a waste-to-energy plant for municipal solid waste management at the

8/19/2019 A Waste-To-Energy Plant for Municipal Solid Waste Management at The

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A Waste-To-Energy Plant for Municipal Solid Waste Management at the

Composting plant in Isfahan, Iran

Saeed Esfandiari

Institute for International Energy Studies (I.I.E.S.), Energy

Economics Research Center,

65, Sayeh St., Vali-e-asr Ave., Tehran 1967743711, Iran,[email protected]

Ramin Khosrokhavar ** Iran Polymer & Petrochemical Institute (IPPI),

Pazhoohesh Blvd., Km 17, Tehran-Karaj Hwy, Tehran, I.R.

Iran, P. O. Box: 14965/115,

[email protected]

Masih Sekhavat Parsian Energykaran Development Engineering & Management Co. (PEDEM),

Clean Development Mechanism Office, 1st Floor,

No.6, 18 Street, Yousefabad Avenue, Tehran, 1431894476, Iran,

[email protected]

Abstract — Municipal solid waste problems have become a

major concern in Iran. No concrete study has been done yet ondeveloping Waste-to-Energy technology as a complementarysolution for the current Municipal Solid Waste (MSW) crisis inIran. Apart from the available consistent data on wastecompositions and quantity, the authors of this paper haveconducted a new survey to identify problems and alternatives toimprove the current system.

The study objectives of the current study are as follows:•

To determine the current integrated solid wastecomposition and the generation of Refused Drive Fuel(RDF);

• To investigate the current solid waste management

system of Isfahan in which the compost site plays amajor role.The foremost challenge Isfahan city is facing is from

landfilling. The examination of the project has been carried outthrough interviews with municipal authorities, review ofexisting documents, and field observations.

The organic fraction of solid waste composition in Isfahan

composting plant comprised about 75 percent. The generation

of waste in this plant was estimated to be approximately 844

Ton Per Day (TPD) (308,060 tons of MSW per year) of which,

about 500 TPD is rejected from the composting lines. The

current chain of management system is inefficient, and

recommendations are given by the authors of this paper to use

Waste-to-Energy technology to improve the present situation.

Keywords: Municipal Solid Waste (MSW) Management, Sustainable Development, Waste-to-Energy, Isfahan city,

Composting

I. I NTRODUCTION

Solid waste has turned out to be one of the challengesfacing humanity in the last half a century. Municipal SolidWaste (MSW) is, in fact, a serious business in dry areas likeIran. One of the main reasons behind this environmentaldisaster in Iran is lack of an acceptable system of naturalresource management, including the management of MSW.This is to say that waste is the one of the factors determiningthe fragile system of life in the rural and urban communitiesin Iran and it has not been developed and managed to the

extent required. The lack of Environmental ImpactAssessment is a major factor contributing to the currentdroughts, lack of grasslands, large population growth andincreasing urbanization. These are major factorsexacerbating less carbon emission reduction and thuscontributing to increased climate change vulnerability andenvironmental crises in Iran and its provinces. Problemsstemming from international sanctions such as securingeffective financing and equitable integrated solid wastemanagement technology could become acute in the future.

In Iran, MSW forms part of the political decision-making, and integrated solid waste management technology

could not be reached without first making a major shift insocial and political thinking. The Government, through theInterior Ministry, has the responsibility to create conditionsto provide integrated solid waste management. This ismanifested under article 123 of the Iranian Constitutionformulated after the Iranian Revolution in 1978. For the time

being in Iran, developing Waste-to-Energy technology is acomplementary solution for the current MSW crisis andenvironmental issues. It can also act as a tool for socio-economic development and more importantly, a solution forhuman and environmental health improvements. It istherefore, an important tool for the entire security of thehuman environment and also means building an economicfuture that goes beyond green culture.

II.

MATERIALS AND METHODS

The study was conducted in May 2010 in the compostingand recycling plant of Isfahan Municipality located in theGardaneh Zeynal region, which has a total land area of 100hectares with three parallel production lines. Isfahan had a

population of 3,430,353 in the 2006 Census comprising686,070 households. The study covered the composting andrecycling plant of Isfahan municipality which treats theMSW from Isfahan and its surrounding zones producingapproximately 308,060 tons of MSW per year (around 844tons per day) which otherwise would be disposed in landfills.The landfill sites in Isfahan do not currently have anyinfrastructure for gas capturing systems and such systems are

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2011 2nd International Conference on Environmental Science and Technology IPCBEE vol.6 (2011) © (2011) IACSIT Press, Singapore



not foreseen to be installed in the future. The quantity ofmunicipal solid waste entering to Isfahan compost plant isapproximately 844 TPD (308,060 tons of MSW per year) ofwhich about 500 TPD is rejected from the lines (some partsin the middle of the line and other parts at the end of line).

This study followed 2 stages. Firstly, the municipal solidwaste entered the plant and its composition (Table 1) [5] wasdetermined. Secondly, we would figure out the investigationof current waste management of Isfahan compost andrecycling plant. This was conducted by using the weight ofthe entering waste, the weight of the rejected waste from thelines and their average composition and finally, the proposedsolution for the rejected waste.

TABLE I. E NTERING WASTE ANALYSIS

Name of ComponentYear 2010

Weight ( kg) Percentage %

Organic matter 672849 79.6

Paper Cardboard 32950 3.9

Textiles 16053 1.9

Clothes 18717 2.2

Wood 6434 0.8

Plastics 62196 7.4

PET 6479 1.3

Disposable dishes 6174 0.7

Glass 8254 1

Stone 3510 0.4

Iron 4614 0.5

Others 1105 0.1

To determine the waste composition, five samples werecollected from five different collection spots and aquestionnaire was also provided for engineers at the plantsite to obtain further information regarding the compositionof the waste.

In conclusion, after reviewing the obtained records ofdata and information, the proposed solution for the rejectedMSW from the plant will be provided. [10,4]

III. DISCUSSION AND R ESULTS

Isfahan faces its biggest challenge today which is 500TPD waste deposited into the traditional landfill. It became

apparent to municipal solid waste (MSW) managers that agarbage crisis was imminent in Isfahan’s more heavily

populated regions. Studies of effective waste managementoptions consistently indicated that the frugal practices of acentury ago held the greatest promise of lessening the needfor new composting plant and incinerators. Afterestablishment of Isfahan composting plant, the products ofthis plant have beneficial properties for growing plants in thegreen spaces of the city and also help retain moisture whileallowing good drainage. Nutrients are better able to cling tocomposted soil particles, so the need for chemical fertilizerscan be reduced. Moreover, roots are able to penetrate deeperinto the soil, resulting in healthier plant growth in dry

weather of this region. Less fertilizer and better soil penetration reduce fertilizer run-off into the Zayandeh RoudRiver and streams.

A.

Current Integrated Solid Waste Management in IsfahanThe municipality of Isfahan, based on hierarchy of

integrated solid waste management, employs both of the twotechnologies, namely recycling and composting. However,sanitary landfill is not considered as an alternative, because itmust be developed in whatever system being chosen and alsothe use of landfills is always required no matter whatintermediate treatment process.

Beside composting, separation or recycling, there willalways be residue left that has to be deposited in landfill. Inthis context, Isfahan’s Department of MSW has planned touse the technology of waste incineration which has been thekey technology for MSW treatment in recent decades.Incineration, however, requires a high amount of local wasteand financial resources. MSW contains a large portion oforganic materials for which the biotechnological processesalso offer adequate technologies.

B. Recycling Technology

The recycling process at the Isfahan plant starts with thecollection of valuable waste from waste generators, and isfollowed by processing and reprocessing phases. Therecyclables are collected from curbsides, drop-off or buy-

back centers. Currently, the Isfahan composting andrecycling plant manually recycles the PET materials in orderto reuse some polymer materials from the waste. [1]

Recycling technology is considered to be important because it accounts for a 20 percent reduction of the waste

that must be disposed of in landfills. There are many benefitsoffered by recycling in Isfahan, such as: conserving nature,cutting back on energy use, and increasing landfill life span.Among the valuable materials to recycle are aluminum,

paper and cardboard, plastic, glass and metal.

C. Composting Technology in Isfahan

Composting is a controlled process where organicmaterial is biodegraded by microorganisms to produce the

black and stable compost. The composting process can bedone in many ways; as passives piles, turned windrow,aerated static piles, or in-vessel systems. All the systemshave the same biological principles, but they differ in theaeration system.

TABLE II. WASTE (FOR INCINERATION) ANALYSIS

The name of

components

The contents of

components to a

lump, % weight

Paper, cardboard 3.66

Food waste products 1.24

Irons (metals) 0.59

Textiles 5.15

Glass 0.52

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Stones, ceramics 0.52

Organic matter 33.89

Nylon plastics 52.09

Hard plastics 0.28Pets 0.28

Diapers 0.86

Pads 0.31

Disposable dishes 0.52

Composting offers many benefits such as increasing thediversion rate from the waste disposal areas (50%),

providing compost products for soil amendments, and the promotion of an environmentally-friendly practice. InIsfahan, composting is one of the most common practices tohandle agriculture and urban waste. However, presently,there is just one application for municipal solid waste in theregion where compost comprises almost 70 percent of thewaste in organic materials.[1]

Isfahan MSW composting uses a mechanical process thatincludes the shredding of waste and closely monitors itscondition while it is composting. MSW composting ofIsfahan greatly accelerates the process of turning organicgarbage into a soil-like material called "humus".

IV. "WASTE-TO-E NERGY" A FINAL SOLUTION FOR THE

CURRENT MSW CRISIS IN ISFAHAN

Incineration is a chemical process where carbon,hydrogen, and a few elements mix together with oxygen to

produce heat energy. This technology is able to reducetoxicity, reactivity, and high volume of waste effectively

(can divert 85% of municipal waste from disposal site).However, it is very costly and must be operated by highlytechnical experts.

The three common incineration technologies currentlyavailable are mass burning, refuse-derived fuel, and modularsystems. As discussed before, 500 TPD of the MSW iscurrently rejected from the Isfahan composting and recycling

plant and remain uncontrolled and are discharged in alandfill site in Isfahan. With regards to the high amount of

plastics in the composition, 52.09 %, (Table 2) [5], the bestway for solving the problem is the installation of the Waste-t- Energy (WTE) plant with moving grate incinerationtechnology.

In order to enable realistic predictions, the following

proposed project is made by taking account of the calorificvalue of the contents of the waste burned in the proposedWTE plant:

A. Technical specifications for the WTE plant in Isfahan

• The technology used is moving grate incineration process;

• Producing steam and electricity (18 MW);

• Calculated capacity of the plant is around 180,000tons RDF & MSW per year;

• No humidity and calorific values;

• High level of ash content is 40%;

• Based on the waste analysis (Table 2) the estimation prognosis for caloricity value is around 4300Kcal/kg which is attributed to the high content of

plastics in waste [6-8]. B. Description of the Technology

Grate furnace incinerator is one of the most commontechnologies for incineration of MSW. It usually operates ina gas-temperature range of 750°C to 1000°C. Air forcombustion is supplied by fans or blowers under and over thegrates. The main variations in this technology are associatedwith the design of the grates (either fixed or moving). Themoving grates are designed to increase mixing and air flowin the mass of burning waste in order to achieve a morecomplete combustion. [2]

Moving grate energy from waste plants designed tohandle large volumes of wastes with no pre-treatment. Their

facilities typically have two or three combustion units inwhich the capacities range from 100 TPD to 3000 TPD.Modern waste-to-energy plants tend to be moving grateincinerators: the waste is slowly propelled through thefurnace by a moving mechanical grate, and the wastecontinuously enters at one end and

Figure 1. Grate Incinerator

the ash is discharged at the other end. The combustion process is also aided by gravity. As the waste descends, itgoes through three stages in the process: drying, combustion,and burnout. Considerable attention has to be given to ensurethe necessary conditions for optimum combustion. [9]

By installing such a proposed WTE plant near the Isfahancomposting and recycling plant, all the entering waste (100%)will be treated and therefore there is small portion ofdischarge of waste to the environment. This also improveshealth and sanitation conditions of the local people andresults in efficient processing of waste and a reduction inwaste volume at landfill sites. The local benefits of this

project are recycling of resources, better management of

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solid waste, and producing electricity from green sources(green energy). Since the price of the WTE plant will besubsidized using revenues from carbon credit, the marketingof WTE plant will become easier, and thus ensures thesustainability of the project.

C. Technical Specifications for an Eligible Project within

the Framework of the Kyoto Protocol

The Clean Development Mechanism Projects requiresustainable development, an environmentally sound,additionally cost-effective, and socially acceptablemanagement of municipal and industrial waste.

Landfilling of municipal solid waste (MSW) is known tolead to emissions of a chemical and landfill gas, above allmethane, which contributes to the greenhouse effect. Due tothis traditional landfilling, the Iranian new law directive onthe Management of Solid Waste in 2002 mandated a gradualreduction of biodegradable wastes to be landfilled to reducethe production of methane gas in order to diminish globalwarming and also to avoid any harmful effect on theenvironment; also, residual waste has to be pre-treated priorto landfilling. [3, 7]

As a matter of fact, Isfahan MSW composting was builtunder the visions explained above and it has severalsignificant advantages over traditional composting. Mostimportantly, Isfahan MSW composting plant can make useof a much broader range of household wastes, including

paper and wood products and provides enough feeds for the proposed WTE plant. At the present time, the IsfahanCompost Facility utilizes 70 to 80% of the solid wastegenerated in the city, which would normally go to a landfill,and thereby turning today's refuse into a useable product.

V. CONCLUSION

The Isfahan composting and recycling plant contributesto the mitigation of greenhouse gas (GHG) emissionsthrough the aerobic decomposition of organic waste and also

by recycling of polymer materials like PET into re-usable polymer materials; moreover, the MSW collected fromvarious zones in Isfahan were treated in Isfahan compost andrecycling plant. The main problem is 500 TPD of the MSWrejected from the plant which is disposed in the landfill siteand leads to the anaerobic decay of biodegradable waste; thisultimately results in methane generation among other landfill

gases. Since most of the content of the rejected MSW is plastic and, according to the multidisciplinary investigationobtained from the engineers of the Isfahan composting andrecycling plant, WTE consulting companies, and analysis ofthe waste contents, it is highly recommended that a WTE

plant be constructed near Isfahan compost and recycling toconvert this remaining waste into energy, i.e. electricity.

R EFERENCES

[1] L. A. Manaf, H. Basri, "An Intelligent System for IntegratedSystem for Integrated Solid Waste Management", ProceedingsMalaysia 2008, Vol. 1, No. 2, July 2008, published by Journalof Sustainable Development.

[2] L. Bontoux, “The incineration of waste in Europe: Issues and perspectives”, A Report Prepared by IPTS for the Committeefor Environment, Public Health and Consumer Protection ofthe European Parliament, March 1999.

[3] JE. Bogner, CA Lee, J. Chanton, and K. Spokas “ ReducingGreenhouse Gas Emissions Through Landfill Gas Recovery inSouth Africa”, Proceedings WASTECON 2004, October,2004, Sun City, South Africa, published by the Institute ofWaste Management South Africa.

[4] Norbu, S. Dilokwanich, "Municipal Solid Waste Managementin Phuntsholing City, Bhutan", Proceedings EnvironmentAsia,3(1) (2010), 111-116, published by the Thai Society of HigherEducation Institute on Environment.

[5] T. Bajoul, "Physical and Chemical Analysis of the Waste

(Line 1,Line 2,Line 3)", A report prepared by the IsfahanComposting and Recycling Municipality Organization,August 2010

[6] T. Bajoul, "Feasible study of designing a WTE plant", Areport prepared by the Isfahan Composting and RecyclingMunicipality Organization, August 2010

[7] U.S. Environmental Protection Agency, “Opportunities to

Reduce Greenhouse Gas Emissions through Materials andLand Management Practices”, Office of Solid Waste andEmergency Response, EPA 530-R-09-017, September 2009,(5105T) www.epa.gov/oswer/

[8] V. Shiryaevsky, “Technical Specifications for WTE plant", A report prepared by Stroytransgaz Co., May 2010

[9] V. Shiryaevsky, "WTE Projects, Technological and

Economical Solutions at Glance", A report prepared byStroytransgaz Co., May 2010

[10] YJ. Chang, S. Fu and MD. Lin, “Future Assessment ofMunicipal Solid Waste Management Strategy for TaichungSpecial Municipality in Taiwan”, Proceedings IMECS 2010,Vol. III, March 2010, Hong Kong, published by Theinternational Multi Conference of engineers and computerscientists Hong Kong.

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