impure. The tenacity of quartz is brittle and is 7 on the Moh’s hardness scale. The Guanapo quartzite is a milky quartz which is defined as; “a crystalline quartz that is white and translucent to almost opaque due to numerous evenly distributed gas and/or fluid intrusions” (Akhavan, 2009).

The Quartzite aggregates used in this work were extracted from number of quarry sites in Valencia, Trinidad. These typical types of Quartzite can be classified as a non-foliated metamorphic rock. This is probably because these rocks were once exposed to high temperature conditions, but not to high directional pressure conditions. The parent rock for quartzite was probably a quartz-rich sandstone deeply buried and rising temperature fused the grains together forming highly strong aggregates with low

porosity. Most of Quartzite aggregate is located in the

foothills of the northern range and is normally overlain with 2-3 meters of heavy clay as suggested by (Suite, 1977). Guanapo is relatively pure forms of quartz (~ 99% quartz), the yellow brown colour of the Guanapo is a staining deposit of ferric oxide deposit. Suite (1977) pointed out that this surface deposit has moved over time into the micro cracks of the crystalline particles and in some cases becomes an inter-crystalline impregnation.

Guanapo aggregates are highly weather-resistant that it tends to have a sugary appearance, and when broken, the fractures cut through the sand grains, not around them as is with sandstone.

Chemical Compound % of total weight SiO2 22.06 CaO 65.39

Fe2O3 0.02 MgO 1.13 Al2O3 4.25 SO3 2.98

Na2Oeq 0.53 K2O 0.50 Na2O 0.20

Soundness test was carried according to ASTM C88-76 (ASTM, 1976). The specific gravity of these aggregates was 2.65 and the moisture contents were approximately 2.25%. The variations of moisture content in the mixes were adjusted accordingly, taking into account this increase in moisture so as to maintain specified water/cement ratios.

Figure 2 shows a texture of fractured Quantize Aggregate. The texture shown clearly indicates the possible interlock between aggregate and cement paste. Depending on the water cement ratio these spaces are filled with cement paste forming a stronger bond.

Figure 2. Natural Aggregate magnified x1000

5.4 Recycled Aggregate The recycled aggregates for this experiment were manufactured in laboratory using the above mentioned materials. The mixture ratio and curing process were monitored and recorded.

The cured concrete of the given mixes was crushed to a suitable size (passing the 20mm sieve but retained by the 10mm sieve). This was in an


effort to maintain a nominal size distribution for concrete production. Crushing was done by passing portions of hardened concrete through a Jaw crusher. Different batches of aggregate were done, all depending on the compressive strength of the concrete samples from which they were obtained. In this way, a batch of aggregate derived from high strength concrete was made.

The same process of generating specific grades of recycled aggregate was done to obtain batches of medium strength and low strength. Water Absorption, Relative density on an Oven-Dried (OD) basis, Relative density on a Saturated and Surface-Dried (SSD) basis, apparent relative density – Done according to BS: Part 2 (BSI, 1975) as shown in Table 2.

Table 2. Aggregate Test results including Specific

Gravity, Water absorption and different weight values

Aggregate Type

Weight in

Water (g)

Dry Wt (g)

SSD wt (g)

SG (OD)

SG (SSD)

Water Absorption

(%) LS 1413.2 2273.5 2415.9 2.27 2.41 6.26 MS 1445.9 2326.1 2446.1 2.33 2.45 5.16 HS 1267.6 2048.0 2156.3 2.30 2.43 5.29

Table 4. ACV values obtained for the RA GRADE mix Aggregate Strength

M1 (g)

M2 (g)

ACV (%) (=M2/M1x100)

Low Strength 2262.80 737.00 32.57 Medium Strength

2236.50 697.30 31.18

High Strength 2209.00 669.60 30.31

Average Crushing Value was done according to BS812 Part 110 (BSI, 1990). For the Average Crushing Value (ACV), the higher the value of the ACV number, the weaker the material as shown in Table 3. As expected, the ACV for HS RA was lower than the rest. The ACV for MS RA being lower than LS RA, thus concluding that the grade of the recycled aggregate affects the crushing capacity of the aggregate.

5.5 Grain Sieve Analysis Grain sieve analysis of natural aggregate and recycled aggregates were performed so as to arrive at a more accurate recycled aggregate size distribution as shown in Figure 3.

Figure 3. Grain size analysis of Aggregate

for coarse and fine aggregates 6. Mix Design and Block Fabrication The blocks were fabricated in steel moulds with internal dimensions of 150 x 150 x 150 mm. After mixing the fresh concrete about 3kg of materials were placed into the mould in three layers. All layers were compacted manually 35 times using 25 mm square steel rod punner as described in BS 1881: Part 108 (BSI, 1983a). Cubes were cured according to BS 1881: Part 111 (BSI, 1983b).

Table 4. Mix design for the RA MIX

Samples Mix Component 1 2 3

Cement (kg) 3.80 3.77 3.744 Water (kg) 1.521 0.927 1.872

Fine Agg. (kg) 7.61 7.88 7.7 Coarse Agg. (kg) 11.41 11.589 11.232

Total wt. (kg) 24.339 24.166 24.548 Water loss (kg) 0.636 0.645507 0.625622

w/c 0.4 0.45 0.5 7. Results and Discussion 7.1 Test Methods and Mode of Failure The mode of failure for the concrete using the recycled aggregate was relatively difficult in ascertaining as the general uniformity produced by using recycled aggregate complicated the specific mode of failure. The recycled aggregate itself is composed of coarse aggregate and mortar. When mixed with the other components to obtain the new concrete mix, the transition between old and new mortar may become less apparent. In this way, the meaning of aggregate failure (i.e., the failure of the


coarse aggregate) or bond failure (i.e., the failure due to the bonding between mortar and aggregate) changes slightly, as aggregate failure would encompass the failure of the coarse aggregate within the recycled aggregate, the failure of the bond between coarse aggregate and old mortar or the simultaneous failure of both coarse aggregate and mortar bond.

7.2 RA-NA Mix Compressive Strength Tests The maximum compressive strength achieved overall was for the (w/c = 0.4) mix 28 day result of 58.9 MPa. Compressive strength results for RA MIX (w/c = 0.5) after a period of 28 days showed a maximum of 53.2 MPa while NA (w/c = 0.5) strength results showed a maximum of 40.9 MPa. This is a 30% increase in compressive strength of the NA strength result. When comparing the (w/c = 0.5) RA MIX and the (w/c = 0.55) RA MIX, a discrepancy was observed. The general compressive strength of the (w/c = 0.5) RA MIX was lower than those of the (w/c = 0.55) RA MIX. The invariability of compressive strength when using recycled aggregate could be caused by high degree of absorption of cement gel into the older porous cement making the bonding more stronger hence high compressive strength. It was observed the 7-day compressive strength (w/c= 0.55) was greater than the 14-day compressive strength for both (w/c = 0.4 and w/c = 0.45) as shown in Figure 4.

Figure 4. NA - RA MIX Compressive Strength Results showing the compressive strength for the three mixes,

differentiated by the w/c ratio

The addition of the admixture was done so that the workability of the concrete mix would increase,

thus yielding results without negatively affecting the true result. This apparent need for admixture is as a result of high water absorption rates possessed by the recycled aggregate.

7.3 RA Grade Compressive Strength Tests

Results showed that the higher the grade strength of the concrete from which the recycled aggregate was derived, the stronger the resulting mix of concrete. HS RA showed a general greater compressive strength than that of MS RA in the range of 3.5 MPa (for the 7-day test) to 15.2 MPa (for the 28-day test). MS RA showed a greater compressive strength than that of LS RA by at the least 5.3MPa (for the 7-day test) to 13.6MPa (for the 14-day test). This allows for the hypothesis that for an increase in grade of recycled aggregate, the stronger the corresponding concrete mix. The highest compressive strength was obtained by the HS RA mix for its 28-day compressive strength of 54 N/mm2 which can very well be classified as High Strength NA concrete. Results for the concrete mix using NA showed that generally the NA mix had greater compressive strength than the LS RA mix, but generally weaker than the MS RA and HS RA mixes as shown in Figure 5. Grade of aggregate used is defined in the key to the right of the graph.

Figure 5. RA GRADE mix results 7.4 Micro-Structural Analysis The scanning electron microscope (SEM) was used to analyze the micro-structural nature of recycled aggregate (Wikipedia, 2008). The electrons interacted with the atoms that make up the sample


producing signals that contain information about the sample's surface topography. Magnification in a SEM could be controlled over a range of about 5 orders of magnitude from x25 or less to x 250,000 or more.

The samples were examined for definitive observation points, i.e. areas on the sample that were of interest. The samples were placed on a testing platform, and then coated with a gold mist for better absorption of the electrons in a vacuum sealed chamber as well as to prevent the accumulation of static electric charge on the specimen during electron irradiation. The sample was placed in the electron microscope chamber and a highly focused electron beam was directed towards the sample under observation. The interaction between the sample and electron beam produced signal that was detected and projected by the display. The bonding exists between the mortar associated with the recycled aggregate and that of the new mortar mixed with the recycled aggregate. Using electron beam microscope showed the separation between old mortar and new mortar. Examined was a layer approximately 200μm in depth of a different mortar than that of the rest of the sample. This displayed the approximate bond depth of the two samples. A line of weakness had formed a certain distance away from the bond area, similar to the failure experienced by glued surfaces, adhesion/ cohesion failure.

Figure 6 shows a line of failure/fracture, approximately 5 μm in thickness, the failure crack can be seen extending from the natural aggregate (represented by the darker color) through the mortor (represented by the grey color). This can cause premature failure in a concrete mix containing these recycled aggregates. While not being a general characteristic of recycled aggregate, it does not deny the fact that for a sample amount, certain individual aggregates may be faulty. This creates a somewhat random fault factor.

The general matrix of the concrete after relative curing showed the difference in color of the recycled aggregate to the new mortar which had adhered to it. This being said, a sample was taken so as to examine the definitive line of adhesion between the two, but upon closer examination, nothing was found regarding the definitive adhesion line. This would lend to the hypothesis that the old mortar acts just as the new mortar, in terms of the overall concrete matrix.

While not being a general characteristic of recycled aggregate, it does not deny the fact that for

a sample amount, certain individual aggregates may be faulty. This creates a somewhat random fault factor.

Figure 6 - Image of recycled aggregate. The magnified in the order of 1000X

The general matrix of the concrete after relative

curing showed the difference in color of the recycled aggregate to the new mortar which had adhered to it. This being said, a sample was taken so as to examine the definitive line of adhesion between the two, but upon closer examination, nothing was found regarding the definitive adhesion line. This would lend to the hypothesis that the old mortar acts just as the new mortar, in terms of the overall concrete matrix.

8. Conclusions and Recommendations When using recycled aggregate as coarse aggregate in the production of concrete, it can be recommended that using RA derived from medium or high strength concrete is a better choice than Natural aggregate when comparing compressive strength. RA derived from low strength concrete generally has a lower compressive strength than NA in concrete mix, but still can be used to some degree but may not be economically feasible.

The invariability of using a mixture of strengths of aggregate can lead to variance in compressive strength as shown in the concrete mix containing different strengths of concrete. This invariability may be accounted for with the analysis of the specimens shown under the electron microscope having lines of weaknesses.

A. Mwasha: Natural and Recycled Guanapo Quarzite Aggregates

56

For concrete mix containing RA with a (i.e., w/c < 0.5), it would require the addition of admixture. It is because the mix would become far unworkable for reliable results to be obtained. This inclusion of admixture, including analysis on cost to volume ratios involving admixture should be done.

What should be taken into consideration is the size of recycled aggregate used in the concrete mixes. Normally, particle sizes should not be greater than 25mm, so as to ease the action of compacting, nor smaller than 10mm. A stricter size distribution regime can be assessed where the size of recycled aggregate components can be tested for their compressive strength in concrete mixes.

It was observed in the electron beam microscope analysis that for a specific specimen, a fracture line was observed. A general aggregate test involving the influence of the somewhat randomness of structure of the recycled aggregate should be done.

References: ACI (1999), ACI 221R-87: 1999 - Guide for use of normal

weight aggregates in concrete, ACI Manual of concrete Practice (Part 1). Materials and general properties of concrete, Detroit Michigan, 23 pp

Akhavan, A.C. (2009), The Quartz; available at: http://www.quartzpage.de/index.html (Retrieved 2009)

Arvind, W. (2008), Major Challenges Affecting the Aggregates Industry of Trinidad and Tobago, MSc Thesis (unpublished), Department of Civil and Environmental Engineering, The University of West Indies, Trinidad and Tobago, West Indies.

ASTM (1976), ASTM C88-76. Determination of Soundness Test (sodium sulfate solution), American Society for Testing Materials

BSI (1975), BS: Part 2: 1975 - British Standard Methods for Sampling and Testing of Mineral Aggregates, Sands and Fillers, The British Standards Institution, London.

BSI (1983a), BS 1881: Part108: 1983. Methods of making test cubes from fresh concrete, The British Standards Institution, London.

BSI (1983b), BS 1881: Part111: 1983. Methods of normal curing of test specimens (20 degrees centigrade method), The British Standards Institution, London.

BSI (1983c), BS 1881: Part 116: 1983 Methods of determining compressive strength of concrete cubes, The British Standards Institution, London.

BSI (1990), BS 812: Part 110: 1990 - Methods for Determination of Aggregate Crushing Value, The British Standards Institution, London.

EN (1992), European Standard ENV [1974]

Mark, J. (2007), Potential for the Use Recycled Aggregates in Trinidad and Tobago, Research project. The University of West Indies, Trinidad and Tobago, West Indies

Mwasha, A. and Mark, J. (2008), “Potential for the use of recycled aggregates in Trinidad and Tobago”, Quelle: Construction in Developing Economies; available at: http://www.baufachinformation.de/publikationen.jsp?s=Aggregat

Neville, A.M. (1996), Properties of Concrete, Fourth Edition, John Wiley & Sons, London

Shrivastava, G.S., Kanithi, V., Mwasha, A., and Rao, D. S. (2009), Quarry Operations and the ASA Wright Nature Centre: A Report on Site, The University of West Indies (unpublished), Trinidad and Tobago, West Indies

Suite, W.H. (1977), A Study of Melajo and Guanapo Aggregates and the Properties and Behaviour in the Fresh and Hardened States of Concrete Made with These Aggregates, The University of the West Indies, Trinidad and Tobago, West Indies.

Wikipedia (2008), Scanning Electron Microscope, available at: http://en.wikipedia.org/wiki/Scanning_Electron_Microscope

Biographical Notes: Abrahams Mwasha is presently a lecturer in structural engineering of the Department of Civil and Environmental Engineering at The University of West Indies, St Augustine Campus, Trinidad and Tobago, West Indies. He obtained his PhD in Wolverhampton, England England, Kandydata Nauk (min) equivalent to PhD in Kharkov Academy of Municipal management, Ukraine (KAMM). Previously, Dr. Mwasha was a Resident engineer at the Ministry of Education Tanzania where he was involved in the Construction of Vocational training centre, Morogoro, Tanzania (World Bank project), Extension of Sokoine University, Morogoro, Tanzania, Extension and maintenance of several educational infrastructures in Tanzania, and in the Construction of Mbeya Technical College. He also served as a Lecturer at Stourbridge College and Wolverhampton University in England. Dr. Mwasha was the first prize winner of the BIZCOM social enterprise award, organised by the MERCIA Institute of Enterprise for the idea of "Novel and Sustainable Technology". His research interests include Problematic soils (expansive, collapsible, soft soils), Ground reinforcement, Vegetable fibres, Slope stability, and Wastes management.

V. Seecharan et al: Laboratory Scale Production of Biodiesel from Used Vegetable Oil 57


Vol.38, No.1, October 2009, pp.57-65

Laboratory Scale Production of Biodiesel from Used Vegetable Oil

Videsh Seecharana, Yamani RamnathbΨ and Rodney R. Jagaic

The University of Trinidad and Tobago, Pt. Lisas Campus, Esperanza Road,

Brechin Castle, Trinidad & Tobago, West Indies aE-mail: [email protected]

bE-mail: [email protected] cE-mail: [email protected]

Ψ Corresponding Author (Received 30 April 2009; Revised 22 July 2009; Accepted 25 September 2009)

Abstract: Petroleum has been the fuel of choice for the 21st century. However, due to its high consumption rate, the reserves are fast dwindling and it is necessary to identify an alternative energy source to supplement our conventional fuel. The use of waste cooking oil to produce biodiesel has generated much interest since it makes use of waste which would have been discarded otherwise. As well, the biodiesel contributes less to global warming and contains less contaminant in its emission owing to the renewable nature and organic origin of the precursor vegetable oil. This paper seeks to ascertain whether a generic trans-esterification reaction procedure can be used for different sample types. Refined soybean oil was subject to the same experimental procedure as the recycled cooking oil and the product volume yield of each sample type was compared to theoretical data found for soybean oil. It was found that in this experiment, the recycled oil had a lower yield (48.4%) than the refined oil (78.9%) when compared to the theoretical yield (98%). A significant amount of emulsion was observed in both samples more so in the recycled oil than the refined oil. This was attributed to improper pre-treatment of the recycled sample, incompleteness of the reaction as well as ineffective washing technique. A number of generic procedures are internationally available for the conversion. There are no known published articles that describe the optimised conditions to produce biodiesel on a commercial level employing used cooking oil in Trinidad and Tobago. This investigation is probably a first attempt at a laboratory scale of biodiesel production in Trinidad and Tobago, which is undergoing many changes in developing these optimised conditions. Keywords: Petroleum, biodiesel production, recycled oil, Trinidad and Tobago 1. Introduction Internationally, the use of biodiesel as an appropriate source of energy has moved away from research and development into marketing as a commodity in regions where there is little or no petro diesel, creating a significant cottage industry. Locally in Trinidad, we still exhibit heavy dependence on the petroleum reserves on which our economy is based. Hence, in addition to satisfying the engine fuel specification, biodiesel will have to compete with the petro diesel to sustain its niche in the fuel market. Although biodiesel cannot replace petro diesel, it is justified as a supplementary fuel. According to Gerpen (2005), • it decreases but not eliminates the country’s

dependence on petroleum. • it is renewable and does not contribute to global

warming due to its closed carbon cycle. • the exhaust emission of carbon monoxide, un-

burnt hydrocarbons and particulate emission are much lower in biodiesel than petro diesel.

• blends of biodiesel with petro diesel improve the fuel quality of petro diesel with poor lubricating properties. Historically, vegetable oil partially or fully

refined and of edible grade quality has been used as feedstock for biodiesel. This introduces direct competition for edible oil especially in the face of international food scarcity, and thereby limiting production by the high cost of the raw material. As stated by Haas (2005), a direct implication of this is that the cost of the raw material required to produce the biodiesel could be greater than the finished cost of the petro diesel produced by its competitor.


Despite this, refined soybean oil was used as the starting material to produce biodiesel. It is because the conversion rate of pure triglyceride to Fatty Acid Methyl Ester (FAME) is high and the reaction time is short. This data was used as a baseline comparison to determine the effectiveness of our procedure when compared to empirical values for soybean oil.

In order to make the process economically feasible, the need to identify a low cost lipid feedstock which can be converted chemically into biodiesel is imperative. It is in this context waste cooking oil (i.e., recycled oil) has found much use since a cheaper raw material lowers the cost of production thereby increasing its competitiveness in the fuel market. In addition, as quoted by Gerpen (2004a, b), the cost of disposal of the waste oil and treating of the oily waste waters adds to its desirability as the precursor to biodiesel.

However, a limitation of the trans-esterification is the high concentration of free fatty acid present in recycled oil. These will increase the tendency towards saponification in preference to esterification presenting significant challenge in separating the biodiesel from the glycerol. In addition during the water wash phase formation of gels and foams may occur.

It is suggested by Wang et al. (2007) that 0.5 weight % or less free fatty acid is acceptable when using refined vegetable oil. For waste vegetable oil with a high free fatty acid concentration, an acid pre-treatment is required to esterify the free fatty acid prior to reacting with the base catalyst. This pre-treatment increases the cost of production since excess alcohol is required. In addition, high pressure is recommended necessitating use of stainless steel equipment. To circumvent this, the recycled sample was neutralised with excess sodium hydroxide prior to reacting with the methoxide. 2. Chemical Reaction Bio-diesel production involves many chemical processes despite the fact that its method of production is described as being relatively simple. There are three methods by which Bio-diesel can be produced. These are:

1) Base catalysed trans-esterification of the oil with the alcohol,

2) Direct acid catalysed esterification of the oil with methanol, and

3) Conversion of the oil to fatty acids and then to alkyl esters with acid as a catalyst. For the purpose of this study, the choice of

technique was a base catalysed reaction commonly referred to as a trans-esterification reaction. This selection was the most economically feasible for reasons listed below.

1) Low temperature (150F) and pressure (20 psi) processing,

2) High conversion (98%) with minimal side reactions and reaction time,

3) Direct conversion to the methyl ester with no intermediate steps, and

4) Exotic materials for construction are not necessary. It is planned that the Bio-diesel produced at

the laboratory of the University of Trinidad and Tobago (UTT) will be derived mainly from recycled cooking vegetable oils. In addition, refined vegetable oil is used in this research as a baseline quality control sample to ascertain the effect of cooking on the conversion and quality on the final product and hence its suitability for use in the diesel engine. Vegetable oils comprise of a major component known as triglycerides (see Figure 1). Triglycerides are esters of glycerol with long-chain acids, commonly called fatty acids.

Figure 1.Chemical Structure of Triglycerides Source: Abstracted from Gerpen (2005)

Biodiesel is obtained by trans-esterifying the

triglycerides with methanol. An example of this trans-esterification reaction is indicated in Figure 2. The R corresponds to various fatty acid groups. Also from the products produced, the mixture of fatty ester is referred to as the Bio-diesel.

Figure 2.The Trans-Esterification Reaction Source: Abstracted from Gerpen (2005)


The above reaction is a reversible reaction and

can be forced in the forward direction by increase in the volume of the reactants. From the above equation, it can be seen that stoichiometrically 3 moles of alcohol are required per mole of triglyceride. For trans-esterification to occur, usually 6 moles of alcohol are added for every mole of triglyceride as stated by Meng et al. (2008). This additional alcohol per triglyceride shifts the equilibrium reaction in the direction of the products being formed producing a percentage yield of 98.0 %. The excess alcohol is then recovered and recycled into the process to minimise operating costs and environmental impacts. 3. Materials and Experimental Methods The primary raw material for the bio-diesel could either be vegetable oil (i.e., used or virgin) or animal fats or recycled greases. For the purpose of this research vegetable oil refined and recycled was used. This selection was dictated by:

1) The availability of the raw material as there is several fast food outlets in Trinidad and Tobago.

2) The viscosity of the fluid. Methyl esters formed from the vegetable oil has a lower viscosity than the oil from which it was derived and hence this would minimise the operational problems in the diesel engine such as poor quality fuel injection and the formation of deposits.

3) The exhaust gases produced from the combustion of bio-diesel contains less pollutant when produced from vegetable oil. This is due to the low sulphur content present in other feedstock sources.

The other reactant required for this reaction is the alcohol. Many different alcohols can be used, including ethanol, Isopropanol and butanol to name a few. The popular choice of alcohol used is methanol because:

1) The water content of methanol is lower relative to other alcohols.

2) Methanol has a flash point of 10ºC which it makes it safer to work with.

3) It can be easily recycled. Water is detrimental to the trans-esterification

process since it results in poor yields and high levels of soap, free fatty acids and triglycerides in the final fuel. Other alcohols used are hygroscopic and are capable of absorbing water from the air as stated by

Gerpen (2005). In addition to being a chemically suitable reactant, the selection of methanol for use as the alcohol of choice was further dictated by:

1) Cost of alcohol, 2) Amount of alcohol needed for the reaction, 3) The ease of recovering and recycling the

alcohol, and 4) Global warming issues.

A catalyst is required to initiate the trans-esterification reaction. Catalysts that can be used for this trans-esterification reaction includes base, acid or enzyme. The acid catalyst is not used as they are generally considered to be too slow for industrial processing. Enzyme catalyst is not used for this reaction process, on a commercial basis, as the costs are too high, rate of reaction is slow and yields to methyl esters are typically less than 98.0% required for fuel grade. By default, the major reason for using the base catalyst is that it is able to increase the rate of the reaction which is in accordance with de Oliveira et al (2005), when compared to the other catalyst. In this research, sodium hydroxide was the catalyst of choice. 4. Experiments and Results A One Litre (1L) sample size of recycled oil was heated to 60ºC to remove any free water and allowed to settle for 24 hours prior to reacting with sodium methoxide. This was not necessary for the refined soybean oil since the water content was negligible. In order to decrease the saponifiction tendency in the recycled oil, excess sodium hydroxide was added to the sodium methoxide to neutralise the free fatty acid present. This was not necessary with the refined oil sample. Both samples were reacted using ambient conditions (i.e., temperature -25ºC and atmospheric pressure).

The refined sample was placed into a separatory funnel and mixed with an appropriate volume of sodium methoxide and shaken vigorously for 15 minutes and allowed to settle overnight. The recycle sample after its pretreatment was mixed, with an appropriate volume of sodium methoxide containing excess sodium hydroxide, in a conical flask using a magnetic stirrer for 30 minutes and left to settle overnight.

The crude biodiesel was separated from the glycerol and was washed three times with warmed water (40ºC) in a pre-cleaned separatory funnel to remove the water-soluble contaminants. The volume of the washed biodiesel was measured and recorded. Table 1 shows the volume of product collected.


Table 1. Volume of Product Collected

Volume Collected Refined

Vegetable Oil Recycled

Vegetable Oil

Volume of Unwashed Bio-diesel/mL

1066 1065

Volume of Bio-diesel after wash/mL Experimental Percentage yield/%

815

78.9

500

48.4

Volume of Glycerol/mL Experimental Percentage yield/%

110 8.8

84 6.72

For theoretical purposes, assuming soybean oil

consists of pure triolein (a triglyceride in which the fatty acid chains are oleic acid). The transesterification reaction is illustrated below: O

//

CH2-O-C-(CH2)7CH= CH (CH2)7CH3

O

//

CH-O-C-(CH2)7CH= CH (CH2)7CH3 + 2 x 3 CH3 OH

NaOH

CH2-O-C-(CH2)7CH= CH (CH2)7CH

//

O Triolein Methanol

O

//

CH3-O-C (CH2)7CH=CH (CH2)7CH3 + CH2-OH + XS CH3 OH

CH-OH

Methyl oleate CH2-OH

(Bio-diesel) Glycerol Calculating the relative molecular mass per compound in the equation, the following were obtained:

Triolein: 885.46g Methanol: 6 x 32.04 = 192.24g Methyl oleate: 3x 296.50 = 889.50 Glycerol: 92.10g.

Using Volume/L = mass (kg) / density (kg/L), the theoretical volumes per litre of refine oil was calculated as given in Table 2 For refined oil,

Actual Percent yield of bio-diesel = 815/1033 x 100% = 78.90 %.

For recycled oil, Actual Percent yield of bio-diesel = 500/ 1033 x 100 = 48.40 %

Table 2. Comparison Between Theoretical and Experimental Yields Using Soybean Oil

Compound

Mass/kg

Density

kg/L

Volume

/L

Theoretical Volume

/mL Per litre of

oil used.

Experi-mental

Volume/ mL

Per litre of oil used.

Triolein

0.8854

0.8988

0.9851

1000.0

1000.0

Methanol

0.1922

0.7914

0.2429

246.5

250.0

Methyl oleate

0.8895

0.8739

1.0178

1033.0

815

Glycerol

0.0921

1.2613

0.0730

74.1

110

Excess methanol

0.09612

0.7914

0.1214

123.0

Did not quantify.

5. Discussions The Bio-diesel produced experimentally was generated using two types of oil- Refined and Recycled. A product yield of 78.9% was generated from the refined oil whilst 48.4% was generated from the recycled oil. In addition to the above finding, other findings emanating from the experiments include: Large amounts of colloidal suspension was formed due to vigorous shaking and incompleteness of the reaction, hence leading to a loss of product; Large amounts of emulsion was formed which resulted in the further lengthen of time for obtaining the final product. Ideally, the reaction is broken down as follows: 1) Preparation of the methoxide. Sodium hydroxide acts as a base catalyst in this reaction and is needed to initiate the reaction since methanol is sparingly soluble in the oil phase. The methoxide ion thus formed promotes an increase in solubility as stated by Gerpen et al. (2004a, b) which allows the reaction to occur at a feasible rate. Basically, the sodium hydroxide reacts with the methanol to form the sodium methoxide as illustrated in the reaction below. It is a simple mixing of 2 reagents.

2) Reaction This is the combining of the methoxide ions with the warmed oil samples (i.e., refined or recycled). This is done in a closed system to prevent loss of the alcohol and at a low temperature to increase the speed of the reaction. This mixing is critical since improper mixing can result in incomplete substitution of the triglyceride and thus formation of


the dreaded mono and di-glyceride compounds. It is recommended that thorough mixing at the start of the reaction is essential to increase the contact between reactants. Towards the end of the reaction, a slower agitation is desirable to effect better phase separation of the immiscible products, glycerol and bio-diesel (Gerpen et al., 2004a, b). It is this CH3 O- ion that attacks the ester components in the glycerol molecules forming the bio-diesel as is illustrated below. 3) Separations of Products The trans-esterification reaction of oil with alcohol yields glycerin and bio-diesel. It is imperative to note that this is a reversible reaction and for it to proceed in the direction of the bio-diesel the alcohol is in excess. Upon settling, two immiscible phases are observed viz. the glycerine phase being denser settled to the bottom and is simply drawn off from the bottom of the separatory funnel whilst the pale amber colored crude biodiesel is retained to remove the water soluble contaminants. 4) Methyl esters Wash After the reaction is completed, the majority of catalyst and soap is contained in the glycerol. However, there are small concentrations of these water soluble contaminants resident in the bio-diesel and should be removed (Gerpen et al., 2004a, b). The crude bio-diesel is purified by washing gently with warm water to remove residual catalysts and soaps and then dried by warming. The final product should be a clear amber yellow liquid with a viscosity similar to petro diesel.

For the purpose of this research, refined oil in this experiment refers to store bought vegetable oil that was not used in any way, whilst recycled oil refers to vegetable oil that has undergone some level of heating via cooking. The experimental procedure 1 (see Appendix 1) details the exact steps that were used in the conversion of oil into bio-diesel and was done using a 1L sample size of refined vegetable oil.

Most researchers used a combination of a blender/ processor for thorough agitation of the oil

with the methoxide. In this experiment, a 2L separatory funnel was used, and agitation was done manually. It is theorised, the rougher the agitation, the better the combining of reactants and the higher the quality of the product since the reaction would have gone to completion. The main drawback to this method was that a 1L sample size was too heavy to shake vigorously for 15 minutes continuously. Hence, the reaction may have been incomplete and resulted in emulsion formed during the water wash phase.

The second trial was performed using recycled vegetable oil (see Figure 3 and Procedure 2 of Appendix 1). A 1L sample size was also used here. The difference in the methods allows for the possible presence of water and free fatty acids in the recycled oil arising from high temperatures. It is necessary to limit the water content, as soap may form in preference to bio-diesel. Besides, the free fatty acids should be neutralised before the reaction is initiated. This is due to the increased feasibility of the saponification reaction in preference to the trans-esterification reaction. If this is not done as stated by Gerpen et al. (2004a, b), the base catalyst will react with the free fatty acids to form soap and water very fast and goes to completion even before the trans-esterification begins.

Figure 3. Transesterification Using Recycled Oil

1 Litre used oil + sodium meth oxide

In addition, it is necessary to limit the acid

content in the final product since this may have adverse effects on the engine. It was noted that upon heating the recycled oil and its subsequent cooling for the water molecules to settle, the oil has re solidified and necessitated reheating again. As a result the water may not have been eliminated from the reaction vessel.

Another modification to the original procedure 1 was in the mixing of the reactants, in trial 2. In this case, instead of using the separatory funnel, the oil was stirred in a 2L conical flask using a magnetic bar. As the procedures outlined, the sample was


stirred for 30 minutes prior to placing into the separatory funnel for separation into glycerin and biodiesel.

The results show that comparable volumes of Bio-diesel were collected in both instances (see Table 2). At this point, the bio-diesel is in a crude form since it contains the excess methanol and other water soluble impurities (see Figure 4), namely soaps, small amounts of sodium hydroxide, and some free glycerine. As a result, it is necessary to water wash the crude bio-diesel to remove them.

Figure 4. Purification of Bio-diesel from Recycled Oil

Figure 5 shows the comparison of bio-diesel formed from refined and recycled vegetable oil. The water washing process involves adding warmed (40ºC) water to the crude bio-diesel in the separatory funnel. Shake them vigorously and allow settling into an organic phase (i.e., bio-diesel) and the aqueous phase. The contaminants would have been concentrating in the aqueous phase, so that three successive washings would significantly reduce the level of contaminants.

In actual practice, the first washing of both bio-diesel samples (i.e., from refined and recycled oil), a colloidal solution was observed. This took about three days to break (i.e., upon standing without agitation). The volume of emulsion formed with the recycled oil was more significant than that of the refined oil. With the refined oil, after three successive washings, distinct aqueous and organic layers were observed. With the recycled oil, after the third washing, there was clearly a visible third layer of emulsion formed (see Figure 6).

The presence of emulsion in the water-washing phase is a clear hint that the bio-diesel is of poor quality. It indicates the presence of mono and diglycerides, as well as glycerine in the bio-diesel hence the difficulty in separating the layers and the formation of the emulsion. These mono and diglycerides are formed owing to the incompleteness of the reaction and are not washed out from the

product. A high level of these unreacted glycerides and vigorous shaking yields the dreaded emulsion.

Figure 5. Comparison of Bio-diesel Formed from

Refined vegetable oil

Recycled vegetable oil

Bio-diesel

Glycerol

Bio-diesel

Emulsion

Crude Biodiesel prior to washing

Water washing of the crude washing

Refined and Recycled Vegetable Oil

Refined vegetable oil

Recycled vegetable oil

B io-diesel aqueous phase

Emulsion aqueous phase

Figure 6. Third Water Wash

The result shows that the refined oil yielded a volume of 815mL Bio-diesel and the recycled oil produced a volume 500 mL biodiesel after the washing was completed (see Table 1). This discrepancy in volumes produced is a direct result of the higher emulsification with the recycled oil which can be correlated to the insufficient mixing of the reactants resulting in an incomplete reaction. The mere presence of emulsion in both bio-diesel samples is indicative of incomplete reaction. In this case, the recycle oil was the one with the more unsubstituted glycerol.

It was found from the comparison between the theoretical and experimental yields, using the refined soybean oil as the precursor (see Table 2). The first trial using the refined oil had a yield of 78.90%. This may be attributed to:

1) Vigorous shaking was done, but not for a long enough time in mixing the reactants.

2) Any effect of temperature on completion of reaction was not considered, and

3) Too vigorous shaking during water washing led to emulsion formation and loss of product.

The second trial using the recycled oil had a yield of 48.40 %. This may be attributed to:

1) Presence of water molecules in the original


sample used. 2) Incomplete neutralisation of the free fatty

acids. 3) Mixing was not vigorous enough and was not

long enough for the reaction to go to completion.

4) Any effect of temperature on completion of reaction was not considered.

5) Too vigorous shaking during water washing led to emulsion formation and a significant loss of product.

From literature data, Trilinolein was the component of choice as a standard glycerol compound since the major free fatty acid in soybean oil is linoleic acid. Hence, in its simplest form the triglyceride most prevalent would be Triolinolein (where the fatty acid would be Linoleic acid).

Using the density data and relative molecular mass for each compound, the theoretical yield of biodiesel per ratio of reactants used was calculated (See Table 2). Based on this, it is expected that 1,000 ml of oil would produce 1,033 mLs of Biodiesel. The percentage yield of biodiesel actually produced was calculated using this expected value. Table 1 illustrates this data. The refined oil had 78.9% yield, whilst the recycled oil sample had a yield of 48.4%.

Research has shown a 98% conversion is possible using the trans-esterification reaction to produce biodiesel. Comparing the experimental yield obtained to this theoretical data implies a lot more work is needed to optimise the reaction conditions to improve the product yield.

It is recommended that future trials should consider the following:

1) Use of a smaller sample size. 2) Using a temperature close to the boiling point

of the alcohol. 3) Use vigorous shaking for longer periods. 4) Use bubble washing as an alternative

technique for removing the water soluble contaminants.

5) Ascertain quality of product by testing per ASTM D-6751.

6) Use pre-treatment for recycled oil. 6. Conclusion The base catalysed trans-esterification reaction for biodiesel production is often the method selected owing to its lower cost of production and simple processing conditions yielding higher conversion of oil to biodiesel. Research has shown with these conditions, a 98% yield of biodiesel is possible. It

was noted the refined soybean oil had a 78.9% yield, whilst the recycled cooking oil had a 48.4% biodiesel yield. In order to improve the yield quantity, it is encouraged to implement the recommendations made. Further to this for the recycled cooking oil, some level of pre-treatment is required prior to reacting with the sodium methoxide. Hence, the procedure for trans-esterification can be used for both the refined and recycled oils, but an appropriate pre-treatment is necessary for the recycled oil using clearly define optimised conditions. References: de Oliveira, D., Di Luccio, M., Faccio, C., Rosa, C.D.,

Bender, J.P., Lipke, N., Amroginski, C., Dariva, C. and de Oliveira, J.V. (2005) “Optimisation of alkaline trans-esterification of Soybean Oil and Castor oil for Biodiesel production”, Applied Biochemistry and Biotechnology, Humana Press, 999 Riverview Drive Suite 208 Totowa, pp. 553-560.

Gerpen V.J. (2005), “Biodiesel processing and production”, Journal of Fuel Processing Technology, Vol.86, No.10, pp. 1097-1107

Gerpen V.J., Shanks, B., Pruszko, R., Clements, D. and Knothe, G. (2004a), “Types of biodiesel production processes”, in Gerpen V.J. (ed), Bio-diesel Production Technology, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado, pp.30.

Gerpen V.J., Shanks, B., Pruszko, R., Clements, D. and Knothe, G. (2004b), “Soap and catalyst measurement”, “Fuel property measurement” and “Fatty acid composition, and total and free glycerol”, in Gerpen, V.J. (ed), Bio-diesel Analytical Methods, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado, p.31, 37, and 63.

Haas, J.M. (2005), “Improving the economics of biodiesel production through the use of low value lipids as feedstock: vegetable oil soap stock”, Journal of Fuel Processing Technology, Vol.86, No.10, pp. 1087-1096.

Meng, X., Chen, G. and Wang, Y. (2008), “Biodiesel production from waste cooking oil via alkali catalyst and its engine test”, Journal of Fuel Processing Technology, Vol.89, No.9, pp.851-857.

Wang, Y., Young, W., Ou, S., Liu, P. and Zhang, Z. (2007), “Preparation of biodiesel from waste cooking oil via two-step catalysed process”, Journal of Energy Conversion and Management, Vol.48, No.1, pp.184-188

Appendix 1: PROCEDURE 1: Procedure for BIO-DIESEL Conversion from Refined Vegetable Oil.

1.1. Weigh accurately 3.5 g of Sodium Hydroxide into a


500mL HDPE wide mouth container. 1.2. Measure and carefully add 200mL of methanol to

the container using a glass funnel. Place a magnetic bar into the solution and mix slowly until all the sodium hydroxide pellets are dissolved. Remove the bar and label this SODIUM METHOXIDE.

1.3. Preheat the 1 Liter of new oil to 55ºC and pour into a 2L separatory flask.

1.4. Carefully pour the prepared Sodium methoxide into the oil.

1.5. Shake the flask vigorously for 15 minutes taking care to vent the pressure that is building up in the separatory funnel.

1.6. Cap and label the container and allow settling for 12-24 hours. (As the mixture cools it will contract and you might have to let some more air into the bottle later).

1.7. Two immiscible layers will be noted in the funnel. The darker colored glycerin settles to the bottom of the container. This is collected into a pre-cleaned jar. The bio-diesel is the clear supernatant which is collected into a clean, dry glass jar. DO NOT TRANSFER ANY OF THE GLYCERINE LAYER INTO THE BIO-DIESEL.

1.8. Transfer the bio-diesel into a new 2L separatory funnel; add half a liter of warm tap water. Cover the funnel and shake vigorously, taking care to vent the funnel initially. Allow to equilibrate for three hours. Bleed the water through the tap, retaining the bio-diesel in the funnel.

1.9. Repeat the above steps 2 more times. 1.10. When the bio-diesel is clear, heat gently to 48ºC

and allows cooling. This will evaporate off the remaining water.

PROCEDURE 2: Procedure for BIO-DIESEL Conversion from Recycled Vegetable Oil.

2.1 Heat 1.0 L of the waste oil slowly to 60ºC and maintain this temperature for 15 minutes and allow settling for at least 24 hours.

2.2. Pipette the supernatant from the top 90% of the vessel.

2.3. Determine the acid content via titration using 0.1% w/v solution of sodium hydroxide and phenolphthalein indicator. 1) Measure 1g of sodium hydroxide and dissolve in

1L of distilled water. Label the container 0.1% NaOH.

2) Dissolve 1.0ml of the waste oil in 10mLs of isopropyl alcohol in a conical flask

3) Place the conical flask in a hot water bath stirring until the oil is completely dissolved in the alcohol

4) Add 2 drops of phenolphthalein indicator to the contents in the flask.

5) Titrate the contents in the flask with the sodium

hydroxide solution from the burette whilst continuously swirling. Add NaOH slowly until a magenta color is observed and holds for 15 seconds

6) Record the titre volume of NaOH used for neutralisation of the Free Fatty Acid (FFA)

2.4. Add the titre value from the above step to the 3.5 g NaOH required for conversion of 1L of fresh oil to produce the total mass of NaOH required for reacting with the 200mL methanol.

2.5 Weigh accurately the total mass (3.5g + x mL) of Sodium Hydroxide into a 500mL HDPE wide mouth container.

2.6 Measure and carefully add 200mL of methanol to the container using a glass funnel. Place a magnetic bar into the solution and mix slowly until all the sodium hydroxide pellets are dissolved. Remove the bar and label this SODIUM METHOXIDE.

2.7 Preheat the 1 Liter of new oil to 55ºC and pour into a 2L conical flask.

2.8 Carefully pour the prepared Sodium methoxide into the oil.

2.9 Place the conical flask onto a magnetic stirrer and adjust the stirring rate to prevent splashing. Start with a low speed and increase slowly.

2.10. Stir for 20 – 30 minutes, or longer. 2.11 Pour the mixture from the conical flask into a 2L

separatory funnel. Cap and label the container and allow settling for 12-24 hours. (As the mixture cools it will contract and you might have to let some more air into the bottle later).

2.12 Two immiscible layers will be noted in the funnel. The darker colored glycerin settles to the bottom of the container. This is collected into a precleaned jar. The bio-diesel is the clear supernatant which is collected into a clean, dry glass jar. DO NOT TRANSFER ANY OF THE GLYCERINE LAYER INTO THE BIO-DIESEL.

2.13. Transfer the bio-diesel into a new 2L separatory funnel; add half a liter of warm tap water. Cover the funnel and shake vigorously, taking care to vent the funnel initially. Allow to equilibrate for three hours. Bleed the water through the tap, retaining the bio-diesel in the funnel.

2.14. Repeat the above steps 2 more times. 2.15 When the bio-diesel is clear, heat gently to 48ºC

and allows cooling. This will evaporate off the remaining water.

Biographical Notes: Videsh Seecharan is a Research Assistant currently

employed with the University of Trinidad and Tobago (UTT). He graduated from the University of the West Indies with an honors degree in Chemistry, and obtained a Masters of Science degree in Petroleum Engineering from UTT. At UTT, Mr. Seecharan is

V. Seecharan et al: Laboratory Scale Production of Biodiesel from Used Vegetable Oil

65

involved in a joint research, in the area of alternative renewable energies.

Yamani Ramnath is a Chemist currently employed at the

University of Trinidad and Tobago. She graduated from the University of the West Indies with an honors degree in Chemistry with a minor in Analytical Chemistry. At UTT, Ms. Ramnath is responsible for planning, designing and managing activities of the laboratory. This includes designing the layout of the laboratory, procuring and commissioning laboratory instruments, and performing analytical measurements related to identification and quantification of various parameters especially in oil, water and waste-water samples. Ms. Ramnath is actively involved in the research area of alternative renewable energy.

Rodney R. Jagai is presently the Programme Leader for Petroleum Engineering Programmes based in the Centre for Energy and Offshore Engineering at the University of

Trinidad and Tobago. He has actively participated in the development of curriculum and academic regulations, and chaired several validation committees and accreditation initiative for UTT. Mr. Jagai graduated from the University of the West Indies with First Class honors in Chemical engineering and held a Masters of Science Degree in Petroleum Engineering at the University of Tulsa, Ok, USA. Before joining UTT, Mr. Jagai had held various senior managerial and technical positions in leading energy sector organizations. He was also active with the Department of Chemical Engineering at UWI, in both Petroleum and Chemical engineering. Mr. Jagai has been appointed as CL Financial Fellow in Oil and Gas Technology.

M.J. Joab and M. Andrews: Investigating Slop Failures Using Electrical Resistivity 66


Vol.38, No.1, October 2009, pp.66-75

Investigating Slope Failures Using Electrical Resistivity: Case Studies

Malcom J. Joab aΨ and Martin Andrews b

Geotech Associates Ltd. 4 Niles Street, Tunapuna, Trinidad, West Indies

aE-mail: [email protected] bE-mail: [email protected]

Ψ Corresponding Author (Received 30 April 2009; Revised 8 July 2009; Accepted 17 September 2009)

Abstract: The purpose of this paper is to present case studies and outline a methodology used to estimate the location of failure surfaces in landslides in clay slopes in Manzanilla and Tarouba, Trinidad. The methodology outlined consists of conducting a borehole investigation in conjunction with a topographic survey of the failed area and a series of 1D electrical resistivity measurements taken along a section line down the slope. When these measurements are inverted, compared with the results of the borehole investigation and plotted on a cross-section of the slope, estimation of the location and shape of the failure surface are improved. Typically, in the back analysis of a failed slope, the only guide in estimating the shape of the failure surface is based on visual observations of the topography and vegetation and the location of the back scarp of the landslide. The depth to the failed surface must be estimated from the results of the borehole investigations at a few locations. The use of electrical resistivity provides a quick and cost-effective means of extending the investigation and improving the confidence in the results of the slope stability back analyses. The routine use of electrical resistivity that supplements the results of a borehole investigation in failed clay slopes is unique to the field of geotechnical engineering in Trinidad and Tobago. Keywords: Electrical resistivity, slope failure, water content, clays 1. Introduction The surficial soil types which predominate in central and south Trinidad consist of stiff to very stiff clays. These soils, however, are prone to slope instability. In fact, slope gradients as gentle as 4:1 (horizontal: vertical) have been known to be unstable. Traditionally, methods of geotechnical investigation of slope failures include:

1) Drilling borehole(s) and retrieval of soil samples

2) Conducting topographic surveys 3) Lab testing of representative samples 4) Recommendation/design of remedial

measures Generally, the primary focus of step 1 above is

to determine the depth to failure/slip surface. In simple terms, the failure/slip surface refers to the interface between the soil which has moved and the soil which has not (See Figure 1). The shape and location of the failure surface is very important in the recommendation and design of remedial measures. However, one drawback of the conventional

borehole method is that it provides an estimated location of the failure surface at one point along an entire surface. Therefore, in order to improve the reliability of the slip surface location, multiple boreholes must be drilled. However, this is time consuming and it is not cost effective. Therefore, the total number of boreholes typically used in investigations of this type is three.

Figure 1. How Slip Surface is Defined This paper presents case studies outlining a

method of obtaining information on the location and shape of failure surfaces in failed clay slopes in a quick and cost effective manner. The method, it is


suggests, should be used to supplement the borehole data. 2. Location of Failure Surface

Hutchinson (1981), in his seminal paper outlining methods of locating slip surfaces in landslides, pointed out that the analysis of the water pressure within a soil matrix (known as the pore-water pressure) is one means of identifying the location of a slip surface. He indicated that in clays or loose sands, the shear disturbance associated with a slip surface causes a tendency for the soil particles to collapse to a closer packing. In saturated soils this produces a local rise in pore-water pressure, which dissipates with time as the shear zone consolidates. The result of this is a cusp of increased pore-water pressure. In the case of dilatant materials, such as stiff clays, a negative cusp of reduced pore-water pressure would tend to be associated with a slip surface.

In the longer term, the positive and negative cusps of pore-water pressure dissipate, leaving behind inversely correlated negative and positive cusps of water content. In other words, in terms of water content, contractant and dilatant materials exhibit decreased and increased water content locally within the shear zone/failure surface, respectively.

Another characteristic is the presence of soft zones or layers (Hutchinson, 1981). This is as a result of softening during shearing/failure (which is typical of stiff clays) or re-moulding during shearing (which occurs in soft clays). In these cases there is a concomitant increase in water content. This observation has been made in a number of landslides in clay slopes in Trinidad. In fact, in the clay slopes which predominate in central and south Trinidad, during failure the moving soil is re-worked to the extent that it has a markedly lower consistency (i.e. it is softer) and it exhibits higher moisture contents. 3. Electrical Resistivity 3.1 Basic Theory Prior to outlining the methodology used, it would be beneficial to describe basic electrical resistivity theory.

Electrical resistivity methods rely on measuring subsurface variations of electrical current flow which is exhibited by an increase or decrease in electrical potential (voltage) between two electrodes. It is commonly used to map lateral and vertical changes in subsurface material.

With the exception of few minerals, most common rock-forming minerals are insulators. Therefore, rocks and soils conduct electricity via electrolytes within the pore water. Therefore, the resistivity of rocks and soils is largely dependent upon the amount of pore water present, its conductivity, and the manner of its distribution within the material.

The electrical resistivity may be quantified as follows (Guyod, 1964):

2nwρρ = Eq. 1

where, ρ = Electrical resistivity of soil/rock ρw = Electrical resistivity of pore water n = Porosity of soil/rock

Therefore, this suggests that, for a given pore

water chemistry, the higher the porosity of the soil/rock, the lower its electrical resistivity. The equation also suggests that, for a given soil porosity, there is a proportional relationship between resistivity and pore water resistivity. The electrolyte or ‘salt’ content of the pore water reduces its resistivity, and by extension the electrical resistivity of the soil/rock. 3.2 Method for Measuring Electrical Resistivity in

the Field The basic method for measuring in-situ electrical resistivity is by using a combination of four electrodes (two electrodes to apply current into the ground and two to measure the potential difference); a current source; current meter and voltmeter (See Figure 2).

Note: C1 and C2, P1 and P2 refer to the current and voltage electrodes respectively.

Figure 2. Basic Concept of Resistivity Measurement

Source: Abstracted from Benson et al. (1988)


In this case, the electrical resistivity is calculated according to the following formula which is based on Ohm’s Law:

IVk Δ=ρ Eq. 2

Where ρ = Electrical resistivity ΔV = Potential difference (voltage) I = Applied current k = Geometric factor

There are several standard combinations of

electrode geometries which have been developed. The value of the geometric factor, k would depend on the particular electrode geometry used.

ASTM D6431-99 (2005) indicates that the most common electrode geometries used in engineering, environmental and ground-water studies are the Wenner, Schlumberger and dipole-dipole arrays. These arrays are shown in Figure 3.

Figure 3. Standard Electrode Geometries Source: Abstracted from ASTM D6431-99 (2005)

When electrical resistivity measurements are

conducted in the field, the values obtained are referred to as the apparent resistivity. These apparent resistivity values must be inverted in order to determine the true resistivity. The process of inversion entails comparing plots of apparent resistivity versus depth with master or theoretical curves. This process not only determines the true resistivity, but it also gives an estimate of the respective layer thickness. For the case studies

outlined later, the inversion process was conducted using the computer programme W-Geosoft/WinSev version 6.1. 3.3 Use of Electrical Resistivity in Landslide

Investigation Jongman and Garambois (2007) point out that geophysical methods are applied to subsurface mapping of landslides for two primary reasons. The first is to determine the location of the vertical and lateral boundaries of the slide debris i.e. the failure surface. The second reason is the detection of water within the slide debris. In fact Lebourg et al. (2005), Bruno and Marillier (2000) and Lapenna et al. (2005) indicate that the electrical method is one of two methods most applied to investigate this (the other being electromagnetic).

The particular use of electrical resistivity in investigations of clay slopes which is globally homogeneous stems from the fact that the action of slope failure alters the soils characteristics (i.e. moisture content and consistency). Therefore, geophysical contrast then develops between the slide debris and the unaffected mass (Caris and van Asch, 1991; Méric et al., 2005; Lapenna et al., 2005; Schmutz et al., 2000; Lebourg et al., 2005 and; Bruno and Marillier, 2000), from the cumulative or separate action of soil movement, weathering and an increase of water content (Jongman and Garambois, 2007).

In terms of the direct correlation between electrical resistivity and soil water content Banton et al. (1997) quoted the findings of Kachanoski et al. (1988) and Vaughan et al. (1995) who established relationships between apparent electrical conductivity (which is the reciprocal of electrical resistivity) and water content. The regression analyses obtained in the Vaughan et al. (1995) and Kachanoski et al. (1988) studies were 0.53 – 0.60 and 0.88 – 0.94, respectively. These suggest moderate to strong correlation. Given, therefore, that there is a correlation between electrical resistivity and water content, there is the potential for the use of electrical resistivity profiling to estimate the location of a failure surface. 4. Case Studies The following is a description of geotechnical investigations conducted for a total of four landslides in clays in which electrical resistivity methods were used to supplement the results of the borehole investigation and to give a further indication of the


vertical extent of the slide debris and by extension, the likely location of the failure surfaces. Three of the failures occurred at Manzanilla and the other occurred at Tarouba. 4.1 Slope Failures at Manzanilla 1) Site Description The facility at Manzanilla was constructed between 5 – 10 years ago in North Manzanilla. It was constructed at the top of a small hill, the top of which was flattened to provide an area for its construction. Shortly thereafter, slope instability was noticed on the southern flank of one building and the car-park area. Two other areas of instability have also been observed nearby.

These landslides were located adjacent to one another. At the time of the investigation they were 10 – 18 m wide and extended between 20 – 40 m down slope each. Visual observations revealed that the vertical displacement between the average ground floor elevation and the slide material varied from 2 – 4 m. In each case horizontal displacements were not obvious. The ground within the sliding mass was hummocky and large fissures up to 75 mm wide were also observed. Within the slide debris of two of the three failures, 150 mm diameter PVC drainage pipes were observed. These pipes presumably were placed to drain surface runoff from the school. These appeared to issue directly onto the area of instability. The surrounding vegetation consisted of low to high grass with few trees.

Based on a visual appreciation of the geometry of the slide, it appeared that the landslide was a rotational slide, which meant that the shape of the failure surface was probably circular.

2) Field Investigation The field investigation consisted of drilling a total of nine (9) boreholes (three per landslide); carrying out a topographic survey of the affected areas and; geophysical survey in the affected areas.

The boreholes were advanced with an Acker portable drill rig employing wash boring techniques. Each borehole was drilled to a depth of 8.1 m below the ground surface. Samples were taken at intervals of 0.75 m for the first 3.0 m and at 1.5 m intervals thereafter. Both disturbed split spoon and undisturbed Shelby tube samples were taken.

A topographic survey of the affected areas was also conducted. The aim of this exercise was to provide topographic information of the site; to provide input information in the stability analyses

and; to provide a basis for the proposed remedial measures.

The geophysical profiling consisting of a series of electrical resistivity measurements was conducted using the Schlumberger array. The purpose of these measurements was to aid in the determination of the interface between the soft slide debris and the in-situ material. The measurements were conducted as follows:

• Landslide 1: Four soundings at 3 m intervals to a depth of 6.5 m below the ground surface each

• Landslide 2: Five sounding at 3 m intervals to a depth of 6 m below the ground surface each

• Landslide 3: Four soundings at 3 m intervals ranging from 6-12 m below the ground surface

3) Soil Conditions In each case, the soil profile encountered consisted of fine grained material (e.g., silts and clays). Landslide 1: (Boreholes B1 – B3) The soil profile encountered was divided into three (3) major soil units. The first unit extended from the ground surface to depths ranging from 1.5 – 3.0 m below the ground surface. It consisted of medium stiff silty clays. This unit likely represents slide debris. The samples tested may be classified using the Unified Soil Classification System (USCS) as CH, meaning that they can be described as inorganic clays of high plasticity. These were underlain by stiff to very stiff silty clays, trace sand, which extended to depths ranging from 4.6 – 6.1 m. These samples were also classified as CH. Further underlying these were hard fissured clays and silty clays. These extended to the end of the boreholes at a depth of 8.1 m. Samples within this unit were also classified as CH. Landslide 2: (Borehole B4 – B6) The soil profile encountered was divided into three (3) major soil units. The first unit extended from the ground surface to a depth of 1.5 m below the ground surface. It consisted of medium stiff silty clays. This unit likely represents slide debris. The samples tested may be classified using the Unified Soil Classification System (USCS) as CH, meaning that they can be described as inorganic clays of high plasticity. These were underlain by stiff to very stiff silty clays, trace sand, which extended to depths


ranging from 3.0 – 6.1 m. These samples were also classified as CH. Further underlying these were hard fissured clays and silty clays. These extended to the end of the boreholes at a depth of 8.1 m. Samples within this unit were also classified as CH. Landslide 3: (Boreholes B7 – B9) The soil profile encountered was divided into two (2) major soil units. The first unit extended from the ground surface to depths ranging from 4.6 – 6.1 m below the ground surface. It consisted of stiff to very stiff silty clays. A sub-unit of medium stiff silty clay was also encountered in each of the boreholes at the following depths:

• Borehole B7: 1.5-3.0 m below the ground surface

• Borehole B8: 1.5-2.3 m below the ground surface

• Borehole B9: Ground surface to a depth of 1.5 m

This unit likely represents the failure zone – i.e. slide debris. The samples tested may be classified using the Unified Soil Classification System (USCS) as CH, meaning that they can be described as inorganic clays of high plasticity. These were underlain by hard-fissured clayey silts and silty clays. These extended to the end of the boreholes at a depth of 8.1 m. Samples within this unit were classified using the USCS as ML and CH. Therefore, they can be described as inorganic silts and clays of low to high plasticity, respectively. 4) Electrical Resistivity Soundings (ERS) The 1D electrical resistivity measurements were taken using the Schlumberger array along three sections (one section per landslide). These are referred to as Section A-A, B-B and C-C for Landslides 1, 2 and 3, respectively. They were conducted wherever possible along a line which corresponded with the location of the boreholes, so that a better correlation of the results could be achieved. In the case of Section C-C, a few soundings either had to be conducted off-centre or had to be omitted all together due to the presence of tall trees and other obstructions along the intended section line. The following is a discussion of the results of the inversion.

Landslide 1: The results of the inversion of the field results are summarised in Table 1.

Table 1: Summary of Results of Inversion of Field Results – Landslide 1

Location ID Layer No.

Layer Thickness

(m)

Layer Resistivity

(Ωm) 1 1.8 12 1A 2 - 2.3 1 0.9 30 1B 2 - 3.3 1 1.9 9.5 1C 2 - 1.6 1 1.0 18 1D 2 - 2.8 1 2.6 6.4 1E 2 - 1.7

A review of these results reveals the following: • Layer 1 extends from the ground surface to

depths ranging from 0.9 – 2.6 m. This layer has resistivities ranging from 6.4 – 30 Ωm.

• Layer 2 extends from the base of Layer 1. This has resistivities ranging from 1.6 – 3.3 Ωm.

• A comparison with the borehole results clearly suggests that Layer 1 represents the medium stiff clays (slide debris) mentioned above and Layer 2 represents the stiff to very stiff silty clays.

Landslide 2: The results of the inversion of the field results are summarised in Table 2. Table 2. Summary of Results of Inversion of Field Results

– Landslide 2


Layer Thickness

(m)

Layer Resistivity

(Ωm) 1a 1.8 12 1b 0.6 6.3 2A 2 - 1.4 1 0.8 16 2B 2 - 4.4 1a 0.5 9.2 1b 0.6 9.9 1c 1.5 6.9

2C

2 - 2.6 1a 0.6 7.5 1b 1.0 7.4 2D 2 - 2.9


depths ranging from 0.8 – 2.6 m. This layer has resistivities ranging from 6.3 – 16 Ωm.



80.00

85.00

90.00

95.00

100.00

105.00

110.00

115.00

120.00

125.00

130.00

80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155

Distance (m)

Ele

vati

on (

m)

B7B8

B9

Unit 1/ 2 Int e rfa ce

Re sist ivit y S ounding

Exist ing Grd. Leve l




8 0 .00

85.00

9 0 .00

95.00

10 0 .00

105.00

110 .00

115.00

12 0 .00

125.00

13 0 .00

80 85 90 95 100 10 5 110 115 12 0 12 5 130 13 5 14 0 145 150 15

Distance (m)

Ele

vatio

n (m

)

B4B5

B6




• A comparison with the borehole results suggests that Layer 1 represents the medium stiff clays (slide debris) mentioned above and Layer 2 represents the stiff to very stiff silty clays.

Landslide 3: The results of the inversion of the field results are summarised in Table 3. Table 3. Summary of Results of Inversion of Field Results

– Landslide 3


Layer Thickness

(m)

Layer Resistivity

(Ωm) 1 0.5 30 2a 1.8 7.4 2b 1.9 7.5

3A

3 - 2.8 1 0.3 21 2a 2.3 8.3 2b 0.75 7.3

3B

3 - 3.6 1 0.5 21 2a 0.9 10 2b 0.4 8.2

3C

3 - 2.7 2a 0.1 5.8 2b 1.2 8.3 2c 0.7 7.2

3D

3 - 3.3 A review of these results reveals the following: • Layer 1 extends from the ground surface to

depths ranging from 0.3 – 0.5 m. This layer has resistivities ranging from 21 – 30 Ωm.

• Layer 2 extends from the base of Layer 1 to depths ranging from 1.8 – 4.2 m. This has resistivities ranging from 7.2 – 10 Ωm.


• A comparison with the borehole results suggests that Layer 1 and 2 represent the medium stiff clays (slide debris) mentioned above. The higher resistivities in Layer 1 are probably due to a higher degree of fissuring. Layer 3 represents the stiff to very stiff silty clays. The stratigraphy at each landslide location was

determined based on the results of both the borehole investigation and the electrical resistivity soundings.

These are shown in Figures 4, 5 and 6.

80.00

85.00

90.00

95.00

100.00

105.00

110.00

115.00

120.00

125.00

130.00

80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 1

Distance (m)

Ele

vati

on (

m)

B1B2

B3

5

Figure 4. Landslide 1 (ERS): Section A-A

Figure 5. Landslide 2 (ERS): Section B-B

Figure 6. Landslide 3 (ERS): Section C-C 5) Slope Stability Analyses (SSA) Slope stability analyses were performed using the computer programme STABL5M to compute the factors of safety against rotational shear failure using Bishop’s Modified Method of analyses (after Bishop, 1955). The analyses were conducted on the following basis: • The shear strength parameters were

determined from the results of the geotechnical investigation;

• The pore-water pressure regime varied from dry soil to saturated soil;


• The soil stratigraphy was as shown in Figures 4, 5 and 6;

• The pre-failure cross-section was inferred from an appreciation of the topography of the area using the survey information and;

• The constraint that the location of the failure surfaces analysed coincided with the observed position of the back scarp. The analyses showed a factor of safety of ≈1,

which indicates a valid failure mechanism. Additionally, the most critical failure surface obtained was superimposed on each of the sections above. These combined sections are shown in Figures 7, 8 and 9.

Figure 7. Landslide 1 (SSA): Section A-A

Figure 8. Landslide 2 (SSA): Section B-B

Figure 9. Landslide 3 (SSA): Section C-C

A review of the results indicates very good correlation between the location of the failure surface determined from the results of the slope stability analyses and its location estimated from the resistivity measurements and inversion for Landslides 1 and 2. For Landslide 3, the correlation is good. However, it probably could have been improved with additional measurements between Boreholes B7 and B8. 4.2 Slope Failure at Tarouba 1) Site Description Visual observations revealed that the failure passed beneath two houses in the development. The maximum vertical displacement was approximately 1.2 m. The landslide caused major damage to the external works to the houses including apron, slipper drains and sewer connections. But there was minimal observed damage to the houses. The landslide was approximately 24 m wide (maximum) and 16 m long. It extended about 6 m beneath the houses to a concrete drain approximately 11 m north of the houses. The ground within the sliding mass was hummocky and very moist. Within the landslide, the slide debris toppled a short retaining wall. This wall consisted of 0.15 m wide, 1.2 m high concrete blocks.

80.00

85.00

90.00

95.00

100.00

105.00

110.00

115.00

120.00

125.00

130.00

80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155

Distance (m)

Elev

atio

n (m

) Infe rre d OGL

Failure P la ne

Unit 1/ 2 Int e rfa c e

Resist ivit y S ounding

Exist ing Grd. Le ve l

B1B2

B3

Topographically, the site sloped gently downwards from south to north, toward a paved drain at the base of a small valley. The surrounding vegetation consisted of low grass. Based on the site reconnaissance, it appears that the landslide was a shallow rotational landslide.

80.00

85.00

90.00

95.00

100.00

105.00

110.00

115.00

120.00

125.00

130.00

80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155

Distance (m)

Elev

atio

n (m

) Infe rre d OGL

Failure P la ne




B4B5

B6

2) Field Investigation The field investigation consisted of drilling two (2) boreholes and conducting a geophysical survey in the affected area.

The boreholes were advanced with an Acker portable drill rig employing wash boring techniques. Each borehole was drilled to a depth of 8.1 m below the ground surface. Samples were taken at intervals of 0.75 m for the first 3.0 m and at 1.5 m intervals thereafter. Both disturbed split spoon and undisturbed Shelby tube samples were taken.

80.00

85.00

90.00

95.00

100.00

105.00

110.00

115.00

120.00

125.00

130.00

80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155

Distance (m)

Ele

vati

on (m

) Infe rre d OGL

Failure P la ne




B7B8

B9 The geophysical profiling consisted of a series of 1D electrical resistivity measurements using the Wenner array. The purpose of these measurements was to aid in the determination of the interface between the soft slide debris and the in-situ material. A total of nine (9) soundings were conducted at the following intervals: 1, 1.5, 2, 2.5, 3 and 4 m. A


topographic cross-section survey was also conducted along a section line.

3) Soil Conditions The soil profile encountered consisted of fine grained material (silts and clays). Three (3) major soil units were identified. The first unit extended from the ground surface to depths ranging from 2.3 – 3.0 m below the ground surface. It consisted of soft to medium stiff silty clays. The base of this unit likely represents the zone where the slip surface is located. The samples tested may be classified using the Unified Soil Classification System (USCS) as CH, meaning that they can be described as inorganic clays of high plasticity. These were underlain by stiff to very stiff silty clays, trace sand, which extended to depths ranging from 4.6 – 6.1 m. These samples were classified as MH and CH, meaning that they can be described as inorganic silts and clays of high plasticity. Further underlying these were hard clays and sandy clays. These extended to the end of the boreholes at a depth of 8.1 m. Samples within this unit were also classified as MH and CH.

4) Electrical Resistivity Soundings The electrical resistivity measurements were taken using the Wenner array along one section referred to as Section D-D. These were conducted along a line which corresponded approximately with the location of the boreholes. The results of the inversion of the field results are summarised in Table 4.

85.00

90.00

95.00

100.00

105.00

90 95 100 105 110 115 120

Distance (m)

Ele

vati

on (

m)

Bo reho le Inves tiga tio nUnit 1/2 InterfaceRe s is tivity So undingExis ting Grd. LevelLikely Failure P lane

B2B1

Location of failed wall

Table 4. Summary of Results of Inversion of Field Results


Layer Thickness

(m)

Layer Resistivity

(Ωm) 1 2.2 4 1 2 - 2 1 2.7 4.9 2 2 - 1.0 1 2.3 5.2 3 2 - 0.9 1 2 4.8 4 2 - 1.1 1 2.4 4.7 5 2 - 0.8 1 1.8 4.3 6 2 - 1.7

7 No result – the results of the iteration did not converge

1 0.9 4.1 8 2 - 2.0 1 1.7 3.1 9 2 - 2.8


depths ranging from 0.9 – 2.7 m. This layer has resistivities ranging from 3.1 – 5.2 Ωm.


• A comparison with the borehole results suggests that Layer 1 represents the medium stiff clays (slide debris) mentioned above and Layer 2 represents the stiff to very stiff silty clays.

5) Determination of Failure Surface Comparison the soil stratigraphy was based on the borehole investigation and the geophysical survey on a plot of a cross-section of the landslide (See Figure 10). It reveals that the interface between Units 1 and 2 obtained from the two methods compare very well. Additionally, closer inspection of the stratigraphy obtained from the electrical resistivity is circular in shape. A circular failure surface is expected based on the visual observations. In fact, drawing a circular arc shows a very good correlation with the data, and confirms that geophysical electrical resistivity can provide a very good estimate of the location of the failure surface in clays.

Figure 10. Section D-D: Likely surface failure location at Tarouba

5. Conclusions Based on the analysis of the study findings, it can be concluded that:

1) Conducting 1D vertical electrical resistivity soundings in clays correlates very well with the location of the failure plane. This method readily shows the likely location and general shape of the failure plane. This finding is supported independently by the results of back analyses of the failures presented using the Bishop Modified Method (Bishop, 1955).

2) The conduct of additional electrical resistivity


measurements was very quick and cost effective in comparison to conducting additional boreholes at the site. Additionally, the advancing of boreholes does not provide more than simply general guidance regarding the likely area within which the failure plane may be located.

3) Based on the very good correlation of the electrical resistivity results and the results from the back analyses, it may be concluded that variations in the electrolyte concentration did not have a significant influence, if any, on the results. However, a detailed investigation of its influence is beyond the scope of this study and it could form the basis of future research.

4) It is suggested that the investigation of slope instabilities in clay soils be supplemented, where possible, with electrical resistivity soundings to improve the quality of the back analyses. References: ASTM D 6431-99 (2005), Standard Guide for Using the

Direct Current Resistivity Method for Subsurface Investigation.

Banton, O., Seguin, M.-K. and Cimon, M.-A. (1997), “Mapping field-scale physical properties of soil with electrical resistivity”, Soil Science Society of America Journal, No.61, pp 1010-1017.

Benson, R., Glaccum, R.A. and Noel, M.R. (1988), Geophysical Techniques for Sensing Buried Wastes and Waste Migration, National Water Well Association, Dublin, OH, USA, pp 236.

Bishop, A.W. (1955), “The use of slip circle in the stability analyses of slopes”, Géotechnique, Vol.5, pp 7-17.

Bruno, F. and Marillier, F. (2000), “Test of high-resolution seismic reflection and other geophysical techniques on the Boup Landslide in the Swiss Alps”, Survey Geophysical, Vol. 21, pp 333-348.

Caris, J.P.T. and van Asch, Th.W.J. (1991), “Geophysical, geotechnical and hydrological investigations of a small landslide in the French Alps”, Engineering Geology, Vol.31, pp 249-276.

Clayton, C.R.I., Mathews, M.C. and Simmons, N.E. (Undated), Site Investigations, Chapter 4, 2nd Edition, Department of Civil Engineering, University of Surrey, UK; available at www.geotechnique.info.

Geotech Associates Ltd. (2008a), Soil Investigation of Three (3) Landslides at Manzanilla High School GA 08 246, Prepared for National Maintenance Training & Security Company Ltd.

Geotech Associates Ltd. (2008b), Soil Investigation of a Landslide at Tarodale Housing Development, Tarouba GA 08 408. Prepared for Trinidad and Tobago Housing Development Corporation.

Guyod, H. (1964), “Use of geophysical logs in soil engineering”, ASTM Symposium on Soil Exploration, Special Technical Publication No.351, pp.75-85.

Hutchinson, J.N. (1981), “Methods of locating slip surfaces in landslides”, Proceedings of the Symposium on Investigation and Correction of Landslides, Vol.2, pp.169-203.

Jongman, D. and Garambois, S. (2007), “Geophysical investigation of landslides: a review”, Bull. Soc. géol. Fr. Vol. 178, No. 2, pp. 101-112.

Kachanoski, R.G., Gregorich, E.G. and Van Wesenbeeck, I.J. (1988), “Estimating spatial variations of soil water content using non-contacting electromagnetic inductive methods”, Canadian Journal of Soil Science, No.68, pp 715-722.

Lebourg, T., Binet, S., Tric, E., Jomard, H. and El Bedoui, S. (2005), “Geophysical survey to estimate the 3D sliding surface and the 4D evolution of the water pressure on part of a deep-seated landslide”, Terra Nova, Vol.17, pp 399-406.

Lapenna, V., Lorenzo, P., Perrone, A., Piscitelli, S., Rizzo, E. and Sdao, F. (2005), “2D electrical resistivity imaging of some complex landslides in Lucanian Apennine Chain, Southern Italy”, Geophysics, No.70, B11 – B18.

Méric, O., Garambois, S., Jongman, D., Wathelet, M., Chatelain, J.-L. and Vengeon J.-M. (2005), “Application of Geophysical methods for the Investigation of the Large Gravitational Mass Movement of Sechilienne, France”, Canadian Geotechnical Journal, Vol.42, pp 1105-1115.

Schmutz, M., Albouy Y., Guérin R., Maquaire, O., Vassal, J., Schott, J.-J. and Descloîtres, M. (2000), “Joint electrical and time domain electromagnetism (TDEM) data inversion applied to the Super Sauze Earthflow (France)”, Surveys in Geophysics, Vol.21, pp 371-390.

Telford, W.M., Geldart, L.P. and Sheriff, R.E. (2004), Applied Geophysics. 2nd Edition, Cambridge University Press, UK.

Vaughn, P.J., Lesch, S.M., Corwin, D.L. and Cone, D.G. (1995), “Water content effect on soil salinity prediction: a geostatistical study using Cokriking”, Soil Science Society of America Journal, No.59, pp.1146-1156.

Biographical Notes: Malcom J. Joab has over seventeen years of professional experiences in the field of Civil and Geotechnical Engineering. His experience includes development projects throughout the Caribbean related to commercial buildings, industrial plants, highways, bridges, water supply and sewage, housing, airports, bridge condition surveys and numerous forensic geotechnical engineering studies. He has also appeared as an expert witness and provided expert opinions on landslide litigation matters. At Geotech, he has spearheaded vibration as well as electrical resistivity measurement and analyses. Mr. Joab

http://www.geotechnique.info/

M.J. Joab and M. Andrews: Investigating Slop Failures Using Electrical Resistivity

75

was a Part-time Lecturer in Geology for Engineers at UWI and served on the Executive Council of APETT as Assistant Secretary. He is also a Director at Geotech Associates Ltd. Martin Andrews has over thirty-two years experience in the field of Civil and Geotechnical Engineering. He has worked on project throughout the Caribbean on development projects related to industrial plants, airports, roads, bridges, water supply and sewage, coastal structure and housing. His experience includes forensic geotechnical studies; as an expert witness for arbitration

proceedings and litigation; road pavement condition surveys; slope stability analyses; and earthquake engineering studies. Mr. Andrews is responsible for technical ad administrative management of Geotech’s head office in Trinidad. Mr. Andrews was a Part-time Lecturer at UWI in Soil Mechanics and Foundations Engineering, and currently lectures Introduction to Geotechnical Engineering to Year 1 Civil Engineering students.

K.D. Thomas et al.: Link between Ecotourism Activities and Surface Water Quality 76


Vol.38, No.1, October 2009, pp.76-87

Exploring the Link between Ecotourism Activities and Surface Water Quality: Using Water Quality as a Sustainability Indicator

Ken D. ThomasaΨ, Joniqua A. Howardb, Erlande Omiscac and Maya A. Trotz d

University of South Florida, Department of Civil & Environmental Engineering,

4202 E Fowler Ave ENB118, Tampa, Florida, 33620, USA aE-mail: [email protected] bE-mail: [email protected] cE-mail: [email protected]

dE-mail: [email protected] Ψ Corresponding Author

(Received 30 April 2009; Revised 30 July 2009; Accepted 21 September 2009) Abstract: The fundamentals behind ecotourism include poverty reduction, revenue generation and sustainable development. For the most part, it is assumed that this type of tourism will engage in activities that are sustainable. Various international certifications help to identify tourism destinations with reduced environmental impact, mainly through biodiversity counting and water and energy efficiency audits. Substantial measurements on water quality parameters have not been incorporated into certification procedures and questions remain on the impact of the watershed’s ecotourism activities, inclusive of native populations and visitors alike, on surface water quality. This paper presents a framework for integrating water quality as an indicator that can inform sustainable management of ecotourism facilities. Research at two (2) field sites, Greencastle in Jamaica and Iwokrama in Guyana, are used to discuss the framework. In the rural and often remote areas where ecotourism activities occur, surface water is often utilised for multiple purposes throughout the surrounding community and is vital for several indigenous flora and fauna. The decision as to parameters to monitor was made in conjunction with published literature on monitoring needs for surface water based on intended water use as well as cost and practicality factors. The actual sampling sites to be utilised in the study were chosen during a reconnaissance visit to each site where background monitoring was conducted and commenced the sampling regimen. It is expected that once proper monitoring takes place, longitudinally changes in land use, population and visitation can be used to correlate with the water quality results which can be modeled in STELLA®. Such a tool has great potential to being of benefit to decision makers, ecotourism site managers and planners in attempting to attain more sustainable operations. Keywords: Ecotourism, water quality, sustainability, complex system, STELLA®

1. Introduction

The Caribbean region has traditionally been associated with ‘sun, sand and sea’ tourism since it is the largest revenue earner for over ten Caribbean countries and a major foreign exchange earner for most. As such, all Caribbean countries have some governmental Ministry devoted to tourism, inclusive of ecotourism, for the management, marketing and sustainability of the industry on a country basis. Though the World Tourism Organisation (WTO) is an international level of support for every member country, the Caribbean Community (CARICOM) created a Caribbean Tourism Organisation (CTO) which provides intellectual support for individual

Caribbean member countries on strengthening their tourism products.

Similar to the structure of Ecotourism Societies in the U.S., several organisations exist within the region to attempt to sell a sustainable tourism product. Most of these organisations focus on conventional type coastal/resort tourism (e.g., Blue Flag, Caribbean Tourism Development Company) and only dabble in the sphere of ecotourism. As such, not much data is collected on ecotourism visitation in the Caribbean and it is typically lumped under ‘tourism statistics’. Nevertheless, according to CTO, Dominica leads the Caribbean in the development of a saleable and sustainable


ecotourism product. To ensure the continuation of a sustainable product we need an increased awareness of the complex system that affects the longevity of indigenous flora and fauna, upon which successful ecotourism depends (Tremblay, 2008).

Environmental preservation of biodiverse and unique ecosystems has many challenges in the 21st century and ecotourism is one tool that attempts to sustainably preserve natural habitats (TIES, 2001). The multibillion dollar worldwide ecotourism industry is growing at a rate of 20% per year, and models on how ecotourism activities are best administered and managed to achieve environmental preservation are limited and quantifiable measures of the impact on water quality do not exist. The upsurge of global environmental awareness has pushed most Caribbean and Latin American territories to advertise ecotourism (CTO, 2006), however, only a few have a national technical framework that protects the pristine/unique ecosystems. The Caribbean Tourism Organisation (CTO) believes that most of the interest in ecotourism by stakeholders has come from several lucrative governmental incentives (inclusive of tax holidays, interest free government loans and no import duty on industry related goods) rather than true care about environmental protection and sustainability (CTO, 2006).

Our ongoing work evaluates surface water quality as an indicator of the impacts of ecotourism activities on the surrounding environment where ecotourism activities are taken to be all onsite activity that is needed to support the propagation of the ecotourism business. This includes watershed communities and other businesses operated onsite to offset or sustain ecotourism profits and/or longevity. 2. Literature Review Ever since the WTO declared 2002 as the International Year of Ecotourism, there has been great publicity about the industry both in terms of propagation of ecotourism ventures throughout the world as well as research into the sustainability of ecotourism across the three pillars – societal, economic and environmental sustainability (Parker and Khare, 2005). Circa 2002 there was a misconception that followed ecotourism operations. Since most of these operations are small and ecotourism was founded on the principle of environmental preservation it was usually assumed that all ecotourism operations contributed to sustainable development and hence minimal

environmental impact (Roberts and Tribe, 2008). This realisation has necessitated appropriate tools to improve the environmental, and overall, sustainability of ecotourism operations. Though environmental sustainability of ecotourism is still growing as a research niche, most of the tools developed are qualitative and often assessment is based largely on perception (Schianetz and Kavanagh, 2008). The model that our work attempts to create will add to the science by providing a quantitative framework for planning and management of ecotourism. It needs to be clear that this study attempts to quantify the impact on water quality of the ecotourism activities of which tourist arrival and departure are subsets; such that ecotourism activities refer to the preparatory anthropogenic activities to allow for desired experiences by guests. That is, in order to see the direct impact of the presence of tourists there would be comparison of data during times of no or low tourist arrivals to that of peak tourist flow. This is very much contingent upon the assumed equity ratio of supply and demand, which the study subliminally tests whether pollutant loadings are unaffected by the presence of tourists, which can be modeled as transitory populations.

Ecotourism facilities throughout the world, inclusive of the Caribbean, are often located in rural and remote areas with limited potable water supply (Eagles et al., 2002) and heavy reliance on harvested rainwater and surface water withdrawals (Manson, 2008). This is in addition to the ecosystems services that fresh waterways provide for aquatic flora and fauna, and as such there needs to be concern from both the human health and species propagation angles (Meybeck et al., 1989; Chapman, 1996).

Anthropogenic river pollution can be categorised as emanating from municipal, industrial or agricultural sources (Gleick, 1993). The effluents from municipal and most industrial effluents are point sources as they disseminate into waterways from known points unlike non-point sources (Chapman, 1996). Agricultural pollution and runoff are the most common form of non-point sources of surface water and ground water pollution (Gleick, 1993). Typically agricultural pollution contains, in excess, nitrogen (typically in the forms of ammonium, nitrate and nitrite) and phosphorus which are the key proponents of eutrophication (Biswas et al., 2006). From both point and non-point sources typical pollutants include toxics such as heavy metals, synthetic and industrial organics,


chlorides and salts (Kotti et al., 2004). Not to be omitted are the microbiological contamination that can enter surface waters. This type of contamination is of extreme importance whether the water ways are being used for dinking water sources, recreation (e.g. swimming or boating), irrigation of crops or as a source of fish for human consumption (Meybeck, Chapman and Helmer, 1989; Chapman, 1996).

Ecotourism activities at any ecotourism site are inclusive of some measure of anthropogenic activity. The extent of both on-site and off-site anthropogenic activity is expected to increase as the ecotourism industry continues to grow with time. This necessitates the need for a tool to assess surface water quality in correlation with increasing ecotourism activity (inclusive of tourist visitation). Traditionally, river water quality parameters of environmental concern have included NO¯3 –N, NO2 –N, PO4

3¯–P, BOD and COD. These parameters have been given priority since the classification of river water quality into four categories by both Petts and Eduljee (1994) and Dunette and O’Brien (1992). These authors have called Class I ‘good quality’, Class II ‘fair quality’, Class III ‘poor quality’ and Class IV ‘bad quality’.

The major parameter in determining a Class I water according to their scheme is BOD, such water must have a BOD <3 mg/L so that it is suitable to be used as a potable water supply as well as support aquatic life while having a high amenity value (Kotti el al., 2005). Petts and Eduljee (1994) defined a Class II water as one that needed improvements and known to receive turbid discharges while they described a Class III water as having a dissolved oxygen saturation (DO%sat) below 50% and urgently needing improvement of quality to support aquatic flora and fauna. Class IV was summarised by both Petts and Eduljee (1994) and Dunette and O’Brien (1992) as water that is heavily polluted and possibly anoxic having BOD values in excess of 12 mg/L and consequently unable to support life. It is in consultation with this classification scheme as well as the selection criteria developed by Chapman (1996) that parameters were decided upon for this study. An adaptation of the selection criteria developed by Chapman (1996) is given in Table 1 where only the uses of surface water at the two sites are extrapolated upon.

Since at both sites surface water was used for all the purposes highlighted, that information in Table 1 was intersected with United Nations’ Environmental Programme (UNEP) basic monitoring variable for

stream as existed in its GEMS/WATER programme (UNEP, 2009). The basic stream monitoring variables according to the GEMS/WATER programme are: water discharge/head; total suspended solids; transparency; temperature; pH; conductivity; dissolved oxygen; calcium; magnesium; sodium; potassium; chloride; sulphate; alkalinity; nitrate plus nitrite; total phosphorus (unfiltered); total phosphorus (dissolved); reactive silica; and chlorophyll A (Turner II et al., 1995; UNEP, 2009). The final bias of selection of monitoring variable came down to cost of equipment and analyses.

River water quality varies both spatially and temporally (Gleick, 1993). These variations depend on geography, morphology and pollutant loadings and so water quality is specific to location and its surrounding land use/land cover (LULC) applications (Kotti et al., 2005; Maillard and Pinheiro Santos, 2008). According to Maillard and Pinheiro Santos (2008), in any given watershed, and across any time scale, almost everything within the watershed will be deposited in the streams that drain it. Stormwater runoff is the main source of non-point pollution carrying nutrients and chemicals into receiving water bodies and is the root of the relationship between LULC and water quality (Waite, 1984; Kotti et al., 2005; Maillard and Pinheiro Santos, 2008). Therefore the LULC within a watershed affects the degree of water pollution and surface water quality in any given watershed and so it is important to assess the entire catchment when attempting to monitor and/or manage water quality (Maillard and Pinheiro Santos, 2008).

It is well documented in the literature that statistical modeling has traditionally been used to create water quality models based on a limited number of water samples. This has become increasingly popular and applicable due to the high cost in water sampling and consequent analyses. For instance, the study of Maillard and Pinheiro Santos (2008) utilised fifteen sample points to compute a statistical model. Similarly the Fisher et al. (2000) and the Basnyat et al. (1999) utilised ten and eight water sampling sites throughout the respective watersheds in computing multivariate statistical water quality models. Though these models were based on data collected over both the dry and wet seasons, this approach is only acceptable since there is an underlying assumption that the LULC at each watershed is predictable in the future.

K.D. Thomas et al.: Link between Ecotourism Activities and Surface Water Quality

79

Table 1: Summary of Selection Criteria of Variables for Water Monitoring Program

Agriculture

Background monitoring

Aquatic life and fisheries

Drinking water source

Recreation and health Irrigation Livestock

watering

General variables Temperature xxx xxx x

Colour xx xx xx Odour xx xx

Suspended solids xxx xxx xxx xxx Turbidity x xx xx xx

Conductivity xx x x x Total dissolved solids x x xxx x

pH xxx xx x x xxx Dissolved oxygen x x

Hardness xx Chlorophyll a xx xx

Nutrients Ammonia x xxx x

Nitrate/nitrite xx x xxx xx Phosphorous or

phosphate xx

Organic matter Total organic carbon xx x x

Chemical oxygen demand xx xx

Biochemical oxygen demand xx xxx xx

Major ions Sodium x x xxx

Potassium x Calcium x x x

Magnesium xx x Chloride xx x xxx Sulphate x x x

Trace metals Heavy metals xx xxx x x

Arsenic & selenium xx xx x x Microbial indicators

Fecal coliforms xxx xxx xxx Total coliforms xxx xxx x

Pathogens xxx xxx x xx Remarks: x – xxx: Low to high likelihood that the concentration of the variable will be affected and the more important to include the variable in a

monitoring programme Source: Adapted from Chapman (1996)

This underlying assumption is what inherently dismisses the idea for application to ecotourism as land usage in the watershed introduces new water quality interchanges to the natural hydrological cycle (Biswas et al., 2006). The normative principles

behind tourism, and ecotourism alike, often concur the LULC issues. This is especially true in the years of infancy, the place at which the both sites chosen for this study are at in the development of a saleable ecotourism product. Therefore, to accurately model


water quality in these watersheds there must be a sustained water quality monitoring program to transcend seasons (i.e. wet and dry), watershed population increases, development of ecotourism activities (inclusive of increased visitation) as well as natural fluctuations in stream flow in times of flooding and natural disasters. 3. The Research 3.1 Purpose The goal of this research is to develop a model that successfully links ecotourism management practices and ecotourism activities with quantifiable effects on surface water quality that can help to inform and improve the ecotourism industry by its use as a scenario planning and management tool. The International Ecotourism Society, TIES (2001) offers a succinct and widely accepted definition:

“Ecotourism is responsible travel to natural areas that conserves the environment and sustains the well-being of local people.”

The World Conservation Union (IUCN) also provides a slightly expanded description of ecotourism’s key characteristics:

[Ecotourism is] environmentally responsible travel and visitation to relatively undisturbed natural areas, in order to enjoy and appreciate nature (and any accompanying cultural features – both past and present) that promotes conservation, has low visitor impact, and provides for beneficially active socio-economic involvement of local populations.

The above definition and expanded description are what have been taken in forming this study.

3.2 Study Sites The two sites were chosen because they are relatively young in ecotourism and each one is offering a different type of ecotourism product. The Jamaica site, Greencastle Estate, is rural, but not remote and has much smaller scale operations and riverine networks than the Guyana site (Iwokrama). Greencastle Estate represents an island site whilst Guyana represents the larger, non-island land masses in the region. Greencastle Estate has had a long history of traditional agricultural practices (both cropping and animal raring) while the Iwokrama Forest in Guyana is considered to be pristine by both the World Wildlife Fund and Conservation International. During the course of the project both sites are expected to undergo some aspect of LULC and so it is hoped that the data collection can capture the onsite effect of LULC.

The Greencastle Tropical Study Center, the non-profit entity of Greencastle Estate, is located on the windward side of Jamaica within St. Mary’s parish on Greencastle Estate on the North Coast of Jamaica. This site lends to ridge-to-coast assessment of water quality changes due to ecotourism activities in the watershed of concern. Greencastle Estate’s watershed is fed by two communities – Robin’s Bay and Rosend – located at higher elevations. Thus, any assessment of impact needs to include potential impact from these two communities.

Greencastle Estate offers ridge to coast tourism, making it able to attract the typical ecotourist, the coastal ecotourist, as well as the sun-sea-and-sand tourist. Figure 1 shows the Estate House, the sole current ecotourist accommodation onsite, and the major ecotourism activities in the surrounding area. Jack’s Bay and Fisherman’s Beach are in walking distance and are frequently utilised by guests. The Blue Hole, an inlet bay at the coast with an old sunken boat and its turquoise blue waters, is an ideal candidate for snorkeling. All these coastal features are included in the Estate tour along with a tour of the craft shop, Taino ruins as well as an 18th century historic windmill and waterfall. Besides these tourist activities, guests are often entertained at nearby bars and eating places in the surrounding communities (Robin’s Bay and Rosend). The North Coast Highway passes through the Greencastle Estate’s mangrove ecosystem closer to the coast.

Figure 1: Google Earth Image Showing the Greencastle Amenities in Relation to Surrounding Communities. Plans for the ecotourism expansion project

include the construction of five (5) to ten (10) boutique suites to be completed in 2014. Figure 2 shows the sample points used for the collection of baseline data at Greencastle.


81

(a)

Greencastle Estate, St. Mary’s Parish

(b)

Figure 2: Satellite Images Showing Spread of Sample Points over Greencastle Estate. (a) General Location of Greencastle within St. Mary’s Parish.

(b) Location of the Chosen Sample Points Throughout Greencastle

Iwokrama, a million hectare area, lies in the center or Guyana’s Region 8 and is managed by The Iwokrama International Centre for Rain Forest Conservation and Development (IIC) (see Figures 3 and 4). IIC has strong ties with the indigenous communities of the North Rupununi and Fair View Village and the impact of these areas on the ecotourism industry is currently being assessed. IIC, the government-affiliated autonomous organisation that manages ecotourism activities at Iwokrama, has an ongoing timber business that involves a number of the surrounding communities inclusive of Fair

View Village which actually lies entirely within the Iwokrama forest boundary. Fair View Village owns 22,000 hectares of Iwokrama forest. The business only operates in areas designated as Sustainable Utilisation Areas (SUA). Note that IIC is involved in the timber business with sixteen (16) other surrounding communities, most of which lie in Region 9. Iwokrama is certified for sustainable forest management and good practice timber production by the Forest Stewardship Council (FSC).


Figure 3: Location of Iwokrama in Guyana and Some of

the Features of the Iwokrama Forest Source: Abstracted from IIC (2004)

Figure 4. Google Earth Satellite Image with the Actual Iwokrama Sample Points

IIC has onsite four (4) researcher/staff

accommodation buildings each with a capacity of ten (10) persons. Also, at the main site are five (5) bungalows for tourists as well as a business center that houses conference and training facilities among other amenities (such as a mini grocery/craft store, the kitchen and equipment storage areas). In the next 1 – 4 years, IIC is expected to exactly duplicate (in both design and construction) its researcher/staff accommodation, inclusive of bathroom facilities.

3.3 Methodology The research has three basic components: (1) water sampling and monitoring; (2) surveying of the

community in the areas where ecotourism is taking place; and (3) using the results of (1) and (2) to model the complex water quality system in each watershed. (1) and (2) have commenced and is currently underway for less than one year at both sites and the visits to each site was used to train respective management by demonstration. On that visit precise GPS coordinates were recorded for sampling to be done at those selected locations. These locations were chosen based on flow directions to ensure that every stream that enters and leaves the property of the chosen watershed segments is monitored. Once these sample points were chosen the appropriate judgment-biased sampling plan was developed to incorporate the both dry and wet seasons and tourist high and low seasons. Typical areas utilised by tourists were sampled both upstream and downstream.

With little or no form of baseline known to be available for both the Jamaican and Guyanese study watersheds, there was first a need to start building a database from the first visit. Grab water samples were taken and preserved for analysis according to the USEPA’s standard operating procedure (SOP) for the collection of chemical and biological ambient water samples after alkalinity measurements were carried out in situ. Table 2 shows a summary of proposed ex-situ analytical methods to be utilised for water samples

In situ measurements were, and will be, done also but with less frequency. These measurements are of simple stream quality parameters with the use of a Quanta HydrolabTM multimeter. This meter is able to give instant readings of pH, temperature, dissolved oxygen, conductivity, turbidity, salinity and total dissolved solids. In the future at the same time that the HydrolabTM is being used, stream flow will be obtained by use of a flow meter so as to further categorise trends between laminar and turbulent flow during both the dry and wet seasons.

Within 6 hours of sample collection, 100 mL of the grab sample has to be put through membrane filtration so as to incubate for 24 hours to then check for, and count, the E. coli colony forming units (CFUs) present in accordance with STM methods. Alkalinity measurements are done within 24 hours of sample collection by titration of a known volume of sample with 0.02N H2SO4 to a methyl orange end point (before samples are acidified for preservation). This data will allow for calculation and determination of carbonate species in surface waters. It is expected that these in situ measurements will


83

continue to be done at varied depths, so that depth profiles can be created over time.

4. Background Monitoring Data

Initial monitoring took on both social and water quality dimensions. Samples were then analysed for the components described (as shown in Table 1). Table 3 summarises background results.

Table 2: Summary of Proposed Ex-situ Analytical Methods to be Utilised for Water Samples Parameter Units Methodology Reference Maximum

Holding Time Preservation Technique

Phosphorous mg/L Spectrophotometry STM 4 Weeks Acidified with H2SO4; pH≤ 2 NN3-N mg/L Spectrophotometry STM 2 Days Refrigerate at 4oC COD mg/L Spectrophotometry and

Hach Test n’ Tube EPA 2 Weeks Acidified with H2SO4 or

HNO3; pH≤ 2 BOD5 mg/L Incubation STM 2 Days Refrigerate at 4oC TOC/TN mg/L Block digestion STM 2 Days Refrigerate at 4oC Total Hardness mg/L

CaCO3 Titrimetric, EDTA STM 6 Months Acidified with H2SO4 or

HNO3; pH≤ 2 Ca, Mg mg/L Titrimetric, EDTA

Atomic Absorption STM 6 Months Acidified with H2SO4 or

HNO3; pH≤ 2 Total Metals (Cd, Cr, Cu, Ni, Pb, As, Hg, Al, Fe, Na, K, Se)

µg/L Atomic Absorption EPA 6 Months Acidified with H2SO4 or HNO3; pH≤ 2

Dissolved Metals (Cd, Cr, Cu, Ni, Pb, As, Hg, Al, Fe, Na, K, Se)

µg/L Atomic Absorption EPA 6 Months Acidified with H2SO4 or HNO3; pH≤ 2

E. coli CFU/100 mL

Incubation STM 6 hours Refrigerate at 4oC

Remarks: STM – Standard Methods (AWWA, 1998); EPA – (USEPA, 1979).

Table 3: Background Water Quality Data Collected at Both Sites Ranges Average values

Parameter Iwokrama Greencastle Iwokrama (n = 14) Greencastle (n = 13)

Temperature (oC) 26 - 28.27 25.61 - 33.05 27.27 28.209 Specific conductivity (mS/cm) 0.014 - 0.024 0.299 - 1.066 0.019 0.768 Dissolved oxygen (mg/L) 6.98 - 10 0.86 - 7.84 7.99 4.069 DO (% sat) 81 - 106 10.1 - 89.5 92.78 45.32 pH 5.39 - 6.25 5.99 - 8.22 5.79 7.425 Total dissolved solids (g/L) 0 - 50 0.2 - 0.7 9.12 0.4 Turbidity (NTU) 13 - 32.2 0.6 - 153 17.11 23.42 Salinity (ppt) all 0.02 0.31 - 13.9 0.02 4.921 ORP (mV) 31 - 109 ND 80.4 N/A Total alkalinity (mg/L CaCO3) 20 - 80 100 - 542 41.54 296 Caustic alkalinity (mg/L CaCO3) all 0 0 - 22 0 8.2 Carbonate alkalinity (mg/L CaCO3) 20 - 80 100 - 542 41.54 287.8 Total phosphate conc. (mg/L) 0.298 - 0.477 0.6107 - 2.5688 0.3991 0.9231 Polyphosphate conc. (mg/L) 0.178 - 0.447 0.0914 - 0.7132 0.3303 0.4834 Orthophosphate conc. (mg/L) 0.0298 - 0.119 0.1307 - 2.4773 0.0688 0.5387 Total hardness (mg/L CaCO3) 40 -100 40 - 232 55.38 136.89 Ca conc. (M) 0.0002 - 0.0006 0.0003 - 0.00166 0.0003 0.0008 Mg conc. (M) 0 - 0.0004 0.0001 - 0.00096 0.0002 0.00056 COD (mg/L) 0-2 2 - 8* 0.6 3.7* Dissolved As (ppb) all <5 all <5 N/A N/A Dissolved Se (ppb) all <5 all <5 N/A N/A Dissolved Cd (ppb) all <5 all <5 N/A N/A

Remarks: *Values obtained from June 2009 monitoring; ND - no data; N/A - not applicable


The entire data set generated was used to determine correlations among parameters via regression analysis. Only correlations with regression coefficients greater than 0.6 were taken as significant for this study. Tables 4 and 5 show a summary of strong background correlations for Iwokrama and Greencastle, respectively.

Table 4: Summary of Strong Background Correlations for Iwokrama

Independent Variable

Dependent Variable

Regression Equation

Total hardness (mg/L CaC03)

Mg conc.(M) y = 25.701e2994x R2 = 0.62

Total hardness (mg/L CaC03)

Ca conc.(M) y = 125000x + 15 R2 = 0.7728

Total phosphate conc. (mg/L)

Polyphosphate conc. (mg/L)

y = 0.6696x0.4639 R2 = 0.6911

Carbonate alkalinity (mg/L CaC03)

Total alkalinity (mg/L CaC03)

y = x R2 = 1

ORP (mV) Total phosphate conc. (mg/L)

y = 145.56Ln(x) + 221.63

R2 = 0.5525

Dissolved oxygen (mg/L) DO (%sat) y = 3.0642e0.0103x

R2 = 0.6174

Specific conductivity (mS/cm)

DO (%sat) y = -0.0004x + 0.0544 R2 = 0.7086

Temperature (oC) DO (%sat) y = 6.4314Ln(x) - 1.8388R2 = 0.6067

Temperature (oC) Specific conductivity (mS/cm)

y = -160.28x + 30.276 R2 = 0.6685

These correlations are of importance in

determining possible LULC issues within the watershed as well as outside the watershed that may be affecting the quality therein. Once these correlations are done after each sampling schedule is complete, variations in strong correlations over relatively small time steps are able to give postulations in ongoing LUCL. Note that in order to utilise a correlation for model development there is need to have at least three (3) years of continuous data to ensure the LULC, climatic, seasonal, and social dynamics are incorporated for a more ‘true’ representation (Chapman, 1996).

To incorporate the possible interactions of the populations in and around the watershed, social and environmental audit methods were utilised. These included a person-administered community survey, screening and scoping exercise as well as interviews with the ecohotels’ management and community

members during the background monitoring period at each site.

Table 5: Summary of Strong Background Correlations for Greencastle

Dependent Variable

Independent Variable

Regression Equation

Total alkalinity (mg/L CaCO3)

pH y = -1086.3Ln(x) + 2479.5 R2 = 0.8728

Carbonate alkalinity (mg/L CaCO3)

Salinity (ppt) y = -80.232Ln(x) + 415.99 R2 = 0.7516

Salinity (ppt) pH y = 3E-09x10.493 R2 = 0.6463

DO (% sat) Dissolved oxygen (mg/L)

y = 12.936x - 7.3226 R2 = 0.965


pH y = -1128.7Ln(x) + 2554.8 R2 = 0.8652

Total hardness (mg/L CaCO3)

Specific conductivity (mS/cm)

y = 176.82x + 2.7913 R2 = 0.5546


Orthophosphate conc. (mg/L)

y = 0.6222e-0.7776x R2 = 0.936

Total alkalinity (mg/L CaCO3)

Temperature (oC)

y = 2E+07x-3.3206 R2 = 0.645

Caustic alkalinity (mg/L CaCO3)


y = -38.177x + 28.595 R2 = 0.8858

Turbidity (NTU) Total phosphate conc. (mg/L)

y = 76.894x - 48.632 R2 = 0.951


Ca conc. (M) y = 99267x + 62.39 R2 = 0.7682

Total alkalinity Ca conc. (M) y = 239190x + 118.31 R2 = 0.8246



y = 129.66e0.0058x R2 = 0.7571

In the section on Water and Sanitation of the survey, it was determined that all community respondents at the Iwokrama site that lived in the vicinity all depended on the river water as a household potable water source and only 14% of them did some form of pre-treatment before consuming the water. All the respondents that lived in the Iwokrama area also utilised latrines and let their grey water out onto the soil near their houses. However, none of the respondents at Greencastle utilised the river system as a source of potable water with 75% of them having on-lot septic systems and the remaining 25% having latrines. Nevertheless, all the respondents disposed of their grey water


produced by discharging it onto the soil surface. The survey is one measure of assessing LULC at the household level which can affect the quality of water in the watershed.

Due to the great cost with travelling frequently to the study sites in Jamaica and Guyana there has been talk to find collaborators to assist with sampling in both territories. These are not yet concretized. Testing for TOC, TN, BOD5 and NH3-N all must be done within 2 days of taking the sample which in itself is a limitation to the study. As a result there may need to be a tailoring of the study parameters for certain sampling regimens. Note that this sampling regimen is to continue for about one more calendar year to transcend both the change in seasons as well as to allow for the inclusion of tourist arrival fluctuations. Nevertheless, measurements with the Quanta HydrolabTM will be done at least four times during a calendar year of sampling. These measurements will be done when visits are made to sites along with measurements of alkalinity and E. coli.

This final step can be broken down into: 1) Modeling the population that affects the

concentration of the chemical parameters of concern in surface water. Thus there is a need to understand how the community may be affecting the surface water quality. This is to be done through surveying. Visit or communicate with governmental agencies that are responsible for water, water resources and environmental protection to obtain whatever data is available for the areas of concern. Collect maps of the integrated watersheds of the two countries (in digital format or hard copy).

2) Use correlations between HydrolabTM measurements and results of ex situ analyses (inclusive of heavy metals) to develop correlations in consideration of possible loadings and losses. These are being done on a seasonal basis (i.e. dry and wet).

3) Once the model has been calibrated, it can be used to look at three scenarios (for example increased/decreased population; rainfall; and increased solar intensity and deactivation of chemicals).

5. Water Quality Modeling One of the major goals of this study is to determine whether the ecotourism activities at the both chosen study sites are (or will be) having a negative impact on the surface water quality and hence

environmental conservation efforts. Also of importance is which chemical compound is having a greater impact on pH and dissolved oxygen concentration. The model is to be such that for inputs of population and select water quality parameters there will be an output of estimated concentrations of the chemicals of concern in the watershed’s surface water at various sampling points. The trend data can also be used to develop a general model which will hopefully allow for the determination of the maximum loading capacity of the river system. It is desired to use STELLA 9.0.1 (ISEE Systems, Inc.) for this model development. This will inevitably be a complex system (requiring a system approach for solution) that will take on the structure in Figure 5. Once the model is developed, it will be compared to the empirical data collected for reliability, once available.

Figure 5. General STELLA® Interpretation of the Ecotourism Water Quality Model

Population

arriv als

Chemicals

departures

inf low outf low

chemical conv erter

The STELLA® software is specifically designed

for modeling the dynamics of highly interdependent systems (Hannon and Ruth, 2001). The software allows one to represent complex systems conceptually through a series of simple building blocks that represent the controlling processes operating to produce an emergent behavior (Ford, 1999). An icon – based graphical interface in the form of “Stock and Flow” diagrams is used to represent the concepts of systems thinking. The model equations are automatically generated and made accessible beneath the model layer.

The model hinges on the establishment of the population that affects the presence of the chemicals/parameters of concern in the environment along with the changing water quality due ecotourism activity (see Figure 5). Some of the data is needed at the household level. As a result there is a need to capture as much of the relevant data


through the use of community surveys as well as environmental audits at the two sites.

With all the data collected in the field with the HydrolabTM, correlations will be obtained between all measured parameters. Thus once correlations are obtained for both wet and dry seasons, with hopefully one flooding event included, the correlation relationships can be entered into STELLA®. It is envisioned that at this point inputs of population data (permanent residents as well as visitor history) as well as basic water quality parameters that the concentration of concern can be estimated (or predicted). 6. Conclusion This project enhances existing research infrastructure in primarily two ways. The model developed as part of this project will represent a significant new tool that expands the environmental engineering research capabilities. This model will allow scientists and environmental administrators and regulators to make predictions and evaluations that are not currently possible with existing tools. Secondly, the data generated in this project will represent a significant water quality database for the St. Mary’s parish region of Jamaica as well as the Iwokrama district of Guyana. This data generated will likely be of great use to other researchers working in that area as well as the availability of such data will serve to attract other researcher to undertake work in that watershed, thus perpetuating addition to science.

Inevitably, this project will benefit society at large. The underlying goal of the project is to make Caribbean legislators and environmental personnel aware of the needs to hopefully bring positive change. Any positive change will reduce the health impact of surface water to those rural communities that depend upon such water sources. Also, any positive changes will mean cleaner waters for eco-tourists to enjoy as well as cleaner ecosystems for the flora and fauna to procreate.

The development of water quality tool for ecotourism areas can hold a wealth of benefit for these rural areas as they typically depend on this water as a source for myriad activities. It also gives a measure of how sustainable the activities to sustain ecotourism once compared to background data and local regulatory standards. This quantitative tool is of great use to ecohotel planners and monitoring agencies where the use of scenarios can be used to ensure these facilities are informed as to what measures need to be put in place to ensure

environmental sustainability. References: AWWA (1999), Water Quality and Treatment: A

Handbook of Community Water Supplies, 5th Edition, American Water Works Association, Washington, D.C.

Basnyat, P., Teeter, L., Lockaby and B., Flynn, K. (1999), “The use of remote sensing and GIS in watershed level analyses of non-point source pollution problems”, Forest Ecology and Management, Vol.128, No.1-2, pp.65-73.

Biswas, A.K., Tortajada, C., Braga, B. and Rodriguez, D.J. (2006) (Eds.), Water Quality Management in the Americas, Springer, The Netherlands.

CTO (2006), Summary of Tourism Activities in the CTO's Member Countries 1990-2004, Caribbean Tourism Organisation, available at: http://www.onecaribbean.org/. Accessed 07/23/07.

Chapman, D. (1996)(Ed.), Water Quality Assessment: A Guide to the use of biota, sediment and water in environmental monitoring, 2nd Edition. E & FH Spon, London.

Dunette, D.A. and O’Brien, R.J. (1992), The Science of Global Change: The Impact of Human Activities on the Environment. American Chemical Society, Washington, D.C.

Eagles, P.F.J., McCool, S.F. and Haynes, C.D. (2002), Sustainable Tourism in Protected Areas: Guidelines for Planning and Management. The World Conservation Union, Gland, Switzerland and Cambridge, UK

Fisher, D., Steiner, J., Endale, D., Steudemann, J., Schomberg, H., Franzleubbers, A. and Wilkinson, S. (2000), “The relationship of land use practices to surface water quality in the Upper Oconee Watershed of Georgia”, Forest Ecology and Management, Vol.128, No.1-2, pp.39-48.

Ford, A. (1999), Modeling the Environment: An Introduction to System Dynamics Modeling of Environmental Systems. Island Press, Washington, 401 p.

Gleick, P.H. (1993)(Ed.), Water in Crisis: A Guide to the World’s Fresh Water Resources. Oxford University Press, New York.

Hannon, B. and Ruth, M. (2001), Dynamic Modeling: Modeling Dynamic Systems, Springer-Verlag, New York, 409 p.

IES (2001), Statement on the United Nations International Year of Ecotourism, International Ecotourism Society, available at: http://www.ecotourism.org/statement_on_un.html. Accessed 09/15/07.

IIC (2004), Iwokrama International Center for Rain Forest Conservation and Development Business Plan 2005 – 2006, Iwokrama International Center for Rain Forest Conservation and Development, Georgetown, Guyana.


87

Kotti, M.E., Vlessidis, A.G. Thanasoulias, N.C. and Evmiridis, N.P. (2005), “Assessment of river water quality in Northwestern Greece”, Water Resources Management, Vol.19, No.1, pp. 77-94

Maillard, P. and Pinheiro Santos, N.A. (2008), “A spatial-statistical approach for modeling the effect of non-point pollution on different water quality parameters in the Velhas river watershed-Brazil”, Journal of Environmental Management, Vol.86, No.1, pp.158-170

Manson, P. (2008), Tourism: Impacts, Planning and Management, 2nd Edition, Butterworth-Heinemann, Oxford, UK.

Meybeck, M., Chapman, D.V., and Helmer, R. (1989) (Eds.), Global Freshwater Quality: A First Assessment, Basil Blackwell Ltd., Oxford, UK.

Parker, S. and Khare, A. (2005), “Understanding success factors for ensuring sustainability in ecotourism development in Southern Africa”, Journal of Ecotourism, Vol.4, No.1, pp.32-46

Petts, G. and Eduljee, G. (1994), Environmental Impact of Assessment for Water Treatment and Disposal Facilities, Wiley-Interscience, New York.

Roberts, S. and Tribe, J. (2008), “Sustainability indicators for small tourism enterprises – an exploratory perspective”, Journal of Sustainable Tourism, Vol.16, No.5, pp.575-594

Schianetz, K. and Kavanagh, L. (2008), “Sustainability indicators for tourism destinations: a complex adaptive systems approach using systemic indicator systems”, Journal of Sustainable Tourism, Vol.16, No.6, pp.601-628.

Tremblay, P. (2008), “Wildlife in the landscape: a top end perspective on destination-level wildlife and tourism management”, Journal of Ecotourism, Vol.7, No.2, pp. 179-196.

Turner II, B.L., Clark, W.C., Kates, R.W., Richards, J.F., Mathews, J.T. and Meyer, W.B. (1995)(Eds.), The Earth as Transformed by Human Action: Global and Regional Changes in the Biosphere over the Past 300 Years, Cambridge University Press, Melbourne, Australia.

UNEP (2009), Global Environment Monitoring System, United Nations Environment Programme, available at: http://www.gemswater.org/index.html. Accessed 7/10/09.

USEPA (1979), Analytical Methods Approved for Drinking Water Compliance Monitoring, United States

Environmental Protection Agency, available at: http://www.epa.gov/safewater/methods/analyticalmethods.html. Accessed on 08/05/06.

Waite, T.D. (1984), Principles of Water Quality, Academic Press Inc., Orlando, Florida.

Biographical Notes: Ken D. Thomas is currently at PhD Candidate at USF’s Department of Civil & Environmental Engineering. Ken obtained BSc Chemical and Process Engineering as well as MSc Environmental Engineering from UWI, St. Augustine. His current research interest lies in linking water quality, management and ecotourism activities in the Caribbean as well as engineering education. Joniqua A. Howard is currently focusing on mercury cycling in the environmental and the potential impact of climate change on environmental mercury concentrations in air, water and soil. She too is a PhD Candidate at USF’s Department of Civil and Environmental Engineering with BS Electrical and Computer Engineering from Hampton University and MS Civil & Environmental Engineering from USF. Ms. Howard is actively engaged in environmental engineering education of elementary and middle school students in the Tampa, Fl area. Erlande Omisca obtained a BS in Environmental Science & Policy and an MPH in Environmental Health from USF. As a current PhD Candidate her current research area is the impact of black plastic storage tanks on human and environmental health. Both Joniqua and Erlande are founding members of USF’s Engineers for A Sustainable World chapter. Maya A. Trotz is an Assistant Professor in the Department of Civil and Environmental Engineering with research interest in water quality of surface water with emphasis on heavy metals especially in the Caribbean landscape. Her PhD and MS degrees were obtained from Stanford after completion of her BS in Chemical Engineering at Massachusetts Institute of Technology.

R.J. Murray and H.I. Furlonge: Market and Economic Assessment of using Methanol for Power Generation 88


Vol.38, No.1, October 2009, pp.88-99

Market and Economic Assessment of Using Methanol for Power Generation in the Caribbean Region

Renique J. Murraya and Haydn I. Furlonge bΨ

Natural Gas Institute of the Americas, The University of Trinidad and Tobago,

Pt. Lisas Campus, Esperanza Road, Brechin Castle, Trinidad, West Indies aE-mail: [email protected] bE-mail: [email protected]

Ψ Corresponding Author (Received 15 May 2009; Revised 19 August 2009; Accepted 23 September 2009)

Abstract: The cost of electricity is an important factor for sustainable development of countries in the Caribbean region. Due to current reliance on oil derivatives (diesel and fuel oil), these economies are susceptible to high prices and volatility. It is proposed here that methanol, traditionally a feedstock for petrochemicals, is an alternative fuel for power generation, requiring only minor modifications to existing infrastructure (such as plant, storage, import facilities and shipping). Modifications would address the particular fuel properties of methanol in terms of its relatively low heating value, low lubricity and high inflammability. In order to assess its overall economic viability, an integrated economic model of the entire methanol to power (MtP) chain is developed in this paper. Based on preliminary cost estimates, it is shown that the use of methanol in new gas turbine installations or retrofitted turbines and reciprocating engines may be cheaper than conventional fuels due in part to the lower market price on an energy equivalent basis. This is found to be the case especially in smaller markets which currently use fossil fuels only in reciprocating engines. However, certain countries, typically the larger ones, obtain discounted prices for diesel, which makes MtP less favorable. The extent to which renewable energy forms part of a country’s energy mix also impacts MtP’s competitiveness. Nonetheless, a reduction of up to about 10 US cents per KWh can be realised, with a potential regional MtP power market size of about 6000 MW or 16.2 billion kWh of electricity generated annually. Hypothetically, this would result in an incremental methanol market of roughly 7.1 millions tonnes per annum requiring 626 MMscfd of natural gas. Keywords: Methanol; alternative fuel, gas turbine; Caribbean power market Nomenclature Am Discount factor COx Oxides of carbon CNG Compressed natural gas FFB Fossil fuel based GP Country replaceable generating capacity H.R. Machine heat rate H.V. Fuel heating value IL Labor cost index IP Power generation cost index IR Retrofitting cost index IS Shipping cost index

IT Storage tank cost index LNG Liquefied natural gas MtP Methanol to power NOx Oxides of nitrogen Pm Methanol market price POpex Power plant operational expenditure PR Cost of retrofitting PS Shipping costs PCapex Power plant capital expenditure r subscript refers to reference data αP Power plant scaling factor αT Storage tank scaling factor

1. Introduction Methanol is primarily known for its use as a chemical feedstock, for instance in the production of formaldehyde and acetic acid. It can also be used to produce olefins and other longer chain hydrocarbons

such as proteins and gasoline (Olah et al., 2006), although these applications are not as extensive. However, as these markets develop, there are significant implications in the light of potentially peaking global crude oil production (Campbell,


2002). Methanol’s use is not restricted to chemical production. One such example is that methanol has been proposed as a solution to addressing stranded gas fields; the key advantages being increased safety and a potentially more economic means of transportation than LNG (Olah et al., 2006). As such, much work is being done to reduce methanol’s cost of production. Traditionally produced by the breakdown of organic matter, methanol is today almost entirely produced by the synthesis gas route. However, it is possible for methanol to be produced by the direct oxidation of methane (Cheng et al., 2006), and from the hydrogenative reduction of CO2. Both of these methods have tremendous potential, and at present there is much effort directed to their development.

Even using the conventional production route, methanol is being considered in fuel applications. With an excellent octane number, methanol has been used in spark ignition engines in various ways, including as a simple additive to improve engine performance, and in the development of special methanol blends for use in racing applications with modified engines (Burns, 2008). In particular, methanol’s use soared in the late 1990’s when MTBE, a derivative of methanol, was used as a common additive for gasoline engines. Several other tests were carried out by different US State agencies to examine the technical feasibility of using methanol and di-methyl ether (DME), which is another derivative, in compression ignition diesel engines for transport purposes (Olah et al., 2006). However, most of these projects came to a halt at the end of the testing stage.

More recently, methanol is finding new fuel applications, namely in fuel cells (Sangtongkitcharoen et al., 2008). It can be catalytically reformed to produce hydrogen gas (H2) for use in fuel cells, or reacted with air in direct methanol fuel cells (DMFC).

In general, methanol’s use as a fuel is becoming more attractive. This is significantly being influenced by recent trends in the global energy market. Firstly, prices of oil and its related products have been at a record high recently. This has been partly attributed to the rapid growth of Far East and Asian markets, which placed higher demands on limited oil resources. This has prompted consideration of other alternative energy sources that are not oil dependent. A second key issue has been growing global concern for the environment and emphasis being placed on the use of fuels having

lower COx and NOx emissions. Methanol offers these advantages, being a derivative of natural gas which is partly de-linked from oil, and is a clean burning fuel.

This is of key significance to countries of the Caribbean region, given that almost all are net importers of fossil fuels, which have been negatively affected by recent fluctuations in crude oil prices. As such, there is a keen interest in sourcing cheaper and cleaner fuel alternatives. Consequently, this work investigates the potential for methanol as such an alternative for the Caribbean region. It presents both a qualitative assessment of MtP relative to other potential natural gas transportation technologies, and a quantitative comparison to the present fossil fuel-based power generation technologies in the Caribbean.

The paper first gives an overview of some of the key technical considerations of the MtP (i.e., Section 2), and outlines important characteristics of the Caribbean power market (i.e., Section 3). In Section 4, factors affecting MtP’s feasibility relative to other means of supplying energy to the region are considered. A description of the economic model of the MtP value chain is presented in Section 5, and results are discussed in Section 6. The paper concludes by highlighting some of the key findings on the suitability of MtP to the Caribbean region, and identifies future work on technical as well as commercial aspects of the technology. 2. Technical Considerations of Methanol as a Fuel The use of methanol as a fuel for stationary engines has previously been investigated (General Electric, 2001). The overall result was that methanol can be used successfully, with only minor modification of the standard machinery to account for the main differences in the fuel characteristics of methanol as compared to those of other liquid fuels. For comparison, Table 1 shows some of the fuel properties of methanol and other fuels used for power generation (Martinez, 2007), along with a summary of key considerations on methanol’s use in a gas turbine engine.

Firstly, methanol has a significantly lower calorific value, which for example, is approximately half that of diesel. This is generally compensated for by a concomitant increase in the volumetric flow rate of methanol which can be achieved without significant difficulty or deviation from usual operating conditions. Special nozzles can be used for high fuel distribution with low pressure drop


(Beukenberg and Reiss, 2006).

Table 1. Comparison of Fuel Properties and Resulting GTE considerations

Fuel property

Methanol DME Natural gas

Diesel Issues of MtP using a Gas Turbine

Density (kg/m3)

790

1.8

0.68 – 0.70

820 – 860

Liquid fuel versus gaseous

Viscosity Coefficient

0.59

0.086 – 0.14

0.01 – 0.012

2.6 – 4.1

Lubrication and fuel-delivery issues

Flash point (K)

285

232

85

330

Safety issues requiring special handling, control and monitoring

Heating value (MJ/kg)

22.7

30

54

45

Increased fuel flow rate requirements

Secondly, the lubricity of methanol is relatively

low. This poses problems with standard fuel-delivery systems, such as those involving the use of valves for flow rate control, and in situations where the fuel comes into contact with other moving parts within the engine. There are generally two approaches to addressing this. If preserving the chemical integrity and consistency of the methanol is not a major requirement, then the use of suitable lubricant additives may be employed, with a consequent alteration in combustion emissions. This may also impact the rate of wear and residue build-up on other engine components. Alternatively, an appropriate pump (e.g. screw type) with effective coatings may be used. The third factor concerns methanol’s combustibility and flammability, which consequently requires specific handling, controls and monitoring.

Despite the foregoing issues, previous work has confirmed that the use of methanol as a fuel for power generation is indeed possible. However, this has been mostly limited to an experimental scale on gas turbines. In addition, Seko and Kuroda (1998) showed that methanol’s use in compression-ignition engines is not only possible, but can be more efficient than using diesel. It also yields lower NOx emissions, with a lower brake specific energy consumption at medium load conditions. The major requirements here are similar to those when methanol is used in gas turbine engines. More specifically, the key issue is increasing the auto-ignition ability of methanol, given that its auto-ignition temperature is higher than that of diesel. This can be achieved chemically by the addition of

combustion enhancers. Several mechanical methods have also been developed. Two of the more common include exhaust gas scavenging techniques (Tachiki, 2007) and flash-boiling the fuel (Seko and Kuroda, 2001). Currently, research into the development of other methods is ongoing. 3. Caribbean Market Assessment

Although the compatibility of methanol as a fuel for use in power generation equipment is important, it is not the sole factor in determining its use in the region. An assessment of Caribbean power markets is also a preliminary step in order to determine trends and key details that were unique to the Caribbean context and would influence the implementation of MtP in the region. The information extracted includes the size of power demand in each country, different energy sources (oil-derivatives, natural gas or renewable), power generation equipment being used (reciprocating engines or gas turbine), cost of electricity and cost of fuel. As noted later on in this section and in section 5, this information is useful in determining the market potential for MtP and also feeds into the economic model.

The market assessment was conducted by gathering data related to energy usage and arrangements in twenty-six countries. This data was obtained from the United States Energy Information Administration (EIA), Caribbean Energy Information Systems (CEIS), Organisación Latinoamericana de Energía (OLADE) and the websites of national power authorities. Table 2 shows some of the main power market data for the countries.

Based on the market assessment, some defining characteristics of Caribbean power markets have been identified:

· Size classification of markets. It was found that the island markets could be differentiated on the basis of size. In general, generation capacities for the countries were either significantly below or above 100MW; there were only three islands with capacities close to 100MW. As such, markets were classed as either small (below 100MW) or large (above 100MW).

· Technology classification of markets. Another basis for differentiation between markets was the type of power generation technology used. For some islands, power is generated solely by thermal processes using turbines or reciprocating engines. However for others,

R.J. Murray and H.I. Furlonge: Market and Economic Assessment of using Methanol for Power Generation

91

power is generated using a mix of renewable energy technologies and thermal technologies. Countries with mixed technologies usually had lower yearly electricity prices than those without. Accordingly, power markets can also be divided into two other categories: single and mixed technologies.

· Turbine and engine market share. The two main types of machinery used for thermal processes are gas turbines and reciprocating engines. However, it was found that their distribution is correlated to the market size of the country. Generally, those with smaller market sizes tended to use reciprocating engines more, while larger markets used gas

turbines. In addition, the assessment revealed that most

countries increase their installed generating capacity by 15% to 45% every 4 to 6 years. Consideration of these factors points to different motivations and configurations for the implementation of MtP in a country. For example, MtP may be implemented via the installation of new turbines to replace existing infrastructure. Alternatively, it may be implemented as a means of satisfying new demand. It is also possible to modify existing turbine and reciprocating engines to burn methanol, as was noted earlier. These options are explored in greater detail in Sections 5 and 6.

Table 2: Installed Electricity-Generating Capacity in the Caribbean Region (2005)

Country Total Installed Capacity

(MW)

Installed FFB Capacity (MW) /

(% of total installed capacity)

Renewables & Other installed

capacities (MW)

Primary FFB Power Generation Technology

Antigua & Barbuda 27 27 (100%) 0 Possibly reciprocating Aruba 150 150 (100%) 0 Mixed: Diesel reciprocating and gas turbines The Bahamas 401 401 (100%) 0 Reciprocating Barbados 210 210 (100%) 0 Gas turbines Belize 52 27 (52%) 25 (48%) Data not found Virgin Islands (UK) 10 10 (100%) 0 Possibly reciprocating Cayman Islands 115 115 (100%) 0 Reciprocating Cuba 3958 3901 (99%) 57 (1%) Data not found Dominica 22 14 (64%) 8 (36%) Reciprocating Dominican Republic 5530 4988 (90%) 542 (10%) Primarily reciprocating, and gas turbines French Guiana 140 140 (100%) 0 Data not found Grenada 32 32 (100%) 0 Reciprocating Guadeloupe 423 411 (97%) 12 (3%) Primarily reciprocating, and gas turbines Guyana 313 308 (98%) 5 (2%) Primarily reciprocating Haiti 244 181 (74%) 63 (26%) Reciprocating Jamaica 1469 1325 (90%) 144 (10%) Primarily reciprocating Martinique 396 396 (100%) 0 Primarily reciprocating, and gas turbines Montserrat 2 2 (100%) 0 Reciprocating Netherland Antilles 210 210 (100%) 0 Data not found Puerto Rico 5358 5258 (100%) 100 (2%) Primarily reciprocating, and gas turbines St. Kitts & Nevis 20 20 (100%) 0 Reciprocating St. Lucia 57 57 (100%) 0 Reciprocating St. Vincent/ Grenadines

24 18 (75%) 6 (25%) Reciprocating

Trinidad & Tobago 1416 1416 (100%) 0 Gas turbines Turks/Caicos Islands 4 4 (100%) 0 Data not found Virgin Islands (US) 323 323 (100%) 0 Data not found

4. Factors Affecting MtP’s Feasibility Present global concerns surrounding energy security and environmental impact have crafted a space for the emergence of a new type of fuel which can satisfy increasing energy demand in a sustainable and cost competitive manner. For countries of the

Caribbean region, natural gas is one of the most promising fuel sources because of its relative abundance, cleaner combustion emissions and proximity to supply, Trinidad and Tobago being the primary one. This section presents a qualitative assessment of various means of transporting natural


gas including via methanol. The main options previously considered, for

instance in Kromah et al. (2003), are gas pipeline, gas to hydrate, gas to wire (GtW), gas to liquid (GtL), and the more familiar LNG and compressed natural gas (CNG). However, given the fact that the proponents of each of these technologies assume the use of the same natural gas source and with markets being small, these technologies cannot be jointly implemented. It follows therefore that these are all competing technologies for the utilisation of natural

gas in the region. Aside from natural gas, it is worth mentioning that the increasing global use of bio-fuels has sparked some level of consideration in the region. Bio-diesel and bio-ethanol have already found use in some countries, but in most instances they have only been explored on a small scale. Consequently, the major focus here is on MtP’s comparison to some of the aforementioned technologies for natural gas utilisation within the region. Table 3 summarises the main factors.

Table 3. Comparison of Natural Gas Transportation Technologies Considerations Pipelines CNG/LNG MtP Shipping None 1. May require multiple vessels,

partial loading/ offloading depending on inventory

2. Special alloy materials needed

May require multiple vessels, partial loading offloading depending on inventory

Harbor None Development of deep water harbor and compressors/ LNG offloading facilities

Use of existing harbor

Storage and other infrastructure Compressors, metering, etc.

New storage infrastructure; re-gasification plants

Use of existing fuel import facility with relatively minor modification

Speed of implementation Long (> 3 years)

CNG (Medium, 2-3 years); LNG (Long, > 3 years)

Short (< 2 years)

Supply flexibility (multiple suppliers, increase in market size, etc.)

Low Medium High

Typical initial capital investment per country (millions US$)

Medium (> 10)

High (> 100) Low - Medium (<100 depending on option for implementation)

4.1 Shipping/Transportation Shipping of methanol uses no specialised containment or materials, methanol being relatively non-corrosive, and a liquid at room temperature and atmospheric pressure. In contrast, LNG and CNG require cryogenic alloy materials (and in most cases double containment), and materials capable of high pressure respectively. 4.2 Infrastructure (Harbor and Import Facilities) Methanol ships consist of a wide range of sizes, so smaller ones may be available which would not require harbors as deep as those for LNG and CNG vessels. Being a liquid fuel, storage and handling equipment at the import terminal would be essentially the same as that of other oil-based liquid fuels, which are already in existence in regional markets. However, compressors would be required for a pipeline, a regasification facility for LNG, and high pressure storage and compression facilities for CNG.

4.3 Implementation Time and Supply Flexibility Unlike other gas transportation technologies, MtP can be implemented in a relatively short space of time given that methanol is a widely traded commodity with significant production from T&T. As such, there is flexibility in supply in terms of the number of countries in the Atlantic Basin region, and the ability to access incremental volumes on a spot trade basis. As mentioned above, no specialised equipment is required which also reduces the time to implement and expand facilities compared to pipeline, LNG and CNG.

4.4 Initial Capital Investment LNG has proven to be economic only for long distances and large volumes, which are not characteristic of regional markets. CNG has been considered for closer and smaller markets but this has not yet been proven economic for this region. An OECS report estimates a construction cost of approximately 5 to 10 million US dollars per island for pipeline transmission (Hertzmark, 2006), which


is relatively small. However, consideration has been given to a single main transmission pipeline, with spurs to each market, since building separate pipelines for each country is not a feasible option. As such, the capital cost, and commercial, legal and political hurdles for such a project may be prohibitive.

Overall, the comparison of different natural gas transportation technologies suggests that MtP has certain distinct advantages particularly for the unique Caribbean power market. Of the competing technologies, it is the most flexible and easily implementable, while potentially being the least costly. As mentioned earlier, MtP can be implemented using gas turbines or by retrofitting reciprocating engines which is the most common power generation technology being used. Consequently, a more detailed economic analysis is required for determining the best solution for MtP’s application. 5. Economic Model of MtP Value Chain 5.1 Integrated Value Chain Model A schematic of a generic value chain was developed to encompass key elements of the MtP process and to allow for a more holistic economic evaluation, see Figure 1. The MtP value chain comprises four key economic activities.

Figure 1: Schematic of Generic MtP Value Chain

1) Methanol production – For the purposes of this

study, the market price of methanol is used as the cost of methanol, obtained from Chemical Marketing Associates Inc. (CMAI). This allows for a fair market-based comparison since it avoids issues such as rates of return and natural gas pricing in determining the cost of methanol production.

2) Methanol transportation – This approach considers the cost for the shipping of methanol to the various markets using standard vessels.

3) Methanol storage – Here, it is assumed that inventory at the import terminal would be large enough for thirty days of power

generation demand. The cost involves the capital for construction of the necessary storage facilities.

4) Power generation – This element of the chain covers the cost of generating power from methanol using either gas turbine engines or reciprocating engines. Both the initial capital outlay and the subsequent operational expenses are considered here.

In order to quantitatively assess MtP’s feasibility, an integrated economic model comprising these activities was developed. The model sought to capture the contributions of each of these four activities to the overall unit cost of generating power for a given year, CMtP, as given by:

CMtP= Cm + CP + CS + CT (1) where all costs, C, are of units US$/kWh. Cm

represents the cost associated with purchasing methanol fuel required to generate one unit (kWh) of power; this is computed by:

Cm = (Pm) * (H.R./H.V.) (2) where Pm is a variable that represents the market

price of methanol for a given year in US$/tonne, H.R. is the heat rate (MJ/KWh) for the gas turbine (or reciprocating engine), and H.V. is the heating value of the fuel (MJ/t).

CP represents the unit amortized capital costs plus the unit annual operating cost associated with the power plant. This can be for the installation of a new power plant or the retrofitting of an existing plant. For a new installation CP is given by (3a), and for a retrofitted plant by (3b):

CP = Am[PCapex * (IP,y/IP,r)] * [(GP/ GP,r) αP] + [POpex * (IL,y/IL,r)] (3a) CP = Am[PR * (IR,y/IR,r)] * [(GP/ GP,r) αP] + [POpex * (IL,y/IL,r)] (3b) The terms (IP,y/IP,r) and (IL,y/IL,r) in (3a) and (3b)

are inflation correction terms for the respective year y relative to the reference year r, and for power plant cost (IP) and operating cost (IL) respectively. Am is the discount factor which adjusts the capital cost (PCapex or PR for new or retrofitted plants respectively) given in million USD to an annual figure. POpex is the annual operating cost. These costs are for a plant of power generating capacity GP (MW). The term [(GP/ GP,r) αP] is a scaling factor adjuster, which alters the capital cost of the reference plant capacity GP,r to the plant capacity GP that will be used for MtP, in the specific island. This accounts for economies of scale. CS represents the unit cost associated with shipping methanol:


94

CS = PS * (IS,y/IS,r) * (H.R./H.V.) (4) with corrections, as before, for inflation and

converting the total cost PS given in US$/tonne to US$/kWh.

Finally, CT represents the unit amortised cost for a storage tank, given by:

CT = Am[PT * (IT,y/IT,r)] * [(VG/VG,r) αT] (5) The usual adjustments for inflation and capacity

requirements for the particular country are made to the capital cost of the tank PT as given in million USD, which is based on a volume of VG,r.

These economic model equations were used to compute the overall cost of power generation for the following scenarios, which arose from the market assessment (cf. Section 3):

· Scenario A – New turbine installation · Scenario B – Retrofit of an existing gas turbine

to use methanol · Scenario C – Retrofit of an existing

reciprocating engine to use methanol. The model treated each scenario differently by

altering the input parameters. It determines the power generation cost using methanol for each country, in a specific year, based on a particular scenario. For example, assuming the island of Grenada selected to retrofit reciprocating engines (Scenario C) in the year 2000, the model determined the unit cost of power generation in US cents per kilowatt-hour (kWh) for Grenada using reciprocating engines in that year. 5.2 Model Inputs and Assumptions The main inputs are shown in Table 4, comprising plant costs, scaling factors and inflation indices. The market assessment provided the countries replaceable generating capacity, GP, which is essentially the portion of the total installed power generation capacity that is derived from fossil fuels.

Table 4. Main Input Parameters for Cost Estimation Parameter Value Unit

Power Plant cost, PCapex 10 Million US $ per 8.5MW capacity (GP,r) Plant operational expenses, POpex 0.025 $/kWh Storage Tank costs, PT 10 Million US $ Cost of retrofitting (mainly for fuel delivery system), PR 0.065 Million US $ Shipping costs, PS 20 US $/tonne Methanol heating value, H.V. 22.7 MJ/kg Country replaceable generating capacity, GP Island specific MW Power plant scaling factor, αP 0.6 NA Storage tank scaling factor, αT 0.57 NA Turbine heat rate, H.R.Turbine 12.77 MJ/kWh Reciprocating engine heat rate, H.R.Recip 10 MJ/kWh Methanol market price (Source: CMAI), Pm Year specific US $/gallon Electric Power Generation index (US Bureau of Labor statistics), IP

Year specific NA

Metal tanks and vessels custom fabricated and field erected index (US Bureau of Labor Statistics), IT

Year specific NA

Utilities: Unit labor cost index _ Nat gas distribution (US Bureau of Labor Statistics), IL

Year specific NA

Deep sea freight transportation index (US Bureau of Labor Statistics), IS

Year specific NA

Pump and pumping equipment manufacturing except hydraulic (US Bureau of Labor Statistics), IR

Year specific NA

The following outlines the cost estimation techniques and key economic assumptions.

1) The model estimates cost on a nominal US dollar basis. All capital investments are amortised over the economic lifespan of twenty years at a discount rate of 8%, used to calculate the discount factor Am in Equations (3) and (5).

2) For the new installation scenarios, the cost of electricity from MtP in any given year was derived by assuming that all the relevant MtP infrastructure capital cost were expended in that particular year.

3) It was found that trends for historical diesel fuel market prices and historical electricity prices for the various countries exhibited a


high level of correlation (greater than 0.9). This was calculated using MATLAB 6.5 and a sample plot illustrating this relationship is shown in Figure 2. As a result, forecasted data for the fuel market prices were used to project the respective electricity prices with an expected reasonable degree of accuracy.

4) Given the data for an 8.5MW gas turbine engine (Breeze, 2005), similar capital cost estimates for machines of higher generating capacities were obtained using a factored estimate with the relevant scaling exponents as listed in Table 4 (Peters and Timmerhaus, 1991), cf. Equations 3 and 5. It was assumed that this estimation technique was applicable up to a plant capacity of 100MW.

The economic model was used to determine the yearly power generation cost for a country, for each scenario, over the period 1996 to 2006. It should be noted that of the twenty-six countries in the region a sample of eight (see Table 5) was considered for the more detailed economic analysis. These countries are representative of a wide range of power market sizes and mix of power generation technologies.

Also, projections for the generation costs in

future years were also determined for each country and each scenario, using a correlation between historical methanol market prices and MtP power generation cost, similar to that outlined in assumption (3). As such, forecasted trend data for methanol prices (CMAI) was used to produce projections for the power generation costs over the period of 2007 to 2012.

Figure 2: Correlation between Electricity Price and Diesel Market Price

Table 5: MtP Cost Difference under Different Scenarios for Selected Islands Country Total Installed

capacity (MW)

Fossil fuel based installed capacity

MtP and FFB cost difference in 2010

(Scenario A)


(Scenario B)


(Scenario C)

Bahamas 401 100% -2¢/kWh -1¢/kWh +4¢/kWh Barbados 210 100% -2¢/kWh -1¢/kWh +4¢/kWh Belize 52 52% -4¢/kWh -3¢/kWh +1¢/kWh Cayman Islands 115 100% -6¢/kWh -5¢/kWh 0¢/kWh Dominica 22 64% -2¢/kWh -1¢/kWh +4¢/kWh Grenada 32 100% +2¢/kWh +3¢/kWh +7¢/kWh Jamaica 1469 91% -1¢/kWh 0¢/kWh +5¢/kWh St. Lucia 57 100% +4¢/kWh +5¢/kWh +9.7¢/kWh

Remarks: +ve values = MtP savings 6. Economic Comparison This section examines the cost of power generation via MtP, as calculated by the economic model described above. The relative cost under the different scenarios is essentially the same for the forecast period. Thus, for comparison purposes, the year 2010 was chosen as a reference, this being a likely timeframe taking into account actual implementation time. The projected power generation cost for each of the three MtP scenarios was compared to the projected fossil fuel-based (FFB) power generation cost in that year. Table 5 summarises the results of

this comparison for several countries, where a positive cost difference indicates that the MtP option is cheaper than the FFB one (i.e. a savings), and vice versa. These are discussed below: 1) MtP is economic using turbines in certain

markets As can be seen from Table 5, islands with relatively small markets and that are 100% dependent on fossil fuels stand to save by switching to MtP. Specifically, the cost of power generation in Grenada and St. Lucia is cheaper (i.e., 2 to 5 US cents per


kWh) using MtP either as a new gas turbine facility installation (i.e., Scenario A) or retrofit of an existing one (i.e., Scenario B). 2) MtP is most economical with the use of

reciprocating engines As can be seen from Table 5, Scenario C yields the cheapest MtP electricity generation cost. Thus, retrofitting reciprocating engines is the best option for employing methanol as a fuel compared to retrofitting gas turbines (i.e., Scenario B) and installing new turbines (i.e., Scenario A) in all countries. It therefore follows that countries which employ reciprocating engines as the primary power generation technology are most amenable to switching to MtP. The main reason for this lies in the fact that reciprocating engines are generally more efficient power conversion devices than turbines, as can be seen by the difference in heat rate values of Table 4; the average heat rates are 12.77 and 10 MJ/kWh for turbine and reciprocating engines respectively. Additionally, the value used for a reciprocating engine heat rate is in fact on the higher end of the spectrum for diesel operation, and some research has shown that it is possible for methanol’s use in reciprocating engines to be more efficient than conventional diesel (Seko and Kuroda, 2001). A more efficient process would mean an even lower cost of MtP electricity generation. 3) MtP is most economical in smaller markets Another key result is that the MtP initiative is cheaper in countries having a relatively small installed capacity (i.e. below 100 MW) and close to 100% fossil fuel dependence, namely for Dominica, Grenada and St. Lucia. The highest savings (achieved under Scenario C) for these three islands are US cents per kilowatt-hour (kWh) 4, 7 and 9.7,

respectively (see Table 5). This amounts to a potential saving of US$ million 9, 30.4 and 82.6 respectively over the period 2010 to 2012, as shown in Table 6. These numbers were derived from the product of MtP Scenario C unit cost savings (taken from last column of Table 5) and annual power consumption. A likely reason for the greater savings in these smaller islands is that the cost of diesel appears to be consistently higher than that for other countries, as shown in Table 7. Hence, the residential cost of electricity is higher, making the differential with respect to MtP greater. 4) MtP is less economical in larger markets Conversely, larger markets benefit less from switching to MtP, for instance in the case of Cayman Islands, Barbados and Bahamas. In addition to the reason proffered above, this may also be attributed to differences in efficiency of the primary power generation technologies, particularly in the case of comparing residential prices to MtP via turbines. Additionally, in some islands, the fossil fuel-based power generation is derived from the use of both diesel and the cheaper fuel oil (see Figure 3). The cumulative effect of this is a decrease in the island’s overall generation costs and hence residential prices, consequently leading to a less competitive MtP price. 5) Impact of renewable energy in energy mix on

MtP’s competitiveness A fifth noticeable result was that MtP also tended to be less competitive in countries whose energy consumption needs are partially met by renewable resources, namely Dominica, Belize and Jamaica. Table 5 shows that of the eight countries, Belize has one of the lowest MtP savings and one of the highest renewable energy components (i.e., 48%).

Table 6. Potential MtP Savings for Selected Caribbean Markets Country Island Power

Consumption in 2005/billion kWh

Cost Savings in 2010/ cents/kWh



Total Savings over the Period 2010-2012/

million US$ Bahamas 1.76 3.5 4.2 3.8 202.4 Barbados 0.89 3.4 4.1 3.7 99.7 Belize 0.16 1.2 1.9 1.5 7.4 Dominica 0.07 4.0 4.7 4.2 9.0 Grenada 0.14 7.0 7.6 7.1 30.4 Jamaica 6.13 4.3 5.0 4.5 845.9 St. Lucia 0.28 9.7 10.2 9.6 82.6


Table 7. Price Paid by Countries for Diesel Country Fuel Purchase

Cost 2001 (US $/gallon)

Fuel Purchase Cost 2002

(US $/gallon)


(US $/gallon)


(US $/gallon) Bahamas 0.680 0.690 0.907 1.082 Barbados 0.804 0.790 0.536 0.583 Belize 0.935 0.775 1.267 1.353 Dominica 0.870 0.836 0.977 1.130 Grenada 0.808 0.825 0.548 1.186 Jamaica 0.686 0.746 0.867 1.186 St. Lucia 0.867 0.832 1.067 1.100 US Gulf Coast Market Price 0.708 0.675 0.822 1.116

Source: Statistics Based on CEIS

In all these cases, the primary renewable energy generation source is hydro-electricity, which is generated by well-established plants and can be expected to be somewhat cheaper than FFB power generation. Consequently, the overall price of electricity in these countries is considerably lower than that of a country with similar installed capacity. This is well demonstrated if one were to compare Belize and St. Lucia (see Table 5). Another example is Dominica relative to Grenada. It should be noted however that the price of such a country’s residential electricity is in most instances more of a weighted average or overall price and therefore does not reflect the true cost of FFB generation alone. It is possible therefore that a switch to MtP for the FFB component of the country’s capacity could lead to an overall lower cost of electricity. 6) Impact of fuel market price differential Figure 3 illustrates the historical as well as projected market prices (up to 2012) for both diesel and methanol on an energy equivalent basis. As can be seen, the difference in price between the two fuels widens significantly during certain prolonged historical and projected periods. This difference increases the savings by switching to MtP under Scenario C, and may also improve the chances of savings under Scenarios A and B. 7) Overall MtP potential in entire Caribbean region Given the foregoing, in order to quantify the total potential for MtP in all twenty-six countries of the region, it is hypothetically assumed that MtP can replace diesel in all reciprocating power generation plants with only minor retrofit. This amounts to over 6000MW of installed capacity and represents about 16 billion kWh of power consumption. This would require approximately 7.1 millions tonnes of methanol yearly, which is just over the total current

methanol production capacity in T&T. The quantity of natural gas required to meet such a market is 626 million standard cubic feet per day (MMscfd), replacing around 5.2 million tonnes of diesel per annum. This market share can be further increased given that turbine-based MtP generation is also cheaper in some instances, thus representing a lower limit for MtP’s potential. Figure 3. Comparison of Market Price for Different Fuels

0

5

10

15

20

25

1996

1998

2000

2002

2004

2006

2008

2010

2012

Year

Diesel price($/MMBTU)Methanol price($/MMBTU)Fuel oil price($/MMBTU)

However, this criterion does not represent the sole basis on which some countries make such decisions; there may be other strategic advantages to another approach that is not considered by this model, such as financing constraints, bilateral trade arrangements involving fuel and other commodities and market penetration incentives which can be lobbied. Nonetheless, to give an idea of the significance of MtP’s potential, an average of just 1 US cent per kWh reduction in electricity prices for the entire region is roughly equivalent to US$ million 200 per annum in savings. As shown previously in Tables 5 and 6, given that some countries may have significant unit cost savings (up to an order of magnitude of 10 US cents per kWh), this figure is not unrealistic, but is subject to more detailed assessment of each of the countries in the region.


7. Conclusion Energy security and affordability are important ingredients to achieving sustainable development. In this regard, it is important for the Caribbean region to move decisively away from its dependence on oil and its derivatives in order to reduce the overall power generation cost and high volatility of electricity prices. As noted here, methanol prices on an energy equivalent basis have been historically competitive with diesel. Relative to other fuels and means of transporting natural gas, advantages also include lower capital cost, minimal infrastructure requirements, use of standard equipment and materials, and ease of shipping. LNG for instance requires large capital investments for ships and storage tanks with cryogenic materials and regasification import terminals. Furthermore, because methanol can be shipped cost effectively in smaller quantities, MtP can be economic for small niche power markets such as in the Caribbean. The legal and commercial hurdles of supplying gas to the region via pipeline from Trinidad and Tobago do not arise with a MtP solution. Additionally, it is a cleaner burning fuel. Methanol is an attractive alternative fuel for meeting the energy needs of niche markets in an economic and environmentally sustainable manner, utilising existing or new power generation infrastructure in the Caribbean.

In order to further assess MtP’s potential, an integrated economic model of the MtP chain has been presented here, taking into account methanol production, shipping, importation and power generation. It is found that MtP proves to be cheaper in smaller islands which tend to pay slightly more for diesel and due to the lower economies of scale and efficiency of power generation at smaller capacities. Retrofitting reciprocating engines, which is the most prominent technology being used in the region, gives the highest savings for MtP, of up to about 10 US cents per kWh. As one would expect, as the gap between the market prices of methanol and diesel widens in favor of methanol, as is expected in the projections obtained and reported here, MtP’s economic advantage improves further. Based on these preliminary findings, there is a potential for MtP to replace at least 6000MW, or put another way 16.2 billion kWh per annum of power generation in the Caribbean region. This will require approximately 7.1 millions tonnes of methanol per annum (or 626 MMscfd of natural gas), thus providing a large new market for methanol, and hence for natural gas. Of course, there are several

factors to consider in implementing a change-out of technology in any one island, including capital outlay and financing, project viability based on detailed engineering and economic evaluation, payback period, commercial arrangement and ownership structures comprising the various stakeholders in the MtP chain, and risk distribution.

One consideration which is important but difficult to gauge is the level of subsidy for electricity provided by governments in the region. This subsidy varies from country to country and for different categories of consumers (e.g. residential versus commercial). As such, the actual data of electricity prices used here, which are known to be subsidised, do not provide a fair reference for MtP’s viability. Therefore, the savings reported are likely underestimates since pure market prices were used for computing the overall power generation cost for MtP. Furthermore, in scenarios where current fuels and technologies showed to be better, MtP may ultimately lead to savings if these subsidies were removed, thereby relieving governments of the economic burden and even provide lower prices to customers. It is estimated that with just an average 1 US cent per kWh reduction in electricity prices via MtP, a total saving of roughly US$ 200 million can be realised per annum in the region. This highlights the potential impact of a cheaper power generation option, and makes MtP worthy of further consideration.

Future work may improve on the accuracy of the cost estimates used in the economic evaluation. A probabilistic approach can be adopted to account for uncertainty and in determining the level of risk in switching to MtP. The issue of regional natural gas pricing was not specifically considered, as well as possible incentives for MtP, both of which are crucial matters at the governmental level. The price structure of natural gas for methanol production would have implications on the fuel price volatility issue which is currently a major concern for countries in the region. The viability of MtP for distant and larger markets was not the focus here, but worth evaluating. Finally, the technical feasibility of MtP needs to be assessed, i.e. equipment efficiency, reliability, availability and maintenance programme. This work is currently being undertaken by The University of Trinidad and Tobago along with Methanol Holdings Trinidad Limited which is overseeing the operation of a demonstration power plant on the Point Lisas Industrial Estate, Trinidad (Furlonge and Chandool, 2007).


99

Acknowledgements: The authors would like to thank the following institutions for their support and contribution:

· Methanol Holdings Trinidad Limited · The University of Trinidad and Tobago · Caribbean Energy Information Systems (CEIS) · The Library Services of Trinidad and Tobago’s

Ministry of Energy and Energy Industries, and Information Services Department of The National Gas Company of Trinidad and Tobago Limited.

References: Beukenberg, M. and Reiss, F. (2006), “Operation of gas

turbines using methanol as the fuel”, Man Turbo Internal Paper.

Breeze, P. (2005), Power Generation Technologies, First Edition, Newnes, Oxford.

Burns, S. (2008), “Tech Bulletin”, In the vpracingfuels webpage [online]. Available from: http://www.vpracingfuels.com/spec/Tech%20Bulletin--Methanol.doc [cited 2 February 2008].

Campbell, J.C. (2002), “Peak oil: an outlook on crude oil depletion”, Greatchange, Available from: http://www.greatchange.org/ov-campbell,outlook.html [cited 11 December 2008]

Cheng, J., Li, Z., Haught, M. and Tang, Y. (2006), “Direct methane conversion to methanol by ionic liquid-dissolved platinum catalysts”, The Royal Society of Chemistry, Vol.2006, pp.4617-4619.

Furlonge, H.I. and Chandool, V. (2007), “Methanol to power demonstration project”, GazChem 2007 Conference, Port of Spain, June, Available from: http://www.utt.edu.tt/utt/ngia/methanol_to_power.pdf [cited 20 February 2009]

General Electric (2001), “Feasibility of methanol as gas turbine fuel” (Internal document), General Electric

Hertzmark, D. (2006), “OECS energy issues and options”, Energy Sector Management Assistance Programme Report, pp.1.

Kromah, M, Thomas, S. and Dawe, R.A. (2003), “Transporting natural gas around the Caribbean”, West Indian Journal of Engineering, Vol.25, pp.18-32.

Martinez, I. (2007), “Fuel properties”, In the Isidoro Martinez fuel properties page [online]. Available from: http://imartinez.etsin.upm.es/bk3/c15/Fuel%20properties.htm#_Toc110338747 [cited 9 October 2007].

Olah, A.G., Goeppert, A. and Prakash, G.K.S. (2006), Beyond Oil and Gas: The Methanol Economy, Weinheim, Germany: WILEY-VCH Verlag GmbH & Co.

Peters, M.S. and Timmerhaus, K.D. (1991), Plant Design and Economics for Chemical Engineers, 4th Edition, McGraw-Hill

Sangtongkitcharoen, W, Vivanpatarakij, S., Laosiripojana, N., Arpornwichanop, A. and Assabumrungrat, S. (2008), “Performance analysis of methanol-fueled solid oxide fuel cell system incorporated with palladium membrane reactor”, Chemical Engineering Journal, Vol.138, pp.436-441.

Seko, T. and Kuroda, E. (1998), “Methanol lean burn in an auto-ignition DI engine”, Technical Paper Series, Society of Automotive Engineers

Seko, T. and Kuroda, E. (2001), “Combustion improvement of a premixed charge compression ignition methanol engine using flash boiling fuel injection”, Technical Paper Series, Society of Automotive Engineers

Tachiki, K. (2007), “Gasoline-blended methanol fuel for internal combustion engines”, In the Patent Storm webpage [online]. Available from: http://www.patentstorm.us/patents/5344469.html [cited 28 November 2007].

Biographical Notes: Renique J. Murray is currently a research assistant at The University of Trinidad and Tobago (UTT), where he is pursing a Doctor of Philosophy degree in the area of fuel technology and power generation. He holds a Bachelor of Science degree in Mechanical Engineering, as well as a Masters of Philosophy degree in the area of vibration analysis of rotating machines from UWI. He also has done some part-time lecturing at The University of the West Indies (UWI) in the subject of Engineering Dynamics. Haydn I. Furlonge has fifteen years of teaching, research and industrial experience in process optimization, gas market analysis, contract negotiation and business development. While at The National Gas Company of Trinidad and Tobago Ltd., he was involved in feasibility analyses of energy projects, and setting up a department for management of LNG and related gas contracts. His current role is to oversee the establishment of the Natural Gas Institute of the Americas at The University of Trinidad and Tobago, which focuses on energy-related research. He is also the Chair and Proceedings editor of the Tobago Gas Technology Conference. He has authored/co-authored about thirty journal and conference papers. He has a Ph.D. degree in Chemical Engineering from Imperial College London. He holds Chartered Engineer (C.Eng.) status, is a Registered Engineer (R.Eng.) in Trinidad and Tobago, and is a member of the Institution of Chemical Engineers (MIChemE), and International Association for Energy Economics.

http://www.vpracingfuels.com/spec/Tech%20Bulletin--Methanol.doc

http://www.vpracingfuels.com/spec/Tech%20Bulletin--Methanol.doc

http://www.greatchange.org/ov-campbell,outlook.html

http://www.utt.edu.tt/utt/ngia/methanol_to_power.pdf

http://imartinez.etsin.upm.es/bk3/c15/Fuel properties.htm#_Toc110338747

http://imartinez.etsin.upm.es/bk3/c15/Fuel properties.htm#_Toc110338747

http://www.patentstorm.us/patents/5344469.html

Call for Papers: Special Issue on Engineering Asset Management: Current Trends and Challenges

THE JOURNAL OF THE ASSOCIATION OF PROFESSIONAL ENGINEERS OF TRINIDAD & TOBAGO Volume 39 Number 1 2010; ISSN 1000 7924 CALL FOR PAPERS Special Issue on “Engineering Asset Management: Current Trends and Challenges” Engineering Asset Management (EAM) is an emerging inter-disciplinary field that combines technical issues of asset reliability, safety and performance with financial and managerial requirements. British Standards Institution defined EAM as “systematic and coordinated activities and practices through which an organisation optimally manages its assets, and their associated performance, risks and expenditures over their lifecycle for the purpose of achieving its organisational strategic plan”. EAM is concerned with assets throughout the lifecycle. The emphasis of EAM is clearly on sustainable business outcomes, risk management and value.

Engineering asset management continues to grow in importance in both public and private sector organisations in both developed and developing countries. It is intended that contributions will provide a better understanding of trends and best EAM practices that meet the diverse needs and challenges in the Caribbean Region. This special issue will present researchers, practitioners and senior managers with tools, models, and the empirical bases for EAM practices. The prime objective of the special issue is to publish original works and empirical results arising from research and practices on EAM and related disciplines. Contributed papers may deal with but are not limited to:

• Financial Management for Engineered Assets • Issues of Asset Reliability, Safety and Performance • Knowledge Management for Engineered Assets • Life-Cycle and Risk Management • Maintenance Requirements Analysis • Managing People in Organisations • Modelling of Engineering Management Systems • Project Implementation and Outsourcing • R&D in Engineering Assets Management • Systems Reliability Engineering • Value Engineering and Management

• Asset Management and Maintenance Strategy • Asset Management Standards and Specifications • Asset Management System Design • Benchmarking of Maintenance Practices • Business Process Re-engineering • Collaborative Maintenance Chain • Concurrent Engineering • Education in Engineering Assets Management • Emerging Maintenance Practices • Engineering Asset Procurement • e-operations and e-procurement

Submission Guidelines and Important Dates Manuscripts should be in English and normally not exceed 6,000 words in length, with all contributions being subject to a double blind review process. There should be a separate title page giving the names and addresses of the authors. Manuscripts must be sent electronically <[email protected]> in both Word document and pdf formats to the Editor no later than 31st October 2009. Notes for contributors can be referred to the official website of The Journal of The Association of Professional Engineers of Trinidad and Tobago (http://www.apett.org/pubs_main.php). Important Dates:

• Extended Deadline for paper submission: 30th November 2009 • First turn of papers review: 31st December 2009 • Second turn of papers review: 28th February 2010 • Final papers submission: 31st March 2010 • Targeted date of publication 30th April 2010

For submission and enquiries, send to:

Or Guest Editor, Prof. Chanan S. Syan Professor of Production Engineering and Management c/o Faculty of Engineering, University of the West Indies, St Augustine Campus, Trinidad & Tobago West Indies E-mail: [email protected]

Eng. Prof. Kit Fai Pun Editor-in-Chief, The Journal of APETT, c/o Faculty of Engineering, University of the West Indies, St Augustine Campus, Trinidad & Tobago West Indies

Fax: (868) 662 4414 E-mails: [email protected]; [email protected]


http://www.apett.org/pubs_main.php


Association of Professional Engineers of Trinidad and Tobago Executive Council 2009- 2010

Eng. Hannah Wei-Muddeen President Eng. Richard Saunders President-Elect Eng. Hollis Eversley Vice President Eng. George Preddie Vice President Eng. Margarita Leonard Honorary Secretary Eng. Simon Westcott Assistant Secretary Eng. Trevor De Landro Honorary Treasurer Eng. Naeem Hasnain Assistant Treasurer Eng. Kala Trebouhansingh Public Relations Officer Eng. Ahmin Z. Baksh Immediate Past President Eng. Stanley West Chair, Mechanical and Industrial Division Eng. Prof. Winston Mellowes Chair, Chemical Division Eng. Collette John Chair, Electrical Division

Author guidelines The Journal of The Association of Professional Engineers of Trinidad and Tobago Copyright: Articles submitted to The APETT Journal should be original contributions and should not be under consideration for any other publication at the same time. Authors submitting articles for publication warrant that the work is not an infringement of any existing copyright and will indemnify the publisher against any breach of such warranty. For ease of dissemination and to ensure proper policing of use, papers and contributions become the legal copyright of the publisher unless otherwise agreed. Submissions should be sent to: The Editor: Professor Kit Fai Pun, c/o Faculty of Engineering, The University of the West Indies, St Augustine, Trinidad and Tobago, West Indies. Tel: 1-868-662-2002 ext-2068/2069; Fax: 1-868-662-4414; E-mails: [email protected]; [email protected] Editorial Aim and Policy: The journal aims to provide a broad international coverage of subjects relating to engineering. It welcomes the submission of papers in various engineering disciplines and related areas. Emphasis is placed on the publication of articles which seek to link theory with application or critically analyse real situations with the objective of identifying good practice cross different engineering and related disciplines. Preference will be given to papers describing original engineering work, or material of specific interest to engineers and those working in related fields, in Trinidad and Tobago and the Caribbean region.

Articles may be of a theoretical nature, be based on practical experience, report a case study situation or report experimental results. The prime requirement for acceptance of an article will not be its form but rather that it: (1) makes a significant original contribution to the field of engineering

and the advancement of engineering practices; (2) is directly relevant to engineering, engineering management and

technology, and related areas; (3) contains elements which have general application; (4) is within the scope of the journal coverage; and (5) has generally not been published previously except in very limited

circulation. If it is felt that a contribution, though technical in nature, will be of

broad interest, it may be published under a "technical paper" heading. A paper can be considered for publication as a "research note" if it reports work-in-progress on research which has not yet reached a stage where there are any final results or conclusions. Its value will be judged by the extent to which it contributes to a debate on the research problem, methodology, techniques of data analysis, etc. The reviewing process: Each paper is to be reviewed by the Editor and, if it is judged suitable for this publication, it is then sent to two referees for double blind peer review. Based on their recommendations, the Editor then decides whether the paper should be accepted as is, revised or rejected. Manuscript requirements: Three copies of the manuscript should be submitted in double line spacing with wide margins. The author(s) should be shown and their details must be printed on a separate sheet. The author(s) should not be identified anywhere else in the article.

As a guide, technical/research papers should be between 3,000 and 6,000 words in length. Shorter articles (Communications, Discussions, Book Reviews, etc.) should be between 500 and 2,000 words. Please provide the word count on the first page of your paper. A title of not more than eight words should be provided. A brief autobiographical note should be supplied including full name, affiliation, e-mail address and full international contact details. Authors must supply a structured abstract set out under 4-6 sub-headings: Purpose; Methodology/ approach; Findings; Research limitations/ implications (if applicable); Practical implications (if applicable); and the Originality/value of paper. Maximum is 250 words in total. In addition provide up to six keywords which encapsulate the principal topics of the paper and categorise your paper.

Where there is a methodology, it should be clearly described under a separate heading. Headings must be short, clearly defined and not numbered. Notes or Endnotes should be used only if absolutely necessary

and must be identified in the text by consecutive numbers, enclosed in square brackets and listed at the end of the article.

All Figures (charts, diagrams and line drawings) and Plates (photographic images) should be submitted in both electronic form and hard copy originals. Figures should be of clear quality, in black and white and numbered consecutively with Arabic numerals.

Figures created in MS Word, MS PowerPoint, MS Excel, Illustrator and Freehand should be saved in their native formats.

Electronic figures created in other applications should be copied from the origination software and pasted into a blank MS Word document or saved and imported into an MS Word document by choosing "Insert" from the menu bar, "Picture" from the drop-down menu and selecting "From File..." to select the graphic to be imported.

For figures which cannot be supplied in MS Word, acceptable standard image form ats are: pdf, ai, wmf and eps. If you are unable to supply graphics in these formats then please ensure they are tif, jpeg, or bmp at a resolution of at least 300dpi and at least 10cm wide.

To prepare screen shots, simultaneously press the "Alt" and "Print screen" keys on the keyboard, open a blank Microsoft Word document and simultaneously press "Ctrl" and "V" to paste the image. (Capture all the contents/windows on the computer screen to paste into MS Word, by simultaneously pressing "Ctrl" and "Print screen".)

For photographic images (plates) good quality original photographs should be submitted. If supplied electronically they should be saved as tif or jpeg riles at a resolution of at least 3oodpi and at least 10cm wide. Digital camera settings should be set at the highest resolution/quality possible.

In the text of the paper the preferred position of all tables, figures and plates should be indicated by typing on a separate line the words "Take in Figure (No.)" or "Take in Plate (No.)". Tables should be typed and included as part of the manuscript. They should not be submitted as graphic elements. Supply succinct and clear captions for all tables, figures and plates. Ensure that tables and figures are complete with necessary superscripts shown, both next to the relevant items and with the corresponding explanations or levels of significance shown as footnotes in the tables and figures.

References to other publications must be in Harvard style and carefully checked for completeness, accuracy and consistency. This is very important in an electronic environment because it enables your readers to exploit the Reference Linking facility on the database and link back to the works you have cited through CrossRef. You should include all author names and initials and give any journal title in full.

You should cite publications in the text: (Adams, 2008) using the first named author's name or (Adams and Brown, 2008) citing both names of two, or (Adams et al., 2008), when there are three or more authors. At the end of the paper, a reference list in alphabetical order should be supplied: • For books: surname, initials, (year), title of book, publisher, place of

publication, e.g. Mulder, K. (2006)(ed), Sustainable Development for Engineers: A Handbook and Resource Guide, Greenleaf Publishing, Sheffield, UK.

• For book chapters: surname, initials, (year), "chapter title", editor's surname, initials, title of book, publisher, place of publication, pages, e.g. Liebowitz, J. (2005), "Conceptualising and implementing knowledge management", in Love, P.E.D. et al., (ed.), Management of Knowledge in Project Environments, Elsevier, New York, NY, pp. 1-18.

• For journals: surname, initials, (year), "title of article", journal name, volume, number, pages, e.g. Nathai-Balkissoon, M. and Arumugadasan, N.S. (2004), “Implementing Hazard Analysis Critical Control Points (HACCP) in a Food Plant", Journal of APETT, Vol. 35, No. 1, October, pp.32-38.

• For electronic sources: if available online, the full URL should be supplied at the end of the reference.

Final submission of the article: Once accepted for publication, the Editor may request the final version as an attached file to an e-mail or to be supplied on a diskette or a CD-ROM labelled with author name(s); title of article; journal title; file name.

The manuscript will be considered to be the definitive version of the article. The author must ensure that it is complete, grammatically correct and without spelling or typographical errors.

The preferred file format is Word. Another acceptable format for technical/mathematics content is Rich text format.

journal of the association of professional … · on the development of sustainable vlsi...

Documents