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Republic of the PhilippinesLocal Water Utilities Administration

SEWERAGE AND SANITATION PROJECTWATER DISTRICT DEVELOPMENT PROJECT

ml.w) WORLD BANK

ENVIRONMENTALASSESSMENT

LU2'ON REPORT

COTABATO CITY

OF9ISArAS

MINDAHAO

co 7'0~~

CO TA BATOCITY

July 1997

TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY 1

Chapter 1 INTRODUCTION 12

Chapter 2 BASELINE ENVIRONMENT - COTABATO CMTY 16

Section I Existing Environment 16Section II Environmental Pollution 18

Chapter 3 PROJECT DESCRIPTION ANID ANALYSIS OF ALTERNATIVES 25

Section I Project Rationale and Objectives 25Section II Sanitation 25Section m Overall Sewerage Scheme 28Section IV Recommended Project Design for Cotabato City 40Section V No Project Scenario 44

Chapter 4 ENVIRONMENTAL IMPACTS 45

Section I Beneficial Impacts of the Project 45Section II Project Implementation Impacts 47Section III Summary 50

Chapter 5 ENVIRONMENTAL MANAGEMENT PLAN 51

Section I Mitigation Plan 51Section II Monitoring Plan 53Section m Implementing Arrangements 54

Appendices

1. Bibliography2. Climatological Normals (1961-1995)3. Typical Noise Emissions of Construction Equipment4. Expected Noise Levels at Various Distances from Construction Equipment5. Environmental Quality Standards For Noise Maximum Allowable Noise Levels6. The Advanced Integrated Pond System (ALPS) of Wastewater Treatment

EnmironmentalAssessmentReport: Cotabato City i

EXECUTIVE SUMMARY

Introduction

In the Philippines, the typical urban area/bulk-up area is characterized by a heavy concentrationof activities, both commercial and industriaL It is also the area where the density of populationis at its highest. These areas are also the sites where the production and consumption of rawand processed materials could be found. Consequently the, pressure on the life supportsystems in these areas are far higher than the suburban and rural areas. Adverse environmentalconditions such as the generation and similarly the discharge of wastes into the environment iscommon in urban and built-up areas. Unfortunately, the amount, type and concentration ofwaste generated exceed the capacity ofthe local environment to absorb and assimilate them.The canying capacity of the life support systems are stretched to the limits. The urgency ofestablishing collection and treatment methods to prevent adverse impacts to the health andwell-being of the residents, and to the ecological systems which sustain them cannot be ignoredand overstated.

Most urban centers in the Philippines rely on individual septic tank systems for thetreatment and disposal of wastewater from domestic and commercial buildings. However,the designs for such systems is often inadequate. Facilities for land disposal of effluentsfrom the septic tanks are generally absent. Hence, the partialy treated septic tank effluentsflow directly into storm drainage systems and other receiving bodies of water, therebyexacerbating an already grave polution situation.

There are several possible options for addressing this problem, including improving thedesign of the septic tank system with the instalation of soil absorption systems. But anenvironmentally sound altemative that is cost-effective and captures economies of scale isto connect individual properties directly to a sewerage system for the collection, treatmentand disposal of the urban wastes.

The provision of a cost-effective centralized wastewater collection, treatment, and disposal isthe primary objective of the proposed Water Districts Development Project. The proposedproject will assist the local govemment units (LGUs) of Dagupan City, Calamba (in Laguna),Cagayan de Oro City, Davao City and Cotabato City, in finding solutions to the problem ofsanitation. Financing assistance will be partly provided by the World Bank (WB) which shallbe conduited through the Land Bank of the Philippines (LBP). Over-all admmiistration will beexercised by LBP's Project Management Office (PMO) with technical support provided by theCentral Sewerage and Sanitation Program Support Office (CPSO) ofthe Local Water UtilitiesAdministration (LWUA).

Environmental Assessment Report: Cotabato City

Better sanitary conditions will thus be achieved in the areas served by the sewerage,drainage and sanitation systems. This will reduce water-borne pollution and water-loggingwithin the cities and in the surrounding water bodies, thereby bringing health benefits tolocal populations. The construction of the systems will protect shallow groundwateraquifers from contamination.

Environmental Assessment Requirements

This Environmental Impact Assessment Report for Cotabato City has been prepared inaccordance with the Presidential Decree No. 1586 otherwise known as the EnvironmentalImpact Assessment Law and Department of Environtment and Natural Resources (DENR)Revised Administrative Order Nos. 36, the Revised Water Usage and Classification/WaterQuality Criteria and Revised Effluent Regulations of 1990 respectively; and World Bank'sOperational Directive 4.01 on Environmental Assessment. The revised Administrative Order36 for Environmental Impact Statement System issued in 1996 is comprehensive and iscompatible with the World Bank's Operational Directive 4.01. It outlines the procedureto be followed by environmental critical projects (ECPs) and projects to be located inenvironmental critical areas (ECAs), in preparing environmental impacts statement(EISs)1. ECP and ECA are defined in the AO. It should also be noted that that localordinances and regulations governing projects of such nature have been taken intoconsideration in preparing this report. Similar EIA reports are being prepared for the other 4cities.

This report has been prepared by a team of local consultants under the aegis ofthe LWUA andthe Cotabato City Government. Much ofthe work relating to the environmental impactanalysis was undertaken as part of the feasibility study done by C. Lotti and AssociatiConsultation with the community is an on-going process. The sanitation component oftheproject will be executed in a participatory manner, and detailed guidelines have been spelledout.

Selection of Priority Cities

The choice of the first batch of Philippine cities for sewerage investments was made afteran initial screening at the national level of urban areas facing the most serious problem ofpollution by untreated wastes. Of the five cities, Davao and Cagayan de Oro represent thelargest class of provincial cities with current population estimates in the range of a millionand half a million respectively. There are several major population concentrations in thecity; each being a source of sewage contamination for nearby surface and ground water.However, the largest volume of sewage is generated by the largest consumers of pipedwater supply; in the Central Business District or Poblacion area. Untreated wastewaterfrom this area has polluted low-lying coastal areas, and basically converted the principalrivers into open sewers. The scale of the pollution problem can be appreciated by the factthat about 90 per cent of the daily water supply of 140,000 cubic meters in Davao city and

This is the termn used by DENR and refers to the standard Environmental Assessment Reportrequired by the World bank as per OD 4.01

Environmental Assessment Report: Cotabato Citv 2

76,000 cubic meters in Cagayan de Oro is being discharged as untreated or undertreatedwastewater. Outside the Poblacion areas, there are pockets of population concentrationspolluting nearby streams, creeks and drainage channels.

In the other three cities of medium size (Cotabato City, Calamba and Dagupan City),current population estimates are close to 200,000. While the scale of urban pollutionproblems are not comparable with Davao and Cagayan de Oro, these cities are locatedclose to environmentally sensitive wetlands and water bodies. In Cotabato city, the urbanarea is actually below the mean sea level, exposing inhabitants to frequent flooding andwaterlogging during the monsoon months. Calamba is located on the shores of LagunaLake, which has experienced a rapid deterioration in water quality over the last twodecades. Dagupan city is close to a large estuarine zone with ecologically sensitivewetlands and fishponds. In each of these cities, Mayors and city officials have recognizedfor some time that unless their complex environmental problems are tackled through astrategic plan of handling waste disposal sustainability of urban growth could be seriouslyaffected.

Overall Project Approach

The proposed project follows a demand-based approach in the sense that facilities will beconstructed only if they conform with the preferences of local stakeholders, and servicesconform to their respective willingness to pay. The stakeholders represent the differenttiers of organizations from the City Council and Barangay (part of the formal LGUsystem), to the more informal purok, neighborhood and household levels. During projectpreparation, the idea of involving communities in the planning process was field-tested inthree barangays of Davao city, and found to be quite successfuL The basic decision-making process is as follows:

For the capital-intensive trunk system, consisting of the main transportationsewers, primary drains and wastewater treatment facilities, the projectdesign and implementation plan has to be approved by the City Council,because the latter is responsible to repay the loan [see Annex 3 of the StaffAppraisal Report (SAR) for the Project on Financial Aspects].

For the feeder system, consisting of collector sewers, secondaly drains and on-sitesanitation facilities, barangays and local neighborhoods will be associatedwith the planning and implementation program. The design criteria havebeen simplified, so that the feeder system can respond to local preferencesand willingness to pay, rather than be bound by any conventional sewerdesign criteria used in industrialized countries. Detailed design will beconducted through a participatory process described in Annex 13 of theSAR

Given the capital-intensive nature of the investments, the proposed project is only theinitial phase of a program to improve the sanitation infrastructure through a strategicplanning approach that involves a mix of on-site and off-site wastewater collection,

EnvironmentalAssessment Report: Cotabato City 3

treatment and disposal. Choice of initial service areas for sewerage has been confined tothe Central Business Districts or Poblacion areas because these are the major contributorsto municipal wastewater pollution. The only exception made is in the case of Davao City,where a second area of high growth prospects (Toril) has also been included on therequest of the LGU.

The project will construct a sewer network that will discharge sewage to a verticallyintegrated pond system designed to treat both sewage and septage. In each of the cities,with the exception of Davao, the treatment site was selected in areas free fromencumbrances.

For the sanitation and drainage components, the entire city has been included in theproject area, with final selections being made on the basis of demand. On-site treatmentsystems through the construction of VIP (ventiliated improved pit) latrines, pit latrines,pour flush toilets and septic tanks will also be constructed if there is demand fromproperty owners. For those properties with uncertain land tenure (as in squattersettlements), the project will finance the construction of communal toilets, to be managedby non-governmental organizations (NGOs) and/or the private sector. The specificlocations of these facilities will be driven by the willingness to pay for the services bybeneficiaries at the barangay level provided of course that these are technically feasible.

Analysis of Alternatives

The recommended solutions for wastewater treatment were arrived at after an intensiveprocess of evaluating alternatives during the project preparation in order to achieve costeffectiveness and acceptabilty. The alternatives considered were anaerobic/facultativePonds, modified lagoon systems and mechanical treatment. The evaluation of alternativesindicated that the modified lagoon systems, despite having a higher operation &maintenance (O&M) costs compared to anaerobic/facultative ponds (as it requiresmechanical aerators and recirculation pumps) was appropriate. The selected option metthe following criteria the effectively:

Minimize overall pond area required

Minimize odor production

Meet DENR effluent quality criteria, including fecal coliform reduction

Minimize sludge production rate

Maximize potential to use surrounding land for recreational purposes

Environmental Assessment Report: Cotabato City 4

Summary Information on Project Cities

Davao Cagayan de Oro Cotabato Calamba Dagupan

Population (1990) 849.947 339.598 127.065 173.453 128.000

Housmg 163,329 47.724 21.581 32.109 21.219

Size of Central 1 000 hectares 400 hecares 120 hectares 95 hecLares 50 hectaresBusmness Distrc(CBD)

Morbidity rateper 595 for 733 for diarrhea 3050 for diarrhea S18 forparasiti 528 forgastro-10.000 from diarrhea(tbird rank (third rank) (first rank) (secmd rank) eateitis (third rank)diseases arnong diseases)

Water bodies at Davao river and al1 Cagayan nver and About 50%0 of city Laguna Lake About 50Y. af cityrisk because of beaches close to adjoining beaches area ceasints of expeiencing area are wetlands.mnumicipal poUution citv not fit for an Macajalar Bay wetlands, fish poids mrnease in turbidity used for fish

recreaticsal unfit for and eisuarine area and rapid farmingpurposes recreat mal aitrophicaucn

purposes because offeaal_________ tcanamination

The urban area/built-up areas in the project cities are characterized by a heavy con-centration of commercial and industrial activities. It is the area where population densityis highest. These areas also represent the bulk of economic activity in the informal sector -such as, the production and consumption of raw and processed food, light manufacturingactivities and retail distribution. A large proportion of piped water supply from the localWater District is also consumed in the Central Business District (CBD). Consequently, thepressure from both solid and liquid wastes in these areas greatly exceed the capability ofthe land and water resources to absorb, assimilate and recycle them.

Cotabato City

Impact During Construction Phase

The implementation of the project and its components is projected to produce onlyminimal adverse environmental impacts. The socio-economic impacts will be beneficial,and will result in a better standard of living for the municipalities and cities concerned. Inthe short-term, the project will provide employment and livelihood opportunities to thepopulation of the surrounding communities through the jobs generated during theconstruction phase. In the long-term, better sanitary conditions will reduce sicknessescaused by water-relatet- problems. Thus an improvement of the existing environmentalconditions is expected. The project will undertake mitigating measures to minimize, or ifat all possible, eliminate adverse impacts.

Environmental Assessment Report. Cotabato City 5

Air Quality. The implementation of the project will result in an increase in the ambientconcentration of suspended particulates in the vicinity of the project site. This would beattributed to dust from land clearing and excavation activities, which expose soil to windand vehicular traffic over unpaved road.

Water Quality. Excavation activities in the project sites could also loosen soils andtransport of these materials to any surface waters, thereby increasing siltation andturbidity.

During the rainy season, surface runoff may increase total suspended solids, and causetemporary stress at the discharge points. However, the impact will be localized, and whenthe vegetative cover returns, impact on the receiving body of water caused by surface run-off will be eliminated.

Noise. The noise impact during the construction stage is expected to be generally minimaland will not require any special noise abatement measure. The treatment plant sites shallhave a setback away from residential clusters, which will definitely provide the necessarybuffer to reduce noise impact during construction of the modified lagoon systems.

During pipe-laying, some noise will be generated due to the construction activities and thetemporary operation of heavy equipment. Noise from breaking concrete pavement andsidewalks may also pose a temporary problenm However, the noise level at the streets isexpected to be within the ambient noise quality standards.

Ecological Effects. As there are no rare, endemic species of flora and fauna in any of theproject areas, project implementation has minimal impact on the terrestrial ecology.Vegetative covers are expected to be cleared, unavoidably, during civil works.

Impacts During Operation Phase

Air Quality. The operation of the wastewater treatment facility will have minimal impacton the air quahty of the area. Aside from the occasional odor nuisance, it is not projectedto have adverse effect at all.

Water Quality. The implementation of the project will be beneficial to the generalenvironment of participating cities and their environs. Discharging of untreated domesticwaste water from the high volume consumers in each city's Central Business Districts intonearby bodies of water would thus be mniimized or eliminated. However, operations andmaintenance failures may result in occasional discharges.

Socio-economic. The provision of sanitation facilities in the project cites wouldundoubtedly benefit the general populace of these areas. The occurrence of epidemic-scale diseases caused by current unsanitary conditions will be reduced. This will result in amore healthy and productive population.

Environmental Assessment Report: Cotabato Cty 6

Sludge Disposal. The recommentded modified lagoon system or vertically integratedpond system of .reatment will require sludge disposal at very infrequent intervals. Thesludge in the anaerobic pond/s remains for an extended period continuously undergoingorganic decomposition. This may take place over a 20-30 year period. One system inoperation in the U.S. has not been desludged in thirty years. Recent testing of this systemhas indicated that the sludge is well-digested and very stable. If desludging does becomedue, arrangements can easily be made with the city environment office for disposal at thesanitary landfill.

Mitigating measures to minimize, or if possible, eliminate adverse impacts will beimplemented. Measures to enhance the existing environmental conditions in the projectsite shall be implemented to maintain the environmental sustainability of the area. Theimplementation of the project will inevitably cause impacts, both adverse and beneficial.

Table 1 shows the potential impacts, risks and the proposed mitigating actions.

Implementation and Monitoring of Management Plan

The PMO, with the assistance of LWUA-CPSO and consultants to be engaged in theproject, would monitor compliance with the ECC and carry out the requisite datacollection. Monitoring reports would be submitted to DENRJEMB and the World Bankperiodically. While responsibility for the various mitigation activities have been identified,the PMO will ensure that the requirements are complied with; in addition, feedback fromcommunities, city officials, NGOs, etc. will be pro-actively sought through the city publicaffairs programs, regular monthly meetings of barangay captains and other methods.Finally, DENR, through its planned PPA system, would also periodically monitor andaudit compliance with the ECC, assisted by independent contractors.

Table 2 summarizes the responsibilities and timetable for the Mitigation Plan.


Table 1: Mitigation Actions

Construction Phase

Potential Impact & Risks Mitigation Action

l Poor quality of construction . Design and supervision contract will be separated from supplyand installation contract as a means of assuring quality ofconstruction. Works engineers, with a relatively independentsource of information on construction progress, will be hired.

Air Pollution * Careful construction planning and work phasing, specificationsand construction methods to reduce the length of time that the

• Construction equipment and soil is exposed to the environment.vehicles may cause higher * Provision of adequately and properly maintained storage forsuspended particulates, odors and construction materials and equipment.fumes emissions - C02 , CO, NO, . Expeditious and prompt removal of excavated materials or

dredged spoils from construction sites.* Exposure of fine-grain particles to * Regular and adequate sprinkling of water on dust-generating

wind and vehicular traffic will mounds/piles resulting from earthmoving activities and civillikely result in a decrease in air works.quality. . Good housekeeping for aU construction affected areas and

workplaces.* Control of motor vehicle and equipment emissions.* Use of protective gear by all workers.

Water Pollution and Soil Erosion * Provide temporary drainage and storage facilities for excavationsoils, for fuel and oils needed for equipment.

* Siltation * Careful and rational planning of construction and post-construction phases of the project.

* Maintenance of adequate drainage system.

* Noise from operation of construc- * Erect temporary sound baniers around the work sites; avoidtion equipment would be about 70- simultaneous use of heavy equipment; nimit daytime work,SO dBA at 10 m; 50-70 dBA at 30 vehicle speed at 20 kph; regular maintenance of equipment

l m. * Use of appropriate mufflers and sound proofing of construcfionl ~~~~~~~~~~~machinery, equipment, and engines. Use of appTopriate shock-l ~~~~~~~~~~~absorbing mountings for machinery.

l *~~~~~~~~~~ Establishment of buffer zones and noise zones.

* Temporary Disruption of Traffic . To the extent possible, feeder and collection sewer lines will beFlow located along secondary streets.

l Scheduling and increasing input resources so that period of trafficdisruption in primary roads are reduced.

* Coordinate with city traffic management office and the PNPTraffic Management Command

* Clear directional signs and barriers in case traffic rerouting isneeded.

* Public Information campaign.


Operation PhasePotential Impact & Risks Mitigation Action

* Envirorunental hazards due to * Carefully designed post-construction maintenance, contingencyaccidents and man-made or natural and monitoring programs.disasters. * Well designed plan for detection of accident or natural events

* Breakdown or malfimction of the including precautionary and remedial measures to besewer liflt station will increase taken/observed.level of pollution at the Rio Grande * Adequate plans for environmental rehabilitation, clean-up,de Mindanao near the center of the restoration, and disposition of temporary structures and facilitiescity as raw sewage will have to be installed during the construction phase.dumped directly.

Water Pollution . Upgrade laboratory facilities ofthe Cotabato City Water District(CCWD) to be able to undertake wastewater analysis.

* The effluent discharge point of the * Following the bubble concept, wastewater discharged into thetreatment plant may well be Rio Grande de Mindanao River shall, in the long-term, conformaffected by tidal conditions to the water quality standards established by the Department of(estuary). Environrment and Natural Resources as set forth in DAO No. 34

and 35, Revised Water Usage and Classification/Water QualityStandards and Revised Effluent Regulations of 1990,respectively.

* A dispersion/dilution modeling study will be conducted to priorto locating the outfall. Treated effluent discharge into the RioGrande de Mindanao shall be timed based on tidal conditions.The adoption of the ALPS process for the treatment plants shouldresult into attainment of effluent standards.

l Noise would be at about 65-85 * Establishment of buffer zones and noise zones.dBA, principally coming fromseptage trucks unloading at thetreatment plant.

* Odors (organic and sulfur com- . Maintenance of greenbelt zones and vegetation.pounds mainly from the trucks * Provision of landscaped open spaces which will improve theunloading septage) aesthetics in the area by planting the green strips with appropriate

plant or tree species.

Manaeement and O&M ofthe System Institutional:* Management Contract with CCWD which has proven utility

* Poor maintenance of pumps management and operations capacity.* User consultation at detailed engineering design stage to ensure

* Low connections connection.* Sewerage surcharge should be sufficient to provide incentives for

CCWD to maintain system.* Require M&E reporting to the DENR and LWUA* Explore feasibility of BOO/BOT contracts for recreational

activities in unused lands at treatment sites.. Provide adequate training of CCWD and city staff.Regulatorv:. Require compulsory connection for all commercial, industrial

and high domestic water users.* Utilize Public Performance Auditing system being set up by

DENR to monitor adverse impacts.Technical:. Provision of adequate maintenance equipment and spares with

CCWD.

EnvironmentalAssessment Report: CotabatoCitv 9

Monitoring and Implementation Arrangements

Construction Phase

Ambient air quality measurements will be undertaken near construction sites. This will bemostly near locations where sewer network is being laid and treatment plant sites. Whenselecting sites due consideration will be given to sensitive receptors like schools, hospitals,houses etc. Total suspended particulates (TSP) will be measured once a fortnight, for 8 or24 hours, over the construction period.

Noise will measured at the same locations as TSP. Leq and Lg0values will be measured andrecorded.

Operation Phase

Receiving water quality will be monitored by the DENR through its regional officeswhich is monitoring the status of Rio Grande de Mindanao River and estuarine waterquality on a periodic basis. The PMO will collect information on present conditions,observed changes in pollution loads etc. It should be noted that all the pollution load willnot be removed but the proposed sewerage infrastructure will greatly reduce the problem.Once the plan becomes operational, the treatment plant operator, viz-a-vis, the CotabatoCity Water District (CCWD) would be required to set up a laboratory and measure theeffluent quality.

The Treatment Plant Operator will institute a monitoring program to measure effluentdischarges. Daily representative values of PH, 5-day BOD, COD, Total Nitrogen andTotal Phosphorus will be measured during the start-up period. Once the plant operationsstabilize, weekly measurements (24-hourly basis) will be taken.

Quarterly reports showing the trends of effluent discharge and receiving water quality willbe reported to the PMO and DENR Regional Office.


Table 2Summary of Responsibilities and Timetable for the Mitigation Plan

Activity Responsibility Start Completion

Secure ECC clearance from DENR. CPSO-LWUA Decerrber 1996 Septenber 1997

Collect referaence ambient air paraacters Citv PMU. %vith DEN1R Septemnber 1997 June 1998aroutnd the proposed treatment plant sites at regicutal officeproject cities

Ensurethat the bid documents include PM() Januarv 1998 August 1999provLscmas for mitigaticn under the responsibi-hitv of the cmltaaor: review cootrad or's workplans to ensure comphance with en-virinmental mitigaticn plan provisicins.

Traim operators om O&M practice & handlmng PMO and CPSO-LWUA January 1999 June 2000energency situations.

Assess and upgrade the laboratorv facilities of Project City PMU and local March 1998 June 2000the Cdtabato City Water Distict. Water District

Casdiuc use cankstaicus aad infomation Preject City PMU, with January 1998 Jne 2000[ cmiamstx assi5tanceofNGO.

Matitor and report an compliance PMO Bi-amual basis Bi-amual basis

LWtJjc,C7XSUM.DOCF2299-


1. INTRODUCTION

In the Philippines, the typical urban area/built-up area is characterized by a heavy concentrationof activities, both commercial and industriaL It is also the area where the density of populationis at its peak. These areas are also the sites whiere the production and consumption of raw andprocessed materials could be found. Consequently the, pressure on the life support systems inthese areas are far higher than the suburban and rural areas. Adverse environmental conditionssuch as the generation and similarly the discharge of wastes into the environment is common inurban and built-up areas. Unfortunately, the amount, type and concentration of wastegenerated exceed the capability ofthe local environment to absorb and assimilate them. Thecarying capacity ofthe life support systems are stretched to the lmits. The urgency ofestablishing collection and treatment methods which wil prevent adverse impacts to the healthand well-being ofthe residents, and to the ecological systems which sustain them cannot beignored and overstated.

T he provision of a cost-effective centralized wastewater coRection, treatment, and disposal isthe primary objective of the proposed Water Districts Development Project (WDDI). Theproposed project will assist the local governments ofDagupan, Calamba , Laguna, Cagayan deOro, Davao City and Cotabato City, in finding solutions to the problem of sanitation.

Most urban centers in the Philippines rely on individual septic tank systems for thetreatment and disposal of wastewater from domestic and commercial buildings. However,the designs for such systems is often inadequate. Facilities for land disposal of effluentsfrom the septic tanks are generally absent. Hence the partially treated septic tank effluentsflow directly into storm drainage systems and other receiving bodies of water, therebyexacerbating an already grave pollution situation.

There are several possible options for addressing this problem, including improving thedesign of the septic tank system with the installation of soil absorption systems. But anenvironmentally sound alternative that is cost-effective and captures economies of scale isto connect individual properties directly to a sewerage system for the collection, treatmentand disposal of the urban wastes.

Better sanitazy conditions will thus be experienced in the areas served by the sewerage,drainage and sanitation systems. This will reduce water-borne pollution and water-loggngwithin the cities and in the surrounding water bodies, thereby bringing health benefits tolocal populations. In Davao, Cagayan de Oro and Calamba cities, pollution from humanwastes have affected recreational areas, such as beaches and lake front areas. Projectinvestments in wastewater collection and treatment will also have positive benefits interms of improving prospects of saving the remaining beaches for the city residents. The


construction of the systems will protect shallow groundwater aquifers from contamination[particularly in Toril area, in the case of Davao City, where the aquifer underneath is amajor source of the city's water supply system].

Overall Approach of the Proposed Project

The proposed project follows a demand-based approach, in the sense that facilities will beconstructed only if they conform with the preferences of local stakeholders, and servicesconform to their respective willingness to pay. The stakeholders represent the differenttiers of organizations from the City Council and Barangay (part of the formal LGUsystem), to the more informal purok, neighborhood and household levels. During projectpreparation, the idea of involving communities in the planning process was field-tested inthree barangays of Davao city, and found to be quite successfuL The basic decision-making process is as follows:

(a) For the capital-intensive trunk system, consisting of the maintransportation sewers, primary drains and wastewater treatment facilities,the project design and implementation plan has to be approved by the CityCouncil, because the latter is responsible to repay the loan [see Annex 3 ofthe Staff Appraisal Report (SAR) for the project on Financial Aspects].

(b) For the feeder system, consisting of collector sewers, secondary drains andon-site sanitation facilities, barangays and local neighborhoods will beassociated with the planning and implementation program. The designcriteria have been simplified, so that the feeder system can respond to localpreferences and wilingness to pay, rather than be bound by anyconventional sewer design criteria used in industrialized countries. Detaileddesign will be conducted through a participatory process.

Given the capital-intensive nature of the investments, the proposed project is only theinitial phase of a program to improve the sanitation infrastructure through a strategicplanning approach that involves a mix of on-site and off-site wastewater collection,treatment and disposal. Choice of initial service areas for sewerage has been confined tothe Central Business Districts or Poblacion areas because these are the major contributorsto municipal wastewater pollution. The only exception made is in the case of Davao City,where a second area of high growth prospects (Toril) has also been included on therequest of the LGU.

The project will construct a sewer network that will discharge sewage to a verticallyintegrated pond system designed to treat both sewage and septage. In each of the cities(with the exception of Davao), the treatment sites selected are in areas free fromencumbrances.

For the sanitation and drainage components, the entire city has been included in theproject area, with final selections being made on the basis of demand. On-site treatment


systems through the construction of VIP latrines, pit latrines, pour flush toilets and septictanks will also be constructed if there is demand from property owners. For thoseproperties with uncertain land tenure (as in squatter settlements), the project will financethe construction of communal toilets, to be managed by NGOs and/or the private sector.The specific location of these facilities will be driven by the willingness to pay for theservices by beneficiaries at the barangay leveL provided of course that these are technicallyfeasible.

The recommended solutions for wastewater treatment were arrived at after an intensiveprocess of evaluating alternatives during the project preparation in order to achieve costeffectiveness and acceptability. The alternatives considered were anaerobic/facultativeponds, modified lagoon systems and mechanical treatment. In all the five cities, theevaluation of alternatives indicated that the modified lagoon systems, despite having ahigher O&M costs compared to anaerobic/facultative ponds (as it requires mechanicalaerators and recirculation pumps) was more appropriate. Details are available in projectfiles. The selected option met the following criteria the effectively:

(a) Minimize overall pond area required

(b) Minimize odor production

(c) Meet DENR effluent quality criteria, including fecal coliform reduction

(d) Minimize sludge production rate

(e) Maximize potential to use surrounding land for recreational purposes

Environmental Impact Assessment

This Environmental Impact Assessment Report for Cotabato City has been prepared inaccordance with the Presidential Decree No. 1586 otherwise known as the EnvironmentalImpact Assessment Law and Department of Enironment and Natural Resources RevisedAdministrative Order Nos. 36, the Revised Water Usage and Classification/Water QualityCriteria and Revised Effluent Regulations of 1990 respectively; and World Bank 'sOperational Directive 4.01 on Environmental Assessment. The revised Administrative Order36 for Environmental Impact Statement System issued in 1996 is comprehensive and iscompatible with the World Bank's Operational Directive 4.01. It outlines the proceduresto be followed by environmental critical projects (ECPs) and projects to be located inenvirommental critical areas (ECAs), in preparing environmental impacts statement(EISs)'. ECPs and ECAs are defined in the AO. It should also be noted that that localordinances and regulations governing projects of such nature have been taken into

This is the term used by DENR and refers to the standard Environmental Assessment Reportrequired by the World bank as per OD 4.01


consideration in preparin this report. Similar EIA reports are being prepared for the other 4cities.

This report has been prepared by a team of local consultants under the aegis of the Local WaterUtilities Administration (LWUA) and the Cotabato City Government. Much of the workrelating to the environmental impact analysis was undertaken as part of the feasibility studydone by C. Lotti and Associati Consultation with the community is an on-going process. Thesanitation component of the project will be executed in a participatory manner, and detailedguidelines have been spelled out.

LWUAjrCTCHMP7RIDOCA prl 22. 1997 4:26 PM


2. BASELINE ENVIRONMENT - COTABATO CITY

Introduction

This chapter is in two sections. Section I profiles he existing environmental situation inCotabato City and Section II analyses water pollution impacts (historical) of uncontrolledsewage discharge.

Section I - Existing Environment

2.1 Land Resources and Use

Cotabato City is situated in the northwestern portion of Maguindanao Province It lies on theshores of Moro Gulf in the west-central section of the Island of Mindanao. It is bounded onthe northern flank by the Rio de Grande de Mindanao, the Moro Gulf on the west and theTamontaca River in the South. [Figure 2.1]

The City has a total land area of approximately 176 sq.km., of these 51% are classified asagriculurat fishponds and wetlands and the remaining 49% are residentiat commercialindustrial ana institutional areas including parks and open spaces. [Figure 2.2]

Along the banks of the Rio Grande River are located high-density residential development.The slum areas are located near the supermarket, the interior areas of Parang Road, and theinterior areas of Mabini along Manday River. [Figure 2.3]

2.2 Phv ahy and Geology

The city is basically a delta formed by the Tamontaca River in the south and the Rio Grande deMindanao River in the north. It is generally flat and low lying with nearly 90% ofthe total landarea close to mean sea leveL Pedro Colina Hl and the mimako Hill are the highest points withelevations of 60 meters and 46 meters above sea level (masl), respectively. Perennial marshesand ponds as well as the meandering creeks and rivers dominate the topography within its vasttract of plain.

The expansive outwash plain of the Rio Grande de Mindanao River is made up of recentalluvium prinarily composed of beach deposits, sand, gravel and clay. Hills of raised coralreefs, basically limestone and probably remnants of coral islands during the earlier period arelocated within this flat valley. This indicates that the area was once a waterway connected to


the Moro Gulf that was filled by alluvium deposits. This alluvial valley is surrounded on threesides at varying distances by relativelv high mountain ranges mainly composed of limestone andvolcanic rocks. Marine clastics and tuffaceous rocks form the lower hills.

The city has fairly good land suitable for limited agriculural cultivation. The soils, as classifiedby the Bureau of Soils and Water Management of the Department of Agriculture. is dominatedby the Faraon Clay which makes up 80% (14,079 has.) of the total land area. The other typesof soil are the Tamontaca Clay (15% of total land area) and the San Miguel Clay (5% of totalland area).

2.3 Climate

The climate in Cotabato City is Classified as Type IV based on the Modified Corona'sClassification of Philippine Climates. This type of climate is characterized by a relatively evendistribution of precipitation during the year. There are two distinct seasons in the City; the dryseason which starts from November and lasts till April, and a wet season, beginning in Maythrough October. The average monthly rainfall is 79.97 mm with the highest rainfll occurringin the month of June with 118.3 mm. Mean annual temperature is 27.4°C wle the maxiunmtemperature was registered in the month of April at 34. 1°C. The average annual RelativeHumidity is 79% with the month of July as the most humid at 83%. Appendix 2 shows theclimatological normals for Generals Santos City, the nearest PAGASA station to Cotabatocity.

2.4 Hydrology and Water Ouality

The City of Cotabato is bounded on the northem and southem flanks by two major riversystems, the Tamontaca and Rio Grande de Mindanao. These river systems drains into IanaBay. The Rio Grande de Mindanao for al practical purposes functions as the Citys naturaldrainage system, and the receiving body of water for storm, surface runoff and domestic waste.As such the water quality of the river has continually deteriorated. The river, as per DENRstandards is classified as Class C waters.

2.5 Vegetation and Wildlife

The vegetative cover of the proposed site for the wastewater treatment plant is predominantlywild grass interspersed with coconut trees with some portions being planted to rice. As iscommon in most sites near buil-up areas, the floral and fauna communities are highlyinfluenced by the economic activities of the hurman population. The flora and fauna in the areais strictly limited to the requirements of the settlers. Cash crops and domesticated animals arecommon in the area.

2.6 Socio-economic Aspects

As projected based on the 1990 NSO Population Data the population of Cotabato City in 1995was placed at 138,885 persons with a density of 18.46 persons/hectare. The most populous


barangay based on the projections is Bgy. Rosary Heights with approximately 57,506 residents.It is projected that by the year 2015 the population ofthe City will reach 171,058 persons.

Section II - Environmental Pollution

As in most other major cities, the urban area/built-up area in Cotabato City ischaracterized by a heavy concentration of commercial and industrial activities. It is alsothe area where population density is highest. These areas are also the sites where theproduction and consumption of raw and processed materials could be found. Con-sequently, the pressure on the environment in these areas are far higher than the suburbanand rural areas. Adverse environmental conditions such as the generation and discharge ofwastes onto the environment are common in urban and built-up areas. Unfortunately, theamount, type and concentration of waste generated exceed the capability of the local envi-ronment to absorb and assimilate them. The carrying capacity of the life support systemsare stretched to the limit.

2.7 Existing Sanitation Conditions

Informal interviews conducted during the several technical field investigations regardingon-site sanitation facilities reveal that most of the households interviewed were satisfiedwith their existing toilet facilities.

The relatively high degree of reasonable satisfaction with their existing systems suggeststhat heads of households have little concern for the unsatisfactory disposal of these wastesonce they leave the dwelling, but could also relate to how the inquiries were conducted.In any event, it is clear that the present system is far from satisfactory, despite the opinionof the users, because:

About half of the households have inadequate on-site sanitation facilitiesPractically all of the households are disposing of their wastes in a manner whichposes risks to the public health of the people of the City.

2.8 Health Problems Faced by Cotabato City Residents

As in the other project cities, sewage contamination is a prime cause of diarrheal diseasesin Cotabato City. The City Health Office (CHO) maintains records of morbidity andmortality in the City. Among the ten leading causes of morbidity and mortality in 1991,water- related diseases such as diarrhea, typhoid fever and dysentery are ranked first, sixthand eleventh in the list of morbidity, and diarrhea is hsted as eighth, among the causes ofmortality.


2.9 Existing Environmental Conditions of Moro Gulf and Rio Grande de MindanaoRiver

The Regional Office of the Environmental Management Bureau (EMB) under theDepartment of Environment and Natural Resources conducts monitoring of water qualityof Moro Gulf and Rio Grande de Mindanao River. Samples are collected at selectedpoints and are sent to the laboratory for physical and chemical analyses.

The results of the monitoring programs in September 1990, July 1991 and July 1992indicate that Rio Grande de Mindanao River is experiencing oxygen depletion indownstream reaches near the City. Dissolved oxygen (DO) levels range from 6.2 mg/l atthe wharf area in the City to 0 - 0.7 mg/l at Barangay Kalanganan. The EMB allowableminimum DO level is 5 mg/i for Class C rivers such as Rio Grande de Mindanao. Class Crivers are suitable for fishery water for the propagation and growth of fish and otheraquatic resources, and recreational water for boating or related purposes. TheBiochemical Oxygen Demand (BOD) level was 0.8 mg/l at the wharf area and 115 mg/ldownstream at Barangay Kalanganan. EMB sets maximum BOD levels at 10 mg/l forClass C rivers.

The BOD and DO levels indicate that the river is badly polluted in the downstream reach.It is clear that organic pollution from untreated wastewater discharges into the river is theprincipal cause of the adverse environmental conditions.

Water samples collected from Moro Gulf at Parola Beach, Bgy. Kalanganan in July 1992indicated that these waters also suffer from oxygen depletion, with a DO level of 1.9, wellbelow the minimum standard level of 5 mg/L Bacteriological examination of water at thesame beach conducted in August 1992 determined that fecal coliform levels wereexcessive.

2.10 Reduced Opportunities for Commercial Development

Accelerated high-rise construction and sharp increases in property values haveaccompanied the installation of sewerage in the Makati district of Manila and the centralbusiness district of Jakarta, Indonesia. In some Latin American cities, central-cityproperty values are reported to have increased by as much as 20% after sewerage wasinstalled. It would not be surprising to see similar results in Cotabato City if seweragewere installed in the Poblacion district. The city is well-positioned to become acommercial hub for its region, and the city leadership clearly aspires to this role for thecity. Rapid expansion of high-rise commercial activity in Poblacion seems very unlikelyunless the area is served by a sewer system.

2.11 Summary of Findings on the Existing Environment

Environmental conditions in the City are unsatisfactory. Two activities constitute theprincipal sources of pollution:


Excreta and Wastewater Disposal. As noted at the beginning of this Chapter, about halfof the population are without satisfactory on-site sanitation facilities, and most of thewastewater from household with acceptable facilities finds its way into the City's drainsand water courses. These deficiencies aggravate the poor environmental conditions ofCotabato City.

Solid Wastes. Solid wastes are collected only from the Poblacion and its outlying areas andlarge amounts of these wastes are littered casually at the places where they are generated.Much of these wastes find their way to the City's drainage system, hampering the drainsfrom conducting runoff during rains and contributing to flooding and general uncleanliness.Wastes that are collected are improperly disposed of burned and left uncovered at an opendump near residential areas of Bgy. Rosary Heights.

Health-related problems related to sewage contamination are of uncertain magnitude, butare an important consideration for the city leadership. Waterbome and other sanitationrelated diseases continue to be a major public health problem in the country. In 1990 aNSO survey reports that 27% of the total households in Cotabato City have unsanitarytoilet facilities while 16% have no toilet facilities. Morbidity and mortality figures showthat adverse sanitary condition is one of the main reasons why diarrhea ranks number onein the leading causes of diseases in the City. It also ranks eighth among the leading causesof mortality in Cotabato.

Overhung latrines are a familiar sight along river banks and along main drainageinterceptors. In these areas human waste is directly discharged below the structure andabsorbed by the Rio Grande River. Manday River which cuts across the city is similarlypolluted with domestic solid and liquid wastes.

Tlhe health statistics and the existing water quality conditions of the citys water bodiesclearly show that there is a need to address the deficit in sanitation to improve the city'shealth and environmental conditions.

Water qualty monitoring results of DENR Region showed that the permissible hmits onsuspended solids and dissolved oxygen are exceeded for Class C water in Rio Grande deMindanao. The deteriorated water quality of Rio Grande de Mindanao is obviously due tothe proliferation of households constructed along the river without proper toilet facilities.Human excreta are directly discharged into the river, with the people unmindful of thehealth and environmental consequences it may result. Based on the ocular inspectionconducted, the Manday River which runs through the city is similarly polluted. The riverreceives all types of waste, including human wastes from houses constructed along theriver banks.

Pollution of the Moro Gulf is closely related to drainage from the neighboring population.Adverse environment conditions exist in the rivers feeding into the gul£ particularly theRio Grande de Mindanao River, due to organic pollution from untreated wastewater


discharges into them Pollution reduction will then depend on the proportion of the localpopulation whose sewage are treated or safely removed from septic tanks.

As in Davao City and other project cities, fishing productivity, in the gulf waters hasdeclined, but sewage contamnination has not been a significant factor.

Commercial development in the Poblacion is repressed by the absence of sewerage.Installation of a system would permit high-rise construction and a significant increase inproperty values.

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3. PROJECT DESCRIIPTION AND ANALYSIS OFALTERNATIVES

Introduction

This chapters begins with an explanation of the rationale of the proposed project and thengoes onto describe the project. The main components -- sanitation and scheme aredescribed separately. Description includes the analysis of alternatives considered inarriving at the final choice. The chapter concludes with the recommended design and plan.

Section I - Project Rationale and Objectives

Chapter 2 describes the existing environmental situation in Cotabato City, and illustratesthe worsening health impacts caused by the uncontrolled discharge of sewage. There isnegligible piped sewerage in the city. There are no treatment and disposal facilities forseptage removed from septic tanks. Septic tank soakaways and overflows enter the drainsand the groundwater.

The proposed project is, therefore, aimed at addressing the problems of inadequatesanitation and sewerage in the City of Cotabato by providing sustainable sanitation andsewerage facilities, thereby reducing public health risks and environmental pollution fromwastewater sources. The project is designed also to provide a learning experience-forfuture expansion of sustainable sanitation services for the city as well as for other cities.The selection of final project design is driven by: (i) demand-based approach; (ii) level ofwastewater treatment to be achieved; and (iii) the need for protecting the environment.

Section II - Sanitation

Proposed Facilities

The sanitation component will include the construction of 2,200 VIP latrines, 734 pour-flush toilets and 33 commrunal toilets city-wide. The sanitation works were based upon anidentified deficit of sanitation facilities of 48%. The choice between individual andcommrunal facilities will be driven by technical feasibility and demand by key stakeholdersand not by tenure status. Locations of individual as well as commrunal toilets are not

EnvironmentalAssessment Report: Cotabato City 25

defined yet and will depend on the consultation of potential beneficiaries. The areas to beserved by the communal toilets mav include public areas such markets and low-incomesquatters or blighted areas.

The possibility to construct on-site facilities is site specific. As the majority of squattersare located on government owned property, that is. along river banks and shoreline it isunlikely that communal toilets. with on-site disposal will be technically feasible. In theselocations communal toilets will only be feasible if there can be a direct discharge to aproposed sewer. The sizing of the facility is dependent upon the depth to groundwater,the permeability of the ground and the availability and cost of land. The objective is toconstruct the communal toilets in areas where, through public consultation, there is anestablished demand and willingness to pay for the service. Arrangements for constructionand operation could take many forms such as:

(i) City constructs and operates;

(ii) City constructs and contracts out the operations either to a private company or tothe local community the facility is serving through a leasing arrangement;

(iii) Construction and operation contracted through a concession arrangement.

It is recommended that arrangement (ii) be given preference over the others, particularly ifthe local community is willing to operate the facility.

The different arrangements should be examined following consultation between the Cityand users, in order to implement the preferred option. Then following a monitoringperiod, the more successful operation can be repeated. A balance has to be soughtbetween affordability to construct (the quality) and willingness to pay. The facility has tobe made "attractive" to the users and provide the service they require and, therefore, inselecting the option the following aspects should be considered:

- Site - central location to proposed users (designed to serve 250 users, orapproximately more than 40 properties);

- proximity to a proposed sewer line, if any, of the land area required(including for septic tank/soakaway)

- availability of water supply;

- availability of power supply;

- area not prone to flooding.

* Services - need for inclusion of showers/laundry facilities.

* Design - attractive to users;

- clean, odor/insect free;

- well lit; good security;

- facilities designed for intense usage; need to be functional and durable.


Cost Estimates

A. Capital Cost

The capital cost for the sanitation component is as follows:

Facility Cost Beneficiaries(P million) __ _ _ _ _ _

On site facilities 21.38 16,800Communal Toilets- Construction 10.22 8,250- Land

Total 43.86

The construction cost includes 5% physical contingencies. The cost of engineering hasnot been considered on the assumnption that the design and construction supervision can behandled directly by the City's concemed department because of the simplicity of thestructures.

B. Operation and Maintenance Cost

Annual O&M costs for each communal toilet has been estimated at P192,780. This wouldrequire an user fee of about P1.20-1.40 per visit on the assumption of 250 persons usingthe facility twice daily. It is intended that the cost of O&M plus the operator's fee have tobe covered by the users.

Implementation Schedule

It is assumed that the 2,200 VIP latrines, 734 pour-flush toilets and 33 communal toiletswill have to be constructed during four of the 5-year implementation period of the project.Therefore, an average of 550 VIP latrines, 183 pour-flush toilets and 8-9 communal toiletswould be constructed annually including the required time for consultation and design.However the construction of the sanitation component can be extended over the 5-yearproject implementation period.


Section III - Overall Sewerage Scheme

Classification

Sewerage refers to the collection and treatment, at a single location, of water-borne waste(sewage) discharged from individual properties. It includes the collection and treatment of"domestic" sewage only and not for any "industrial" waste discharge.

The sewage is collected and transported through a network of underground pipes, orsewers, to a WWTP, where the sewage is treated to produce an effluent that can bedischarged to a receiving water body (river, sea, etc.). Sewage flows along the sewers bygravity, that is, the pipes are laid at a slope or gradient which is sufficient to ensure thatthe sewage will flow without causing blockage.

To minimize depth of excavation, sewers, generally, should follow the slope of theground, that is, they go downhill. If the depth of a sewer becomes too deep (greater than5 m) a pump station would be used to elevate the sewage, either to another sewer or tothe WWTP. The sewers are divided into two classifications:

- collector sewers - sewers connecting an individual property or group of severalproperties to a sewer located in the street or right-of-way;

* transportation sewers - those sewers receiving the sewage flow from the"collection" sewers and transporting the sewage to the WWTP.

The transportation sewers can be considered as the "main road", with the collector sewersacting as the "feeder roads".

Selection of Service Areas

A. Poblacion

The Poblacion area is considered a priority area for the following factors:

* increasing population density and limitations for on-site sanitation;

* presence of large commercial establishments, and institutions such as schools,universities, coUege, government offices and hospitals;

* health hazard and risk posed by the increasing wastewater flow on the municipaldrainage system;

* high level of urban development with a population density capable of payingwastewater service charge;


* biological degradation of rivers which have been found to be polluted with humanexcreta and positive for fecal coliforms. Disposal of septic tanks effluent to thedrainage system contributes to aggravate this pollution problem

The identified Initial Service Area (ISA) comprises a total of 27 barangays with an area of1.527 has. and a total population of about 122,770 in 1995 projected to increase to about151.210 in 2015. The ISA is bounded on the north by the Rio Grande de Mindanao, onthe west by Barangays Bagua I and Bagua 2, on the east by the Matampay River, and onthe south by the Estero River.

As shown in Figure 3.1, the ISA is subdivided into three stages of implementation.

Stage I Service Area has been outlined to include those areas which can provide thehighest impact in terms of improvements to the environment as well as to the social andeconomic conditions of the City. The areas included are:

* the Pobalcion's center where commercial and institutional establishments, such asuniversities, hospitals, and offices, are located;

* the barangays that are highly urbanized and densely populated adjacent to thePobalcion.

The Stage I Service Area has a land area of 283 has. with a population of about 72,030 in1995 projected to increase to about 77,850 in the year 2002 (starting of operations) and toabout 88,720 in 2015.

The population which will connect to the system has been estimated at 60% of the servicearea population. At the starting of operations, in the year 2002, the system will serveabout 46,710 users, with 8,341 connections, projected to increase to about 53,230 users in2015 with 9,506 connections.

The figure that 60% of service area population will connect to the system is based on theassumption that 85% of the population (year 2015) would be connected to the CCWDsupply system, and of those, 70% would be connected to the sewer. Expansion of thesystem would be dependent upon the number of sewer connections and the sewage flowfrom each connection. The capacity of WW1TPs and pump stations would have to beincreased once the 60% design flow is reached. This may or may not correlate to theactual connected population.


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Potential Treatment Plant Sites

The strategy to identify potential treatment plant sites for Stage I was:

* take advantage on the availability of small parcel of lands with minimal number ofsettlers. if not totally vacant;

* divide the system into smaller catchment areas considering the potential treatmentplant sites, as well as topography and drainage characteristics.

In consultation with the City the following potential sites were identified:

* Rio Grande de Mindanao* Barangay Lugay Lugay* Kakar* Lua-Luan

None of the sites will require relocation of inhabitants. The sites at Rio Grande deMindanao and Barangay Lugay Lugay have no specific use at present. The other sitescomprise of farm land. A land value of P 300/sq.m. has been used for the WWTP sites asindicated by the City Planning Department. However, the Kakar and Lua-Luan sites havenot been considered for Stage I because they are of considerable distance from the servicearea but, as may be necessary, could be utilized in the future for Stages II and m.

Treatment Process Options

For the treatment of sewage to be collected from the Stage I service area, three processoptions were assessed, as follows:

* anaerobic/facultative lagoons;

* modified lagoons;

* mechanical activated sludge.

1. Anaerobic/Facultative Lagoons

This system comprises of two or more ponds in series: the initial anaerobic pondfollowed by facultative pond(s). Each pond is defined as follows:

* Anaerobic Pond - used primarily as a pre-treatment process for high-strengthwastewater. They may be used for septage, night-soil, and high-strengthdomestic sewage. The advantages of using anaerobic ponds are that theyeffectively decrease the land requirements of subsequent facultative andaerobic ponds and the accumulation of large sludge banks in subsequenttreatment ponds is avoided.


* Facultative Pond - are the most common type used for wastewater treatment.Raw wastewater enters at one end of the pond and suspended solids settle tothe pond bottom. Over a period of time, a sludge layer develops that is voidof dissolved oxygen. The bottom sludge decomposes anaerobically. Abovethe sludge layer, the pond has a facultative layer that alternates from aerobic,during daylight hour, to anaerobic at night. The upper layer of the pond isaerobic at all times due to oxygen supplied primarily by photosynthesis andwind action. Facultative pond effluent would have to be further treated forthe removal of suspended solids before discharging to the receiving water tomeet the effluent discharge standards.

The Feasibility Report selected this process for the initial septage treatment facilityand for identifying the land area requirement for the deferred sewage treatmentplant.

The design criteria for the process is as follows:

* Anaerobic Ponds

- Dual ponds; depth of 4.0 m; side slopes of 3:1; rectangular with length of 1. 5to 2 x width.

- Organic loading of 0.3 kg of BOD/day per cu.m of pond volume.- Detention time at least 1.5 days.

- Pond volume to be determined by the higher value.

- Assumed BOD removal for subsequent treatment of 65%.

* Facultative Ponds

- Dual ponds in series; depth 1.5 m; side slopes 3: 1; rectangular shape, withlength 2 x width.

- Organic loading rate of 400 kg of BOD/day per hectare of pond surface area(based on 40 g of BOD per capita and 10,000 persons per ha). Loading rate tobe applied to residual BOD in effluent from anaerobic ponds.

- Detention time to be 6 days, total for all ponds in series.

- Pond volume to be determined by the higher value.

- Estimated BOD removals of 70% of influent BOD (overail BOD removalsestimated at 90%).

While providing a treatment system that has a reduced land take (compared toa complete facultative lagoon system) and utilizes no mechanical equipment,


there are concerns as to its ability to operate satisfactorily. Concerns raisedinclude:

* Anaerobic Pond

- Will produce odors - particularly if sulfates are present in the influent.

- Sometimes difficult to manage if pH varies on the acid side. Processeffectiveness decreases or fails completely. Short detention period tends toreduce buffer capacity. Once the system becomes acid, it must be treated withlime or some other chemical to neutralize the system.

- Removal of sludge required. Frequently depends on severity of the solids -BOD loading and nature of composition (sludge disposal was not addressed inthe Feasibility Report).

- Ability to treat low strength domestic sewage and variable rates of flow.

* Facultative Pond

- Shallow ponds at depths of 1.5 to 1.75 meters subject to turnover because oftemperature variations or wind and wave action. Temperature not as much ofa factor in areas of low fluctuations.

- Anaerobic and aerobic processes tend to be in state of flux and vacillatebetween stages reducing treatment effectiveness.

- Tends to increase land requirements because of the relatively shallow depth.

- Limited detention period will not ensure the removal of fecal coliforms to anacceptable level.

2. Modified Lagoons

The modified lagoon system, [e.g., the Advanced Integrated Pond System (AIPS),see Appendix 6] is a non-structural design which utilizes earthen constructionpractices to simplify and reduce construction costs. The system is designed tooptimize natural biological processes in order to improve treatment effectivenessand reduce power requirements and chemical additives while limiting landrequirements. The design concept is to miimize sludge production, eliminatedaily sludge handling and restrict desludging to a long term 20- to 30-year cycle.

The modified lagoon system is an integrated, multi-stage biological reactor systemtreating municipaL agricultural and industrial wastewater. The reactors may berelatively deep and constructed of compacted earth as open surface pond areas.The biological reactor has discrete and isolated biological zones integrated into a


single unit; a deeper anaerobic cell(s) at the bottom of the reactor, sludge blanketsuspended over the deepened zone and an overlying aerobic zone comprised ofaerobic bacteria, algae and a saturated oxygen media provided by a combination ofalgae and surface aeration.

In many cases the initial reactor is followed by a similar second reactor operatingin series with the provision to recirculate to the first pond depending on conditionsand circumstances. Recirculation lends flexibility and buffer (shock loading)capacity and adsorption abilities with highly variable hydraulic or organic loadingsor where there is a potential for receiving toxic spikes.

The primary facultative pond with an aerobic surface and extremely anoxic internalcells for sedimentation and fermentation is the initial treatment element in the seriestreatment train. In this element raw or screened wastewater is introduced directlyinto the bottom of a relatively deep internal cell(s) wherc settleable solids aredigested anaerobically. The overflow velocity in the cell is maintained at a lowrate such that the suspended solids and BOD5 removal efficiency approach 100 and65%, respectively. These rates are maintained at less than the settling velocities ofhelminth ova and parasite cysts. Consequently, the majority of these organismsremain in the cells and are permanently removed from the effluent. Settled solidsin the anoxic cells ferment to the extent that only ash remains due to the large cellvolume. Hence, sludge removal is seldom required.

The rising gases and upwelling of wastewater from the anaerobic cell pass througha thick anaerobic sludge blanket, that is formed as a result of the fermentationprocess, and remains suspended above the anaerobic celL The hydraulic detentiontime in this anaerobic zone and corresponding rise velocity is variable by designand nature of the waste stream.

Treatment of soluble waste continues in the overlying aerobic zone, comprised ofaerobic bacteria and algae. These organisms are maintained in an oxygenated stateby photosynthesis, recirculation and surface aeration. The nature of the surfaceaeration creates a circular motion over the entire pond surface area which in turnensures an oxygen rich continuity.

Soluble wastewater components undergo aerobic oxidation and furtherdegradation in this zone. Thus, two normally seemingly incompatible biologicalwastewater treatment processes can be made to coexist uninterrupted in the sameearthwork reactor.

The horizontal velocity of the circular motion is reduced over secondary deepenedzones as a result of the added volume, allowing the aerobic solids to settle bygravity into a secondary digester for further decomposition and stabilization. Asludge blanket is formed in this area and remains suspended over this zone. Thesurface aerobic circulation pattern reliably controls odors.


The further function of the isolated reducing anaerobic zones includesdenitrification, precipitation of heavy metals and fractionization of toxiccompounds to a less toxic state.

Seasonal, (temperature) and wind or wave action driven turnovers of the pondsis prevented by placement and design geometry of the internal cells andsuppression of the thermocline. Turnovers are a complex phenomena oftemperature changes, wind action, pond depths and configuration of the ponds.The advanced pond design features and method of cell integration serves tomaintain the integrity of the system thus preventing potential pond turnovers.

Sludge in the anaerobic cell(s) remains for an extended period continuouslyundergoing organic decomposition. This may take place over a 20 - 30 yearperiod. One system in operation has not been desludged in thirty years. Recenttesting of this system has indicated that the sludge is well digested and very stable.

The second pond in the series is similar in nature to the first with the exception thatthe size and number of internal cells differ depending on the design and type ofwaste treated. Recirculation of the highly oxygenated water from this second pondis introduced to the surface of the primary facultative pond to provide an oxygenrich overlay of this pond. This oxygen quickly acts to oxidize reduced gasesemerging from the fermentation cell and thus mitigate possible migrating odors.Algae in the recycled water tend to adsorb heavy metals that may be present in theincoming waste stream. These algae tend to settle in the primary pond. Thus asignificant fraction of heavy metals can be removed from the primary pond effluentin the form of reduced metal sulfides or as attached to algae solids.

The modified lagoon system is proposed and an appropriate treatment method fora variety of wastewater treatment applications. These include normal dischargesas well as variable hydraulic flows and organic loadings, particularly where theremay be limited industrial pretreatment and source control of high strengthunbalanced wastes and toxic and heavy metal discharges. The design elementsprovide for flow equalization, buffer capacity and recirculation capabilities toachieve secondary and advanced treatment for municipalities, agriculture andindustry.

The design criteria for the process is as follows:

* Basic Design: Three ponds in series to meet coliform requirement<l,OOO/lOOml

- Primary Facultative with anaerobic cells

- Secondary Facultative with following anaerobic cell- Tertiary - maturation pond

* All systems designed with parallel facultative ponds.


Detention period: Primary pond - 5 days

Secondary pond - 3 days

Tertiary pond - 3 days

Note: Could use 4 ponid series with 5,2,2,1 days detention to achieve higherpercenitage coliforn? removal.

* Pond design depths: Primary and Secondary - anaerobic sections - 4 m

- aerobic sections - 3.5 m

Tertiary Pond - 3.5 m

* Supplemental aeration included for circulation and BOD requirements becauseof reduced area requirements.

* Recirculation from Secondary pond to Primary included for mediareinforcement and as a source of oxygen.

* Land requirements low because of short detention and pond depths.

* Combination of anaerobic and aerobic in same reactor improves efficiency.

* Berm width - 3.64 m in all cases.

3. Mechanical Activated Sludge Plant

The treatment plant would be constructed of reinforced concrete tankage andwould have the following major components:

- Inlet Works: mechanical screens; grit removal; flow measurement

- Primary Settling Tanks

- Aeration Tanks

- Final Settling Tanks

- Anaerobic Sludge Treatment

Together with associat..d control building/laboratory, pump stations andmaintenance buildings, partial standby power generation capability would berequired.

Based on intemational experience, mechanical activated sludge plants, althoughrequiring smaller land area, are more expensive than any lagoon system in terms ofcapital as well as operation and maintenance expenditures. Furthermore, skilledstaff is required to operate the plant. Therefore, the construction of a mechanicalactivated sludge plant is not considered a viable alternative for the city.Consequently, design criteria have not been developed.


4. Recommended Treatment Process

A previous feasibility report (CDM, 1994) selected the anaerobic/facultative pondsfor the initial septage treatment facility and for identifying the land arearequirement for the deferred sewage treatment plant. However, the process hasraised concerns as to its ability to operate satisfactorily without upset. In fact,with the reduced detention times, it is unlikely that any reduction in fecal coliformwill be achieved, which is a major requirement for the protection of the rivers andthe gulf. Any upset to the system has the potential for the production of odors.Unless sufficient land is available, large buffer zones between the lagoons andinhabitants should be provided to reduce the level of odor reaching the nearbyinhabitants.

On the other hand, based on international experience, the adoption of mechanicalactivated sludge plants, althnugh requiring smaller land area, will be moreexpensive than any lagoon system in terms of capital as well as operation andmaintenance costs. Furthermore, skilled staff is required to operate the plant.Therefore, the use of a mechanical treatment plant is considered not a viableoption.

The modified lagoon system utilizes mechanical aerators and recirculation pumpsand, thus, has higher O&M costs compared to anaerobic/facultative lagoons.However, the modified lagoon system has the ability to treat variable strengthflow; minimize odor production; meet effluent qualty criteria, including fecalcoliform reduction; and has a minimal sludge production rate. These featuresallow the modified lagoon system to address the concems related to theanaerobic/facultative ponds

As a result of the above analysis, taking into account the quality of effluent aftertreatment, the availability of land as well as capital and operating costs, themodified lagoon system is recommended for all the WWTP to be included in thealtemative schemes identified for Cotabato City.

Comparison of Alternatives

The altemative schemes identified are briefly described as follows:

AlternativeScheme Description

I The system will drain the sewage of the whole area to the WWTP (modifiedlagoon system) located at the Rio Grande de Mindanao site.

2 The system will drain the sewage of the whole area to the WWTP (modifiedlagoon system) located at the Barangay Lugay Lugay site.


3 The system is divided in two areas: the sewage flow of Area North will drainto the WWTP (modified lagoon system) located at the Rio Grande deMindanao site; while the sewage flow of Area South will drain to the WWTP(modified lagoon system) located at the Barangay Lugay Lugay site.

1. Design Assessment of Alternatives

Specific design parameters for the treatment plants to be considered for the threealternatives are as follows:

Alternative WWFP Connected Total Flow BOD LoadingLocation Population (cum/d) (kg)

Rio Grande deMindanao

I - Sewage 53,232 10,274 2,129

- Septage - 130 650

Total 10,404 2,779

Luana-Luang2 - Sewage 53,232 10,274 2,129

- Septage - 130 650

Total 10,404 2,779

Rio Grande deMindanao

- Sewage 6,338 1,223 254

- Septage - -

3 Total 1,223 254Luang-Luas

- Sewage 46,894 9,050 1,876

- Septage 130 650

Total 9,180 2,526

Assumption: - Flow 213 Ulcap/d- BOD 40 g/cap/d- 60% of the population is connected to the sewerage system.- Septage BOD 5,000 mg/I

2. Financial Assessment of Alternatives

To evaluate the alternative schemes a set of construction unit costs were developed on thebasis of costs derived from the Feasibility Report and other relevant studies and data


gathered by the consultant. For fiuther information, reference should be made to theFeasibility Report.Comparison of the three alternatives is as follows:

(i) Capital Cost

Capital Cost of AlternativesFacility (P million)

1 ~~~~~2 3SEWERAGE1. Collection 74.26 74.26 74.262. Propert Comections 81.13 81.13 81.133. Transportation Systen 34.65 32.28 45.414. Pumping Station 17.96 26.75 22.945. Force Mains 0.40 7.62 6.606. Pump Station (Land) 0.13 0.19 0.167. WWTP 43.09 43.09 47.348. WWTP (Land) 24.00 24.00 27.009. WWTP (Resettlement) _ ___

Total 275.62 1 289.32 304.84

Notes:

Capital costs include 5% physical contingencies plus 15% for engineering and training.

At a cost per hectare of P261,625 (includes for contingencies, engineering, etc.) asdevelopedfrom two study areas in Davao and Dagupan. Collection sewers proposed are"condominial", that is, they are routed through private property to optimize the sewerlength and minimize cost of connection to the transportation sewer. Property owners haveto be consulted and agree to the condominial sewer design.

3 The cost of a house connection to a sewerfor an existing property, requiring theabandoning of a septic tank, has been estimated at P9,726 (includes for contingencies,engineering, etc.). Assumes 60% of the year 2001 population connected to the seweragesystem.

(ii) O&M Costs

The O&M costs will increase in relation to the number of connections. Annual O&Mcosts have been computed for each alternative from the year 2001 (starting of operation)to the year 2015. The following table shows a comparison of the O&M costs for the year2001 and 2015.

Annual Cost 2001 Annual Cost 2015Alternatives (P million) (P million)

1 3.58 4.792 4.21 5.573 4.52 5.80


(iii) Net Present Value

The above capital and O&M costs have then be used to determine the net present value(NPV) at 15% discount rate. The result of the analysis is as follows;

Alternatives NiPV_______ _______ _______(1F m illion)

1 180.482 200.083 211.43

(iv) Conclusion

The above NPV shows that Altemative I is the most economic (by about 10% over thesecond) and, therefore, is recommended for implementation. The recommendedalternative is for a collection and transportation sewer network, in the Poblacion area,discharging to a single WWTP located at the Rio Grande de Mindanao site. The WWTPwould use the modified lagoon treatment process and would treat both sewage andseptage. The treated effluent would be discharged into the Rio Grande de MindanaoRiver. The treated effluent will meet the discharge standard prescnbed by DENR

Section IV - Recommended Project Design for Cotabato City

Description and ComDonents

The recommended plan will include the following five components: (i) on-site andcommiunal sanitation facilities; (ii) sewerage system in Poblacion; (iii) maintenanceequipment, tools and spare parts for the operation and maintenance of installed sewerageinfrastructures; (iv) institutional support; and (v) drainage facilities.

Sanitation Facilities

The sanitation component will include the construction of 2,200 VIP latrines, and 734pour-flush toilets with septic tanks to benefit 16,430 residents as well as 33 communaltoilets which will benefit about 8,250 residents in the city.

The on-site sanitation facilities include: "VIP latrine and pit" and "pour-flush toilet andseptic tank". The demand for on-site facilities will, therefore, be established by public

Environmental Assessment Report: Cotobato City 40

consultation concerning rented dwellings and owner occupied houses. Communalsanitation facilities to be provided under the project may be either on-site or off-site,connected to the sewerage system, depending on technical feasibility. The choice betweenindividual and communal facilities will be driven by technical feasibility and demand by keystakeholders, and not by tenure status. However, in slum areas and squatter settlements,the demand will be ascertained not only from the tenants, but also from land owners andfrom local government officials representing public interest.

The communal toilets will be constructed in areas where, througha public consultation,there is an established demand and willingness to pay for the service.

Seweraee Svstem

The sewerage system will include: (i) house connections; (ii) feeder sewers for thecollection of wastewater in neighborhoods, puroks and barangays; (iii) trunk sewers andpumping systems for wastewater conveyance from barangays to treatment plants; and (iv)sewage and septage treatment plants.

The connection of properties to sewers will be made under the project in order to ensuregood workmanship and timely connection of households to installed sewer systems.Recovery of house connection costs will be spread over a period consistent with demand.Feeder sewers will consist of simplified and condominial sewers. Where condominialsewers are used, communities will be given a choice between location of the sewers inbackyards and locating them in front of their properties. Simplified sewers will be used fortrunk and main transportation sewers.

A modified lagoon system as in the ALPS treatment process will be used to treat bothsewage and septage. Its principal unit is a deep vertically integrated pond with ananaerobic pond below a facultative pond system. The geometry prevents turnovers,thereby minimizing odor problems as well as sludge accumulation.

The project proposes the construction of sewerage facilities in the Poblacion of CotabatoCity. In the Poblacion, the Stage I sewerage system will cover a service area population,in 2015, of about 88,720 of which about 53,230 (or 60%) will be served.

The Stage I system proposes the construction of a sewer network that will dischargesewage to a single vertically integrated pond system designed to treat both sewage andseptage. The treatment plant is located at the Rio Grande de Mindanao site and thetreated effluent will be discharged to the Rio Grande de Mindanao River.

The system (see Figure 3.2) wiil include the following facilities:

* collection sewers covering an area of 283 ha;

* transportation sewers with a total length of 7,200 m and diameter from 150 to 600mm;


t~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Wo K:M.

< | ~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~Figulre 3.2l

S(:lltMATIR AYONE (1, f/kvX > "^ICH tINtA 5 _ ~~~~~~~~~~~~~~~~~~~~~~~~SEWtRA(1.t SYSIIPA

i~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~si

* two pump stations with a capacity of 3,341 and 13,580 cu.m/d and a landrequirement of 134 and 296 sq.m, respectively;

* a force main with a length of 200 meters with diameter of 300 mm;* a WWTP with a capacity of 10.404 cu.m/d and a land requirement of 8.0 ha;

* a total of 8,341 connections in the year 2001. The additional 1,165 connections upto the year 2015 will be constructed by the CCWD.

Maintenance Equipment and Spares

Equipment will be provided to the Cotabato City Water District including vehicles,machinery and tools needed for proper operation and maintenance of the sewerage andpumping facilities. Spare parts for critical equipment will also be supplied.

It should be noted that the sewerage systems will, after construction, be turned over to theCCWD not only for operation and maintenance but also for construction of additionalconnections. It is envisaged that the cost of new connections will be paid up-front by theusers at the moment they request to be connected to the system. This will surelyconstitute a constraint and may restrain the users from being connected. To mninmize thisproblem in the first one-two years of CCWD operation, it is proposed to include in theproject the procurement of stored material (pipes, fittings, etc.) necessary for theconnections. This would reduce the up-front amount required from the users and the costof material could be charged by the CCWD monthly on the water bilL

Institutional Support

The project will include: (i) consulting services for detailed design, consultation ofbeneficiaries and construction supervision; and (ii) training of CCWD staff responsible forthe operation and maintenance of installed sewerage infrastructures.

The consulting services required are detailed in Section 6.5 of the Feasibility Report (C.Lotti & Associati, 1996). The services to be provided by the consultant also include thetraining of staff for the operation and maintenance (O&M) of the sewerage systems andparticularly of ponding systems. The consultant will have to prepare an O&M manual andtrain the operators on basic ponding treatment concepts as well as flumiliarity with theO&M manual. The training program should also include an overseas visit to a countrywhere the adopted treatment method is already in operation.

Drainane Facilities

Tne drainage component has been included in the project following a specific request bythe LGU. The LGU and the World Bank agreed to include a lump sum of P52 million inthe project cost for the construction of drainage ditches which are considered of high


priority by the City Government. Since no details were provided, the drainage componenthas not been the subject of any technical analysis under this study. However, the drainagehas been evaluated in the financial analysis to ascertain the capability of the LGU to repaythe loan.

Cost Estimates

Based on the estimates, the capital cost of the Cotabato City project has been estimated atP367.22 million (US$13.98 million) excluding price contingencies and interest duringconstruction. The cost is composed by P90.89 million (US$3.46 million) of foreigncomponent and P276.33 million (US$10.52 million) of local component. By includingprice contingencies and interest during construction, the total project cost is P429.74million (US$16.36 million).

The project cost by component is as follows:

Component I million

SANITATIONConstruction of facilities 31.60LandPrice contingencies 6.31Interest during construction 12.14Total Sanitation 50.05SEWERAGEConstruction of facilities 218.69Land and resetdement 24.13Maintenance equipment & spares 8.00Institutional support 32.80Price contingencies 44.13Interest during construction 84.05Total Sewerage 411.80DRAINAGE l

Construction of facilities 52.00Price Contingencies 12.08Interest Dunng Construction 19.99Total Drainage 84.07

Total Investment 429.74Total interest during construction 116.18Total Project Cost 545.92


Section V - No Project Scenario

Chapter 2 vividly describes the worsening environmental and health situation as a result ofpoor sanitation and uncontrolled discharge of sewage. Though the proposed project onlycovers around 36% per cent of the population, this project is seen as the first step in along term program to provide Cotabato City the require sanitation and sewerageinfrastructure. The proposed project is anticipated to contribute to the gradualimprovement of the city's environment and improvement of the condition of its RioGrande de Mindanao and the nearby beaches.

LWUA/jerWDDPICfCHPTh3..DOCF231997 4:23 PM


4. ENVIRONMENTAL IMPACTS

Introduction

This chapter has three sections. Section 1 describes the beneficial impacts of the projecton the environment. Section II identifies and evaluates the different impacts of theproposed project on the environment. Section Im summarized the environmental impacts.

Section 1 - Beneficial Impacts of the Project

The implementation of the sewerage and sanitation project for Cotabato is foreseen toresult in positive impacts, namely:

* Health and Environment Benefits

One of the positive impacts anticipated to result from the implementation of a sanitationand sewerage program for Cotabato City is the reduction in the incidence of water borneand water related diseases. From a health point of view, this is very significantconsidering that diarrhea, a water related disease, ranks as first and eighth leading causesof morbidity and mortality, respectively in the City. I

Improvement in sanitation will no doubt improve public health conditions by decreasingthe probability of human contact with excreta.

Also a major impact of the project is the improvement in water qualty of the city's waterbodies. This is due to the fact that the deterioration of the city's water bodies, particularlyRio Grande de Mindanao is caused by organic loadings from domestic wastes. Withhouseholds without proper sanitation facilities proliferating the river banks, domesticwastes (solid and liquid) are discharged/dumped directly into the river. As such,improvements in solid waste management should also be implemented parallel with theprogram to maximize the benefits of the sewerage and sanitation project. This will notonly improve water quality but also contribute towards bringing about aesthetically cleansurroundings.


* Recreational Opportunities

In Cotabato City the water bodies are vital resources people utilize in their day to dayactivities. The people, specially those living along the river banks, use the river forswimming, bathing, cleaning and fishing. Therefore, sound management and protection ofthese water bodies would ensure that they continue to be used for such domestic purposesand contribute in providing recreation opportunities.

* Increase in Productivity and Income

The reduction of mortality and morbidity levels of water borne and water related diseasesis expected to increase the productivity of the households. This is because, when peopleget sick, they become indisposed and thus become economically unproductive. The timelost is a potential for generating income. There is also potential for savings in medicalexpenses resulting from the reduction of incidence of diseases.

* Increase in Economic Growth, Employment

With improved health and living conditions, Cotabato City becomes attractive for peopleto live in and to do business. Consequent water quality improvement contributes inpromoting fishery production in the bay, a source of livelihood in the city. These arepotential areas for economic growth and development.

During the implementation phase, the project is expected to generate employment not onlyduring the actual construction of sanitation and sewerage facilities, but more so duringoperation, for example in desludging operations whereby private contractors will beencouraged to participate in the project which consequently would be expected togenerate the corresponding employment for this new business venture.

* Increased Property Values and Commercial Attractiveness

The city's poblacion, the initial area to be served by the sewerage system, has a strongadvantage in when it comes to property valuation and commercial attractiveness because itcontains the Cotabato's central business district. Sewerage in the district would allowconstruction of high-rise office buildings, positively leveraging property values and taxcollections. In addition, the central business district is the most visible area for potentialinvestors. A conservative impact estimate suggests that a sewerage project could be self-financing in the central business district.


Section II - Project Implementation Impacts

As described above. the implementation of the project is expected to have beneficialimpacts in the long termn However, the construction and operation of the system is boundto result in impacts that require mitigation. This section identifies such impacts andassesses the scale and magnitude.

Construction Phase

A. Air QOgitv

The implementation of the project will result in occasional, marginal and acute increase inthe ambient concentration of suspended particulates in the vicinity of the project site. Thiscan be attributed to land clearing and excavation activities which expose soil to wind andvehicular traffic over unpaved road.

B. Water Ouality

Excavation activities in the project sites could also loosen soils and transport of thesematerials to any surface waters will result in siltation or increase in turbidity.

During the rainy season, surface runoff will tend to increase total suspended solids and isexpected to cause temporary stress at the discharge points, but the impact is localized. Assoon as the vegetative cover of the site is re-established on open spaces, impact on thereceiving body of water caused by surface run-off will be eliminated.

C. Noise

The noise impact during the construction stage is expected to be generally minimal andwill not require any special noise abatement measure. The treatment plant sites shall havea setback away from residential clusters, which will definitely provide the necessary bufferto reduce noise impact during construction of the treatment facilities.

During the pipe-laying, some noise will be temporarily generated due to operation ofheavy equipment and from breaking concrete pavement and sidewalks. In addition, sometraffic congestion may be expected on during pipelaying.

D. Ecological Effects

As there are no rare, endemic species of flora and fauna in the project area, projectimplementation has minimal impact on the terrestrial and aquatic ecology. There wil beclearing of trees during actual construction where unavoidably necessary.


Operation Phase

E. Air Quality

The operation of the wastewater treatment facility shall have minimal impact on the airquality of the area. Aside from the occasional odor nuisance, it is not projected to haveadverse effect on the air quality. Odor production at the AIPS treatment plants iscontrolled by the natural processes employed by the systern In existing installations,residences, a convalescent home, and recreational areas like golf courses are within"sniffing distance" of the plant facilities.

F. Water Quality

The implementation of the project will be beneficial to the general environment ofCotabato City and its environs. The current practice of discharging untreated domesticwaste into nearby bodies of water would thus be reduced or ehminated. Diffusion effects -- the adoption of the modified lagoon system (or ALPS) treatment process should attainhigh rates of BOD, TSS, and colform removals. Discharge to the receiving bodies ofwater should therefore pose no significant pollution risks. However, to further ehminatethis risk, proper studies would be conducted on the mixing and dilution before locating theoutfall. In the unlikely event that projected removal rates appear to be unattainable, thetreatment system particularly the maturation ponds can be designed for larger capacitiesand/or longer detention times to further enhance removal efficiencies and thereby negatethe risks of polluting receiving waters.

H. Socio-econornic Aspects

The provision of sanitation facilities in Cotabato City would undoubtedly benefit the ge-neral populace of these areas. The occurrence of epidemic-scale diseases as a result ofunsanitary conditions shall be minimized. This will make for a more healthy andproductive population.

I. Sludge Disposal and Management

The modified lagoon treatment system is designed and actually performs so that solds atthe bottom of the deep anaerobic pits in the facultative pond (first biological pond reactor)remain for very long periods of time, continuously decomposing. Due to large pit volumeand its depth, and its reducing environment, settled solids ferment there to a point whereonly ash remains. Thus minimizing the generation of bio-solids, hence sludge removal isseldom if ever required.

Since sludge is retained in specially designed pit digesters and remains there indefinitely,daily transfer of sludge is not necessary and energy needs for sludge transfer areeliminated. Also because digestion proceeds over years of time, heating and mixing (as inconventional sludge digesters) are not required therefore reducing costs of operation.


The oldest plant in operation treating domestic wastewater from the city St. Helena inCalifomia, USA, has not had to remove bio-solids for nearly 30 years. (Recent testings ofthis system have indicated that sludge is well-digested and very stable.) Owing to itsstability. the sludge/residue, if desludging does become due, can be disposed of witharrangements with the city, at the city's sanitary landfill. Because of its relatively stablenature, desludged material could even be barged to the open sea for disposal say once inevery 15, 20 or even 30 years.


Section m - Summary

The implementation of the project and its components is projected to produce onlyminimal adverse environmental impacts. Moreover, there are socio-econornic impacts thatwill essentially be beneficial, and will provide employment and livelihood opportunities tothe population of surrounding communities as jobs will be generated during the projectimplementation. In the long-term, better sanitary conditions wil result in the project areas.Consequently, an improvement and enhancement of the existing environmental conditionsin the project areas shall be experienced.

During project implementation, mitigation measures will be incorporated to minimize, or ifat all possible, eliminate adverse impacts. Moreov..r, measures to enhance existingenvironmental conditions in the project site shall be implemented to maintain thesustainability of the area. The implementation of the project will inevitably produceimpacts, both adverse and beneficial. The mitigation actions are outlined in the nextchapter.

LWVA,icriWDDPICTCHPTR4.DOCF229-


5. ENVIRONMENTAL MANAGEMENT PLAN

Section I - Mitigation Plan

Construction Phase

Potential Impact & Risks Mitigation Action

Poor quality of construction * Design and supervision contract will be separated from supplyand installation contract as a means of assuring quality ofconstruction. Works engineers, with a relatively independentsource of information on construction progress, will be hired.

Air Pollution * Careful construction planning and work phasing, specificationsand construction methods to reduce the length of time that the

* Construction equipment and soil is exposed to the environment.vehicles may cause higher * Provision of adequately and properly maintained storage forsuspended particulates, odors and construction materials and equipmentfumes emissions - C02 , CO, NO. * Expeditious and prompt removal of excavated materials or

dredged spoils from construction sites.* Exposure of fine-grain particles to * Regular and adequate sprinkling of water on dust-generating

wind and vehicular traffic will mounds/piles resulting from earthmoving activities and civillikely result in a decrease in air works.quality. * Good housekeeping for all construction affected areas and

workplaces.* Control of motor vehicle and equipment emissions.* Use of protective gear by all workers.

Water Poliution and Soil Erosion * Provide temporary drainage and storage facilities for excavationsoils, for fuel and oils needed for equipment.

* Siltation * Careful and rational planning of construction and post-construction phases of the project.

* Maintenance of adequate drainage system.

* Noise from operation of construc- * Erect temporary sound barriers around the work sites; avoidtion equipment would be about 70- simultaneous use of heavy equipment; limit daytime work,S0 dBA at 10 m; 50-70 dBA at 30 vehicle speed at 20 kph; regular maintenance of equipmentm. * Use of appropriate mufflers and sound proofing of constuction

machineries, equipment, and engines. Use of appropriate shock-absorbing mountings for machinery.

* Establishment of buffer zones and noise zones.

* Temporary Disruption of Traffic * To the extent possible, feeder and collection sewer lines will beFlow located along secondary streets.

* Scheduling and increasing input resources so that period oftraffic disruption in primary roads are reduced.

* Coordinate with city traffic management office and the PNPTraffic Management Command

. Clear directional signs and barriers in case traffic rerouting isneeded.

* Public Information campaign.


Operation PhasePotential Impact & Risks Mitigation Action

* Environmental hazards due to * Carefully designed post-construction maintenance, contingencyaccidents and man-made or natural and monitoring programs.disasters. . Well designed plan for detection of accident or natural events

* Breakdown or malfunction of the including precautionary and remedial measures to be taken/sewer lift station will increase level observed.of pollution at the Rio Grande de . Adequate plans for environmental rehabilitation, clean-up,Mindanao near the center of the restoration, and disposition of temporary structures and facilitiescity as raw sewage will have to be installed during the construction phase.dumped directly.

Water Pollution * Upgrade laboratory facilities of the Cotabato City Water District

(CCWD) to be able to undertake wastewater analysis.* The effluent discharge point of the * Following the bubble concept, wastewater discharged into the

treatment plant is affected by tidal Rio Grande de Mindanao River shall, in the long-term, conformconditions (estuary). to the water quality standards established by the Department of

Environment and Natural Resources as set forth in DAO No. 34and 35, Revised Water Usage and Classification/Water QualityStandards and Revised Effluent Regulations of 1990,respectively.

* A dispersion/dilution modeling study will be conducted to priorto locating the outfall. Treated effluent discharge into the RioGrande de Mindanao shall be timed based on tidal conditions.The adoption of the AIPS process for the treatment plants shouldresult into attainment of effluent standards.

* Noise would be at about 65-45 * Establishment of buffer zones and noise zones.dBA, principaDly coming fromseptage trucks unloading at thetreatment plant.

* Odors (organic and sulfur com- * Maintenance of greenbelt zones and vegetation.pounds mainly from the trucks * Provision of landscaped open spaces which will improve theunloading septage) aesthetics in the area by planting the green strips with

appropriate plant or tree species.

Managenent and O&M of the System Institutional:* Management Contract with CCWD which has proven utility

* Poor maintenance of pumps management and operations capacity.* User consultation at detailed engineering design stage to ensure

* Low connections connection.* Sewerage surcharge should be sufficient to provide incentives for

CCWD to maintain system.* Require M&E reporting to the DENR and LWUA* Explore feasibility of BOO/BOT contracts for recreational

activities in unused lands at treatment sites.* Provide adequate training of CCWD and city staff.Regulatory:* Require compulsory connection for all commercial, industrial

and high domestic water users.* Utilize Public Performance Auditing system being set up by

DENR to monitor adverse impacts.Technical:l Provision of adequate maintenance equipment and spares with

CCWD.


Section H - Monitoring Plan

Construction Phase

Ambient air quality measurements will be undertaken near construction sites. This will bemostly near locations where sewer network is being laid and treatment plait sites. Whenselecting sites due consideration will be given to sensitive receptors like schools, hospitals,houses etc. Total suspended particulates (TSP) will be measured once a fortnight, for 8 or24 hours, over the construction period.

Noise will measured at the same locations as TSP. Leq and Lgo values will be measuredand recorded.

Operation Phase

Receiving water quality is to be monitored by the DENR through its Regional Officewhich has been periodically monitoring the status of the Rio Grande de Mindanao Riverand estuarine water quality. The PMO will collect information on present conditions,observed changes in pollution loads etc. It is to be recognized that all the pollution loadwill not be removed yet it is also expected that the proposed sewerage infrastructure willgreatly reduce the problem.

Once the plan becomes operational, the Treatment Plant Operator, vis-a-vis the CotabatoCity Water District would have to set-up a laboratory and institute a monitoring programto measure the effluent discharge. Daily representative values of PH, 5-day BOD, COD,Total Nitrogen and Total Phosphorus will be measured during the start-up period. Oncethe plant operations stabilize, weekly measurements (24-hourly basis) will be taken.

Quarterly reports showing the trends of effluent discharge and receiving water quality willbe reported to the PMO and DENR Regional Office.


Section m -Implementing Arrangements

The WDDP-PMUI. with the assistance of LWUA-CPSO and consultants, would monitorcompliance with the ECC and carry out the requisite data collection. Monitoring resultswould be submitted to DENR/EMB and the World Bank periodically. Whileresponsibility for the various mitigation activities have been identified, the WDDP-PMUshall ensure that the requirements are complied with. In addition, feedback fromcommunities, city officials, NGOs, etc. will be proactively sought through the city publicaffairs programs, regular monthly meetings of barangay captains and other methods.

DENR, through its planned PPA system, would also periodically monitor and auditcompliance with the ECC, assisted by independent contractors.

Summary of Responsibilities and Timetable for the Mitigation Plan

Activity Responsi ility Start Completion

Secuze ECC clearance from DENR. CPSO-LWUA Decamber 1996 September 1997

Coiled referenoe amnbint air parmaem around the City PMU, with DENR September 1997 June 1998proposedtreamgitplant sitessatprojea citis regimal offioe

lEnre that the bid documents ncludeprovisims for miti- PMO January 1998 August 1999gatiun umder the resp3ns1bihtv of the cmiractor; revew|ontractors work plans to ansure cocimpiance with en-vircnmental mrnigatbon plan provsicoes.

Train oprators n O&Mpradici &haadliagernergecy PMO and CPSO-LWUA Jaiuany 1999 Jme 2000lsmitatios

Asse and upgrade the laboratory facilities of the Proeui City PMU and local Mardi 1998 June 2000Cotbato city Wala Distict. Water District

Ceonduc ua ccmsuer atics and infonnatim campai8i Projed City PMU. with January 1998 Jme 2000as asce of NGO.

Momitor aad report an compliance. PMO Bi-amual basis Bi-ual basis

LWVUA/jcrCTCHPIRS.DOCF221997


Appendices1. Bibliography2. Climatological Normals (1961-1995) for General Santos City (PAGASA

Station nearest to Cotabato City)3. Typical Noise Emissions of Construction Equipment4. Expected Noise Levels at Various Distances from Construction Equipment5. Environmental Quality Standards For Noise Maximum Allowable Noise Levels6. The Advanced Integrated Pond System (AIPS) of Wastewater Treatment

Appendix IBIBILIOGRAPHY

C. Lotti & Associati, 1996, Updating Feasibility Reports for Sanitation Investments in FiveCities, Final Report, Vol. 4, Cotabato City, November

C. Lotti & Associati, 1996, Updating Feasibility Reports for Sanitation Investments in FiveCities, Final Report, VoL 6, Davao City, November

CDM Intemational 1994, First Stage Feasibility Report for Sanitation and Sewerage:Cotabato City, Philippines, January

Environmentally Sustainable Development (ESD) Vice Presidency, World Bank, 1994, WaterSupply, Sanitation and Environmental Sustainability, The Financing Challenge

WASH, 1990, Health Benefits from Improvements in Water Supply and Sanitation:Survey and Analysis of Literature of Selected Diseases, Technical Report No. 66, July

Whittington, Dale, Donald Lauria and KyeongAe Choe, 1993, Households' Willingness toPay for Improved Sanitation Services in Davao, Philippines, July

Whittington, Dale, et. al., 1995, Economic Benefits of Surface Water QualityImprovements: Davao CV Study (mimeo.)

Yniguez, Cesar, 1996, Urban Sanitation User Demand Study: Technical Consultant'sReport, May

Lee, E. W., 1990, Ponding Systems Treat Wastewater Inexpensively, USEPA SmallFlows, October

Oswald, W. J., 1990, Advanced Integrated Wastewater Pond Systems, 1990 ASCEConvention Proceedings, Am. Soc. of Civil Engineers, New York

SOA, Inc., 1996, Advanced Integrated Pond Systems: Innovative and Alternative,Environmentally Sound and Low Cost Solutions for Wastewater Treatment into the21st Century, (Hand-out)

Appendix 2CLIMATOLOGICAL NORMALS(1961-1995)

Station 851 - General Santos City

Latitude 06°07'N

Longitude 12501 'EElevation 15.0 meters

Amt. of No. of = = Tern erature C) = = RH MSL Wind Cloud Days w/ Days w/Month Rainfall Rainy Max Min Mean Dry Wet Dew Vapor (%) Press. Speed Dir. Cover Thunder Light-

_____ (mm) Days Bulb Bulb Point (mbs) (mbs) (octa) storm ningJanuary 72.4 9 32.9 21.9 27.4 27.1 23.9 22.7 27.4 77 1,009.7 2 N 5 I 4

February 67.2 8 33.1 22.1 27.6 27.2 23.9 22.7 27.4 76 1,009.9 2 N 5 I 5

March 43.8 7 33.9 22.2 28.1 27.8 24.3 23.0 28.0 75 1,010.1 2 N 5 I 6

April 52.4 7 34.1 22.7 28,4 28.2 24.8 23.6 28.9 76 1,009.5 2 S 5 3 9

May 73.6 11 33.0 23.0 28.0 27.8 25.0 24.0 29.7 80 1,009.2 2 S 5 5 15

June 118.3 14 31.8 22.5 27.1 27.1 24.7 23.8 29.4 82 1,009.7 2 S 6 3 12

July 102.2 13 31.3 22.2 26.7 26.8 24.5 23.7 29.1 83 1,009.6 2 S 6 3 8

August 82.1 13 31.5 22.1 26.8 26.9 24.5 23.6 29.1 82 1,009.7 2 S 6 2 9

September 89.8 11 31.8 22.1 27.0 27.0 24.6 23.7 29.3 82 1,009.8 2 S 6 3 10

October 104.0 13 32.2 22.3 27.3 27.2 24.7 23.8 29.4 81 1,009.6 2 S 6 4 11

November 83.8 11 32.9 22.2 27.5 27.4 24.7 23.7 29.2 80 1,009.3 2 S 5 4 1I

December 70.0 10 33.0 22.0 27.5 27.3 24.4 23.4 28.6 79 1,009.5 2 N 5 2 8

Annual 959.6 127 32.6 22.3 27.4 27.3 24.5 23.5 28.8 79 1,009.6 2 S 5 32 108

Source: PA GASA

Appendix 3TYPICAL NOISE EMISSIONS OF CONSTRUCTION EQUIPMENT

Typical Sound Pressure LevelsEquipment at 15 m from Source

[in dB (A)]Air Compressor 75-87Backhoe 71-92Compactor 72Concrete Mixer 75-88Concrete Pump 82Cranes 76-88Front Loader 72-81Generator 72-82Grader 80-93Jack Hammer 81-97Paver 87-88Pile Driver 95-105Pumps 70-90Tractors, Bulldozers 78-95Trucks 83-93Vibrator 68-81

Appendix 4EXPECTED NOISE LEVELS AT VARIOUS DISTANCESFROM CONSTRUCTION EQUIPMENT[in dB (A)]

Equipment 30 60 1 120 240 metersmeters meters meters

Air Compressor 69-81 63-75 57-69 51-63Backhoe 65-87 59-81 53-75 47-69Compactor 66 60 54 48Concrete Mixer 69-82 63-76 57-70 51-64Concrete Pump 76 70 64 58Cranes 70-80 64-74 58-68 52-62Front Loader 66-75 60-69 54-63 48-57Generator 66-76 60-70 54-64 48-58Grader 74-87 68-81 62-75 56-69Jack Hammer 75-91 69-85 63-79 57-73Paver 81-82 75-76 69-70 63-64Pile Driver 89-99 83-93 77-87 71-81Pumps 64-84 56-78 50-72 44-66Tractors, Bulldozers 72-89 66-83 60-77 54-74Trucks 77-87 71-81 65-75 59-69Vibrator 62-75 56-69 50-63 44-57

Appendix 5ENVIRONMENTAL QUALITY STANDARDS FOR NOISEMAXIMUM ALLOWABLE NOISE LEVELS[in dB (A)]

Class Area Day Morning/Evening Night

AA Hospital/School 50 45 40

A Residential 55 50 45

B Commercial 65 60 55

C Light Industrial 70 65 60

D Heavy Industrial 75 70 65

Note: The divisions of the 24-hour period shall be as follows:Morning 5:00 AM - 9:00 AM Daytime 9:00 AM - 6:00 PMEvening 6:00 PM - 10:00 PM Nightime 10:00 PM - 5:00 AM

Appendix 6THE ADVANCED INTEGRATED POND SYSTEM (AIPS)1

of WASTEWATER TREATMENT

Preface: The Sewerage and Sanitation Component of the World Bank-assisted WaterDistrict Development Project has proposed the adoption of the modified lagoon systemvis-ai-vis the Advanced Integrated Pond System (AIPS) as the process for treatingcollected wastewater (and septage). The following describes the technology and benefitsof the aforesaid treatment system.

The AIIPS is an integrated, multi-stage biological reactor system treating wastewater. Thesystem utilizes compacted earthen construction to reduce costs. The system optinizesnatural biological processes to reduce power requirements and need for chemicaladditives. The concept is to minimize bio-solids production rather than to maximizeaeration solids resulting into minimal power requirements and solids management.

AIPS consists of a series of at least four ponds, each designed to best perform one ormore of the basic treatment processes. First is the primary biological reactor or afacultative pond with an aerobic surface and extremely anoxic internal pit forsedimentation and fermentation. The pond reactor has three discrete and isolatedbiological zones integrated into a single unit: a deep anaerobic pit at the bottom, a sludgeblanket suspended within the deep pit, and an overlying aerobic comprised of aerobicbacteria and algae oxygenated by photosynthesis, supplemented by horizontal mechanicalaerators when needed. Anaerobic microbes in the pit are protected by surrounding wallsor berms from the intrusion of cold surface water containing dissolved oxygen. Rawsewage is introduced directly into the pits where sedimentation and methane fermentationoccur. Overflow velocity in the pits is maintained so low that suspended solids removalapproaches 100% and biochemical oxygen demand (BOD) removal approaches 70%. Theoverflow velocities of one to two meters per day are less than the settling velocities ofhelminth ova and parasite cysts so most of these remain in the pit and consequently arepermanently removed from the effluent.

Solids at the bottom of the deep anaerobic pits remain for very long periods of time,continuously decomposing. Due to the large pit volume and its depth, and the reducingenvironment, settled solids ferment there to a point where only ash remains. Thusminimizing the generation of bio-solids, hence sludge removal is seldom if ever required.The oldest plant in operation treating domestic wastewater from the city St. Helena inCalifornia, USA, has not had to remove bio-solids for nearly 30 years.

The second pond is a high rate pond where microalgae grow profusely releasing oxygenfrom water by photosynthesis. Algae produced are highly settleable and after

l Oswald, W. J. , Advanced Integrated Wastewater Pond Systems, 1990 ASCE Proceedings, Am. Soc. ofCivil Engineers, New York

Appendix 6: The Advanced Integrated Pond System(AIPS) ofWastewater Treatment

sedimentation, the remaining water has a BOD that is generally less than 20 mg/lRecirculation of algae bearing water from the High Rate Pond to the Facultative pondprovides an oxygen-rich cap on the facultative pond. This oxygen quickly oxidizesreduced gases emerging from the fermentation pit thus mitigating odors.

The third pond provides for sedimentation of algae. Algae which settle tend to hibernateand thus do not immediately decompose and produce nuisance.

The waters emerging from the settling ponds are sufficiently low in BOD and suspendedsolids. They can be percolated readily into the ground or used for irrigation. They stillhowever high E-coli count of more than 1000 MPN per 100 ml. and therefore may requirestorage prior to disposal or reuse. Then comes the fourth pond which has a dual purposeof added disinfection and storage for irrigation or other uses.

Performance: Following algal removaL the degree of pollutant removal in the AIPS isequivalent to that of mechanical secondary plants but as is to be emphasized at a muchlower capital and operation & maintenance costs. The treatment action of the ALPS isvery similar to and realizes the advantages of an upflow anaerobic sludge blanket (UASB)reactor. The AIPS however does not inherit the rigorous operation and maintenanceproblems like clogging and sludge handling inherent to UASB reactors.

There now more than 85 operational treatment plants in the US and in other countries.Notable among them is the wastewater treatment plant for the city of St. Helena, inCalifornia, USA. The St. Helena system has been recognized as the Plant of the Year bythe California Water Pollution Control Association for 5 MGD plants in 1994 and waslikewise accorded by the California Energy Commission the "Energy Efficiency ShowcaseAward" also in 1994.

The St. Helena plant treats domestic wastewater at a peak capacity of 2 MGD.Performance data indicate that for the period of 1990 to 1995: average influents of BODof 290 mg/I and TSS of 263 mg/l were treated to 24 mg/I BOD (92% removal) and 34mg/l TSS (87% removal), respectively. A treatment plant in Hollister, California, USA,with capacity of 2 MGD, exhibited similar removal efficiency, reducing an influent BOD of194 mg/l to a mere 7 mg/l after treatment.

Performance of AIPS plants can be expected to reduce pollutants in the following ranges:2

* BOD 95-97%* COD 90-95%* Total Nitrogen 90%* Total Phosphorus 60%* MPN- E-coli 99.999%

2 Lee, E., "Ponding Systems Treat Wastewater Inexpensively", USEPA Small Flows, October, 1990

Appendix 6: The Advanced Integrated Pond System(AIPS) of Wastewater Treatment 2

On sludge management, the earthwork digesters (fermentation pits in the facultativeponds) can be made large to permit complete digestion and thus reduces sludge generationto the extent that sludge handling is eliminated for many years. The St. Helena plant in 27years of continuous operation, accumulated less than 1 meter of residue or just 3centimeters per year! Thus daily or frequent sludge removal is eliminated thus attainingcost and energy savings. The Hollister plant also showed the same very low rate ofaccumulation in 12 years of operation.

Because the sludge undergoes full fermentation, the sludge or residue resulting from theprocess is relatively inert and stable, and the volume is small. Disposal then should not bea major operation problem.

In terms of costs, Oswald compares the cost of a conventional treatment of $350 to $700per cu. m. (1990) to that of the AIPS which would cost less than $5 per cu. m. (1990),100 times cheaper.

In essence, the AIPS of treatment has the following advantages:

* Efficient organic pollution reduction and nutrient removal comparable if not betterto secondary and tertiary treatment.

* Energy efficient -- the design provides for reduces oxygen requirements on thefront end

- Less construction cost, as compared to ALPS:* Oxidation Ditch 3.5 times more expensive* Trickling Filters 4* Activated Sludge 4.5* Stabilization Pond 1.4

* Less operation cost- Oxidation Ditch 3 times more expensive- Trickling Filters 3- Activated Sludge 3.5* Stabilization Pond 1.3

* Virtually no odor - odor production is naturally controlled. In the case of the St.Helena (CA. USA) treatment plant: A convalescent home is within 300 feet of theponds. In Hollister (CA, USA), the treatment plant is practically within "sniffingdistance" of a golf course and residences in the area.

* No daily sludge handling. St. Helena's Treatment Plant has not removed sludge in30 years of continuous operation.

* Pond buffer capacity enables the system to handle effectively variable organic andhydraulic shock loads.

Appendix 6: The Advanced lntegrated Pond .Svstem(AlPS) ofWastewater Treatment 3

Selected Bibliography:

Lee, E. W., Ponding Systems Treat Wastewater Inexpensively, USEPA Small Flows,October, 1990

Oswald, W. J., Advanced Integrated Wastewater Pond Systems, 1990 ASCEConvention Proceedings, Am Soc. of Civil Engineers, New York, 1990

SOA. Inc., Advanced Integrated Pond Systems: Innovative and Alternative,Environmentally Sound and Low Cost Solutions for Wastewater Treatmentinto the 21st Century, (Hand-out)

* Further relevant information and reference materials on the AIPS are attached forreference.

Appendix 6: The Advanced Integrated Pond Svstem(AlPS) of Wastewater Treatment 4

ADVANCED INTEGRATED POND SYSTEM(ALPS)

Natuiral, Biological Wastewater Treatnentfor

Municipalities, Agriculture and Industry

!Inovalyeand,Alternative,-~~~~il Sound and Low Cost

3 1 ~VVSolutions

For Wastewater TreatmentInto the 21st Century

1340 Arnoid D)rive, Suiie I110Martinez, CA 94553510-228-5801 F:u: 51fl-228-5804

SOA, Inc. Martinez,

AIPS llighiligihts

Efflcient pollution controlE.fijeove organiic reduction and nutrient removal for secondary and tertiary treatment.

LEnergy Efficiency with AIPSThe integrated, multi-stage anaerobic and aerobic reactor design reduces oxygen r equirements(and energy requirements) on thefront endofthe system. St. Helena .s wt'asiewiater treatmentplant was awarded the California Energy Commission Efficiency Shosv Case . ward in 1994anid 1994 Plant of the Year Award by California Water Pollution Control Associalion.

Construction Cost SavingsOxidation Ditch 3.5 times more expensive than AIPSTrickling Filters 4 times more expensive than AIPSA1ctivated .VIwt4e 4.5 times expensive than AlPS.Stabilization l'otid 1.4 times more expensive ihan AlPS

Operating Cost SavingsOxidtation D)itch 3 times more expensive than AIPS7)-ickling filters 3 times more expensive Ithan AIPSActivated Sludge 3.5 times more expensive than AIPSStabilization Potid 1.3 times more expensive than AIPS

Viriually No odorsO,lrs are controlled naturally. Winery Treatmnent Plant is within 300feet of a convalescenthisxpital in the City of St. Helena, California.

No daily bio-solids bandUngSt. lkleena's Js W7P has not removedsludge in 30 years of continuotus operation; for industrialplalnts sludge removal every 7-10 years, depending on waste characteri.stics.

Pond buffer capacity to accommodate variable organic and hydraulic shock loadslWin er v organic variability rangesfrom 100 to 20,000 mg/l of BOD in one week.

& Adva iceel Water Treatment Achievable with AlPSNutient ,etimoval...Denitrification in anaerobic zone and algal uptake in aerohic zone.PhiospIinov oxidizes in the aerobic zone, assimilated with algae, naturaliy co-precipitated, andthen .settled lby gravity.

P I'tential for Enhanced Habitat for Wildlife & Recreational BenefitsiVtural integration with constructed wetlands and habitat restoration. Landwape pond1

ontribwue aestihetic value and can provide recreational use.

Reilucedl Fiscal Impact on RatepayersLess cost to ratepayer due to reduced life cycle costs because of lower constrc tion cosrs A9 Nlol)erations & maintenance costs and long term replacement.

tartinez: 510 2'8-58'11 Fax: 510-228-5804

Ic. IYIC Martinez. CA

AIPS i'ecliology

All'S utilizes conmpacted earthen construction pracdces to reduce construction costs. The systemopatimizes natiu,ml biological processes to reduce power requirements and need for cheliciial additives.The desigin concept is to minimize bio-solids production rather than to maximize aeration solids and 1as a result minirnize power requirements and solids managemenL

AllPS is an integrated, multi-stage biological reactor system treating municipal, agricultural andindustrial wastewater. The reactors are relatively deep and constructed as an open surface pond ofcompacted earth. The biological reactor has three discrete and isolated biological zones integrated intoa'sinele unit: deep anaerobic pit(s) at the bottom of the reactor, a sludge blanket suspended withiin the(leepl pit, and an overlying aerobic zone comprised of aerobic bacteria and algae and oxygenated byphotosynthesis, supplemented by horizontal mechnical aerators when needed.

In most case:;, the plima;ry reactor is followed by a second reactor operating in series, wilh tt lC capabilityto tucirculate. (lepeniding on site specific condidons. Recirculation provides flexibility andsc sliockab3orption abilities for variable hydraulic or organic loadings, or where there is the potential for toxicspikes. .

ilie intilent wastewater enters thte deep anaerobic pit at the bottom of the reactor where settlable solidsare deposited arounid the inlet and where acid fernentation and methane generation occurs. The risinggases and up-welling of wastewater flow through the thick anaerobic sludge blanket that is fonnedwithin tie deep pit. The overdying aerobic zone is comprised of aerobic bacteria and algae and keptoxygenale(d hy horizontal surface aerators and photosynthesis. The aerobic zone reliably controls o(lorsanid soltuble wastwvaler components undergo aerobic oxidadon and further degradation. T'le horizonitalaeratois also crcate a circular motion over the whole surface area; the bacteria anrd algae circuilate overthe far cnd of the reactor where a second deep anaerobic pit is located. The horizontal velocity of thereactor is reduicetd while circulating over the secondpit and the aeration solids are settle( by gravity intothis pit hviiere the solids are decomposed and stabilized

Solids at the bottom of the deep anaerobic pits remains for very long periods of littme, continuouslydeconiposini. 'Ilits. biosolids minimization is accomplished. The oldest plant in operationt, treatingdomestic wastewater, has not had to remove biosolids for nearly 30 years. Seasonal tulnover of itlic ponds is preveiited by isolation of the dcp anaerobic pits. AlPS's design features and cell geometryrmainit lin tile iiitegrity of die system thereby suppressing turnovets.

AIPS is appi olinate lbr wastewater applications for nornal flow situations as wvell as whletee there arevariable hydiaulic flows and organic loadings, particularly where there may be limited industrial pre-treatineni and source control of toxic contaminants and heavy metals. AIPS design elemenits provideflow equalii.atlon, buffer capacity and recirculation capabilities to achieve secondat y anti advalIcedtreatiticmnt for, nutinicipalities, agriculture and industry

4i

Marlini,7: 51-228-5-01 Fax: 510-221-5804 2 12

Inc. - hiinez, CA

AIPS Techniology

AIPS utilizes compacted earthen construction practices to reduce construction costs. Thie systeinoptimfluzes natual biological processes to reduoe power requirements and need for chemical additives.The desigi concept IS to minimize bio-solids production ather than to maximize aeration solids andas a result minimize power requiements and solids management.

AlPS is an integrated, multi-stage biological reactor system treating municipal, agricultural andindustrial wastewater. The reactors are relatively deep and constructed as an open surface pond ofcompacted earth. The biological reactor has thre discrete and isolated biological zones integrated into IQa'single unit: deep anaerobic pit(s) at the bottom of the reactor, a sludge blantket suspendled within thedeep pit, and an overlying aerobic zone comprised of aerobic bacteria and algae and oxygenaled byphotosynthesis, supplemented by horizontal mechnical aerators when needed.

In rdost cases, the piinalry reactor is followed by a second reactor opeating in series, wigti the capabilityto a ctcirculate, dvepeething on site specific conditions. Recirculation provides flexibiliy an shockabsorption abilifties for variable hydraulic or organic loadings, or where there is the potential for toxicspikces.

Tle influent vastewaier enters the deep anaerobic pit at the bottom of the reactor where settlable solidsare deposited around the inlet and where acid fermentation and methe generation occurs. The risinggases and up-welling of wastewater flow through the thick anaerobic sludge blanket that is formedwithin the deep pit The overlying aerobic zone is comprised of aerobic bacteria and algae and keptoxygeniated by horizonta surface aerators and photosynthesis. The aerobic zone reliably controls odlorsand soluble wastewater components undergo aerobic oxidation and further degradation. thrne horizoftalaerators also create a circular motion over the whole surface area; the bacteria and algae circulate overthe far end of tee reactor where a second deep anaerobic pit is located. The horizontal velocity of thereactor is reduced while circwating over the second pit and the aeraton solids are settled by gravity intothis pit where the solids are decomposed and stabiliz ed

Solids at the bottom of the deep anaerobic pits remains for very long periods of time, continuouslydecoposing. Tihus, biosolids minimization is accomplished. The oldest plant in operytion, treatingdomestic wastewater, has not had to remove biosolids for nearly 30 years. Seasonal turnover of'thleponds is preve nted by isolation of the deep anaerobic pits. AIPS's design features and cell geometrymaintaln the integrity of the system thereby suppressing trovers.

AlPS is appropriate for wastewater applications for normal flow situations as well as wher-e there arevariable hiydi aulic flows and organic loadings, particularly where there may be limnited industrial pre-treatment anti souirce control of toxic contaminants and heavy metals. AlPS design elements providieflow eqluali2.ation, buffer capacity and recirculation capabilities to achieve secondary andi advancedtreatmient for- nitnicipalities, agriculture and industry.

Martine7: 5 IO-228-5801 Fax: 510-228-5804 2

SOA, lnc. Martinez2A

Acceptance and Support.

AIPS is a state-of-the-art pond-based wastewater treatment system.

* Proven* Reliable* Inherent Buffer Capacity for hydraulic and organic shock loading and toxic spiking* Advanced Microbiology .

* Energy Efficient 1

* Minimizes Sludge Production/Management/Handling* Maximizes Natral Photosynthetic Oxygenation* Minimizes Power Requirements

O&M Costs are low when compared to Acdvated Sludge, Oxidation Ditch, Trickling Filters orconventionial Stabilization Ponds.

SOA, Inc. is a design engineering firn, 25 years old and specializes in the conceptual to detaiiled designof innovative and altemative, low cost, simple to operate wastewater treatment systems. SOA alsoprovides start-up and training services, and on-going consulting services.

SOA has experience in designing innovative and low cost municipal wastewater treatment systemsfunded by tie World Bank and other international agencies.

* Caliimomia Water Resources Control Board supports AlPS technology.* California Water Quality Control Boards' supports AIPS technology.

AIPS Plant Overview:

* City of St. Helena, California Wastewater Treatmnent Plant1994 Plant of the Year Award - Redwood Empire Region -- by Califirmia WaterlPollution Control Association (Under 5 MGD Category)California Energy Commission's Energy Efficiency Showcase Award, 1994

* City of Hollister, Califomia Wastewater Treatment Plant

* 1-iollister Industrial WastewaterTreatment Plant (Cannery Wastes)

* Industrial - Winery Wastewater Treatment Plants, Califomia

* Rodney Bay Wastewater Treatnent Plant, St. Lucia, West Indies

Mas1inez: 510-223-5XO01 Fax: 510-228-5804 3

N

\ ; .AlP'- .6,1OC s an. integrated rn-uRi-staga bialogical rea-^.or sSztern ireaiting rnui'1c;P,a;. igriciltural ard industrial wastewaters. Tihe reactors

rc;aiing W.ds consost of tree suete andisolated biologicai zones: dee n>t o' ~~~~~~~~~anaerobic pits at them bottom of the reactor. a siudge b:anx3t

s usenea over the deeo pit and an over!'.'ina Zerb; izonreccm rsed z^f 3ercb,c baca'2na and algae wh':cl ,ssupersaturat3dwiti ax-gen produced by algae and rnechanicai aeratorm.

A.Ul wcather moadway All weather roadway

A3 O Aobicizone I d 2na

/ zs~~~~~econdarv_* _tulil. t \~~~~SemfOg /\ PXs/Secon I/ O tlt;_ _

w \ ~~~Setting .v on Discharge to additional\ ^ t Zone / \ ponds opera4ng in serias and

naerobic3zone / 4 1. AemobicOxiaton

U J ~~~~~~2. Photosytefc Oxygenaton3. Organic Add Formaton4. Mr-euhane Fenmemawon

SOA, Inc.1340AmoldDrive,Suite110 MartinezCA 94553 510-228-5801 Fax:510-228-5804

Rerrinwtd; slrf-m iny Siqam,) ing A h rnaravra !¢ Six Bill'ion Pevpl r,.- in Se., i,' .,. . .,

5Ipjlig Water and fEi .SCF S:.:: *,

SaUVi ig the Environrrient AD%ANCED INTEGRATEDIS" EUNAT c, ITS

fq r S. x BilliOn PUor ~tt \i!iam J. Oswald, F. ASCE'1oI%.%r Six Billlion Peors-leA BSTR ACT

By incorporating special environments for methane fermentation andphotossnthetic oxygen3tion. advanced integrated panding systems attain highdegrees of primary and secondary treatment and significant degrees of tertiary and

of selcete sessionsfrom the 190 ASC~ Cnvent ionquatern3ry treatment of sewage and organic industrial wastes. When properlYPioccdtJirlgs of selected sessions from the 190 ASCE Conventlon designed in appropriate locations, the svste,s virtuallv eliminate sludge disposal,

minimize power use, require less land than conventionral ponds, and are much moreJponsored by the reliable and economical than mechanical svstems of equal capacity.

ELnvironrnental Eugineering Division INTRODUCTION

Irliqalion and Drainage Division.,. . J.: : -Water Resources Planning and Management Division As is well known to Environmental Engineers. wastewater treatment to the

ol the American Society od Civil Engineers * . : secondary degree invoglves removal and digestion of settleable and foatable organicsolids (primary treatment) followed by removal and digestion at microbial solidsproduced during aeration of the primary effluent (secondary treatment). Such

San rratscisco. Calilornia treatment traditionally has been done in reinforced concrete and/or steel structures

November 5-8. 1990 with materials moved by motorized pumps and aeration provided by mechanicalmeans. Sometimes for economy and simplicity in small communities, ponds are

Edited by UJdat f! Sangh and Otto J. flelveg used to replace mech m ach3nical systems. The greatest advantages of ponds are theirEdiedby da FIL Memhpnd his J 5t~ite nvegt simplicity, economy. and reliability. their greatest drawbacks are their high landCt12tM ttlLL Me:mphis State U)niversity use. their potential for odor, and their tendency to eutrophy or fill in with sludge

Emeryvilie, CA Memphis, TMt and to become less effective wilh age. Our research, devoted to maintaining theadvantages of ponds while mitigating their drawbacks, has led to the developmentof Advanced Integrated V astewater Pond Systems (AIAPS). These require muchless capital, energy, oper3tion and maintenance than mechanical systems andrequire less land, produce less odor. and fill in or age much more slowly thanordin3rv ponds. In this paper I wish to introduce AIWPS as a system worthv ofconsideration for many waste treatment applications. Due to space limitations,howeser. only a brief description of AIWPS design and performance can be madehcren. Mlore detailed information is as 12hl- in the dissertationr teaching s !2h.pipers. :and engineering reports quoted in the reference section iOswaid. 190i.

T Iir-E c I5T E \l

In their most effective. reliable and economical form AIWlp" consist ol aseries of at least four ponds, eacn designed to best perform one or more oi -he

Professor of Environmental Engineering and Public Health, Department of Civil

tublishcd by the Engineering. 659 Davis Fiall, University of California, Berkeley, California Q4720.

Aiericjrs 5c ielv of Civil EnC4iftcta 7

34s5 f.351 4 71ti Stilee3Mew Yuat Mew 'tuck Wi201722.:3d

SUPPlYINNG WATER AND SAVING ENVlRONMEN'IN I~NEf Nl(iR A iFL) ~1ir ,YSiT7t,A-Q

boiJc rre.itmrnt orocesses isee Fieure i. First is 3 Facultmtive pond .ith ;caerohic surface and atn extremelv anoxic internal pit for sedimentation and | .:, ' .I<:

Fermnentaton. Anaernhic microhes in the pit ore protected by surrounding vJ!, or -eMs Urm the intrusion of :old surface water containing dissolved oxyge. Raw / 'I7' -. t . ':uvs .lP

sewage is introduced directiv into the pits where sedimentation and methane SoL / rn i2's5L

*orinentation occur. Overflow velocity in the pits is maintained so low (see Figure d ' /that :uspended solids removal approaches 100% and biochemicn3 oxygen d-n trd at

t noI remnoval approaches 70%. The overtlow velocities of one or two meters per ; Ida -:!rets than the ventlin; velc:ities of helminth ova and parasite cysts so m7jr 4 C U4_ -

; <e -tm, itn thn ;pit and consequently are permanently remosed from tue i.W'512 ,effluent.

IL 110WRAVI" PM t SO-m P1 2 L /"-IM

4- L m mom -KSJOW -* M~.A

°sc \ N

4L mv.4vILSm $A Wm" I PA*W%N. 1

4 ~ Q| TO'5 f t r - t w

4 _ ^1 ft W . warI I n

4 _I_Ao m.LS _fw_t m \ \ _.

t tao 2r Sodim, atat±o_

~TVL* PrfOMMC*ShoingAfIWPS Overflow Ratesn

Fending Sytem. (ScImastie)

TAWLI Antother potential benefit of' anoxic pits is conversion of chlorinatedSE WAIOOPA.ADAEIASO S

hydrocarbons to forms that may be biodegradable ini an aerobic environment RO PENNATDLE O W LGAL-MIXECTERHIRAL S NDS(1Douer aind McCarty. 1933). ipm.w4he larg pit votume and- its reducinag FRMAPO HS IE IHRT ODmovironmeg.se lment there to pnt Where only ash remainst hence _ _ M P _ _

13rWeTe-n-5. Ca- Tio;wa N~~~~tGi PATE SEt-natGNsyI I1PCU`Itest MW ) sludge removal has not betn required for over 25 years. A WQCA EFFLUNTA I S_ TWIO

second AIWPS at Htollister, California. evidences little sludge build up after twelve FEI2 1

s ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~~~~~~~A 1_55 10 91 _s

ye3ri. "0KhR 150 I 20 I 7

The second pond of 3l A-IWPS series is a paddle wheel mixed shallow APO 1W0 O r $ uHigh Pate Pond. In such a pond microalgae grow profusevW 233 z: ma

releasing oxygen frtom water by pnotosynthesis. Ts is oxygen is immediately .UN as0 3A ofavai.abba to bacteria to oxidize most of she soluble and biodegroadable ROD J1U 00A O 20 n

(B~~~~~~~~~~~~~~~~~~Agepoducerd duCrt.lD)tFingXpiwi *i> | . . z 159

remnaining in the ev fluenit from the facultative pond. Ala roue drn ma paddle wheel mixing are highly settleable (see Table ) (Eisenberg. 1981) ana. 12 i3 after ai4al rem uval by sedimentation. or disslved air flotation (K2rotta and Wang, 52 9019e4). Ae remaining water has a BOO that is geneally less than 20 mg/liter. t welRecirculation of algae-bearing water from the High Rate Pond to the Ficultative f 90.ePond provides an oxygen rich cap on the facultative pond. This oxygen quicklyoxidies reduced gases emerging from the fermentation pit thus mitigating odors. di24 :3C. S3m0 atiAftelr flseoerg e 1111e

76 SUPPLYING WATER AND SAVING ENViRONMENT *;;: SED:,NTEGRATED PCND SYSTE.- 77

1600 i 1 '.aters eMC7g;n; tr1jr the etziLing ponds are sufficiently low in BOD and, suspended 5o;ida to rerc"iate retdiiv into the ground or to be used for irrigation-

The. will. hoê er. iiEris uria,s ic. :.;ir'N greater than 1000 per 100 ml andhence ma:, re,uire i-r,s! 5tsr: - rior to use. The fourth pond of an A UrMs_ 14 C 1 often called a Nlaturition pondt ha, the dual purpose of added disinfection andC- |tiimtraee tor arrigtion. The use of pond effluents for irrigation is more fully

In ' | discussed elsew here f0s%31d. 1989: Pahren. 1985: Sheikh and Cooper, 1984). Ac T recent publication bc the U%orld Hea!th Organization outlines major concerns alindCa 1200 _ | satetv factors reiated to the use of wastewaster for irrigation (Shu%al, 1989).I ; - A ccrding fo Shuv: 2rd others the mn3or danger in developing cotintries isNcza ~~~~~~~~~~~~~tnranmission oi hernminth ova. This is s irtuallv precluded bv the use of four Po)ndso QS<r ini ,sr.r;;f Add,55i ed rt t,t;-înth~ nl -a.r fur ison'ds5 lin series should be an admcniTiont 1oo0 Fccultative Ponds in - against short circuiting uwhich can on!v he avoided by alternating surface and

Series 50 Percentiles submerged intakes ;n pipes transferritig water from one pond to another.00 After Romoni e'. al. 1975

_ . TABLE 2PERMOR.'ANCE OF ADVANCED INTEGRATED

o 600 WASTEWATER PONDS- ST. HELENA (Annual Means) (1)

E 400 PARAMETER UNrTS STATION Percent.. ^ : . ,: . . . . T ,* 2 t ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~30 t *: 2 V Rerno"d

- Rw Tm DAYS 0 20 I1 5 _) ..S '~ ~ 200 I . .: . .BOD Mg/I 223 17 . * ~7 07L )20 COD MgoI 436 124 74 5. 32 I3

TOTALC Mg/I 21 6 144 83 69 50 77 ¶_ IN PO~ I P 2 PND4 T0tAL N Moll 4 0 '56 * 3 a 4 9g0O INF POND I POND 2 POND 3 POND4 ITOTALD I A 1 3 1 2 S 64

Flgure 3. ôtal Chromium Retsoval Itue :o Algal (1) Att@t Mefon 1970 HOLLISTER (Annusl Means) (2)Grcwct ant! Sed±atentit±ott .n WrA5t5W tr Pondo

Gr.w-th .nd Sedimentation in wauttwat ponds PARAMETER LUNI TS STATION * Poicent

PtIl T-* I CAkYS C I 3 2 C1 7 t* .Ale3e in the recsc)cd weiters tend to adsorb any he3vy metals that mav be present ___________* - . ' 7 7 _ 9oSCO I moil t;4 43 go 0in the incom,iinc %J.le Jnd to sett;e In :ke fac.rltative pond. thus removing most of TV i 00 i-3 3 I 3i7 42the .sdsorbrd ntetci,1 :rem .he fa:utilri,t pon. efflues ter FiIure il 9Raml 93nd - TV S I U i E0 E' _ . 99 9go

Oswald, 1945)1.

TF-r ttird pond of the AlUWPS series provides for sedimentation of algae in (2) Aftwe M;K.es ( i85the effluenr of the hieh rite pond. As noted atove a p3ao!e wheei mixed ni,g rjte .(3 E, Cto-nd sends n, set:c : r -alga shae are s- eah 1e whPn not in a mixing field(Nurdoein. !'45!- H311, IQ8ut. Algae wnich entie tend tu hibernate ind thus do Apooeimt. eatoence time Ve!is With Season)not immnedialtl der.smpoqe or produce nuisance. In tact if two settling ponds inparallel are used. one or the c:her car, b^ driined and dried every three or four * Key 5. tn8u.nt Sews * oIIsss Senln PonC EttlusnI Isscars so rc*r.n:-e :n":cnrated agt Ii ges Dried alRal sluJge is rich in nitrogen, 2 F P,pphosphorus, and potash and hence is an~i escellent fertili?er for fast growing plants . cu. e P- Duc.rstgo To Netutal Orevel Per:O!eficniNNlettang znU! P,rne. 1 9S67. Thec:t Soi ;!I ctha1nce that dried algae would contain DiSaCigton s Threg To Noatusal EffvluPernltiitfeutirrius e i but I" Is. h at.a it ;hnuld onlv be used on ornamentals and . Sensing oro B r Tiers No Sur anc Eduentcrops no' evten rt3 1l alifornij state, 9-8; C;unnerson e- 31- 1984). 5* Matut,atort Pon.

^zl SUPPLYING WAT[ER .\ND SAVING L.\ARUNMNI ' .L'V.xs._L tNle'2iY. s : dtN St!L'O _,t

PERgRM \NCj the jerobic surface waters. rhe huhhies th.rn enier-e 3nd ihe wrtcies ith fhe:fn:Jtering an,zsli h-tz'r:;a ire ' ree *.- igain :ett:' dawn throuqh the '..w4v ris.n!

Table presc:ss performance data from the , PFS ;: St. ile .nal Merun. ''d io :mtuLft s ea. In :ts W3 te entire raw see. c la o ,s P ed :nroueh a!9 C anjd 'Ic!lister (Mosquer3. 198?). It is clear trom these data that the ma:,r %,,Iune of inten,e hnox,c Jcts t ere bo7h insoluble and soluble an:: mattc7frction of Bot)D remonal occurs in the facultative p,nds aiid, froii Ish, Si. liclena is adso;rhed and zonn;erted to ;;n bk,n dioxde. .tfer. iefh:ine and or .,een eas,dlia. that m naior friction ott the total nitrogen is removed in the faculaitise pond. Te Pdosittve action in deer AFP oits is ver' similnr %o th3t of the weliiI lu:ti<ier h:h sot'nitli divsnived %nlids nriejin-te from na npainr 7e!iarniafnn t nlant irteninutt urt'io'.: a 3trM ilt,d^t -tt'i! ! ' .ztr tS.ss:V tu- e0

-rtct.h.^e*liil^ renr 7n:ng hevond the tae',ilanttvr nri 4isd -rte -nd Yr w.t r-!" s^. STT it .tP -- L['. *---.7--y. ' -^: . -s~r:Xto ctrh asn:erobic and aerobic degradation. TThe high rt!e e!nds do tm * mainsenatnce e''ern for a .hort t:me, ire n irted, " -SP3 ar. prcremoe a great deal of SOD but contribute oxygenation to the facultatise ponds with rags. plastic bags and % kth compacted sludge or grit, ani hence requiireano ail in removOi of nitrogen. Pnosphorus ano carron. Following 1i;ai removal rigorous management including tail sale pretreatment, freouent sludee removalthe degree of pollutant removal in AIWPS is equikalent to :nat of mechanicil and otter maintenane. In :he casc AM' PS. sludge removal is not ufirei requircU,second.siv VtIants, with the addedc benefit of significant nitroGe;.n ard carbo.n CiCgg.ing s smpossiole and maintenance :s minimal. Thus the main prrnciples andremoval (Table 2. St. Helena). removal of heavy metals iF-igure ji and a deree oat adtantages at` U.%SB reactors are realizeJ in adsanced iacultat,.e p.,ids whih fewfail safe disint'ection (Table 2. Hollister) (also ace Sznta.a and Sartei. 19S?1. of the disadvantages and with lower costs.

DISCt 55TON The helminth ova removal projected fur fermentation pits is of particularinterest in developing countries where millions of children are weakened bv

Neither Hollister nor St. Helena are compnete AIWPS because they lack parasites and consequently fall prey to childhood diseases.paddle wheel mixing in the high rate pond, Also residence times in the high rateponds 3re excessive, exceeding the time required to aczumulate sufficient solar The economy of AIWPS results from a number of factors be'.ond operationenergy to release sufficient photosynthesic oxygen to meet the BOD. The high rate tnd maintenance. For example, consider the cost of reactor volume: reinforcedpond in Hollister is mixed with screw pumps and in St. Helena with propellar concrete reactors such as settling tanks and digesters are likelv to cost 5350 LIS.pumps. Both are a waste of energy compared with paddle wheels, The data in 11990) to S700 U.S_(1.990) per m3. On the ilther hand, formed earth reactors areTable I is from paddle w'-eel mixed experimental 1;4 acre (0.1 hectare) ponds at . vQli:eriVCo cosfless thaaMV.1LS ([990) per.t--a hundred-fold less. By usingRicL..inond. and indicates the excellent natural algal removal that results from ' earthwork ponds. largeTreactor volumes can be created very economically. Thegentle mixing. The interrelationship between paddle wheel mixing and algae microbes involved in treatment are, of course, unaware of the CoSt of their reactorsedimentation was first noted in high rate pond studies in the Philippines (Oswald and. provided the environment is suitable and constant, perform as well inet al. 1978) and was confirmed in extensive subsequent studies at Richmond . earth-ork ponds as they would in the most elaborate digesters. Aiso'sirce tey3Z (Eisenberg. 1981). Both Nurdogan (1988) and Hall (19S9) have studied the reasons ' : little earthwork digeters (fermentation pits) can be made large enough tofor improvement in algal sedimentation following paddle wheel mixing. Nurdogan -gm s comiplet digestion andi thus the elimination of day by dae siargelendlinog t has found a natural selection for larger algae which settle in a quiescent field and *ormany yer s. _ tHall has emphasized the natural filaments produced by 31gae and their tendency tocause agglomeration of cells with consequent improved sedimentation. Both CONCLUSIONphenomena appear to be important in natural separation. Neither is related to thephenomenon of auto flocculation that occurs due to high pH in poorly misted Development of economical and reliable AIWPS is timely because of theponds resulting in precipitation of calcium carbonate, magnesium hydroxide, and problems small communities now have with financing their treatment systems.calcium phosphate. This type of precipitation, as well as thermal stratification, is The past trend, under government and state subsidies. has been toward complexprevented by continu. us mixing at a linear velocity of about 1/2 foot per second and expensive mechanical treatment plants. many of which work poorly and are(I5 cm per sec) (Oswald, 19 8). difficult to operate reliably in small communities and developing countries. Now,

most government and state subsidies for sewage treatment are being decreased atThe energy required to paddle wheel mix a shallow pond at a velocity of terminated and economy is becoming a major criterion in the selection or

l/Z fo.t per secund is onhN about 5 kwhrs per hect.ure per iJv and ., '!ts in ihe I upgrading of a community's wastewater treatment system. Based on ourrelecse r water of more than 100 kg of dissolved os: senper h-ctare per dav-- experience at St, Helena airr Hotlistmr. AIW'PS. when Properly designeo. are notthat 's k kg !r oxvgen per kilowatt hnur (kwhr'. This should be cornpared wth shon:y onojnical and effecli- but 31s^ attractive and nuitarice free. F^.mechanical aeration which normally transfers one kilogram of oxygen per kwhr 1 communiiies in the sunny part of the world AIWPS can provide a new oooortunitv

arith. ig 3). The energy savings is thus more than ;0 fold. to h3%e adequate. simple. rettavle 3nd nuisance f'ree waste water treatment withi;s,ninicant oppfrtuntiri ?, Sr reciantation ano en%ironmental enhancemenrt an at aTh.i phenomena that occur in the fermentation pits of facuitative ponds are price most communite- shoul-I be able to alford.

somewhat unque and deserve consideration. Quiescent sedimentation :s oni: :nefirst reaction. Apparently then, in the intensely anoxic volume in a pit, surfaces ACKNOWLETX *\IFNTof all sorts of solid particles that settle from raw sewage become populated by acidlorming and methane producing bacteria. As gas is released on their suil'aces. the I am indebted to Rose Ann Nitzan for typing this manuscript and tosolid particles become buoyant and tend to rise due-to the attached gas bubbles. It Patrick Oswald for preparing the tables.the pits are sufficiently deep (5-6 meters), the gas bubbles expand as the% rise andusualiv will break away from their attachment to the particles before ihev reach

S??.;'.'. "v TER kND S 51(iI '"RI,)o ! .ns, % \ 1:1) IN n:GRATl D iPON9D SN'S;-.'

R P R. CR , .'.. lnid R S J3aues l)H841 Wastewater efFluent reu.e ur

rrr;\:Ic:,ri !S 'a.-eateT ron sSm:t:t :: I-e- e studan. ca rrbr,n .. 9.:rB.u,er. E. J., and P. .1;0Crt . !83) T rmat:rsn ut 1- a nd - carb on Reuse. N%ater Reuse Ss mprislum II, ProcLeuins, Vo1. - p. p.

halogent:8d al3ihaii: rtrgintc -omrounds under rnthanr:cetic ' ^s. . attrworks A\ssuciatiusn eies3rch rounJazion. 6666 Quin.c. ; . '.au' em.*I F. rownment:il %Ii ;oioloitv. rD. 1v. 1'Sh C oira3di USA 53035

,,; ',,t >c i 3 -,- I S Wi- 1 astaiter r03am3t;(-n it-r, 'An - r! t e'rr m :ne jhu i. I;el ' S7 R::r.zI lcr F"gr!t's. 2ideK-ses i t-um:sn ' .

.* :;8- .r.-; mrltn:^r e Code. T!tlte D.r%s-,n l!r. ) lDi 5) o tui u69. State 8''l''t'''r t ' '.".'. '

La i;:'-.: .. : '.,5r:r-crrstof Hra!th Ser% rer. S?.nitrv Frl.invran J1i r. -r U'xr'5n. St% 111 8.c -3Cr"sr fr .... ,7BerleleX 'W'y. Berkeley. CA 94704. US.A. St%rrlnd.

r...-e , flt Do M1. ( 19811) Proaucuvit% Harseftibiii8 irid Fcrmn.',.l Smin Rohert (147i E!ectricai Power Consumdtion for Wastewater Treatmenrt,MI: oalae in P3ddle Wheel Mixed Hizh Ratc Ponds. P.o.D. Dissertation. EP!t-R2-'3-2I 9 p1 F O -. Nitional Ens Res. Center. Cinc:nniru Onio .;oS.Urvrsictu of CaliFornia. Berkeley, C.A. S%Bzenb.aum. Mike. ed. (1985) Anaerobic Treatment of Sewag:.f No. E.E.

Gunntrvm. C. G.. 11. 1. Shusal. and S. Arloscrof (!1°. ji Hr!.h ,Frecs 39.SŽ-S. PrceeCdirngs ot a Seminar \'orkthop neid June -5 --' . atwastewater irrigation ind their control in develstpiig *.ouniries. pp. pp 6'8. L niersitv of Massachussetts at Artsnerst. Amherst, NMassactlu%etts UIC,3.in Future of W\ater Reuse in Water Reuse Sympcsiumr 111, prrceeding5. Vol. 3.American Waterworks Association. Research Foundarian. 66o6 QuincyAvenue, Denver, Colorado. USA 80235.

Hall. T. W. (1985) Bioflocculation in high rate algal ponds--implemenation of aninno,ative wastewater treatment technology. Ph.D. dissertation. University ofCalifornia. Berkeley.

Krofta. M.. and L. K. Wang (1984) Development of innovati\e flotative filtrationsystems for water treatment first-full sandfloat process in U.S. p3rts A.B.C. p.1226-1:64 in Future of Water Reuse, Water Reuse Svmposium fil. vol.. 3.American Waterworks Association Rescarch Foundation. 6666 W. Quincv Ave.. ErrataDenver, Colorado. USA 80235. 2

Meron. A. (1970) Stabilization Pond Systems for Water Quality Control. Ph.D. pg. 75 fig 2 lower scale gal/ft /dayDissertation, University of California at Berkeley, pp. 31t. . r

Metting, B., and J. W. Pyne (1986) Biologically Active Comrounds from , pg. 7c 3rd to last line(Metting and Pyne 1986)Microalgac. Enzyme Microbiol. Technology g, 386-94. -:

Mosquer-a. J. F. (1988) Performance of Advanced tntegrated Ponding Systems. ,.pg. 78 Discussian 4th line phoMaster of Engineering Thesis. Sanitarv and Environmental Engineering. ,'- 8 * 4 l o , :ge,Unisersity of California. Berkeley, California. pp. 1-4.-

Nurdogan. Y. ( 1988) Microalgal Separation from High Rate Ponds. Ph.D.Dissertation, University of California. Berkeley.

Oswald. W. J. (1978) The engineering aspects of microalgae. In CRC Handbook ofmicrobiology. ed. A. 1. Laskins. pp. 519-52. Baca Raton: CRC Press.

Oswald. W. J., E. W. Lee. B. Adan and K. H. Yao (1978) New WastewaterTreatment Method Yields a Harvest of Saleable Algae. WHO Chronicle, 32.348- 350.

Oswald. U'. J. ( 1988) Nlicro:lgae and Wastewater Treatment. Chapter 12. pp. 305-3:S. in Mlicroileal Bihtechnrlogy. Borowitzka and Borowitzka Ed. CambrdigeUni.crti., Press. U.K.

wald W J. t 1989) Use ot W3stew3ter Effluent ;n Ai;uizt;urc. Desz!inization..'-S0. Elsevier Sctence Publishers. B. V Amsterdam. Netherlands.

Oswald. 'N. J. 1 1990) A S%labits of Waste P-nd Frndamentals. EnvironmentalEngineering and Public Health, Universitv of California, :erkelev.

Plahren. H. R. ( 1985) EPA'i Research Program an Healrt: Effects of wot'sew3rerReuae fer Potable Purposes. Chapter 10 in Artificial Recharge ofG.roundwater. TaKashi Asano Ed. pp. 319-328. Butterworth.

Ramani. R.. 3nd W. J, Oswald ) 1975) Studies of pond performnance and piFot aJgaeseparation at Napa sanitation district, report by CSO Internationai zo Napasanitation district, 950 tmola Ave. West, Napa. C.A 94558.

Sarika3a, H. Z.. and A. M. Saatci (1987) Bacterial die-otf in waste stabilizationponds. Journal of Environment Engineering. Vol. 113. No. 2. p. 366-;',82 Env.Eng. Div. American Society of Civil Engineers.

Small Flot

ETCHNOLOGY .. ::Ponding systems treat wastewater inexpensively

by Edwin W. Let, ?.E.

fi i rn us'e zI l aphrelrrtf thefreltoes-in; raticle ts aseff-ernplaedtconsultngnennine and also ttmffiiauaeld weth Sar.ronjot. Ou-lMidandAiaocietesiin Alartinex. Calilornia. lk -7

preiotr/slywo,kreda eie nenwironntenfaltngieertwithtleeU.S.BuraoeuofRerlnmeaion in ; , **

Sacreamento, (a ,IJerniia and as a ranetary engineer with the IVorld healfth Organizati *'

inthePhilippmnrs. lie eLeeeed hishachelor'soando saer'sdegreeinneletlisanitary;

enstnetringfrom the Urneraity vfCalifornia at Berkeley.

11c integrtoed pording system is a low-cosi advanced wtaste Itatiment pFocess for I! -'

municipal sewage. oleanic indusisial waste. snd organic agricultural waste. The ainte ..ic.ily. econorny, and ret lanaltion patentiis of the Advanced Integrated Ponding Sstm -se

tAIPSri mtkie nt tzIctiv trt those cosmunities wishing to transform polluting wcstes Wetoassels at minituat cost. low capital cost, high ttlibility a;nd low opeation ani nsi ne_ssnce cost favor tie Utse of AIPS eYCr conventional secondary Vn adva ned wass_rettnsent wherevcr cibnate amid leedi avilsbility penniL_

ks shown in Figure 1. an AlPS involves a selected seguence of ponds. Each pond iacientifically designtd to accomplish, by natural meatn. cat or mwoe emit u perionp ht Inraged processes leading up to advanced level of waste teamnt. The ttgd of An aeriadlt ew f am AIPS in lHlester Califetnia rdhtt erve a level of 16,000 people.

inegraiuon is selected lo ntet the tbectives of the site specific projeCL Sectetdy The 274mw potad nl-acr disposal area treat towo ailli. guians oJ varatwaxeerPeratmhent can be achiteed vithh a deep facultative pond followed by secondary pondL dJsy ush we d *lechas'e.

itrent removal and bionmass reelamation can b e aclsiesved with selected Iration elecificaly designed ponds consnruction costs result nminly fronusthic eninirnizaiion of use of rinforeed concrete

tidge and grease lcneoval are accorrplished in deep facalulaive ponda wih special bhllh. suettrs by. tenneduthdeep pit di1gete -en r. cLoieot n and attin prrtial oxidation in the e d upp le. -ower operation and mainteeanct csss res,ult tins:entity oxygen can ke ifriernlimced by jecireulating highly-oxygenated emfuent rmn * Elimnationi of day-by -ay ludge handhiesg: lenegrateel paneis are dssifned ar2llow. slov ly tecin tzaecd algal grrv-th tnits tetmeed lhigh-rate ponds." the tsndary reuaIn sbdge in tl deep in-pevd .ligestess (or massy yees. Sludge umt Isis of the systen. hlticruscopic algae in ihe high-rate pond use solar energy to sintula. thereby reduecd to a minieteuiet in prolonged degesmiie. i he residual sludge it3.sly accoinplish tvrvtosytietctic oxygen prduction. high pil disinfection, ad mntrientn reiatively inert, and its volume is smsilh. islosal is not mayal opier ttionsl

novad. Bacere isin tfi ligh-ral fpai xuse oxygen opduced bys ge loosidte all but problM.most reiractory organiic siebseances. Following oxidatiotl in the high-aste pond. both * Oereated asergy requirerents: Eergy nedc for aera tion, sludle handling. saewe an bacteria biomtass shiould be separated frorn the efieMeaL digestion ere decreased. Each pound of mieicrilgae releaset 1.6 pretndk r.f oxyges.

whih Is dissolved in wattr anrid tius irmtoediaicl available for bacierial u xidutiotal-bacterial separations are accomnplished in tertniay ponds specially designed to penatm of waste organic maiter. An ace of algal culttere will prodice t1. lbs. of usairle)ral sedimenlation otf algae pmoduced in the high-rate pond. Natual aedientation is dissolved oxyget eah day, equivalent lo INtX#) horsepower hours 4e mechasicalelerted by a self-indlesd biollocculation pcesit Renoval a ritetutt of a ponio, f aeratio, le tansux n enfcrgy requibnKcnt is 1110 kilowatt-hour petkitsgsaer ofalgae biornsss may be needed for seeding into the pritmas pond or hight pond. ROD.-age of tratted water lot controlled teuse is pvided in quamtettaty ponods called *;Deerad ngy cts or sludge handlittg- Since sludge is retained in peciUllteuration" or stortge ponds.' Storige ponds nmay be used lo pg!pp f&_t etrdob htlw 1. d esiged pit digestes nd renains there indefittiely. daily tsnsfeer of slulge Is ietst oftarluacic life if detieedr The li vner cmm c ponds also Is suff- nettttiry anudyenergy needtegres(ldgertrdnsfee an e elie inaied, Also.6eecutuseed ftr use for greu id v-ater rech;rge, irrigation of foiage;era. golf eotrrae. of digestion proceeds over years ref time. liaeticeg and miting of sludge ate natetainirswueforahghiatt E - -- ,p etquired. (unth redcing energy retuiremenmS.

* Decretsed manpower requireneents: ittentition of elcctro-ntechatticat

rns ef the iniegratrd scqmect:e are designed to utilize naturnl decontprshiot equipment h an integrai pasu r,f tie sysateen mesign. Tlis also minitisites tFctIrmicat-sses. W. I. OsA ld. tiD., Uliveesity oCalifoeinat Berkeky. hasstudiedeheis persnitnelrequired to oierite and rnaintsin equispnent.-sss s end deeelf"d tbe systc n durngl momt dtsn 40 years of fesearch Tht effuttrt:eae an deele1'edthesyactr duing estte Ita 40year ofresaret. lee fflent Ilehti-related risk reduction advantages of integratei pondls include:ry attained In such pinvling systems is comparable to the effluent deuived fi-ne ; tineiration o oppotunitiesleca)oemrtirrtesin praienent plants inco1 leratitLg complet advanced tremsuent stages costing several times Ot bacteria, and viruses in efllueot stcsms. 1is is accornplished by I raviding leiwg

detention periods for sludge in the pet digesters. short-circuit eafegusids. ligh plI

arrance of All'S can be expected to redtrce pollutants in the following rangesr levels in secondary ponds, aeel erftcient reparation prrncesses.Minimination or elimsinatinin of eshe meet feet chemeicael disieslctiiionof ttflsuette

BOD 95-97% with a resultant increase in reliability snd a kecrease hi co-t, The politlial lesrajrisCOD 90-95% of nutajgen. ternogen. and tiaeinogen proeductiin fi the rel etlusel by osToull Nitrrgen 90 iinat disinfection processes ca;n be avoided.Total Ptsotphorus 60% * Removal of heavy nmtals through co-precipitution and sedinemation.MFN - E. Coli 99°99S With remard to envionamental impuct, the major objection to waste stabilitsaion pouts of

st advantages of Itesegated ponds over eerventionsl treatment processes result conventional design has bees the production of odors at certbin time of the year, theirfromn lower conrstrction costs and lower operation tnd maintenance costs. tow large land requirements, and the peesence of suspended algae in their effluarts. AiPS

- USEPA Small Flows Oct. 1990

October 1990 Page 5

TCHNOLOGY

KEY TO NUMBERS ON FIGURE BELOW1. SCREEtilNG & GRIT REMOVAL 7. PADDLE WHEEL MIIXER 13. Al.GAE HAnVEST

2. DISlRIBUTOR 6. HIGH RATE POND 14. LOW LEVEL TRANSFER

3. FEAMENTATiou PITS 9. HIGH LEVEL TRANSFER 15. MATURATION POND

4. FACuLTATIVE POND 10. ALGAE SUBSIDENCE CHAMBERS 16. HIGH LEVEL TRANSFER

5. OXYGENATED WATER RETURN 11.ALGAE SETTLING PONDS 17. WArER REUSE

6. LOW LEVEL TRANSFER 12. SETTLED ALGAE RETUIRN 1 SUPPlEMENTARY AERATION

Figure Iadvanced Irnlegralead Algal-Bacterlal System for Llquid Wast Trealmenl and Oxygen, Waler, arid Nutrlenit Recovery or Rause

c tt ihese objecions lo a considerable extent becaut daey are designed to tiaiste Efltuens (rmm stotage poudit ale of l0Suitable fof aqutcultutc dcveloptacttt sd i'ritatlosie of ihe land for ponds. to avoid objectionable odors. asd to remove Sipe. d f(un etpg beca:

ie 11ty ate lif o pamsita ova and dependably low in coliform and oaher eatericianld occupied by prrslserly designed ponds tvDI: sIactersia due high pHit Idiasion in she prsasry and high-ale poad amd bnl

Prvidc open space wd acishteic views. con"sd tuenitia ih comt muty dea daI jimesn i doe sysmplanning. * They ant lw in uiltuo ind hpiosphorats and will not ovas'er.llize.* Pemtit developmn5 of aquaculsume tnd vwetland habtssats.* Be easily atsd inexpensively reclaimable. usually tt highly apprecIatd load Mkaagae prdceld is integrated ponds have grati potenial ror:value. should future developsnsttk lad so alteadtiv c eesst ttustaltuihd. * Developstt s iahigrtein fccd supplesnc(st fl fish. chickes. swinet an

- I romiantsrtionable odors sic avoidcd in nitegirted ponds by: - * te u a lit a d sR tolr d feslW ee for rapidly-growing crops:* Assuring the onset of alialine fermentation. which deters odor enssdiubts i doe * Use as a usbat for make fesnensasion:primrty ponds of ilt syssn. by contrilled p sian-up prcees. * ExtnctiotofoiL pip _m nd collsriis.* Prosi.ting s urllus osxygen. s el uas aIl seeding. thtotgh reciculatilmonflgh-iste pottd elluen lo the sus face of llte p issty ponds. whnever lw disolved To suamiaze. a propedy designed Advanced autcgtated Pandint Systemn con ptruvideoxygen levels in the prin,ary ponds Indicate a need, wae tuanagensit std recltisasl tht Is mom reliable. economical, amd eviontsas-

tadly-souAdm IFrn eonnlof V/1Jmsarvesting is pronoledl by:* Natural biofloccislation of algae in prtperly designed and mixed high-tate ponds. ReIa,ncea* Iligh nutnens rosiilt that enhance sedimtentation ld retarrd additional algl fi)Oswald WiJ 119t2) Lage Scatg e AlgaeA Culture Systems; Engineeing Aslects. Ingtwth in recei-ing tsets. Micro-Alg*l Biotecbrology, Chapter 12. Borowitzka. hi. and orDowitha, L ests. Cant-

svnced waste tnrasment prcess should be considettd for use by: ledg Usiversity Press. New Yak.* Any comnsuniiy involved citter in devettopin new "ate Irfaesment sad diapoSl Oswald. WJ. (1931) The Role af Algae in Uquid Waste Treatmeni and Reclutution,;ysermsor in upgrading thcir present ieatment system. Chapcr 12. pp. 255-211 in hfiroallamnndllasnsaiAffairs. C.A. lamb tnd IR. Waal

Comnunities in taid or seTni-atid ares desiring to practke wastewater rclwat- and eds. Cambridge University Pefss New YorLion.

Organic idsustrits requiring independent wase dispol systems. Oswald, WJ. 11919) Initodcilai lo Advanced Integrated Wasiewater Potding System,Animal feed lo, dairies, and poultry falsa inquiring watste naensgem NW Depa rnest of Cvii Engirateng. University of Californit. Betklqy.

ntrient recycle.Communities wvih sufficient amounu of available laId.

f If 1 1 Alternative Waste waterTreaftment:

?'mT1 J%~I[Advanced IntegratedPond Systems

i4J | *1st Advanced in concept and simple in design, a nemi wasle water treatmenttu 4 t{: t1 4' t 't echnology may offer a solution for communiities beset by iitIensifying

cost constraints and water quality regulations.

Why not buiid a sewage treatment thinking. In c'mio nitiilll plants, forfacility that tses much less energy examplev ac ,alit lo dii n-i consumeSsthan i aciiiivcntional onew and produces 6fl/1Mor iwt% ol the rV-¶rical energyno todors, tstecially if construction, used inl ' aievdlIr It,atment. In con-operation, and maintenance costs are trast, inim roalg Ic in all All' systemal-iodramatically lower? This question provide Ii'.sNlvi't o.gn throughmay occur to many who have visited photosyillh si.. ulh;I;antially reduc-the Waslewater Treatment atd lRecla- ing elkdric-al o;intimption. Not sur-niatioin Ilaiit in St. 1-ielena, California, prisinglv, tlies-' l;ysltn a-e optinmalpartictilarly to visitors fnrm coniiiimu- for sunt'clt . iiir,init-s.iiitits feeiniij precssure froni fderalanid state enivironmental regulations. 'At St. I ItulenI,% p i- poven this

~i'4 10 fvalrd P-,,1 1% Id ;qIrr technology witIll a i-markable qualityvr ("!;# (1"I'l ION) f i ,*.. Ir ., f

~ :;;, 'Z;;: ;:72~ ~ ,,,,, ~.,, Basecd on the concept oif Advanced of treatmentil.' -;avs I. wocrge Milanes,,*,,,,,,,l , ,,,,, ,,}*,,~ Integrated Vond (AIP) systems (see chief nilie mhw il,it 1h Iit. "The eco-

!d,re Ohaf 11'tr .du lw(asti thry ,11.i d fig p. 5 for dnsteripion), the St. 1-oA vena nofmis it wh"t it talX. it) put one off fmimii d*i, t ritltirr tht B plat,' marks a radical departure froim these t gether j m-t a i kes gotd finan-

frr d . rtle conventional wastewater treatment cial sense. This sIIOulI really be thetechnology of hoict,e br smaller com-

munlitie; (if 211-ml '(1 t (.110, people."

"All' Iilin,,.tp i,-; t,,, lim-ited tosnialli rt iningimti i',, huen~ , et-,r Cost

l41 idqt t$t vi + 9 ;;2;^2(compariions I itli ohlier treatmentmethod< letid to favor All' svstemsin manlfv larger r(otimlhtilttiti(s as~ well,"says S;aly ailki r, I iiwt:thr ot

, , i .ii iIl;,ri It ci; tIt iIat lit tn in

JP h | s >,,l,Ii,.,, A ,1iI,','it 1'i'"ll' '.ie''

" bItPLI'II lilitl [ Construction and Energy Costs

/IIP Z 'ant *l,,lll |Maintenance Costs

(01153111111(' 1t7lJt1I 011C- Good finaincial sense begins with shiould t onsune .boutil one-quarter tofacility costs. Becatise solar actfated one-fifti tlie cnerg) of a conventional

q:trtfr tof onc- fifi flie ponds are built of formed earhli rathier mechanical Nvaslew,-ater trteatmentthan (if reiniforced concrete, [ie1ev cost planlt I ihis translates directly into

(1f1 1t dy of' a ( Oni'itiollitl about 1(1(1 tirnes less to build per cost savings. Onit' significant soLurcecubic foott of containment than do of savings lies in using solar energy)

171I:1nw11aiCi as 7 lW(t'7t'trj convt.nltional Ireatment piant reac- rather thani elec ii citl energy for aerators. The total pond area needed is j tion. ( oiventoinial plants aerate by

JfIllnJlnfli ihIII. ThXis'n mucih larget than that neede,l for a using, electricofl rnc-rgy to blow or mix

I,'anshgl.*I toirr(t'hil iiilo 4conventitnal plant, but ponds siould air bult'Ie; into lthe astewvater. In an*ranslaiv direc-1 iltostill cost only one-third to one-half as All' sNstem, alg Ie uIse solar etiergy

It it ;dlv'iU' r mtiuch to blild, according to William Dnd lhctosviyihh -si to supersaturateOswal.d, who designed St. I lelena*s tile wV.te'at alo r wifth Ili: oxygen thiatsystem in the early 1960s. Oswald is a mic-hlles iicee tI bre(ak do(wn waste.professor vimerituis at llte Univvrsityof California, Berkeley (UC-Berkeley) "Ior peoleit who hil vet alwaysand inventor of the AIP system. thouigill in tel m 4 ot i tonventional

treatenciin. it.s Ii mt to unlsderstanid1'roponenits of the technology believe that you catn vit ate witliout anythat maintenance costs for the new meclimni:ol *;ay.i Oswald.pLimits ate alsot lower because suci 'Usiing nit ci h.nmic t wration, you

in.;t.5 of a Convati?lional Plant planits minimize the use of mcchani- need abo(utl I Iiliie.'it-lhour of elec-vs. an AIP Plant cal equipment and require a smaller tricitv lot- ea(h t:ilog;arn of dissolvedconihys nI thrialsncs invenloryl of spare parts and stipplies. oxygtcn. In an All' svstem in a god(l

K-_ > 8eJ ll_ __ J Operation costs are reduced because climate, vou tgel anfunitl 20 kilogranisI. |: :1 the plants can be run with smaller (44 pounkd) (if ixv geon per kilowatt-.. - --- I staffs. hour, becu- youriergyis essen-1 in-; tially fi ev I hal energy is solar

Another important advantage of A1P encrgy.* jI 4__ _ _ _ plants is lie simiall amount of sditidge

0 , 1 j Xm they priduce. In these ponds, sludge St. t lelcena 's tlant still uses more! ' I; -W .-. . fernient uitintil notliing is left but a energy tIlin imn nllilinal, tp-to-date

* 1' if l' smiaill volumte of residue. For exam- All' plimlt Wvoitil ieqifire. 11hat'spie, dtiring 27 years of opiration, St. becausevSt. I leliia's pnlant, designedilelenia's wastewater theatmcnt plant 30 year s ago. uies cnvenitional

; I l l has never had to remove residue. A pumps to circulate water in the pondrecent measurement at St. Helena where aiat ion takes place. Calcula-

: I %1 .lt fib lj , showed thlat in nearly 3 decades, leS tions th atl nowshow thie five-to-one---, t| :ti¢l .904 8 ithan I methr (3.28 feet) of residue had energv advantage of an All; plant

$257 2 accumulated at the bottom of the are based on designs usinig paddlei C.pital ! . ____ .1 j deep-l) digester pit. lThlis represents a whetels frg cilrcultilionll. Paddle wheels

Capital Arinua substa * 1tiillbenefit in termills of Ijie.td- are tow a pro% iiti*I linolotgy com-Cost operating cost inig environmenital regulations for monilv tised il coninc ercial algae-

I (-eliJeniional pl.tr tt AIP pl,iill. .riehin re SOt t A rt ,W pldn tine U residue disptsal. grov% ing operatioini. Vaddle wheel.'u~ .OA .. .. ... circtllati( in hIls bveen iilcili porated in

SIIOrTI ,it"i {Vl jS ni io~I .-IiPtip,irtl711 l . an A l' svsteni thait UC-lBerkelev iset rqFrriviilew dantil fI 7S milliop, designing for-a St. I lelena-sizedli,e rs II ri,,illia,llall ,,a * 'i1 ?'i dai,- - wasttews aler trealiltim t plant in Cali -

oil ,,*( l . e ti'iI flifuu " Ifnt1f f.r fottia- ValleN. St. H-lelenat-wsl opt.iri nt kir t e, wrin,larii is al'l c-olnsiderit ig a tzonvtrsion toI rr,i .tini t. p-hin, icF' in ssI.ttgt, talst-rii *e11 .. j paddle wlheels.:;tut nnirXd Ii,f irrn It-r l'girlud j,tirtw. |

Was ivwater: A nesoturce,Not a Waste

*^0 l!|t t ~~~~~~~~~~~~~Ac ., ,, 9t,t ()I t,fl, i,,,.l cr-il regii .s,-

'I i ;lgt ' | i,g, -ltri Ctv ing Ioiuglhcr iqt'giililkios

( h.it * 'I i Hit .11 II ', 11 t,I sub-.l11ir g of

Ai j.'' ".i,1' rec , Iiloll. L -t ,,5os

J fI IV-\ IT Ifi VIt Ir 'ldIc1c'lilf-,

II( - { .I oit . r,I VI' illl, p 1 oil;9 t I- I !l I I 1, do% II toxi s, tlb

r~~~~~~~~~~~~~~~~~~~~~~~~~~~~0cn ,;,iSi- LJC .

,{ i .ll §W@k ti IR4, 'I' 't B -. w111v ill 1 w the

£"~~~~~~~~~ ~~ ~~~~~~~~~~~~~~ tho 1 E! ]t, mf§, , ict vorn,,

add(ifioii, mo.8l (,I flt-1 lic;lvy metalwls in'Ii7x'!t.'tIIfiltit1'z,1//? 1 . .s4at~~~~~~%wagc ;1(r-t- piet iitati,clanid remain

i"d I, Ic j kti- nw, / I,r,li,*a ' While aeration bZy algae anti solar trappl '1din Il tat itlniative pond'sftir vfwI lirl'ir. energy can greatly reduce the elec- digestor i it

tricity ctisumed by an AlP plant,anoliher soutirce it eiergy -lecti-icity- Furiltir, riit1 in'i,-I i h iias nitrogengeneration through combustion of and plhphln t!. u all d lamage aquaticnmethane-could climinate e lecttical ecosy .Ieims inif vd Iih effluent may

p iiower co sts completely. Metlihani ca be t isuarg l All' plants are betterle plro(dticed by fermentinig algae har- than coinveiitni nal plants at removingvested frmo i the plant's settling pond. thewe ,,uiri nlt';. Niltogen removal

occltS ill Ihe wligt ';ion phase in theConvenitionial plants typically install facultative I (ond. In addition, nitro-large tanks known as digesters, in geni and phosllphorus are taken upi which slild and effluent solitis fer- anti continii"d bly algae in tIhe high-niict to ptHkiuc melhaline. In an All' rate pi m1. (tsw.ail chamrpions the usepIliant, mlethane fromiil natural fermen- of a ha ilsgl Id l-omn Aff 'plants astitdilii ill the digester pit cotld 1e cap- f'itiliv-z ht-cn.;st 11w niutritenis con-tured at the surface of the facultative taimedti in algav w tild be released

Pout1. 1 )eI e- lopling a giMuti t mlilvtnrcial more 'loI1 tl; lii votld the water-i let1Ilililt caiptire system iilr All' sys- solnble formns in chemical fcrtilizersltemis is iinder Way.T hIe Flvir(oinimlen- an lI lims bh t,N likelv t(o rettirn to

F.l g I iil leering di Itl I leailt it Sx ie me Iake s dIt k stri ;im Ins ii 1-titr(nff.Laboratorv (ULC-lerkeley) in Rich-mioiod, tCalif(ornia, is working (on thatdexc elopmnlt with fundis froumii tle I(Cllilornlia Fn.1*t'gy ' ('nmsio,tll andl1te Cali(orni lt isnstitte f(Ir Ineigy

All' svsvtw F itki4 exceed co(tifttit'llill 'hut (lh 1izutiftil if) 1, filir; inctias-

prim midli i .--e-.ondary treatnmeit ingly strint -fit t r-egiil,ti,ii; i'i cnst

llantts a,t killigl" pathlogenis htecali'u' tIf says (Gir "'If vot i ve -n', 'd 2(f(1 .i tonatural dlirinfv(ttion by higih alkalinity 300% . vol ur cui'ts otn the fiont nld,and ultraviolet (UV) expostire. With - with Stiffr¶ (Iegrc ui itu If iirv a n (Id i I -i1t.1 ilrI oli1CI tICa1tinen0t, eIfflulenlt ternai It ,iti Imciif iff II" lIairgai,i, o)0fronm a tniir-1oitid All' plant sl-11M may ha'f' 1itllre to plit rito UJV

lhe suffiriei l to Ineet the most ffecerit cdisinfert itin (r d iszlvcd air fl(utation!Vorltl Health Organization recom- i and still (ine outit alrif(idf the

rt "Pat if. rci,r,iih, iiueicldltiolir mor iniigation wate r, at- gar-l.''i ~tiii' iii- I)? 1. ''tr''''iic~ cordlinig to ( )cwald. 'ihe St. I lek n1i

*t :1'Pf.*1g g R i ... u11 plant is highlrglhtitlg the beneficial- I r e Ar, t i, , 17rese (If itS euiclainied water by groiw-

n-i fst. irleFf'? inig pumpkits, corn, melons, flowers, Conclusion.'U^r raifrl IVt ItI" . roses, and more than 0.8 hectares

(2 acres) of wine grapes. Tlhe St. I lelenia plant has detnion-Still, not even the most enthusiastic strated tire All' ci rucept fir nearly

SVtill, nt even 1he most enthtisiastic 30 years. -h it, th air 'i Ivr; brid Al'l Irolonenits of All' systems claim that plants an'' mion'u irlhi,, iig, elilerits

11l ! J E tile hasic futir-stage system of ponds of the All' tuom ef it iii fli' lnitedI!1! M alone cari produrte effltent meeting States arid i 'ttr ':Ooutlli)if' Must of1 t standards for drinkinyg water or for them like zt. !!', i;r pl ant e

"unrestricted" uses such as swimming very litti( sliilgr' [laittv of them use a

pofols antd irrigationi of public parks. conibiiiatit to -t rite lia;nical and solarAn All' system, like other treatrnent aeration, a 'Iti fi' ( 11i,if ;till re(uires

1A , |t . , -onlcepts, can onily achieve tlese goils less elect i.i it It, (to -; 'nviventionallw addilional treatnient (e.g., disin- treatinemit an, I 1 I. 1ii u I ai ea thanlection, filtration, anid solids removal). does a s'y'st'nit lo 1i' il 41. I elena's.

_---- __ _ -_ - As the ber(i't iu, All' - 'iittIllS

ic- Adi anced lnt'gra8led Pond System Concepts In Your Community beconie pti i, w' 'It 1 i i% i. ltttWeV(ore

if tilr! ;-v4ta,n eirulirits us!;e iti AlP high-rale pond can reduce the need for, or ment cclii itt' i; l i4 ! \ 'o glowt rnaolncv (in be w';rrl in con;iinct lin substitute for, mechanical aeration equip- I - ri. i .l-i.

- ' I r.{~~~~~~~~~~~~~~plitical climl.ifr ,)I inhlt'w';2lngri.eutiortpf vn.t:~ miatpri tei'rrmenrt ment. The primary or secondary reactors'o(ijy tn ctealt' a tivlh idt (y.un atid mechianical aeration equipment are regulatiiiri id o a i *iI ( luinate in

lIifjtinr: tltose AlP eletneilts allows usually the most expensive and energy- whiich c(tttnIri'i ti''ir, imu.iinenriance,r3 actmirve the "hest of botli wirrlts" intensive elements of a conventional treat- and optratiahim I * &i; inc iicreasinigly

plal ring a waslew tler t eatiretit ment facility. And because of the long importiiit, the n\ lI It iay,on. delention time of organic material in the prove to lii' flu' idk,tl i I o Itruutlogyr,chnolugy hars beei arounrd for flarultative pond's digester pit, organic for use Iv n1.!ni, lInuid 'va- tewaterIU yrears alg d has 1e)nr auplied in material is completely removed from the \ manager;. MIl ears. World viae mhe~ tal~pld in rwastewaler. This sludge undergoes con-

:;taulltiuns Wre rotd uir' sit e ele- tinuous digestion until only a small vol- !;f1 All" tecnolrulv. l u rsrng ttte.Cie- une of residue remains. Daily sludge'I le chriclt y ,l Muns Gie int removal and disposal are eliminated, thussinrj liscal pressilte on lou;al gtiven- achiievinig dollar and energy savings.anti the higlh rapilal costs of coII- Wastewater treatment mranagers are fac-

ilfl v astevlaler treatmrent plt;s, ing toughier state and federal regulationsts bnlicve interest in AIP concepts is affecting tthe quality and handling oftI iPvasing. Y'rtl c(mirrllrlv may sludge and effluent trom their plants.litt; hi'trid appurwch inakes tlie Using AlP technology to design hybridsen3e. systeniis or complete AIP systems can

a n~plt~ usr of a fa! ultativ'. p('rul help your conrmitnity meet regulationsl *' tO .i or.elimi etrd and save dollar s and energy-a "win-winl"

low yo~u to rlokviisize or elirnninate tlasituation. .ry or se'ofidary reactor. Use o a

4

| escpitiion of ati Advancep, Inlegrated Pond SystemAn Arivanmeil liiiegrated Pond ,(AIP) sys- micto.dlpae 1he rpil'l1 pfOwIh ol a!gaoterin consists of four basic types of ponids, also raises the alkatiinity of the vwaterinterlinked and working together. killing pathogens Because tihe algaeFacullative o F' nd {Pond tsupersaturate the high-rite pond wlti.1ii 1 1 !13 Pond (Pondists #1) anoPen oxygen. some of this pond's viater isIlefacultative pond consists of ail open reicitdtoheuorae otepond containin;j a "digester pil. Sewage iacllatNe pond to bolster its oxygenentering the system is inlected at the hot- coli, tlnrs reducing or elinrorafingtom of tihe digester pit, where sludge ispernianenily trapped and consumied by

. l w 2 9 , fernrentati(rn In newer AIP systerii Settling Pond /Pond #3)designs, in which the water table is low More than lialt Ihe almie p)roduced inenough, the tacultative pond is about the hirih-rate poinld settle ouit. Sufficient4- to 5-meters (13- to 16.4-feet) deep. algae settle in tflr hilr-rate pond to

.I,/7,tflim. Inhcqritvird I .d ,,-a ,,-irr The pond has an oxygen-rich upper layer meet total susleiided- solids dischargeP,ertmrfrri fariiity, cf. Cf Iir'ic, f fIifilf,ira about 1 -meter (3.28-feet) deep, which requireliellts

helps to oxidize any malodorous gases Maturafion Ponds (Ponds J4 and #5)rising from the digester pit. Treated water is f!Posed to tthe sun's

Hiph-Rate Pond (Pond #2) UV ra,s and stored liit il rigation andWater from tile facultative pond flows to dispo-a4the highi-rate pond, where aerobic bacte-ria break down dissolved organic malter.Oxygen is supplied photosynthetically by

ni; 1gram ol rI. Hlenna s AMP System

fRecirculation ofoxyqpn-tich water

FaFttulativepond #1

'HI

ItIphi-rata pond pf#Maturation Mat|ratIon_____________ ~pond #4 pond #5

Effluent -i

Setlling pond #3 dIscharge r r I I

!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~v h l 1, \,'a"T}

To Irrigation t u weahi

To Irrigalion{|..... ¢l@

-7m ^- -- -t-,a0. cotabato -...

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