Cagayan De Oro City 16

Public Disclosure Authorized Public Disclosure Authorized

X--~~~~~~~~~~!K !l~~~~L4 a.S;_,s,';,XB Public Disclosure Authorized Public Disclosure Authorized I Republicof the Philippines Local Water Utilities Administration

SEWERAGEAND SANITATION PROJECT WATERDISTRICT DEVELOPMENT PROJECT

WORLDBANK

ENVIRONMENTAL LUZON ASSESSMENT REPORT

CAGAYANDE ORO CITY

MINDANAO CAGArANDEORO

August1997 I TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY 1

Chapter 1 INTRODUCTION 12

Chapter 2 BASELINE ENVIRONMENT - CAGAYAN DE ORO CITY 16

Section I Existing Environment 16 Section II Environmental Pollution 20

Chapter 3 PROJECT DESCRIPTION AND ANALYSIS OF ALTERNATIVES 27

Section I Project Rationale and Objectives 27 Section II Sanitation 27 Section III Overall Sewerage Scheme 30 Section IV Recommended Project Design for Cagayan de Oro City 41 Section V No Project Scenario 44

Chapter 4 ENVIRONMENTAL IMPACTS 47

Section I Beneficial Impacts of the Project 47 Section II Project Implementation Impacts 49 Section III Summary 51

Chapter 5 ENVIRONMENTAL MANAGEMENT PLAN 52

Section I Mitigation Plan 52 Section II Monitoring Plan 54 Section III Implementing Arrangements 55

Appendices

1. Bibliography 2. Climatological Normals ( 1961-1995) 3. Typical Noise Emissions of Construction Equipment 4. Expected Noise Levels at Various Distances from Construction Equipment 5. EnvironimenitalQualitv Standards For Noise Maximum Allowable Noise Levels 6. The Advanced Integrated Pond Svstem (AlPS) of Wastewater Treatment

IlvIrrfllh'1f1 ta/ . I.xcs%sesentrRepoti: ( cgavanOdr)ru ( 'It' I I EXECUTIVE SUIqMARY

Introduction

In the Philippines,the typical urban area/built-uparea is characterizedby a heavy concentration of activities,both commercialand industrial. It is also the area where the density of population is at its highest. These areas are also the sites where the production and consumption of raw and processed materialscould be found. Consequentlythe, pressure on the hfe support systemsin these areas are far higher than the suburbanand rural areas. Adverse environmental conditionssuch as the generation and similarlythe dischargeof wastes into the environmentis common in urban and built-up areas. Unfortunately,the amount, type and concentrationof waste generated exceed the capacity of the local environmentto absorb and assimilatethem The carying capacity ofthe life support systemsare stretched to the limits. The urgency of establishingcollection and treatment methods to prevent adverse impacts to the health and well-beingof the residents, and to the ecologicalsystems which sustain them cannot be ignored and overstated.

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

The provision of a cost-effectivecentralized wastewater collection.treatment, and disposalis the primary objective of the proposed Water Districts Development Project.The proposed project will assist tle local governmentunits (LGUs) of Dagupan City, Calamba(in Laguna). Cagayan de Oro City. Davao City and Cotabato City. in findingsolutions to the problem of sanitation. Financingassistance willbe partly provided by the World Bank (WB) which shall be conduited through the Land Bank ofthe Philippines(LBP). Over-all administrationwill be exercisedbv LBP's Project ManageinenitOffice (PMO) with technical support provided by the Central Sewerage and Sanitatioi Pr-ogramSupport Office(CPSO) of the Local Water Utilities Administration(LWUA!.

]L/7VI)UflfllC?17 1I/ s ?ent7fsi n. Rcpurr ( 4/g'll Cie O() 0 ( 111 better sanitary conditions will thus be achieved in the areas served by the sewerage and sanitation systems. This will reduce water-borne pollution and water-logging within the cities and in the surrounding water bodies, thereby bringing health benefits to local populations. The construction of the systems will protect shallow groundwater aquifers from contamination.

Environmental Assessment Requirements

This EnvironmentalImpact AssessmentReport for Cagayande Oro has been prepared in accordance with the Presidential Decree No. I586 otherwiseknovwn as the Environmental Impact AssessmentLaw and Department of Environmentand Natural Resources (DENR) Revised Administrative Order Nos. 36, the Revised Water Usageand Classification/Water Quality Criteria and Revised Effluent Regulations of 1990 respectively;and WorldBank's OperationalDirective 4.01 on EnvironmentalAssessment. The revised Administrative Order 36 for Environmental Impact Statement System issued in 1996 is comprehensive and is compatible with the World Bank's Operational Directive 4.01. It outlines the procedure to be followed by environmental critical projects (ECPs) and projects to be located in environmental critical areas (ECAs). in preparing environmental impacts statement (EISs)'. ECP and ECA are defined in the AO. It should also be noted that that local ordinances and regulationsgoverning projects of such nature have been taken into considerationin preparingthis report. SimilarEIA reports are beingprepared for the other 4 cities.

This report has been prepared by a team of local consultantsunder the aegis of the LWUA and the Cagayan de Oro City Government. Much of the work relatingto the environmentalimpact analvsiswas undertaken as part of the feasibilitystudy done by C. Lotti and Associati Consultationwith the communityis an on-goingprocess. The sanitationcomponent of the project willbe executed in a participatorymanner, and detailedguidelines have been spelled out.

Selection of Priority Cities

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

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

1i Inrj,e1 iitul .11.X0WN.IC/7 71f,,,R I1. ( cItgu in (fi,' ()iC., Ci1( 2 76.000 cubic meters in Cagayan de Oro is being discharged as untreated or undertreated wastewater. Outside the Poblacion areas, there are pockets of population concentrations polluting 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 pollution problems are not comparable with Davao and Cagayan de Oro, these cities are located close to environmentally sensitive wetlands and water bodies. In Cotabato City, the urban area is actually below the mean sea level, exposing inhabitants to frequent flooding and waterlogging during the monsoon months. Calamba is located on the shores of Laguna Lake, v uichhas experienced a rapid deterioration in water quality over the last two decade! Dagupan city is close to a large estuarine zone with ecologically sensitive wetlands and fishponds. In each of these cities, Mayors and city officialshave recognized for some time that unless their complex environmental problems are tackled through a strategic plan of handling waste disposaL sustainability of urban growth could be seriously affected.

Overall Project Approach

The proposed project follows a demand-based approach in the sense that facilities will be constructed only if they conform with the preferences of local stakeholders, and services conform to their respective willingnessto pay. The stakeholders represent the different tiers of organizations from the City or Municipal Council and Barangay (part of the formal LGU system), to the more informal purok, neighborhood and household levels. During project preparation, the idea of involving communities in the planning process was field- tested in three 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 transportation sewers. prinary drains and wastewater treatment facilities, the project design 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 Staff Appraisal Report (SAR) for the Project on Financial Aspects].

For the feeder system, consisting of collector sewers, secondary drains and on-site sanitation facilities, barangays and local neighborhoods will be associated with the planning and implementationprogram. The design criteria have been simplified,so that the feeder system can respond to local preferences and willingness to pay, rather than be bound by any conventional sewer design criteria used in industrializedcountries. Detailed design will be conducted through a participatory process described in Annex 13 of the SAR.

Given the capital-intensive nature of the investments, the proposed project is only the initial phase of a progr-amto improve the sanitation infrastructure through a strategic planninigapproach that involves a mix of on-site and off-site wastewater collection.

['111'(r( 1 t', / \IVS. AM0i 7Re vl? ( (Rgeal ti7 ()rCn (L Itl J treatment and disposal. Choice of initial service areas for sewerage has been confined to the Central Business Districts or Poblacion areas because these are the major contributors to 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 the request of the LGU.

The project will construct a sewer network that will discharge sewage to a vertically integrated 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 from encumbrances.

For the sanitation compone ts, the entire city has been included in the project area, with final selections being made on the basis of demand. On-site treatment systems through the construction of VIP (ventilated improved pit) latrines, pit latrines, pour flush toilets and septic tanks will also be constructed if there is demand from property owners. For those properties with uncertain land tenure (as in squatter settlements), the project will finance the construction of communal toilets, to be managed by non-governmental organizations (NGOs) and/or the private sector. The specific locations of these facilities will be driven by the willingness to pay for the services by beneficiariesat 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 intensive process of evaluating alternatives during the project preparation in order to achieve cost effectiveness and acceptability. The alternatives considered were anaerobic/facultative ponds, modified lagoon systems and mechanicaltreatment. The evaluation of alternatives indicated that the modified lagoon systems, despite having a higher operation & maintenance (O&M) costs compared to anaerobic/facultativeponds (as it requires mechanical aerators and recirculation pumps) was appropriate. The selected option met the 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 surroundinigland for recreational purposes

f 111iruJnmelllnl a .I:SXe. ?/r I?epCr: ('naga and erC()Jl ('if 4 Summary Information on Project Cities

Davao Cagayan de Oro CoLabato Calamba Dagupan

Populatim (1990) 849,947 339.598 127.065 173.453 128.000

Housmg 163.329 47.724 21.581 32.109 21.219

SLzeof Central 1.000 heulares 400 hetares 120 helares 95 hedtares 50 hectares Busness Disnct (CBD)

Morbiditv rate per 595 fSr 733 for dianhea 3050 for diarrhea 818 for parasitisn 528 for gastro- 10.000 from diarrhea(t rd rank (third raak-) (frst rank) (secmd rank) terntis (third rank) diseases amnog di ses)

Water bodies at Davao river and aU Cagayan river and About 50% of city Laguna Lake About 50% of city risk because of beacbes close to adjoining beaches area ccxsists of experiencmg area are wdlands. municipal city not fit for au Macajalar Bay wetlands, fish ponds increase in turbidity used for fish wastewater recreaticnal untit for and estuarine area and rapid farming pollutio purposes recreational eutrophicatic purposes because of fecal ocmtaminaticm

The urban area/built-up areas in the project cities are characterized by a heavy concentration of commercial and industrial activities. It is the area where population density is 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 manufacturing activities and retail distribution. A large proportion of piped water supply from the local Water District is also consumed in the Central Business District (CBD). Consequently, the pressure from both solid and liquid wastes in these areas greatly exceed the capability of the land and water resources to absorb, assimilate and recycle them

Cagayan de Oro City

Impact During Construction Phase

The implementation of the project and its components is projected to produce only minimal 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. In the short-term. the project will provide employment and livelihood opportunities to the population of the surrounding communities through the jobs generated during the construction phase. In the long-ternt better sanitary conditions will reduce sicknesses caused bv water-related problems. Thus an improvement of the existing environmental conditions is expected. The project will undertake mitigating measures to minimize, or if at all possible. eliminate adverse impacts.

!"M mmetl lsstnLemll.IXNc Nx (J?(pJr): ( 'jWq1-atan cde (h)o (at'.D Air Quality. The implementation of the project will result in an increase in the ambient concentration of suspended particulates in the vicinity of the project site. This would be attributed to dust from land clearing and excavation activities, which expose soil to wind and vehicular traffic over unpaved road.

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

During the rainy season, surface runoff may increase total suspended solids, and cause temporary stress at the discharge point . However, the impact will be localized, and when the vegetative cover returns, impact oi the receiving body of water caused by surface runoff will be eliminated.

Noise. The noise impact during the construction stage is expected to be generally minimal and will not require any special noise abatement measure. The treatment plant sites shall have a setback away from residential clusters, which will definitelyprovide the necessary buffer 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 the temporary operation of heavy equipment. Noise from breaking concrete pavement and sidewalks may also pose a temporary problem. However, the noise level at the streets is expected to be within the ambient noise quality standards.

Ecological Effects. As there are no rare, endemic species of flora and fauna in any of the proiect 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 Qualitv. The operation of the wastewater treatment facilitywill have minimal impact on the air quality of the area. Aside frorn the occasional odor nuisance. it is not projected to have adverse effect at all.

Water Quality. The implementation of the project will be beneficial to the general environment of participating cities and their environs. Discharging of untreated domestic waste water from the highi volume consumers in each city's Central Business.Districts into nearbv bodies of water would thus be minimizedor eliminated. However. operations and maintenance failures may result in occasional discharges.

Socio-economic. The provision of sanitation facilities in the project cities would undoubtedlv benefit the general populace of these areas. Thle occurrence of epidemic- scale diseases caused by cuirent unsaniitaryconditionis will be reduced. T'his will result in a more healtlhyand productive populatioln.

1-17\'ifl 7L',7I1/ . IsnL'Xw;9no Repe: ( /IgtII a1 dc ( hr ( ill Sludge Disposal. The recommended modified lagoon system or vertically integrated pond system of treatment will require sludge disposal at very infrequent intervals. The sludge in the anaerobic pond/s remains for an extended period continuously undergoing organic decomposition. This may take place over a 20-30 year period. One system in operation in the U.S. has not been desludged in thirty years. Recent testing ofthis system has indicated that the sludge is well-digested and very stable. If desludging does become due, arrangements can easily be made with the city environment office for disposal at the sanitary landfill.

Mitigating measures to minimize, or if possible, eliminate adverse impacts will be implemented. Measures to enhance the existing environm ital conditions in the project site shall be implemented to maintain the environmental srX ainability of the area. The implementation of the project will inevitablycause impacts, both adverse and beneficial.

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

Anvz,y,,,,,,7'niaI- ].c.%V.VIez7c1I kI)OPI ( 'fIgCrlVI c ()ru7 ( '11 Table 1: Mitigation Actions

Construction Phase

Potential Impact & Risks Mitigation Action

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

Air Pollution * Careful construction planning and work phasing, specifications and construction methods to reduce the ngth of time that the * Construction equipment and soil is exposed to the environment. vehicles may cause higher * Provision of adequately and properly mamtained storage for suspended particulates, odors and construction materials and equipment. fumes emissions - CO2 , CO. NOx . 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 civil likely 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 Pollution and Soil Erosion * Provide temporary drainage and storage facilities for excavation soils, for fuel and oils needed for equipment. * Siltation . Careful and rational planming 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. avoid tion equipment would be about 70- simultaneous use of heavy equipment. limit daytime work, 80 dBA at 10 m: 50-70 dBA at 30 vehicle speed at 20 kph: regular maintenance of equipment m. * Use of appropriate mufflers and sound proofing of construction machinery, 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 be Flow located along secondary streets. * Scheduling and increasing input resources so that period of traffic disruption in primary roads are reduced. * Coordinate with the local traffic management office and the PNP Traffic Management Command : Clear directional signs and barriers in case traffic rerouting is needed. * Public information campaign.

:l l;-tf oini,es1tal.].-vse,v.nZ)eii Rejport: ( 'ag,qanm dL ()ro ( 1Y.e Operation Phase Potential Inpact & Risks Mitigation Action

* Environmental hazards due to * Carefully designed post-construction maintenance, contingency accidents 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 be sewer lift station will increase taken/observed. level of pollution at the Cagayan . Adequate plans for environmental rehabilitation, clean-up, River near the center of the city as restoration, and disposition of temporary structures and facilities raw sewage will have to be installed during the construction phase. dumped directly. l

Water Pollution * Upgrade laboratory facilities of the Cagayan de Oro City Water District (COCWD) to be able to undertake wastewater analysis. * The effluent discharge may well * Following the bubble concept, wastewater discharged into the affect the condition of receiving Cagayan River shall, in the long-term, conform to the water bodies of water and the effluent quality standards established by the Department of Environment discharge point of the treatment and Natural Resources as set forth in DAO No. 34 and 35, plant may also be affected by tidal Revised Water Usage and Classification/Water Quality conditions (estuary). Standards and Revised Effluent Regulations of 1990. respectively. . A dispersion/dilution modeling study will be conducted to prior to locating the outfall. Treated effluent discharge into the Cagayan River shall be timed based on tidal conditions. The adoption of the AIPS process for the treatment plants should result into attainment of effluent standards.

l Noise would be at about 65-85 . Establishment of buffer zones and noise zonesl dBA. principally coming from septage trucks unloading at the treatment plant.

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

Management and O&M of the System Institutional: * Management Contract with COCWD which has proven utility . Poor maintenance of pumps management and operations capacity. * User consultation at detailed engineering design stage to ensure . Low number of connections connection. * Sewerage surcharge should be sufficient to provide incentives for COCWD to maintain system. * Require M&E reporting to the DENR and LWUA. l Explore feasibility of BOO/BOT contracts for recreational activities in unused lands at treatment sites. * Provide adequate training of COCWD and city staff. Regulators l 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 COCWD.

/I9ironmenrtal/ .-IX.sxnienit R?;yz:rr (Caguc,van1c. ()I Cm('tt Monitoring and Implementation Arrangements

Construction Phase

Ambient air quality measurements will be undertaken near construction sites. This will be mostly near locations where sewer network is being laid and treatment plant sites. When selecting 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 or 24 hours, over the construction period.

Noise will measured at the same locations as TSP. Lc41 and Lgovalues will be measmi d and recorded.

Operation Phase

Receiving water quality will be monitored by the DENR through its regional offices which is monitoring the status of Cagayan River 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 will not be removed but the proposed sewerage infrastructure will greatly reduce the problem. Once the plan becomes operationaL the treatment plant operator, vis-a-vis. the Cagayan de Oro City Water District (COCWD) would be required to set up a laboratory and measure the effluent quality.

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

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

Implementation of the Monitoring Plan

The PMO. with the assistance of LWJUA-CPSOand consultants to be engaged in the project. would monitor compliance with the ECC and carry out the requisite data collection. Monitoring reports would be submitted to DENRJEMB and the World Bank periodically. While respective responsibilities for the various mitigation activities have been identified, the PMO will ensure that the requirements are complied with; in addition, feedback firomcommunities. city officials. NGOs, etc. will be pro-actively sought through the city public affairs programs. regular monthlv meetinpgsof barangay captains and other methods. Finally, DENR. througlhits planned PPA svstem, would also periodically monitor and audit compliance with the ECC, assisted by independent contractors.

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

Ant'imrfnmenta . xs.~exsmt Report: (Cqgoqvn le O)ro fty /0 Table 2 Summary of Responsibilities and Timetable for the Monitoring Plan

Activity ResponsibUity Start Completion

Secure ECC clearance from DENR. CPSO-LWUA Decemiber 1996 Sptemnber1997

CoUectreference ambient air parameters City PMU. with DENR September 1997 June 1998 around the proposed treatment plant sites at regional office projecs cities

Ensure that the bid documents include PMO January 1998 August 1999 provisicns for mitigation under the responsibility of the contractor: review cmtraacor'swork plans to ensure compliance with en- vircnmental rmtigation plan provisaMs

T,ram opaators an O&M practce & handling PMO and CPSO-LWUA Januarv 1999 June 2000 emagency situations.

Assess and upgrade the laboratorv facilities of Project Citv PMU and local Marci 1998 June 2000 the Cagayan de Oro City WaterDistict. Water Distnct

Conduct user c tsuatimnsand mformatice Project City PMU. witb Januarv 1998 June 2000 campaigu. assistance of NGO.

M aitor and report i copliance. PMO Bi-annual basis Bi-annual basis

LFWU,4,jcr rdessCtn.doY

fn tz n1mnietal .1x e.xn7LentI?cpoort: (aOgalS2 ta dL' ()roJ ('t II I 1. INTRODUCTION

In the Philippines,the typical urban area/built-uparea is characterizedby a heavy concentration of activities,both commercialand industriaL It is also the area where the density of population is at its peak. These areas are also the sites where the production and consumption of raw and processed materialscould be found. Consequentlythe, pressure on the life support systemsin these areas are far higher than the suburbanand nuralareas. Adverse environmentalconditions such as the generation and sinilarlythe dischargeof wastes into the environmentis common in urban and built-up areas. Unfortunately,the amount, type and concentration of waste generated exceed the capabilityof the local environmentto absorb and assimilatethem. The carying capacityof the life support systems are stretched to the limits. The urgency of establshing collectionand treatment methods which wil prevent adverse impacts to the health and well-beingof the residents, and to the ecologicalsystems which sustain them cannot be ignored and overstated.

The provision of a cost-effectivecentralized wastewater colection, treatment, and disposalis the primary objectiveof the proposed WaterDistricts Development Project (WDDP). The proposed project wiDlassist the local governments of Dagupan, Calamba(Laguna), Cagayande Oro City. Davao City and Cotabato City, in findingsolutions to the problem of sanitation.

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

There are several possible options for addressing this problem, including improving the design of the septic tank system with the installation of soil absorption systems. But an environmentallv sound alternative that is cost-effective and captures economies of scale is to connect individual properties directly to a sewerage system for the collection, treatment and disposal of the urban wastes. better sanitary conditions wiDlthus be experienced in the areas served by the sewerage, drainage and sanitation systems. This will reduce water-borne pollution and water-logging within the cities and in the surrounding water bodies, thereby bringing health benefits to local populations. In Davao, Cagayan de Oro and Calamba cities, pollution from human wastes have affected recreational areas, such as beaches and lake front areas. Project investmenitsin wastewater collection and treatment will also have positive benefits in terns of improving prospects of saving the remaining beaches for the city residents. The

bI1avironnieital I vxexxrnemitReport: ( agc van dle Or

Overall Approach of the Proposed Project

The proposed project follows a demand-based approach, in the sense that facilities will be constructed only if they conform with the preferences of local stakeholders, and services conform to their respective willingnessto pay. The stakeholders represent the different tiers of organizations from the City Council and Barangay (part of the fPrmal LGU system), to the more informal purok, neighborhood and household levi s. During project preparation, the idea of involving communities in the planning process was field-tested in three barangays of Davao city, and found to be quite successful. The basic decision- making process is as follows:

(a) For the capital-intensivetrunk system.,consisting of the main transportation sewers, primary drains and wastewater treatment facilities, the project design 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 Staff Appraisal Report (SAR) for the project on Financial Aspects].

(b) For the feeder system, consisting of collector sewers, secondary drains and on-site sanitation facilities, barangays and local neighborhoods will be associated with the planning and implementation programn The design criteria have been simplified. so that the feeder system can respond to local preferences and willingness to pay. rather than be bound by any conventional sewer design critefia used in industrialized countries. Detailed design will be conducted through a participatory process.

Given the capital-intensive nature of the investments, the proposed project is only the initial phase of a program to improve the sanitation infrastructure through a strategic planning 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 to the Central Business Districts or Poblacion areas because these are the major contributors to municipal wastewater pollution. The only exception made is in the case of Davao City, where a second area of highigrowth prospects (Toril) has also been included on the request of the LGU.

The project will construct a sewer network that will discharge sewage to a vertically integrated 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 from encumbrances.

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

f Itvirumesnmtal .-I.A:weA.ne,1IRepor C(agaan e Ol()ro ( 13 construction of VIP latrines, pit latrines, pour flush toilets and septic tanks will also be constructed if there is demand from property owners. For those properties with uncertain land tenure (as in squatter settlements), the project will finance the 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 willingnessto pay for the services by beneficiaries at the barangay level, provided of course that these are technically feasible.

The recommended solutions for wastewater treatment were arrived at after an intensive process of evaluating alternatives during the project preparation in order to achieve cost effectiveness and acceptability. The altematives considered were anaerobic/facultative ponds, modified lagoon systems and mechanicaltreatment. In all the five cities, the evaluation of alternatives indicated that the modified lagoon systet s, despite having a higher O&M costs compared to anaerobic/facultative ponds (as it requires mechanical aerators and recirculation pumps) was more appropriate. Details are available in project files. The selected option met the following criteria the effectively:

(a) Minimize overall pond area required

(b) Minimize odor production

(d) Minimize sludge production rate

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

Environmental Impact Assessment

This EnvironmentalImpact Assessment Report for Cagayan de Oro has been prepared in accordance with the PresidentitalDecree No. 1586 otherwise known as the Environmental Impact AssessmenttLaw and Department of Environmenitand Natural Resources Revised AdnministrativeOrder Nos. 36, the Revised Water Usageantd Classification/Water Quality Criteria and Revised EffluenitRegulationis of 1990 respectively;and WorldBank's Operational Directive 4.01 on EnvirontmentalAssessment. The revised Administrative Order 36 for Environmental Impact Statement System issued in 1996 is comprehensive and is compatible with the World Bank's Operational Directive 4.01. It outlines the procedures to be followed by environmental critical projects (ECPs) and projects to be located in environmental critical areas (ECAs), in preparing enviromnental impacts statement (EISs)'. ECPs and ECAs are defined in the AO. It should also be noted that that local ordinancesand regulationsgoverning projects of suchnature have been taken into considerationin preparing this report. SimilarEIA reports are being prepared for the other 4 cities.

This is the term used by DENR and refers to the standard EnvironmientalAssessment Report requiredby the Worldbank as per OD 4.01

I:t'l(fI1'1/mvinimnllX. Issessmeni ReporJt: Cqtgvull\t1lie Or1/ (CIl /X This report has been prepared by a team of local consultantsunder the aegis of the Local Water UtilitiesAdministration (LWUA) and the Cagayan de Oro City Government. Much of the work relatingto the environmentalimpact analysiswas undertaken as part of the feasibility study done by C. Lotti and Associati Consultationwith the communityis an on-going process. The sanitation component of the project will be executedin a participatorymanner, and detailedguidelines have been spelledout.

cdIcheR wCrc.doe (; 'Q

i n\ nore,n?.N,laI .vxL'...... 7e)7t I?dJ,arr (ai,L7'atan c/c (1P (Jfitt'...... 1 2. BASELINE ENVIRONNMNT - CAGAYAN DE ORO CITY

Introduction

Thischapter is in two sections. SectionI profilesthe existingenvironmental situation in Cagayande Oro City and SectionII analyseswater pollutionimpacts (historical) of uncontrolledsewage discharge.

Section I - Existing Environment

2.1 Land Resourcesand Use Cagayande Oro City is locatedalong MacajalarBay on the centralcoast of Northern Mindanaoand serves as the capital of the provinceof MisamisOriental as well as the regionalcenter of Region X - NorthernMindanao. The city is about 780 kilometers southeastof Manilaand 190 kilometersnorthwest of DavaoCity. [Figure2.1]

Cagayande Oro City is the major urban centerof NorthernMindanao with a total land area of 48,886 ha. It is amongthe developedurban settlementsin the countrywith an annualgrowth rate of 5.5%, twice the nationalaverage of 2.7%. The urban area whichis approximately2,335 ha, lies along a narrow coastalband expandingsouthward into the citys westernflank. The poblacion,or the city center, occupiesapproximately 400 ha. It lies adjacentto the eastern bank of the CagayanRiver. High densityresidential and commercialdevelopment characterize this area. Urban developmenthas mainlvfollowed a linearpattern adjacentto the NationalHighway which is basicallvthe main transport artery to the rest of Mindanao. The natural limiting factor in the developmentand growth of the Cityis the topographyof the area. Developmenthas been confinedto the coastal strip,however. recent developmentshave been made southwardof the city and in the westem side of the CagayanRiver. The most extensiveurban land-useoutside of the poblacionis medium-densityresidential areas. The center of industrialdevelopment, on the other hand, is locatedat Puntod,Bayabas and Tabon. As of 1992,agricultural lands occupy 72.58% or 35,481.46ha of the total land area. (CPDO) Coconut and corn are the predominantcrops cultivated. Thesemixed cultivated areas are usuallvassociated witlh grasses. This is a manifestationof the presenttrend to

Iknx uro,menta/.-lx / Repf irn (Cagavan i doro (,IfY 16 utilize grasslands for agriculture. Table 2.1 shows the Land-Use by Zoning Districts of Cagayan de Oro City. [Figure 2.2]

Table 2.1 Land-Use by Zoning District Cagayan De Oro City Zoning District Area in Percent Agricultural 81.90 Residential 12.39 Parks, Plazas and Open Spaces 2.00 Industrial 1.68 Commercial 1.26 Institutional 0.77 Total 100.00 Source: City Planningand DevelopmentOffice, Cagayan de Oro City

2.2 Physiography and Geology

In. general the city is dominated by rolling and steep terrain. The lowlands represent an area of about 3,536 ha. Most of these lowland landscapes are broad alluvial plains. As the most extensive land management unit (LMU), they occupy about 82 % of the lowland areas. The soils in these LMUs are generally deep with varying drainage conditions.

The upland areas of about 15.405 ha are represented by widely variable landscapes. The most important agricultural lands in this landscape are river terraces, alluvial valleys, residual terraces, and volcanic hill footslopes which have an aggregated area of 5,891 ha or about 38.2% of the upland areas. These areas in general have well drained, acidic, and deep. clayey soils. The remaining upland areas are mostly low hills that have sloping lands and relativelv shallow degraded soils. The hilly lands of about 16,818 ha are lands where most soil erosion and degraded grasslands are located. The highlands of about 1,416 ha are relatively small but have high potential for the caltivation of high value crops. However. these areas are fragile and their utilization require a well conceived soil management and conservation program.

About 13.166 ha are lands below the 18% limit prescribed for the alienable and disposable lands. In general, the area is dominated by steep and rolling lands with slopes greater than 18% slopes. TIheseareas are mostly the areas devoted to the Integrated Social Forestry (ISF) projects comprising about 16.018 ha or 39% of the city. Areas with slope greater than 30% represent an area of about 2.762 ha (Louis Berger International. Inc.. 1992). nThetwo sites being proposed by the City Government for the wastewater treatment plant a-e situated along the banlks of the Cagayan de Oro River. The Bgy. Nazareth site and the

l/fl'.17 Off11)}81'fl .-l .%.~xf.:h?1 l?'Report: ( a taiee ()u (CY 1 7 Bgy. Consolacion site are within the easement of the river. Both sites are relatively level. There are no settlers/squatters in both of the proposed sites. The two sites are within built-up areas and are adjacent to developed residential communities. It is estimated that the size of each site is less than 3 ha.

2.3 Climate

As per the Modified Corona's Classification of Philippine climates, Cagayan de Oro City, Misamis Oriental belongs to Type HI. It has no pronounced maximum rain period and a very short dry season which lasts from one to three months only. As is common in the country the Northeast Monsoon prevails during the months of November to March exhibiting maximum intensity during January and February. It is a relatively cold and less humid air mass as it originates from the intensely cold anticyclone over continental Asia during winter. From June to September the Southwest Monsoon dominates the area. This air mass is warm and extremely humid and originates from the Indian Ocean crossing the equator and enters the country from the southwest. The North Pacific Trades are generally dominant during April and May.

The mean annual temperature recorded in Cagayan de Oro is 27.60 C. The warmest month is May with a mean temperature of 28.7°C while the coldest is January at 26.4°C. The mean annual maximum temperature is 32.3°C and the mean annual minimum temperature is 22.8°C.

The mean annual relative humidity at the site is 80% which is a typical maritime tropical value. The lowest mean monthly value of 76% was recorded in April, the driest month while the highest is 83% during the month January. Appendix 2 shows the climatological normals for Cagayan de Oro City.

2.4 Hydrology and Water Ouality

Cagayan de Oro City is within the Cagayan River Basiii. This basin has an areal extent of approximately 1,521 square kilometers. The receiviingbody of water for the effluent of the wastewater treatment plant is the Cagayan River. It should be noted that as per DENR Classification, 1993, Cagayan River is classified as Class A. As pointed out by the Regional Office of the DENR- 10. discharging of effluents are discouraged in Cagayan de Oro River as said river is utilized as source of potable water supply. Table 2.2 shows the latest analysis of water samples taken at Cagayan River.

h:ln iromnemal7.1 I %'Xl71 ?It Reporlt. ( 'a natc,1.' ()p.s ( ;j! /X Table 2.2 Results of Physical and Chemical Analysis Cagayan de Oro River, Cagayan de Oro City

Parameters March4,1996 May 1,1996 Color, units 15 15 Odor,T. 0. N. Turbidity,ppm Temperature,Co 27 28 pH 8.18 7.15 DissolvedOxygen, mg/L 7.8 7.5 BOD5,nigL <1.0 <1.0 SettleableMatter, ml/L Total Solids,mg/L 116 130 SuspendedSolids, mglL 14 38 Total DissolvedSolids, mg/L 88 118 Greaseand Oil, mg/L Total Coliform,MPN/100OOml Alkalinity,mg/L as CaCO3 0.0 40 Chlorides,mg/L 50.0 1.0

2.5 Vegetation and Wildlife

Two sites are being made available by the City Government for the Wastewater Treatment Plant, the Bgy. Nazareth site and the Bgy. Consolacion site. Both sites are along the banks/easement of the Cagayan de Oro River. The sites are within well developed areas as such floral and faunal communities are severely inhibited and highly influenced by human activities. The predominant vegetative cover in both sites are wild grasses, coconut trees, shrubs and creeping vines. Domesticated animals such as chicken, goats. and dogs can be seen in the sites.

2.6 Socio-economic Aspects

There are 80 barangays in Cagayan de Oro City. 12 rural and 68 (40 are in Poblacion) urban. Estimates made based on the 1990 NSO Population Data placed the total population of Cagayan de Oro in 1995 at 397.920. The total urban population is estimated at 372.337 persons with density of 17.03 persons/hectare. Recent development aad growth in the City is conicentratedin the urban areas located away from the Poblacion-along the coastal and national higlhway. This is primarily due to the lack of land to cultivate. accessibility. and attraction to developed areas.

AfirtlIfrotinirUtal.% I..sessnent v R jrt.mt' (G'ai,in tie Orn (C*ft' Section II - Environmental Pollution

As in most other major cities, the urban area/built-up area in Cagayan de Oro is characterized by a heavy concentration of commercial and industrial activities. It is also the area where population density is highest. These areas are also the sites where the production 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 suburban and rural areas. Adverse environmental conditions such as the generation and discharge of wastes onto the environment are common in urban and built-up areas. Unfortunately, the amount.,type and concentration of waste generated exceed the capability of the local environment to absorb and assimilate them. The carrying capacity of the life support systems are stretched to the limit.

2.7 Existing Sanitation Conditions

Informal interviews conducted during the several field visits reveal that most of households and commercial establishments recognize the need to improve the present sanitation condition. This is far from satisfactory because:

* Even though water-sealed toilets are considered the "standard" sanitary facility, based on the 1994 survey made by the City Health Office (CHO). about one-fifth of the households do not have one; * Most of the wastewater discharged via drains, ditches or on land ultimately drain to Macajalar Bay, thus increasing bay water pollution; and, * Although more than 60 percent of the households have septic tanks, their design and construction are a cause for concern. The leaching chambers of most septic tanks have unlined bottoms allowing effluent to seep into the groundwater. the principal source of the City's water supply. High fecal coliform couwts for groundwater samples in a previous wastewater feasibility study confirm this problem (LB 11. 1992).

2.8 Health Problems Faced by Cagayan de Oro City Residents

The data on water-borne disease in Table 2.3 suggest that contamination has had serious consequences for human health in Cagayan de Oro. Amoebiasis is endemic, occurring most frequently in the western areas of the city: Carmen, Patag, Kauswagan, Bulua and Bavabas. It is particularly common in areas where the squatter population is high. The regional office of the Department of Healtlhestimates that the city experiences about 130- 150 cases of medicallv-confirmed amoebiasis per quarter.

"iv/ir ll mal.sZvtllIssessinZent Repewto Ccqwlclll d o1-o C)l tw 20( Table 2.3: Waterborne disease in Cagayan de Oro, 1992-1994

1992 1993 1994 Rate Rate Rate Number (/100,000) Number (/100.000) Number (/100,000) Morbidity Diarrhea 2562 696 2065 539 2924 733 Amoebiasis 396 108 215 56 418 105 Typhoid Fever 234 64 232 61 246 62 Mortality Diarrhea 8 2.17 2 0.52 8 2.0 nAmoebiasis 7 1.9 7 1.83 3 0.75 Typhoid Fever 5 1.36 6 1.57 1 0.25

The overall incidence of diarrheal diseases is also quite high. The Office of the City Mayor reports that in 1995, the City Health Office provided medical services to 11.211 people suffering from diarrhea. Cholera and infectious hepatitis are much less common. In 1995 there was one reported case of infectious hepatitis, and none of cholera. In 1996, there have been no reported cases of either disease to date.

Typhoid fever is more common. Its incidence by barangay provides a very useful indicator for our analysis, because medical experts agree that 75% of all typhoid cases are directly attributable to water pollution. The data in Table 2.4, provided by the Regional Epidemiological Surveillance Unit (RESU) of the Department of Health, highlight the same western hot spots. Patag and Bulua have a very high incidence of typhoid. followed by Carmen, Kauswagan and Bayabas.

Table 2.4: Reported Cases of Typhoid, 1995

Typhoid Barangay Cases Patag 33 Bulua l s Carmen 4 Gusa 4 Kauswagan 4 Bayabas 2 Lapasan 2 Nazareth 2 !Balulang tBonbon sBugo_i ! ICamaman-an LPuntod ITablonl

l'auiremimen7tal/. Issessmentl Report ('agayvan dle Ora (CitV' 2.9 Existing Environmental Conditions in Cagavan de Oro

MacaLalarBav - The coastal waters of the Macajalar Bay show signs of high stress due to its multiple use as a recreational and fishing area, transport lane for sea-going vessels, recipient of eroded soils from river basins, and depository of industrial and domestic wastewater from the City and coastal towns. Per water sampling made in 1992 (LBII, 1992). the quality of water in the bay is deteriorating. High levels of oil and grease and heavy metals render the bay unfit for shellfish culture. High fecal coliform counts render the bay unfit for swimming, bathing and other water contact recreational activities.

Groundwat r - Cagayan de Oro clearly has a major problem with contamination of water supplies. . ible 2.5, based on sampling at different points in the city, shows that the groundwater is heavily contaminated. All 11 samples far exceed the maximum allowable limit of fecal coliforms per 100 ml for drinking water.

Table 2.5: Fecal Coliform Counts (/100 ml), Groundwater Samples

Sample I 12 31 14 15 16 17 IS 1 1 1

Fecal 10.600 10,100 16.500 9,700 37.100 5,900 3.700 9,500 7,700 6,000 | 3,700 Coliforms

Caga an River - serves as the sewage outlet for several populous barangays in the central part of the city: Nazareth, Carmen, Kauswagan, Poblacion, Consolacion. Puntod, and Macabalan. Analysis of water drawn from the river at Carmen Bridge (immediately behind City Hall) suggests a high level of organic/fecal contamination. Table 2.6 provides evidence on average contamination of the river during the past few years.' These readings generally exceed DENR's drinking water standard by more than an order of magnitude.

2. 10 Recreational Losses

Table 2.7 shows that fecal contamination of the city's beaches is extensive. Beach areas on the western side of Cagayan de Oro are thought to be more highly degraded than eastern beach areas; our data generally support this perception. Raagas Beach is located in Bonbon. fronting Kauswagan on the north. This beach area extends from Bayabas to Macabalan, interrupted by the mouth of the Cagayan de Oro River. The area is settled thickly by squatter colonies. The data in Table 5 suggest that Raagas is heavily contaminated by sewage, both from adjoining settlements and from the Cagayan de Oro River. Recreational beach use in this area has decreased significantlyover the past 10 vears.

Sampling data were provided by the Environmental Management Bureau ofthe Philippines Department of Environment and Natural Resources (DENR). They extend from April 1987 to January 1994. at irregular intervals. The monitoring equipment broke in 1994. and it has not yet been repaired or replaced.

Ant',rn,u1n?ntLal .1 NNeN?l7elr/ I s l.: ( agir.Cav'an r ()1Or ( 'ri Table 2.6: Coliform Counts, Cagayan River, 1987 - 1994

Year(s) Average Total Coliforms2 Standard Deviation

1987- 1994 21,390 43,089 1994 11,600 10,739 1993 18,000 13,978 1992 47,580 63,204 1991 36,709 67,666 1990 68,640 96,376 1989 13,457 10,705 1988 5,589 6005 1987 7,654 7032

Table 2.7: Fecal contamination of four beach areas

Average Total Standard Beach Sample Years Coliforms Deviation Raagas Beach, Bonbon 1991- 1995 10,515 23,570 Chali Beach, Gusa 1994 46,245 65,707 Acuna Beach, Tablon 1994 760 764 Family Beach, Agusan 1994 1920 2234

Chali Beach in Gusa is located to the east of the Cagayan de Oro River, and is also the site of several squatter settlements which have probably contributed to the high level of fecal contamination. Tablon and Agusan, the locations of Acuna and Family Beaches respectively, are even further east. There are no substantial squatter settlements in these areas. The eastern parts of the coastline are said to be cleaner, partly because their use for recreational purposes is more tightly controlled and partly because neighboring settlements hive lower populations.

There is undoubtedlv a general relationship between the level of contamination at each beach and the size of the unsewered population in neighboring barangays. It is also reasonable to assume that the problem is worse near the mouth of the Cagayan de Oro River and three contaminated drainage creeks. One approaches from the south of Camaman-an. passes behind the Lim Ket Kai Center and discharges into the Macajalar Bay. Another is located to the west of Bulua and discharges into the sea. The third flows from Kauswagan and Bavabas into the Bay.

2 One of the most common reading,s in the data was ">24.000." To compute averages and standard deviations, we adopted the conservative assumption that these readings were only 24,000.

hntzrunrn7ttema/n.1.A:.t)1( Rejort Cagacvtance Oro (Cits 23 2.11 Reduced Opportunities for Commercial Development

Accelerated high-rise construction and sharp increases in property values have accompanied the installation of sewerage in the Makati district of Manila and the central business district of Jakarta. Indonesia. In some Latin American cities, central-city property values are reported to have increased by as much as 20% after sewerage was installed. It would not be surprising to see similar results in Cagayan de Oro if sewerage were installed in the Poblacion district. The city of Cagayan de Oro is well-positioned to become a commercial hub for its region, and the municipal leadership clearly aspires to this role for the municipality. Rapid expansion of high-rise commercial activity in Poblacion seems ver) mlikely unless the area is served by a sewer system.

2.12 Summary of Findings on the Existing Environment

About 20 percent of the population are without satisfactory on-site sanitation facilities, and most of the wastewater from those with acceptable facilities finds its way into the municipality's drains and water courses. These deficiencies are the major contributing factor for the poor environmental conditions of Cagayan de Oro.

Health-related problems related to sewage contamination and inadequate sanitation are of uncertain magnitude, but are an important consideration for the city leadership. Waterborne and other sanitation related diseases continue to be a major public health problem in the country. In Cagayan de Oro, amoebiasis is endemic and occurs most frequently in the western areas of the City - in the districts of Carmen, Patag, Kauswagan, Bulua and Bayabas. Health office estimate that the city experiences about 520 to 600 cases of medically confirmed amoebiasis per year, particularly in areas where the squatter population is high. Overall incidence of diarrheal diseases is also quite high in the City. As underreporting of diarrheal diseases is bound to normally occur, the actual incidence of diarrheal diseases may be indeed quite severe.

Tle City's water bodies appear to be in seriously deteriorated conditions. Fecal contaminationiof the groundwater and Cagayan River has been observed. Pollution of the Macajalar Bav is closely related to drainage from the neighboring population. Adverse environment conditions exist in Cagayan River and three drainage creeks feeding into the bay. due to organic pollution from untreated wastewater discharged into them. Pollution reduction will then depend on the proportion of the local population whose sewage are treated or safely removed from septic tanks. Fishingproductivity, in the bay waters has declined. but sewage contamination has not been a significant factor (as was noted in Davao Citv and the other cities).

Commercial development in the Poblacion is repressed by the absence of sewerage. Installationiof a system would pernit high-rise construction and a significant increase in property values.

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; OCR--';AhC COUNCL OF -H ?PUPP'NE AuSSSANCE PROGRAL( Rp9c o' Lt. Ph;:i@PPr UhJNTED STAT.ES A.ENCY JITRNA-$N7' N O- i LCCAL U._ ADlTL.-TiCT PAP C -troCtN-. *i:-C!5:-C-CO-ACO4 m Son.oro -od S P.Ggrcm Spp.rlC f.:. DMJM.International J-. G- wU.A-,C"Ot10% Figure 2.2 DCCD Engineering Co-porc'.>-. The Services Group LAND USE MAP Damnes & Moore SGV Consul'ing CAGAYAN DE ORO C;TY ,, Nathan Associctes I 3. PROJECT DESCRIPTION AND ANALYSIS OF ALTERNATIVES

Introduction

This chapter begins with an explanation of the rationale of the proposed project and then goes onto describe the project. The main components -- sanitation and sewerage schemes are described separately. Description includes the analysis of alternatives considered in arriving 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 Cagayan de Oro City, and illustrates the worsening health impacts caused by the uncontrolled discharge of sewage. There is negligible piped sewerage in the city. There are no treatment and disposal facilities for septage removed from septic tanks. Septic tank overflows and soakaways enter the drains and the groundwater.

The proposed project is. therefore, aimed at addressiingthe problems of inadequate sanitation and sewerage in Cagayan de Oro by providing sustainable sanitation and sewerage facilities, thereby reducing public health risks and environmental pollution from wastewater sources. The project is designed also to provide a learning experience for future expansion of sustainable sanitation services for the city as well as for other urban areas. The selection of final project design is driven by: (i) demand-based approach; (ii) level of wastewater 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 about 6,882 facilities: VIP latrines and pits 1,835 a Pour flush toilet 1,376 * Flush toilet 918 * Septic tanks/soakage pits 2,753

I nl vrontn7ena/ l. . sn7essmetR?eport. Ccagcaani de ()vo Calz '17 as well as 36 communal toilets city-wilde. The sanitatioll works were based upon an identified deficit of sanitation facilities of 19%0.The choice between individual and communal facilities will be driven by technical feasibilityand demand by key stakeholders and not by tenure status. The location of the individual as well as commiunaltoilets is not defined yet and will depend on the consultation of potential beneficiaries. The areas to be served by the communal toilets may include public areas such markets and low-income squatters or blighted areas.

The possibility to construct on-site facilities is site specific. As thi- majority of squatters are located on government owned property, that is, along river be ks and shoreline it is unlikely that communal toilets, with on-site disposal will be technically feasible. In these locations communal toilets will only be feasible if there can be a direct discharge to a proposed sewer. The sizing of the facihty is dependent upon the depth to groundwater, the permeability of the ground and the availabilityand cost of land.

The communal toilets will be constructed in areas where, through public consultation, there is an established demand and willingness to pay for the service. The arrangements for construction and operation of communal toilets 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 to the local community the facility is serving through a leasing arrangement; (iii) Construction and operation contracted through a concession arrangement.

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

The different arrangements should be examined following consultation between the City and users, in order to implement the preferred option. Then following a monitoring period, the more successful operation can be repeated. A balance has to be sought between affordability to construct (the quality) and willingnessto pay. The facility has to be made 'attractive" to the users and provide the service they require and, therefore, in selecting the option the following aspects should be considered:

* Site - central location to proposed users (designed to serve 250 users, or approximately 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.

l uu,flc'n.,tLi/ IXX4.?%sesstnlentRrI?L)l (CgLluvan 4k ()Oro ( i2 * 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 (P million) Beneficiaes On site facilities 62.90 50,300 CommunalToilets - Construction 6.59 9,000 - Land 3.60 TotalSanitation 73.09

Construction and land costs include 5% physical contingencies. The cost of engineering has not been considered on the assumption that the design and construction supervision can be handled directly by the City's concerned department due to the simplicityof the structures.

B. Operation and Maintenance Cost

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

Implementation Schedule

It has been assumed that the 6.882 on-site sanitation facilities and 36 communal toilets will be constructed during the five-year project period. Therefore, an average of 1,372 on-site facilities and 7-8 communal toilets would be constructed annually including the required time for conisultationand desinn.

Thnvirimrenlil .l.vNsme*nMf7)t Reporl. (Cgani tie ()r) (C1 29 Section III - Overall Sewerage Scheme

Classification

Sewerage refers to the collection and treatment, at a single location, of water-borne waste (sewage) discharged from individualproperties. 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, or sewers, to a wastewater treatment plant (WWTP), where the sewage is treated to produce an effluent that can be discharged to a receiving water body (river, sea, etc.). Sewage flows along the sewers by gravity, that is, the pipes are laid at a slope or gradient which is sufficient to ensure that the sewage will flow without causing blockage.

To minimize depth of excavationi.sewers, genierally,should follow the slope of the ground, that is, they go downhill. If the depth of a sewer becomes too deep (greater than 5 m) a pump station would be used to elevate the sewage, either to another sewer or to the WWTP. The sewers are divided into twvoclassifications:

* collector sewers - sewers connecting an individualproperty or group of several properties 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 "'mainroads", with the collector sewers acting as the "feeder roads".

Selection of Service Areas

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

* increasing population density and limitationsfor on-site sanitation: * presence of large commercial establislhments.and institutions such as schools. colleges, government o&,ivs and hiospitals: * health hazard and risk posed by the increasing wastewater flow on the city's drainage system: * higzhlevel of urban development with a population density capable of paying wastewater service charge; * biological degradation of rivers and Laguna de Bay which havc been found to be polluted with human excreta and positive for fecal coliforms. Disposal of septic tanks effluent to the drainage sister contributes to aggravate this pollution problem.

; nvi,nrn,iLM17101 IN%sOXt17t l?el)pn: ( a,i,'ag an7 01-(l (Ci 30 The Poblacion area is considered a priority area for the following factors:

* increasing population density and limitations for on-site sanitation; a presence of large commercial establishments, and institutions such as schools, colleges, government offices and hospitals; * health hazard and risk posed by the increasing wastewater flow on the city's drainage system; * high level of urban development with a population density capable of paying wastewater service charge; * biological degradation of rivers which have been found to be polluted with human excreta and positive for fecal coliforms. Disposal of septic tanks effluent to the drainage system contributes to aggravate this pollution problem.

The identified Initial Service Area (ISA) comprises a total of 53 barangays with an area of 9,808 ha and a total population of about 289,360 in 1995 projected to increase to about 531,570 in 2015 (see Appendix 11.I - Table 11.1.2). The ISA is bounded on the north by the Macajalar Bay, on the west by Barangays Bulua and Canitoan, on the east by Barangay Lapasan and Macajalar Bay, and on the south by Barangay Macasandig.

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 (Zone I of the Feasibility Report) which can provide the highest impact in terms of improvements to the environment as well as to the social and economnicconditions of the City. The areas included are: * the Poblacion's -centerwhere commercial and institutional establshments, such as, hospitals, and offices are located; • the barangays that are highly urbanized and densely populated adjacent to the Poblacion.

The Stage I Service Area has a land area of 192 ha with a population of about 27,830 in 1995 projected to increase to about 30.080 in the year 2001 (starting of operations) and to about 34.270 in 2015. Details on population are presented in Appendix Il. 1.

The population which will connect to the system has been estimated at 60% of the service area population. At the starting of operations, in the year 2001, the system will serve aoout 18.050 users, with 3.002 connections, projected to increase to about 20,570 users in 2015 with 3.422 connections.

The figure that 60% of service area population will connect to the system is based on the assumption that 85% of the population (year 2015) would be connected to the COCWD water supply system, and of those, 70% would be connected to the sewer. Expansion of the system would be dependenit upoInthe number of sewer connlectionsand the sewage

',1rnMmO11tU/. INSeASfl7t Report: ( galvan de ()O ( 'it' 31 flow from each connection. The capacity of WWTPs and pump stations would have to be increased once the 60% design flow is reached. This may or may not correlate to the actual connected population.

Potential Treatment Plant Sites

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

* take advantage on the availabilityof small parcel of lands with minimal number of settlers, if not totally vacant; * divide the system into smaller catchment areas considering the potential treatment plant sites, as well as topography and drainage characteristics.

In consultation with the City the following potential sites were identified: * Consolacion * Nazareth

The presently identified Consolacion site is located, along the Cagayan River, downstream of the Consolacion site previously identified in the Feasibility Report. The previous site is a reclamation area and, therefore, concerns were raised as to the suitabilityof the site and the cost of reclamation.

The land value quoted by the City for the new Consolacion and Nazareth sites is P3.000/sq.m and this land value has been used for the cost estimates.

Treatment Process Options

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

* anaerobic/facultative lagooiis; * modified lagoons; * mechanical activated sludge.

1. Anaerobic/Faculta:ive Lagoons

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

Anaerobic Pond - used primarily as a pre-treatment process for high-strength wastewater. They may be used for septage, night-soil, and high-strength domestic sewage. The advantages of using anaerobic ponds are that they

/nr7lwir*mcl .-lx nc.fle(sI?eJ)(port. (caga an ile Or() ('Uv1 32 effectively decrease the land requirements of subsequent facultative and aerobic ponds and the accumulation of large sludge banks in subsequent treatment 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 to the pond bottom. Over a period of time, a sludge layer develops that is void of dissolved oxygen. The bottom sludge decomposes anaerobically. Above the 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 is aerobic at all times due to oxygen supplied primarily by photosynthesis and wind action. Facultative pond effluent would have to be further treated for the removal of suspended solids before discharging to the receiving water to meet the effluent discharge standards.

The Feasibility Report selected this process for the initial septage treatment facility and for identifying the land area requirement for the deferred sewage treatment plant.

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 1.5 to 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, deptlh 1.5 m: side slopes 3: 1; rectangular shape. with length 2 x widtlh.

- 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 to be 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 (overall BOD removals estimated at 90%/6).

An 1,ru,7nzJ,?u/ 1x.1exlni. n.is'.ssEsZ'rlC ii,2}'!,,IZ.,l ( ... (,.,,(), ... ,, ( ,t D;3 While providing a treatment system that has a reduced land take (compared to a complete facultative lagoon system) and utilizes no mechanical equipment, there are concerns as to its ability to operate satisfactorily. Concerns raised include:

* Anaerobic Pond

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

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

- Removal of sludge required. Frequently depends on severity of the solids - B OD loading and nature of composition (sludge disposal was not addressed in the FeasibilityReport).

- 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 of temperature variations or wind and wave action. Temperature not as much of a factor in areas of low fluctuations.

- Anaerobic and aerobic processes tend to be in state of flux and vacillate between 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 an acceptable 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 construction practices to simplifyand reduce construction costs. The system is designed to optimize natural biological processes in order to improve treatment effectiveness and reduce power requirements and chemical additives while limiting land requirements. The design concept is to minimize sludge production. eliminate dailv 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 system treating municipal, agricultural and industrial wastewater. The reactors may be relatively 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 blanket

1,i'nvirmnmewtal ssvesmesnt Report. (C'qvana ()ru ('it\ 34 suspended over the deepened zone and an overlying aerobic zone comprised of aerobic bacteria, algae and a saturated oxygen media provided by a combination of algae and surface aeration.

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

The primary facultative pond with an aerobic surface and extremely anoxic internal cells for sedimentation and fermentation is the initial treatment element in the series treatment train. In this element raw or screened wastewater is introduced directly into the bottom of a relatively deep internal cell(s) where settleable solids are digested anaerobically. The overflow velocity in the cell is maintained at a low rate such that the suspended solids and BOD5 removal efficiency approach 100 and 65%, respectively. These rates are maintained at less than the settling velocities of helminth ova and parasite cysts. Consequently, the majority of these organisms remain in the cells and are permanently removed from the effluent. Settled solids in the anoxic cells ferment to the extent that only ash remains due to the large cell volume. Hence, sludge removal is seldom required.

The rising gases and upwelling of wastewater from the anaerobic cell pass through a thick anaerobic sludge blanket, that is formed as a result of the fermentation process, and remains suspended above the anaerobic cell. The hydraulic detention time in this anaerobic zone and corresponding rise velocity is variable by design and nature of the waste stream.

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

Soluble wastewater components undergo aerobic oxidation and further degradation in this zone. Thus. two normally seeminglyincompatible biological wastewater treatment processes can be made to coexist uninterrupted in the same earthwork reactor.

The horizontal velocitv of the circular motion is reduced over secondary deepened zones as a result of the added volume, allowing the aerobic solids to settle by gravity into a secondary digester for further decomposition and stabilization. A sludge blanket is formed in this area and remains suspended over this zone. The surface aerobic circulation pattern reliably controls odors.

EMtlronnmenial ..lsseswysent Ie?tuwl (Caga\van c1e Orn ('itl DO The further function of the isolated reducing anaerobic zones includes denitrification, precipitation of heavy metals and fractionization of toxic compounds to a less toxic state.

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

Sludge in the anaerobic cell(s) remains for an extended period continuously undergoing organic decomposition. This may take place over a 20 - 30 year period. One system in operation has not been desludged in thirty years. Recent testing 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 that the size and number of internal cells differ depending on the design and type of waste treated. Recirculation of the highly oxygenated water from this second pond is introduced to the surface of the primary facultative pond to provide an oxygen rich overlay of this pond. This oxygen quickly acts to oxidize reduced gases emerging 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 the incoming waste stream. These algae tend to settle in the primary pond. Thus a significant fraction of heavy metals can be removed from the primary pond effluent in the form of reduced metal sulfides or as attached to algae solids.

The modified lagoon system is proposed and an appropriate treatment method for a variety of wastewater treatment applications. These include normal discharges as well as variable hydraulic flows and organic loadings, particularly where there may be limited industrial pretreatment and source control of high strength unbalanced wastes and toxic and heavy metal discharges. The design elements provide for flow equalization, buffer capacity and recirculation capabilitiesto achieve secondary and advanced treatment for municipalities. agriculture and industry.

The design criteria for the process is as follows: * Basic Design: Three ponds in series to meet coliform requirement < 1.000/lOOmi - Primarv Facultative with anaerobic cells - Secondarv Facultative with following anaerobic cell

- Tertiary - maturation pond

h.' lsf Environmentl . Lvssessmeiitu9l Reporl: C gqvasle Oi-o (1[CifY 306 * 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 pond series with 5,2,2,1 days detention to achieve higher percenitage coliform removal.

* Pond design depths: Primary and Secondary - anaerobic sections - 4 m - aerobic sections - 3.5 m Tertiarv Pond - 3.5 mn * Supplemental aeration included for circulation and BOD requirements because of reduced area requirements. * Recirculation from Secondary pond to Primary included for media reinforcement 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 and would 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 associated control building/laboratory, pump stations and maintenance buildings, partial standby power generation capability would be required.

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

h,.Znvironni7en7t7l. kvesstn.swent Reporit: CaTgqvan ti ot-o0O('tlv 3 4. Recommended Treatment Process

A previous feasibility report (CDM. 1994) selected the anaerobic/facultativeponds for the initial septage treatment facility and for identifvingthe land area requirement for the deferred sewage treatment plant. However, the process has raised concerns as to its abilityto operate satisfactorily without upset. In fact, with the reduced detention times, it is unlikely that any reduction in fecal coliform will be achieved, which is a major requirement for the protection of the rivers and the 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 and inhabitants should be provided to reduce the level of odor reaching the nearby inhabitants.

On the other hand, based on international experience, the adoption of mechanical activated sludge plants, although requiring smaller land area, will be more expensive than any lagoon system in terms of capital as well as operation and maintenance costs. Furthermore, skilled staff is required to operate the plant. Therefore, the use of a mecilaniicaltreatmenit plant is considered not a viable option.

The modified lagoon system utilizes mechanical aerators and recirculation pumps and, thus, has higher O&M costs compared to anaerobic/facultative lagoons. However, the modified lagoon system has the abilityto treat variable strength flow; minimize odor production; meet effluent quality criteria, including fecal coliform reduction; and has a minimal sludge production rate. These features allow the modified lagoon system to address the concems related to the anaerobic/facultativeponds

As a result of the above analysis.taking into account the quality of effluent after treatment, the availabilityof land as well as capital and operating costs, the modified lagoon system is recommended for all the WWTP to be included in the alternative schemes identified for Cagayan de Oro.

Comparison of Alternatives

The alternative schemes identified are briefly described as follows: Alternative Scheme Description I The system will drain the sewage of the whole area to the WWTP (modified lagoon system) located at Consolacion site. 2 The system is divided in two areas: the sewage flow of Area North will drain to the WWTP (modified lagoon svstem) located at the Consolacion site; while the sewage flow of Area Southlwill drain to the WWTP (modified lagooni svstem) located at the Nazareth site.

Lni-oonnional7 lss:ssmen(.'I. A'puJrr.-(Cqi'atvn dc (t)rn ( f/ 38 1. Design Assessment of Alternatives

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

Alternative WWFP Connected Total Flow BOD Loading Schemes Location Population (cuamld) (kg/d) Consolacion 20,564 I - Sewage 4,113 823 - Septage 183 915 Total 4,296 1,738 Consolacion 16,519 - Sewage 3,304 661 - Septage 183 915 2 Total 3,487 1,576 Nazareth 4.045 - Sewage 809 162 - Septage Total I _809 162

Assumptions: - Flow 213 I/cap/d - BOD 40 glcap/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 the basis of costs derived from the Feasibility Report (DMJM. 1995) and other relevant studies and data gathered by the consultant. For further information, reference should be made to the Feasibility Report.

J:,ivirr,ntne,J71.-ISNL.'XXSmf Reporrt ('agaLan tie Oro (;ty 39 Comparison of the two alternatives is as follows:

(i) Capital Cost

Capital Cost of Alternatives Facility (P million)

______1 2 SEWERAGE I Collection 49.97 49.97 2.Property Connections 32.13 32.13 3. Transportation System 21.60 21.50

4. PumpingStation 2.50 _ 5 ForceMains 0.48

6.Punp Station (Land) 0.24 _ 7. WWTP 22.11 25.01 8 WWTP (Land) 120.00 150.00 9.WWTP (Resettlement) - Total 249.03 278.61 Notes: Capital costs include 5% physical contingencies plus 15%for engineering and training. At a cost per hectare of P261,625 (includes for contingencies, engineening, etc.) as developedfrom two study areas in Davao and Dagupan. Collection sewers proposed are "condominial ", that is, they are routed through private property to optimize the sewer length and minimize cost of connection to the transportation sewer. Property owners have to be consulted and agree to the condominial sewer design.

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

(ii) O&M Costs

The O&M costs will increase in relation to the number of connections. Annual O&M costs 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 year 2001 and 2015.

Alternatives Annual Cost 2001 Annual Cost 2015 (P million) (P million) 201 246 I 2 95 3.40

A1njronnwll .IssVe..meJn1RepOrt ('agaqan tle O1O (Citt 4Y (iii) Net Present Value

The capital and O&M costs have then been used to determine the net present value (NPV) of each alternative, at 15% discount rate. The result of the analysis is as follows:

NPV Alternatives (P million) 1 179.20 2 203.32

(iv) Conclusion

The above NPV shows that Alternative I is the most economic (by about 12% over the other) and, therefore, is recommended for implementation. The recommended alternative is for a collection and transportation sewer network, in the Poblacion area, discharging to a single WWTP located at the Consolacion site. The WWTP would use the modified lagoon treatment process and would treat both sewage and septage. The treated effluent would be discharged into the Cagayan River.

Section IV - Recommended Project Design for Cagayan de Oro City

Description and Components

The recommended plan will include the following components: (i) on-site and communal sanitation facilities; (ii) sewerage systems in Poblacion; (iii) maintenance equipment. tools and spare parts for the operation and maintenanlceof installed sewerage infrastructures; and (iv) institutional support.

Sanitation Facilities

The sanitation component will include the construction of about 6,882 facilities including VIP latrines. pour-flush toilets and other type of toilets with septic tanks/soakage pits as well as 36 communal toilets which will benefit about 9,000 residents in the city.

The on-site sanitation facilities include: "VIP latrine and pit" and "pour-flush toilet and septic tank". The demand for on-site facilities will. therefore, be established by public consultation concerning rented dwellings and owner occupied houses. Communal sanitation 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 between individual and communal facilities will be driven by technical feasibilityand demand by key stakeholders. and not by tenure status. However, in slum areas and squatter settlements, the demand will be ascertained not onlv fiom the tenanits. but also from land owners and from local government officialsrepresenting public interest. The communal toilets will be

1:flitr- )flmefltla .Zxxsexx,?en I?Reporr: ('agan e ()tiOn (tY 41 constructed in areas where, through public consultation, there is an established demand and willingnessto pay for the senrice.

Sewerage System

The sewerage systems will include: (i) house connections; (ii) feeder sewers for the collection of wastewater in neighborhoods, puroks and barangays; (iii) trunk sewers and pumping 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 ensure good 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 simplifiedand condominial sewers. Where condominial sewers are used, communities will be given a choice between location of the sewers in backyards and locating them in front of their properties. Simplified sewers will be used for trunk and main transportation sewers.

A modified lagoon system will be used for the treatment of both sewage and septage. Its principal unit is a deep vertically integrated pond with an anaerobic 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 Cagavan de Oro City. In the Poblacion. the Stage I sewerage system will cover a service area population. in 2015, of about 34,270 of which about 20,570 (or 60%) will be served.

The Stage I system proposes the construction of a sewer network that will discharge sewage to a single vertically integrated pond system designed to treat both sewage and septage. The treatment plant is located at the Consolacion site and the treated effluent will be discharged to the Cagayan River.

The system (see Figure 3.2) will include the following facilities: collection sewers covering an area of 192 ha: * transportation sewers with a total length of 7,210 meters and diameter from 150 to 400 mm; * one pump stations with a capacity of 955 cu.m/d and a land requirement of 81 sq.m; * a force main witlha length of 640 meters with diameter of 150 mm; * a WWTP with a capacity of 4,296 cu.m/d and a land requirement of 4.0 ha; * a total of 3,002 connections in the year 2001. The additional 420 connections up to the year 2015 will be constructed by the COCWD.

AUzli'r(Emfl'n/a1 .-Ixsw.cvmept l Cagor:(gqa m7anLie Oro (itY 42 Maintenance Equipment and Spares

Equipment will be provided to the Cagayan de Oro City Water District (COCWD) including vehicles, machinery and tools needed for proper operation and maintenance of the sewerage and pumping 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 the COCWD not only for operation and maintenance but also for construction of additional connections. It is envisaged that the cost of new connections will be paid up-front by the users at the moment they request to be connected to the system. This will surely constitute a constraint and mav restrain the users firombeing connected. To minimize this problem in the first one-two years of COCWD operation, it is proposed to include in the project the procurement of stored material (pipes, fittings, etc.) necessary for the connections. This would reduce the up-front amount required from the users and the cost of material could be charged monthly on the water bill by the COCWD.

Institutional Support

The project will include: (i) consulting services for detailed design, consultation of beneficiaries and construction supervision; and (ii) training of COCWD staff responsible for the 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 the training of staff for the operation and mainteniaince(O&M) of the sewerage systems and particularly of ponding systems. The consultant will have to prepare an O&M manual and train the operators on basic ponding treatment concepts as well as familiarity with the O&M manual. The training program should also include an overseas visit to a country where the adopted treatment method is already in operation.

Cost Estimates

Based on the estimates. the capital cost of the Cagayan de Oro City project has been estimated at P327.12 million (US$ 12.45 million) excluding price contingencies and interest during construction. The cost is composed by P43.58 million (USS1.66 million) of foreign component and P283.54 million (US$10.79 million) of local component. By including price contingencies and interest during construction. the total project cost is P459.22 million (US$17.48 million).

1kn1"I'irnntal .- Lv....s.ien 'rt: ( agclw tie ()Or (uIll 43 The project cost by component is as follows:

Component (P million) SANITATION Constructionof Facilities 69.49 Land 3.60 Price Contingencies 14.36 InterestDuring Construction 33.54 Total Sanitation 120.99 SEWERAGE Construction of Facilities 112.00 Land and Resettlement 120.24 Maintenance Equipment & Spares 5.00 hIstitutional Support 16.79 Price Contingencies 30.18 Interest During Construction 54.02 Total Sewerage 338.23

Total Investment 371.66 Total Interest DuringConstruction 87.56 TOTAL PROJECT COST 459.22

Section V - No Project Scenario

Chapter 2 has vividly described the worsening environ-mentaland health situation resulting from poor sanitation and uncontrolled discharge of sewage and wastewater. Though the proposed project will cover only a small portion of the population, the project is seen as an important and significant first step of a long term program to provide the City of Cagayan de Oro the sanitation and sewerage infrastructure it urgently requires. The project is anticipated to contribute to the gradual improvement of the city's environment and improvement of the conditions of its Cagayan River, its groundwater and Macajalar Bay.

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IOTII:g * ASS(( IA TI aS SEERGcA[ SoTE 4. ENVIRONMENTAL IMPACTS

Introduction

This chapterhas three sectLions.Section 1 describesthe beneficialimpacts of the project on the environment.Section I1 identifiesand evaluatesthe differentimpacts of the proposed project on the environment.Section m summarizedthe environmentalimpacts.

Section I - Beneficial Impacts of the Project The implementationof the sewerageand sanitationproject for Cagayande Oro is foreseen to result in positiveimpacts, namely:

0 Health and Environment Benefits

On the short term, it is expectedthat the implementationof the sanitationand sewerage projectfor the city of Cagayande Oro will improvethe publichealth conditionsespecially the target beneficiaries.The provisionof sanitarytoilet facilitiesis anticipatedto decrease the possibilityof humancontact with excreta whichleads to a reductionof water borne and sanitationrelated diseases. This healthbenefit is most significantnot onlybecause of the health implicationsbut also becausethe project willmostly be advantageousto low iiicomegroups whichcould not affordproper sanitationfacilities.

Project impactsinclude the improvementof water qualityparticularly of the Cagayan River and other water bodiescurrently observed to be contaminatedwith fecalcoliform due to wastewaterdischarged into them without treatment. The effect of the project on the river though will be long term and not immediatelike the healthimpacts. Furthermore,it shouldbe emphasizedthat parallelimprovements in solidwaste management.drainage and industrialpollution control will have to be implementedto enhanceenvironmental impacts, otherwise effects on water qualitybecome marginal at best. If the water qualityof CagayanRiver is improved,it is expectedthat to someextent, water qualitvat MacajalarBay particularlynear the mouth of the river will likewise improve.

En v'ironmn aiental.%ssesNen7t RJeport: (agavcaro Urff (ciotv7 Also a potential benefit is the protection from the risk of pollution, from septic tank overflows, of groundwater which is the main source for domestic water supply for many households in the city including the local water distiict.

* Increase in Productivity and Income

On the long terrmbasis, the reduction of the incidence of water borne and sanitation related diseases is foreseen to result to increased productivity of usually affected households. Since people become indisposed due to illness, the time lost is a potential for income generating activities. The associated benefits include reduction in medical expenses which increases the money available for otl -r household expenditures.

* Economic Growth and Opportunities

Cagayan de Oro is already an important growth and development center in Mindanao. With improved health and living conditions, the city becomes even more attractive for people to live in and to do business attracting local and likewise international investors interested to put up commercial and busmess ventures and establishments recognizing the advantages of having a clean and healthy environment. Consequently, there will be increasedjob opportuniti.s reducing the unemployment rate.

Duiing the implementationphase, the project is expected to generate employment not only during the actual construction of sanitation and sewerage facilities, but more so during operation, for example in desludging operations whereby private contractors will be encouraged to participate in the project which consequently would be expected to generate the corresponding employmentfor this new business venture.

An improved and cleaner environment likewise bring in local and foreign tourists alike thereby enhancing the city's abilityto benefit from activities and businesses generated by the tourist trade.

* IncreasedPropern Values and Commercial Attractiveness

The city's poblacion, the initial area to be served by the sewerage system, has a strong advantage in when it comes to property valuation and commercial attractiveness because it contains the Cagayan de Oro's central business district. Sewerage in the district would allow construction of high-rise office buildings, positively leveraging property values and tax collections. In addition, the central business district is the most visible area for potential investors. A conservative impact estimate suggests that a sewerage project could be self-financingin the central business district.

1:;fjHmr'flntal .-IveXeVnic',tR?epfwt: C(agaxcmLie ()Or Citl( 48 Section H - Project Implementation Impacts

As describedabove, the implementationof the projectis expectedto have beneficial impactsin the longternm However,the constructionand operationof the systemis bound to result in impactsthat requiremitigation. This sectionidentifies such impactsand assessesthe scale and magnitude.

Construction Phase

A. Air Qualitv

The implementationof the project willresult in occasional,marginal and acute increasein the ambientconcentration of suspendedparticulates in the vicinityof the project site. This can be attributedto land clearingand excavationactivities which expose soilto wind and vehiculartraffic over unpavedroad.

B. Water Quality

Excavationactivities in the project sites could also loosensoils and transport of these materialsto any surfacewaters will result in siltationor increasein turbidity.

Duringthe rainy season, surfacerunoff will tend to increasetotal suspendedsolids and is expectedto cause temporarystress at the dischargepoints, but the impactis localized. As soon as the vegetativecover of the site is re-establishedon open spaces,impact on the receivingbody of water causedby surfacerun-off willbe eliminated.

C. Noise

The noiseimpact duringthe constructionstage is expectedto be generallyminimal and willnot require any specialnoise abatementmeasure. The treatmentplant sites shallhave a setback awayfrom residentialclusters. which will definitelyprovide the necessarybuffer to reduce noiseimpact duringconstruction of the treatmentfacilities.

Duringthe pipe-laying,some noise will be temporarilvgenerated due to operationof heavy equipmentand from breakingconcrete pavement and sidewalks. In addition,some trafficcongestion may be expectedon duringpipelaying.

D. EcologicalEffects

As there are no rare, endemicspecies of flora and fauna in the project area, project implementationhar minimalimpact on the terrestrialand aquatic ecology. There will be clearingof trees duringactual constructionwhere unavoidablynecessary.

j 71z(at1cs1a/-lX>"^}IL7RZeport: (Cagqva tie ()so O'tY 49 Operation Phase

E. Air Quality

The operation of the wastewater treatment facility shall have minimal impact on the air quality of the area. Aside from the occasional odor nuisance, it is not projected to have adverse effect on the air quality. Odor production at the AIlPStreatment plants is controlled by the natural processes employed by the system 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 implementationof the project will be beneficialto the general environment of Cagayan de Oro and its surroundings. The current practice of discharging untreated domestic waste into nearby bodies of water would thus be reduced or eliminated. Diffusion effects -- the adoption of the modified lagoon system (or AIPS) treatment process should attain high rates of BOD, TSS, and coliform removals. Discharge to the receiving bodies of water should therefore pose no significantpollution risks. However, to further eliminate this risk, proper studies would be conducted on the mixing and dilution before locating the outfall. In the unlikely event that projected removal rates appear to be unattainable, the treatment system particularly the maturation ponds can be designed for larger capacities and/or longer detention times to further enhance removal efficiencies and thereby negate the risks of polluting receiving waters.

H. Socio-economic Aspects

The provision of sanitation facilities in Cagayan de Oro would undoubtedly benefit the general populace of these areas. The occurrence of epidemic-scale diseases as a result of unsanitarv conditions slhallbe minimized. This will make for a more healthy and productive population.

I. Sludge Disposal and Management

The modified lagoon treatment system is designed and actually performs so that solids at the 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 volume and its depth, and its reducing environment, settled solids ferment there to a point where only ash remains. Thus minimizingthe generation of bio-solids, hence sludge removal is seldom if ever required.

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

Ati:r(ronertral. %I,e%sovs-entRecpmri: (C'g,-vai dtie(re) (il .50 The oldest plant in operation treating domestic wastewater in the city of St. Helena in California, USA, has not had to remove bio-solids for nearly 30 years. (Recent testings of this system have indicated that sludge is well-digested and very stable.) Owing to its stability, the sludge/residue, if desludging does become due, can be disposed of, with arrangements with the municipality, at the municipality's sanitary landfill. Because of its relatively stable nature, desludged material could even be barged to the open sea for disposal say once in every 15, 20 or even 30 years.

Section III - Summary

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

During project implementation. mitigation measures will be incorporated to minimize, or if at all possible. eliminate adverse impacts. Moreover, measures to enhance existing environmental conditions in the project site shall be implemented to maintain the sustainability of the area. The implementation of the project will inevitably produce impacts. both adverse and beneficial. The mitigation actions are outlined in the next chapter.

[JIlTA c dcINih 4 dcc

1 nvireontoa Iu I/a.Isve.s.smetl Rep9<1rt ( 'cwgclan1 tie Oro (WYl

5. ENVIRONMENTAL MANAGEMENT PLAN

Section I - Mitigation Plan

Construction Phase

Potential Impact & Risks Mitigation Action

Air Pollution . Careful construction planning and work phasing, specifications and 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 for suspended particulates, odors and construction materials and equipment. fumes emissions - CO2 , 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-generati-ng wind and vehicular traffic will mounds/piles resulting from earthmoving activities and civil likely 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 Pollution and Soil Erosion * Provide temporary drainage and storage facilities for excavation soils, 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.

* Notse from operation of construc- * Erect temporary sound bamers around the work sites; avoid tion equipment would be about 70- simultaneous use of heavy equipment, limit dayttme work. l 0 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 construction 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 be Flowh located along secondary streets. * Scheduling and increasing input resources so that period of traffic disr uption in primary roads are reduced. * Coordinate with the local traffic management office and the PNP Traffic Management Command * Clear directional signs and barriers in case traffic rerouting is needed. . Public information campaign.

Anl zronnmeL'taI.Ii.xexsme'nt Report. ('agaQan cle (ro ( 'Y .52 Operation Phase Potential Impact & Risks Mitigation Action

* Environmental hazards due to * Carefully desigred post-construction maintenance, contimgency accidents 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 Cagayan River * Adequate plans for environmental rehabilitation, clean-up, near the center of the city as raw restoration, and disposition of temporary structures and facilities sewage will have to be dumped installed during the construction phase. directly. l

Water Pollution * Upgrade laboratory facilities of the Cagayan de Oro City Water District (COCWD) to be able to undertake wastewater analysis. . The effluent discharge may well * Following the bubble concept, wastewater discharged into the affect the condition of receiving Cagayan River shall, in the long-term, conform to the water bodies of water and the effluent quality standards established by the Department of Environment discharge point of the treatment and Natural Resources as set forth in DAO No. 34 and 35, plant may also be affected by tidal Revised Water Usage and Classification/Water Quality conditions (estuary). Standards and Revised Effluent Regulations of 1990. respectively. * A dispersion/dilution modeling study wil be conducted to prior to locating the outfall. Treated effluent discharge into the Rio Grande de Mindanao shall be timed based on tidal conditions. The adoption of the AIPS process for the treatment plants should result into attainment of effluent standards.

. Noise would be at about 65-85 . Establishment of buffer zones and noise zones. dBA, principally coming from septage trucks unloading at the treatment plant.

* Odors torganic and sulfur com- . Maintenance of greenbelt zones and vegetation. pounds mainly from the trucks a Provision of landscaped open spaces which will improve the unloading septage) aesthetics in the area by planting the green strips with appropriate plant or tree species.

Mana-zement and O&M of the System Institutional: * Management Contract with COCWD which has proven utility * Poor maintenance of pumps management and operations capacity. . User consultation at detailed engineering design stage to ensure * Low number of connections connection. * Sewerage surcharge should be sufficient to provide incentives for COCWD 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 COCWD 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 COCWD.

1JI11-01IM710i .a INA'OSSM07t HCj)(1T' ('g. a17 C/omU(Jro (' [I/ 53 Section II - Monitoring Plan

ConstructionPhase

Ambientair qualitymeasurements will be undertakennear constructionsites. Thiswill be mostlynear locationswhere sewernetwork is being laid and treatmentplant sites. When selectingsites due considerationwill be givento sensitivereceptors like schools,hospitals, houses etc. Total suspendedparticulates (TSP) will be measuredonce a fortnight,for 8 or 24 hours, over the constructionperiod.

Noise willmeasured at the same locationsas TSP. Leqand Lgovalues willbe measured and recorded.

OperationPhase

Receivingwater qualityis to be monitored by the DENR throughits RegionalOffice whichhas been periodicallymonitoring the status of the CagayanRiver and estuarine water quality. The PMOwill collectinformation on present conditions,observed changes in po,lutionloads etc. It is to be recognizedthat all the pollutionload will not be removed yet it is also expectedthat the proposed sewerageinfrastructure will greatlyreduce the problem. Oncethe plan becomesoperational the TreatmentPlant Operator,vis-a-vis the Cagayan de Oro City Water Districtwould have to set-upa laboratoryand institutea monitoring programto measurethe effluentdischarge. Dailyrepresentative values of PH, 5-day BOD,COD, Total Nitrogenand Total Phosphoruswil be measuredduring the start-up period. Once the plant operationsstabilize, weekly measurements (24-hourly basis) will be taken.

Quarterlyreports showingthe trends of effluentdischarge and receivingwater qualitywill be reported to the PMO and DENR RegionalOffice.

EM-Ironmem1tali AIsfsessent Report. ( o,savat tie On ()( n 54 Section m -Implementing Arrangements

The WDDP-PMU, with the assistance of LWJUA-CPSOand consultants, would monitor compliance with the ECC and carry out the requisite data collection. Monitoring results would be submitted to DENR/EMB and the World Bank periodically. While responsibility for the various mitigation activities have been identified, the WDDP-PM[ shall ensure that the requirements are complied with. In addition, feedback from communities, city officials, NGOs, etc. will be proactively sought through the city public affairs programs, regular monthly meetings of barangay captains and other methods.

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

Summary of Responsibilities and Timetable for the Monitoring Plan

Activity Responsibility Start Completion SecureECC clearance from DENR. CPSO-LWUA Decaber 1996 September1997

Collect reference ambient air paranMdersarouid the City PMU. with DENR Septntber 1997 Jtme 1998 prciosed treatment plant sites at project cities regional office

Ensure that the bid documents include provisims for niti- PMO January 1998 August 1999 gatiou wmderthe responsibilitv of the catractor: review citractors work plans to ensure conpliance with en- virtmmeatal mitigation plan provisiims.

Train operators on O&M practice & handting ernergencv PMO and CPSO-LWIJA Januarv 1999 June 2000 situationis

Assess and upgrade the laboratory facilities of the Project City PMtJ and local March 1998 June 2000 Cagayan de Oro City Water Distnct. Water Disinat

Conductuser cxisultatims and information campaign. Project City PMU. with Januarv 1998 June 2000 assirtance of NGO.

Mo|utor and report i conuplance. PM( Bi-anmual basis Bi-annual basis

L4- IIt ,

f ,iirr,mminu7a/.-l esx,nwi I?!'por 1- ( Cal,t a1/kni.' (), ftp. 55 Appendices

1. Bibliography

2. Climatological Normals 1961-1995from the PAGASA Station in Cagayande Oro

3. Typical Noise Emissions of Construction Equipment

4. Expected Noise Levels at Various Distances from Construction Equipment

5. Environmental Quality Standards For Noise Maximum Allowable Noise Levels

6. The Advanced Integrated Pond System (AIPS) of Wastewater Treatment

Appendix I BIBLIOGRAPHY

C. Lotti & Associati, 1996, Updating Feasibility Reports for Sanitation Investments in Five Cities, Final Report, Vol. 2, Cagayan de Oro, November

C. Lotti & Associati, 1996. Updating Feasibility Reports for Sanitation Investments in Five Cities, Final Report, Vol. 1, Main Report, November

DMJM International 1995, First Stage Priority Projects for Sanitation and Sewerage: Cagayan de Oro City, Philippines, Final Report, December

Louis Burger International Inc., 1992, Wastewater Collection, Treatment and Disposal System, Cagayan de Oro, Misamis Oriental, Volumes I and IL March

Environmentally Sustainable Development (ESD) Vice Presidency, World Bank, 1994, Water Supply, 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 to Pay for Improved Sanitation Services in Davao, Philippines, July

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

Yniiguez,Cesar, 1996, Urban Sanitation User Demand Study: Technical Consultant's Report, May

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

Oswald. W. J., 1990, Advanced Integrated Wastewater Pond Systems. 1990 ASCE Convention 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 the 21st Century, (Hand-out) I Appendix 2 CLIMVIATOLOGICAL NORMALS (1961-1995)

Station 748 - Cagay'ande Oro Cit% Latitude 0("29'N Longitude 124"3X'E Elcvation 6.0nmcters

Amt.of No. of Tem erature ("C) RH MSL Wind Cloud Days w/ Days w/ lontl RZainrfall Rainy Max Min Mean Dry Wet Dew Vapor ( Press. Speed Dir. Cover Thunder Light- M onth Rainf(Rim) Days _MI_ax Bulb Bulb Point (mbs) (mbs) Speed Di. (octa) storin ning J aruarv 97.3 I 30.7 220 26.4 26.1 23.8 22.9 27.9 83 1,0mb I N 5 s nin

FJbruar- 965.1 8 31.0 21.9 26.4 26.3 23.8 22.9 27.7 8! 1,010.2 _ N 5 _ = Mruarch 47.0 7 31.9 22.2 27.1 27.1 24.1 22.9 27.9 78 1,010.0 I N 5 2 2 April 37.0 5 33.0 23.0 28.0 28.1 24.7 23.0 28.8 76 1,009.1 I N 4 4 5 MAi\ 88.2 It 33.6 23. 8 28.7 28.6 25.3 23.5 30,0 77 1,008A4 _ N 4 4 5I June 209.2 1(8 32.9 23.4 28.2 27.8 25.1 24.2 30.0 80 1,008.6 1 N 6 13 12 Jukl 211.4 18 32.7 23.0 27.9 27.5 24.7 24.2 29.2 79 1,008.6 1 N 6 13 11 Aulgst 207.6 17 33.0 23.1 28.1 27.6 24.7 23.7 29.1 79 1,008.7 1 SW 6 10 10 September 207.4 17 32.8 23.1 27.9 27.4 24.7 23.7 29.2 80 1,008.9 1 N 6 II0 10 October 187.0 16 32.5 23.0 27.8 27.4 24.7 23.7 29.2 80 1,008.9 1 SW 6 I.I 13 November 1249 12 32.2 22.8 27.5 27.2 24.6 23.7 29.1 81 1,008.8 1 SW 5 6 10 Deccmber 94.5 11 31.3 22.5 26.9 26.7 24.3 23.4 28.7 82 1,009.3 I N 5 3 5 Annual 1,576.5 149 32.3 22.8 27.6 27.3 24.5 23.5 28.9 80 1,009.1 1 N 5 84 92 Source:PA GASA I Appendix 3 TYPICAL NOISE EMISSIONS OF CONSTRUCTION EQUIPMENT

Typical Sound Pressure Levels Equipment at 15 m from Source [in dB (A)] Air Compressor 75-87 Backhoe 71-92 Compactor 72 Concrete Mixer 75-88 Concrete Pump 82 Cranes 76-88 Front Load 72-81 Generator 72-82 Grader 80-93 Jack Hammer 81-97 Paver 87-88 Pile Driver 95-105 Pumps 70-90 Tractors. Bulldozers 78-95 Trucks 83-93 Vibrator 68-81 I I Appendix 4 EXPECTED NOISE LEVELS AT VARIOUS DISTANCES FROM CONSTRUCTION EQUIPMENT [in dB (A)]

Equipment 30 60 120 240 meters meters meters meters Air Compressor 69-81 63-75 57-69 51-63 Backhoe 65-87 59-81 53-75 47-69 Compactor 66 60 54 48 Concrete Mixer 69-82 63-76 57-70 51-64 Concrete Pump 76 70 64 58 Cranes 70-80 64-74 58-68 52-62 Front Loader 66-75 60-69 54-63 48-57 Generator 66-76 60-70 54-64 48-58 Grader 74-87 68-81 62-75 56-69 Jack Hammer 75-91 69-85 63-79 57-73 Paver 81-82 75-76 69-70 63-64 Pile Driver 89-99 83-93 77-87 71-81 Pumps 64-84 56-78 50-72 44-66 Tractors, Bulldozers 72-89 66-83 60-77 54-74 Trucks 77-87 71-81 65-75 59-69 Vibrator 62-75 56-69 50-63 44-57

Appendix 5 ENVIRONMENTAL QUALITY STANDARDS FOR NOISE MAXIMUM 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: Morming 5:00 AM - 9:00 AM Daytime 9:00 AM - 6:00 PM Evening 6:00 PM - 10:00 PM Nightine 10:00 PM - 5:00 AM

Appendix 6 THE ADVANCED INTEGRATED POND SYSTEM (AUpS)' of WASTEWATER TREATMENT

Preface: The Sewerage and Sanitation Component of the World Bank-assisted Water District Development Project has proposed the adoption of the modified lagoon system vis-a-vis the Advanced Integrated Pond System (AIPS) as the processfor treating collected wastewater (and septage). The following describes the technology and benefits of the aforesaid treatment system.

The ALPSis an integrated, multi-stage biologicalreactor system treating wastewater. The system utilizes compacted earthen construction to reduce costs. The system optimizes natural biological processes to reduce power requirements and need for chemical additives. The concept is to minimize bio-solids production rather than to maximize aeration solids resulting into minimalpower requirements and solids management.

AIPS consists of a series of at least four ponds, each designed to best perform one or more of the basic treatment processes. First is the primary biologicalreactor or a facultative pond with an aerobic surface and extremely anoxic internal pit for sedimentation and fermentation. The pond reactor has three discrete and isolated biological zones integrated into a single unit: a deep anaerobic pit at the bottom, a sludge blanket suspended within the deep pit, and an overlyingaerobic comprised of aerobic bacteria and algae oxygenated by photosynthesis, supplementedby horizontal mechanical aerators when needed. Anaerobic microbes in the pit are protected by surrounding walls or berms from the intrusion of cold surface water containing dissolved oxygen. Raw sewage is introduced directly into the pits where sedimentation and methane fermentation occur. Overflow velocity in the pits is maintained so low that suspended solids removal approaches 100% and biochemical oxygen demand (BOD) removal approaches 70%. The overflow velocities of one to two meters per day are less than the settling velocities of helminth ova and parasite cysts so most of these remain in the pit and consequently are permanently 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 reducing environment, settled solids ferment there to a point where only ash remains. Thus minimizingthe 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 in California, 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 oxygen from water by photosynthesis. Algae produced are highly settieable and after

Oswald.W. J., AdvancedIntegrated Wastewater Pond Systems. 1990 ASCE Proceedings,Am. Soc. of Civil Engineers. New York

AppendL {6 7h1 A-ldvunued Integd ated Pond Sxstem(.4lPS) ol'fasrewater 7reatment I sedimentation,the remaining water has a BOD that is generally less than 20 mg,L Recirculation of algae bearing water from the High Rate Pond to the Facultative pond provides an oxygen-rich cap on the facultativepond. This oxygen quickly oxidizes reduced gases emerging from the fermentation pit thus mitigating odors.

The third pond provides Corsedimentation of algae. Algae which settle tend to hibernate and thus do not immediatelydecompose and produce nuisance.

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

Performance: Following algal removal, the degree of pollutant removal in the AIPS is equivalent to that of mechanical secondary plants but as is to be emphasized at a much lower capital and operation & maintenancecosts. The treatment action of the AIPS is very similar to and realizes the advantages of an upflow anaerobic sludge blanket (UASB) reactor. The AIPS however does not inherit the rigorous operation and maintenance problems 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, in California, USA. The St. Helena system has been recognized as the Plant of the Year by the California Water Pollution Control Association for 5 MGD plants in 1994 and was likewise accorded by the California Energy Commissionthe 'Energy Efficiency Showcase Award" also in 1994.

T-heSt. 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 BOD of 290 mg/l and TSS of 263 mg/l were treated to 24 mg/l BOD (92% removal) and 34 mg/l TSS (87% removal), respectively. A treatment plant in Hollister, California, USA, with capacity of 2 MGD, exhibited similarremoval efficiency,reducing an influent BOD of 194 mg/I to a mere 7 mg/l after treatment.

Performance of AlPS 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%

Lee.E.. "Ponding SystemsTreat WastewaterInexpensively", USEPA Small Flows, Oaober, 1990

Appendix 6. TIhe.-fdanced Integrated Pnid vs;!:temI(.41PJof if astetater Treatment 2 On sludge management, the earthwork digesters (fermentation pits in the facultative ponds) can be made large to permit complete digestion and thus reduces sludge generation to the extent that sludge handling is eliminatedfor many years. The St. Helena plant in 27 years of continuous operation, accumulated less than I meter of residue or just 3 centimeters per year! Thus daily or frequent sludge removal is eliminatedthus attaining cost and energy savings. The Hollister plant also showed the same very low rate of accumulationin 12 years of operation.

Because the sludge undergoes fill fermentation, the sludge or residue resulting from the process is relatively inert and stable, and the volume is small. Disposal then should not be a major operation problem.

In terms of costs, Oswald compares the cost of a conventionaltreatment of S 50 to $700 per cu. m. (1990) to that of the AIPS which would cost less than $5 per cu. n. (1990), 100 times cheaper.

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

* Efficient organic pollution reduction and nutrient removal comparable if not better to secondary and tertiary treatment. * Energy efficient -- the design provides for reduces oxygen requirements on the front end * Less construction cost, as compared to AIPS: * 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 the ponds. In Hollister (CA, USA), the treatment plant is practically within "sniffing distance" of a golf course and residences in the area. * No daily sludge handling. St. Helena's Treatment Plant has not removed sludge in 30 years of continuous operation. * Pond buffer capacity enables the system to handle effectivelyvariable organic and hydraulic shock loads.

Appendixx6 7he. I3 ancel int.grated PondS wm,.-1IIXNof astewater 7reatm2nt S Selected Bibliography:

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

Oswald, W. J., Advanced Integrated Wastewater Pond Systems, 1990 ASCE Convention Proceedings, Am. Soc. of CivilEngineers, New York, 1990

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

* Further relevant info nation and reference materials on the AIPS are attached for reference.

>lppendtx6. T he -Idvuancecl Integrated Pond Svstem(.-IIPS) oMff astewvater Treatment 4 ADVANCEDINTEGRATED POND SYSTEM (AIPS)'

Natual,Biological Wastewater Treatrnent for Municipalities,Agriculture and Industiy

r g F a - X - -~~~~~~~~ ~

y noyva;veand Alternative, EnviroAnmentalySound and Low Cost Solutions For WastewaterTreatment Into the 21st Century

1340 Arnold l)rive, Suile 1 10 Martinez, tCA 94553 510-228-5SOI Fxv 51U-228-5804 I SOA, Inc. Martinec

AIPS Ihighlights

I'ficient pollution control EftJictiveorganic reductionand nutrientremoval for secondaryand tertiarytreatment.

Energy Efriciency with AlPS The initegrated, multi-stage anaerobic and aerobic reactor design reduces oxygen requirements (atndlenergy requirements) on thefront end of the svstem. St. Helena wastesliatervs treatment plant wvas awarded the California Energy Commission Efficiency Showv Case. 4 ivard in 1994 anid 1994 Plant of the Year Award by Caliornia Water Pollution Control AssoCiLJiO*L

Construction Cost Savings Oxidation Ditch 3.5 times more expensive than AIPS Trickling Filters 4 times more expensive than AIPS Activated .Sldge 4.5 times expensive tian AIPS Stlabilization J ond 1.4 times more expensive than AIPS

Operating Cost Savings Oxidation Ditch 3 times more expensive than AIPS 7r-ickling Filters 3 times more expensive than AIPS .Ictiva ted Sludge 3.5 times more expensive than AIPS Stabilization Ponud 1.3 times more expensive than AIPS

Virltally No odors OJdors are controlled naturally. Wuiery Treatment Plant is within 300feet of a convalescent hosphial in tie City of St. Helena, California.

No daily 1)io-solidsbandlng St. Hleletas OfWW has not removedsludge in 30years ofcontinuots operation;for industrial plants sludtge removal every 7-10years. depending on waste characterittics.

*PIondbuiker capacity to accommodate variable organic and hydraulic shuck loads JTin erv organic variability rangesfrom 100 to 20,000 mg;4 of BOD in one week.

A*dvanicedl Water Treatment Achievable with AIPS Nuitrient removal.-Denitrrication in anaerobic zone and algal uptake in aero1ic zone. P110hoV[1o0 oxidizes in the aerobic zone, assimilated with algae, naturalli' co-precipitated, and 1ien.settled by gravity.

* otential for Enhanced Habitat for Wildlife & Recreational Benefits Naural integration with constructed wetlands and habitat restoration. Lanpitcape pionid c rzribu!e aesthetic value and can provide recreational use.

Re*tducedl Fiscal Impact on Ratepayers lesi cot to ratepayer due to reduced life cycle costs because of lowver ConStimt tion costs .4NI) operalion & maintenance costs and long term replacement.

Martin-- St') 2'S-Kgnt Fax: 510-228-584 1 ., IGC 0 j,; 0 M!1aruiia, CA

All'S' 'echnology t --

All'S utilizesconipacted earthen constructionpractices to reduce constructioncosts. The systemi optimizesnaltiu-al biological processes to reduoepower requirementsand need for cheinicaladditives. The designconcept is to minimizebio-solids productior rather than to maximizeacration soiids and as a resilltminimize power requirementsand *olidsmanagement. '

All'S is an iniegraledl,multi-stage biological reactor system treatingmunicipal, agricultural and in(dustrialwastewater. The reactorsare relativelydeep and constucted as an opensurrace pond of conilactedearth. The biologicalreactor has three discreteand isolated biological zones integrated into a) a'singleunit: deep anaerobic pit(s) at the bottomof the reactor,a sludgeblanket suspended within the deelppit, and an overlyingaerobic zone comprsedof aerobicbacteria and algae and oxygenatedby photosynthesis,supplemented by horizontalmechnical aerators when needed.

Inniost cases, thc primary reactoris followedbya second reactoroperating in series, witli thecapability to itcir-culate,dependinig on site specificconditions. Recirculation provides flexibilityand sliock aborl)tionabilities for variablehydraulic or organicloadings, or wherethere is thc potentialfor toxic Spikes*.

The iniluieiitvastewater enters the deepanaerobic pit at the bottomof the reactorwhere setlable solids aredeposited arouid theinlet and whereacid fennentationand methane generation occurs. The rising gases and up-wellingof wastewaterflow throughthe thick anaerobicsludge blanket that is fonned withinthe deep pit. T'heoverlying aerobic zone is compnrsedof aerobicbacteria and algae and kept oxygeiialetby borizoittalsurface aerators and photosynthesis. The aerobiczone reliablycontrols o(lors a.ndsoluble wastewater components undergo aerobic oxidation and fiutherdegradation. 'lie horizontal aeratorsalso cicate a ciircularmotion over the wholesurface area; the bacteriaand algae circilate over the farend of the reactorwhere a seconddeep anacrobicpit is locatedwThe horizontalvelocity of the reactoris redticed while circulating over the secondpit and the aerationsolids are settlei by gravityinto this pit wherethe solidsare decomposedand stabilizBd.''

Solids at the bottoin of the deep anaerobic pits remains for very long periods of time, continiously deconiposing. 'hits. biosolids minimization is accomplished. The oldest plant in operatioin,treating domiestic w;tstewater, has not had to remove biosolids for nearly 30 years. Seasonal tuinover ol the l poncisis preventedby isolation of the deep anaerobic pits. AlPS's designfeatuires and cell geometry maituini the integrity of the system thereby suppressing turnovers.

A PI is ;1ppiolria te f'orwastewater applications for nornal flowsituations as well as where there arc variabIeliydi auilic I lows and organicloadings, particularly where there may be limitedindustrial pre- t-eatneni an, souircecontrol of toxic contaminants and heavy metals. AIPS desiginelenienis proviide flowiahiiatioiu, buff'ercapacity and recirculationcapabilities to achieve secondaiyand advanced treaitnitnt for nitoticipahities, agriculture and industry.

Aafl:in,C7:51t-'28-5X4)1 Fax: 51t-228-5204 2 Inc. blartinczCA

AIPS Technology

AIPSutilizes compacted carthen construction practics to reduce constructioncosts. The system opbimizesnatural biological processes to reducepower requirements and need for chemicaladdilives. The designconcept is to minimizebio-solids production rather than to maximizeaeration solids and as a resultminimize power requirements and solidsmanagement

AIPS is an integrated,multi-stage biologic I reactor system treatingmunicipal, agricultural and industrialwastewater. The reactorsare reia vely deep and constructedas an opensurface pond of compactedearh. The biologicalreactor has threediscrete and isolatedbiological zones integratedinto a'singleunit deepanaerobic pit(s) at the bottomof the reactor,a sludgeblanket suspendid within the deep pit, and an overlyingaerobic zone comprisedof aerobicbacteria and algae and oxygenatedby photosynthesis,supplemented by horizontalmechnical acrators when needed.

In mostcases, the primaryreactor is followedby a secondreactor operating in series,wilh the capability to recirculate,depend(ling on site specificconditions. Recirculation provides flexibilityand shock absorptionabilities for variablehydraulic or organicloadings, or wherethere is the potentialfor toxic spik%es.

Thlieinfluent vastewater enters the deepanaembic pit at the bottomof the reactorwhere settlable solids aredeposited around the inlet and where acid fermentationand methanegeneration occurs. The rising gases and up-wellingof wastewaterflow throughthe thick anaerobicsludge blanket that is formed within the deep pit. The overlyingacrobic zone is comprisedof aerobicbacteria and algae andkept oxygenatedby horizontalsurface aerators and photosynthe'is. The aerobiczone reliablycontrols odors andsolubile wastewater components undergo aerobic oxidation and furtherdegradation. The horizontal aeratoisalso create a circularmotion over the wholesurface area; the bacteriaand algae circulateover the farend of the reactorwhere a seconddeep anaerobic pit is located. The horizontalvelocity of die reactoris reducedwhile circulating over the second pit andthe aerationsolids are settledby gravityinto thispit wherethe solidsare decomposedand stabilized

Solidsat the bottomof the deep anaerobicpits-remains for very longperiods of time, continuously decomposing.Ihus, biosolidsminimization is accomplished.The oldestplant in operation,treating domesticwaslewater, has not had to removebiosolids for nearly30 years. Seasonaltumover of thie pondsis preventedby isolationof the deepanaerobic pits. AlPS's designfeatures and cell geometry maintainthe integrityof the systemthereby supprcssing turnovers. t,

AIPSis appropriatefor wastewaterapplications for normalflow situations as ,vell as where thereare variablehydiailic (lowsand organicloadings, particularly where there may be limitedindustrial pretreatment andisource control of toxic contaminants and heavy metals. AIPS design elements providte flow equalihatinoi,buffer capacity and recirculation capabilities to achieve secondary and advanct d treatment for mniilcipalities, agriculture and industry.

MartinC7:51-22F-5XI)1 Fax: 510-228-5804 2 SOA,Inc. Martinez2,

Acceptance and Support.

Al]PSis a state-of-the-artpond-based wastewater treatment system.

* Proven * Reliable * InherentBuffer Capacity for hydraulicand organicshock loadingandi toxic spiking * AdvancedMicrobiology * EnergyEfficient * MinimizesSludge Production/Management/Handling * MaximizesNatural Photosynthetic Oxygenation * MinimizesPower Requirements>.

O&M Costsare low when comparedto Activated Sludge, Oxidation Ditch, Trickling Filters or conventionalStabilization Ponds.

SOA,Inc. is a designengineering finn, 25 yearsold andspecializes in the conceptualto detaileddesign of innovativeand allernative,low cost, simpleto operatewastewater treatment systems. SOA also providesstart-up and trainingservices, and on-goingconsulting services.

SOA has experiencein designinginnovative and low cost municipalwastewater treatment systems fundedby die WorldBank and otherinternational agencies.

* CalifomiaWater Resources Control Board supports AIPS technology. * CalifomiaWater Quality Control Boards' supports AIPS technology.

AIPSPlant Overview:

* City of St. Helena,Califomia Wastewater Treatment Plant 1994 Plant of the Year Award - Redwood Empire Region -- by California Water PlollutionControl Association (Under 5 MGDCategory) CaliforniaEnergy Commission's Energy Efficiency Showcase Award, 1994

* City of Hollister,California Wastewater Treatment Plant

* HollisterIndustrial Wastewater Treatment Plant (CanneryWastes)

* lndustrial- WineryWastewater Treatment Plants, Califomia

* RodneyBay Wastewater Treatment Plant, St. Lucia,West Indiies

Martinez: 51j-223-5OI Fax: 510-228-5804 3 i ," ~ ~~~~~~N. ~~-:'i: v!t " 'd,j"v S Wiat v ,1t$: 4 > 2

./ AAPS,s zn integratedrnufl-staga bNologicalreadcr systein ireating muL,ic,pa;.agricu,itural and indus,rialwasteviaters. Tihereactors Pr-:aif:ngWinds __., consist c,ftthee discrete andisolated biosagica zones: dee1 anaerobic pitsat the bottomof the reactor. a siudge b:annxet l susneneleoaover the deep pit and an over!vin aerobic zone ccmo.rnsed of 3erctictactaria and aigac .vt:e issuaturad with ox'c2enproduced by algae and mechanicat aerators.

Allweather rmadwav Allweather roadway

/ \ zoneAe.obic dt Aci r

/ ~~~~~~~~~~...... scv..*...... Mlipe

SeWn \ zoa1 ulets

V~~~~~~~~~~ Discharg to addistioBsneal

Rawwaserlnflu \ ~~~~~~blanket Anaerobic3 zone /4 .AemobtOxidation 2.Phsoetrfiec Oxygena00on 3.Organic AcidFormabon &MthaneFermemato~n

SOA,Inc. 1340Amold Drive, Suite 110 Martinez,CA 94553 510-228-5801 Fax:510-228-5804 Rerripinieatsip;riuing3wfie,xtand t l-"t-- or Sx Si/ion PeuoplthPr,( Cdines s ii, -u - ;tippJlLllygWater and , S EF

avYiligthe EnvIirovnlient AD%ANCEDINTEGRATEDWASTt^'ATEl

-0t," xilliiam W J. Oswald.F. ASCE' 11rm SixBillion People ABSTRACT

By incorporating special environments for methane fermentation and - photosinthetic oxygenation, advanced integrated ponding systemsattain high degreesof primary and secondary treatment and significant degrees of tertiary and quaternary treatment of sewageand organic industrial wastes. When properly Ftoctceditnqs of seleCted sessions from the 1990 ASIE Convenition designed in appropriate locations, the systemsvirtually eliminate sludge disposal. minimize power use, require lessland than conventional ponds, and are much more Sponsored by lhe reliable and economical than mech3nic3l svstemsof equal c3pacity. Environniental Enigiru_eringDivision Irtigst4onasnd Drainage Division!r *, ...... Waitr Iesources Planning and Management Division. As is well known to Environmental Engineers.wastewater treatment to the of the American Society of Civil t£.nglneerS !4 -,. A - secondary degree involves removal and digestion of settleable and floatable organic -: A .. 4 .- *, - - .- -solids (primary treatment) followed by removal and digestion of microbial solids produced during aeration of the primary effluent (secondary treatment). Such - San r'ranclsco. Calllorn - - treatment traditionally has been done in reinforced concrete and/or steel structures Mlovember 5-8. 1990 with materials moved by motorized pumps and aeration provided by mechanical means. Sometimesfor economy and simplicity in small communities, ponds are Ediled by Udai f Singh and Otto J. Ilelweg used to replace mechanical systems.The greatest advantagesof pondsare their CII2MMemphisfILL Slate University ~~~~~simiplicity,economy,and reliability; their greatestdrawbacks are their high land C112M tllLL Memphis State University use. their potential for odor, and their tendency to eutrophv or fill in with sludge Emeryville. CA Memphis. Tnl and to becomeless effective with age. Our research, devoted to maintaining the advantagesof ponds while mitigating their drawbacks, has led to the development of Advanced Integrated WastewaterPond Systems(AIl;PS). These require much lesscapital, energy, operation and maintenance than mechanical systems and require lessland, produce lessodor, and fill in or age much more slowly than ordinarv ponds. In this paper I wish to introduce AIWPS as a system worthy of consideration for many waste treatment applications. Due to spacelimitations. howe%er.only a brief description of AIWPS design and performance can be made t hcrein. \ore detailed information is a\NilaNlt in the dissertasions teAchinr s.- :, praers,3nd engineering reports quoted in the reference section iOswald. 1990li

THE 5; 5TE\1

In their most effective, reliat!e and economical form AlWPS .onsws of a seriesof at least four ponds, each designed to rcst perform onc or more oi -he

'Professor of Environmental Engineering 3nd Public Health, Department of Civil Plubtished by the Engineering. 659 Davis Hall, University of California, Berkeley. California 94710 Antrtiic,n Sixicty of Civil Erqineti s 34fS .ail 4 .'I i Street 4new 'u. flew 'us 10l7-2.zd 4. . . SUPPIA1NG; WATER AND SAVING ENVlRONN1tNT

pond 'vith an _c__ ii:iii treatment orocesses isee Fieure i3. First is a Facultative t : .. c 't. t' and aerobic surface and nn extremelv ano-ic internal pit far sedimentation **-. wva!! or I fermentation. Anierohic microbes in the pit are protected ty surroundir.r rni oxygen. Raw jr.4....s ,erms from the intrusion of .old surface water containing dissolved \ methane aoI- sewage is introduced directlv into the pits where sedimentation and the pits is maintained so low tsee Figure .'crmentation occur. Overtlow velocity in at approaches 100% and biochemical oxygen detmard Z) that suspended solids removal J velocities of one or two meter; per t 2OUt removal approaches 701%. The overflow r-' L 4 M.A. and parasite zvsts so most YSCT 3 ar, !les- than the settin; velo:ities of helminth ova SJ;P Rs Z ins ths e remria :n :he pit and consequently are permanently remo.ed trom o- * effluent. I tihattti - \ /s snt \A L =1010=6 CMMNWWAsa sVW" =nILimm _ ft ___ N . . a -rntt_?._ e6 MM IL 00*Wt 74_ d` a1& dm7inttttL m,as.qa _ sCm.mme IaM101 0 &1 0.0

L btV it I s M\ ft

.20 30 40 90 T006so 10

SOC -. 1000 amO WO0O 90 Plpar, 2. £112 Ota±tt.lin.- Por SedSiaag2t±ol ''__.______.___-_i_____i______'______-~' > 7-,PcrforacjS 1 5 Showing AIWPS 0Verflow Rates

Iatgxet. atewater nP1g 5. An £dwateu . loodinIg syut" (3eoa.ktic) ?At9 11 SEDIMENTATONOr ALGAL-8ACTEPIALSO5S benefit of anoxic pits is conversion of chlorinated . Another potential FROMA PADDLEWHEEL MIXED mGimRATr POND. hydrarbons to forms that may be biodegradable in sn aerobic environment ge pi* Volt unLits reduci.g _ (Bouer and McCarty, 1983). toibem Pot L As".1troo orv W.9M where only ash remains, hence -warnms ,ironmne.6se mert there to pont GATI Ms7r PEVNr In tifSornia ; pt-elena, l s * - z _ StPERArANr SErtLo A >NO VFWtLUEM arst AIWP) sludge removal has not been required for over 25 years. little sludge build up after twelve second AIWPS at Hollister. California. evidences JAN 220 IS yeanr. MAS io 20 or '24o 45 t is a paddle wheel mixed shallow Tne second pond of an ATWPS serieS WAS 253 2 .1 called a High Rate Pond. In such a pond microalgac grow profuselv raceway JUsa 320 3 Stl releasing oxygen from water by photosnthesis. This oxygen is immediately JULL 300 20 93 avaiiable to bacteria to oxidize most of the soluble and biodegradable BOD 5? -W 23C 30 : from the facultative pond. Algae prouced during IV 220 is remaining in the effluent 1 12 ' I5 s Table 1) (Eisenberg, 1981) and. paddle wheel mixing are highly settleable (see 123 a to*4 air flotation IKrol'ta and Wang. after asgal removal by sedimentation. or disolved I: Ss 10 to has a BOD that is generally less than 20 mg/liter. 1984). the remaining water SD 90. the High Rate Pond to the Facultative Recirculation of algae-bearing water trem _2_ * quickly IM . J ___ Pond provides an oxygen rich cap on the facultative pond. This oxygen odors. * 24 MM. Se.noum,n oxidizes reduced gas emerging from the fermentation pit thus mitigating AII Elwiberq ttlsI) 76 SUPPLYINGWATER AND SAVINGEN, iRONSMENT .;TEGRATED PONDSYSTEMS 77

1600 i -\aters emrcgonzfro.- the ,et:iing ponds are sufriciently low in BOD and suspendedsolids ro percouiaereadii into the ground or to be used for irrigation ._ They will. hoAe er. iikCis Lurtaiie r. NiPN greater than 1000 per 100ml and I hence mra requirc z'-.-eo.-! str:;e prior to use. The fourth pond of an A IWPS _; 1[400 often calleda %Jatururronpond has the dual purposeof addeddisinfection and C. tttragC for irrigation. The useof pond efriuents for irrigation is more fully discussedelsewhere (Oswalid. 1989:Pahren. 1985;Sheikh and Cooper, 1984i. A recent publication b%ythe World Hta!th Organization outlines major concerns andt i1200 safety t'actors related to the use of wastewater trn for irrigation (Shuval. 1989). A;c;-Nzr din, to Shuv:^and others the ma;ordanger in developing countries 0 ~ ~ ~~~t~ is 0 b trinsmissionin sers;e Added of heiminthion the needi OV3. for This four is pondss irtuallyin seriesprecludedshould by be the an uiseadmonirion or 'our ponds 5 100o Focultative Ponds in - against short circuitinS whichcan orny be avoided by alternating surl'ace and Cs SeriesSO Percentiles submergedintakes in pipestransferring water from onepond to another. cn After Ramanie!. a. 1975 .2 00 t0 : TTABLE2 P2'R--01PMANCEOF ADVANCED INTEGRATED S rWASTEWATER600 PONDS O : ~MELENA :.- .. (AnE(~ -- a:ual 'Means) ... ~-(1) :' -i 6ST. 1E- 400 *. P-'PA EER UNITS STATION __ | Percent

' Ft" Tmn DAY I0 e,'vi 9tv:,-'! , . :- ' ...' :^S.,- '. __.._.___, '1 ,,_,,9., , , t , 0 ...... 20 F So., s- r.. -. _ ,- I .,. .223 Mu.B 200 ~~~ ~~~~~~~~~~CODMoll 439 [124I? 74II So 32 9 TOTALC 6 4 (6 soI2 6 0 7 Z ~~~~~~~~~~~~~~~~~~~TOTALN Mott 40 TO 13 i 4 90 0 INF PONDI POND2POND3 POND4 TOTAlIO Moll 14 1 I 12 8 5 64

rAgure 3. Total ChromiuMtRtemoVal Due 'o Algal (1) Atist Meten 1970 H0LLISTER(Annutl Means) (2) aasc Crovsh. Sedi:sentxaionZn Itte *> -od PARAMETERPARAMMAJUNISUNITS t I 2 STATIONAIO * 'ecn Percent

- _*J * * YS i 0 32 'l Q . . . .* Algae in the recNcle'dwaters tend toladsorb any hesvy metalsthat may be present CI I Mg/I Ii iC 43 7 96 in the incomhngwafie tnd to setlie in th fac^-ltative pond. thus removing most of TV S Mg/I 4 3i3 3 i 347r 42 the iadorbrJ Ancta nrdmtho saeutrttin ^'on.1effluent isee Ficure e) (Ramani *r _ . 4nd Oswald. 11975).

The third rond of the AIATS weriesprovides for sedimentation of algae in (2) AIlS?MzK4#r1 (iq9l8l the effluent of the high rate pond. As nrintedabove a paddle wuee; mixed nign File (3t EeCol tpondtends :.. selc: for algtf that 2aresett/!able vwhpn not in a mixing field (Nurdogan. 1p11191! Hall, Algae which 5ettle tend to hibernate and thus do ApDxrxirns (ReOne l'irne VariesWith Season) not immedinlelv decormposeor produce nuisance. In fact if two settling ponds in parallel are used. oae or the o:her ctn b- drained annddried every three or four Station Key t- lnsEuentSeo te * ol1slels Sorttin Pond Effluent Is y-carsto remos- :0on:cntrated2lgal lUds"gesDried afiMIal51ge is rich in nitrogen, S K FaItunhSts P Sw phosphorus.and potashand hence is an excellent fertilier for fast growing plants octirgeo D-e To NFtufsl Savii Pat.-ols o.n iMietting and Pin.nc 19S674. There is li."le ch-ancethat dried alasewOuld contain 3. Miengietit Pono B TshergeTs No SvtseIG 'luy.ercttr infectious of;anisnr but to be safe it thould only be usedon ornamcentalsand 4- Setting Pono 's. B ThereIsNoSurcertuct crops neoeten ra3 ICalifornii state. 19't; Gunnersoft et 21. 1984). S- MalutationPond, SUt'lLYING WATERA.ND SAVING ENVIRONIENT .XL!" '.'NrBrE'RBD RLSYs SYStMTIO\) -7

the 3erobic surfacoe saters. the huhhl?th.nhemr e .crqe nnti r theoartc withh ..hering aawti.: haz:;-ria.ire tre' t igiin ~ettt~down thriugh the -I ri5'nq Tkble ' presents pertiurrance data from the %0)PS _t St, ite.,tt5 Mtertn. 0eo:tint luent se5wge. In mis 3waNthe entire raw 3ewtee tiloW s oa-!ed :sroueh t l9C-C an2 H _!tister (NIosuera. 19881- It is clear *'rom thesedata that the m3tor :..Ium. of intenze anosic .tiitv ;,here rorh insoluble and soluble O!Sat m3t:er fraction of BtDOremo%ai occurs in the facultsti0e punds aud. froin the St. lielena is ad,3sorhedand conierred to cirbin dioude water. metha:neanti rnrwen gas data. that I maior fraction of the total nitrogen is removed in the f-cititati'e pond. -T't - posit;ve action in deep NFP iits Is ver', similar-3 that of the wcii _nrown l{^-^*lictes h.h nlatile diisnlvpd solidLsnrivinate frnm a paner -i-53mation3ljnt umt'ttfloJ Oubltve X':s 'r, S eh: rb!atte-'t -n r - lifd r -rsitning hevond the f'tu1Xtitjve !nri his'' rFa -ire t"'od r ~-*'-'eV rn .1- *.W' L;i- *__ __:;r - - *' -^; ; ht*C-ts manaerobic. and aerobtedegradation. Th- high pondsp-e winthras. lsti bar a .ho t:mpartedre cte dc!ro tr,sanr.hene remosea sreastdeasl of BOD but contribute oxygenation to the facultative ponds with rJgS. plastic bags and % th eomp3cted slud or rit ands hen anc asid n removal of nitrogen. pnosphorusand carcon. Followvingalgal removal r managementtorus including tati sate pretreatment. freauent sluaee removal the degree of pollutant removal in AIWPS is equivalent to that ot mechanical 2nd Jtner tntenanca. In nhecase AlA PS. sludge removal is not ut.Ct regusre, 1e"ondary t slants.with the added benefit of significant r;trogen and carbon ctogring ts impossiole and maintenance is rninimal. Thus the main princinles and removal (Table 2, St. Helena). removal of heavy metals il-igure it and a deree ot' advantsgesJi UAiSB reactorsare realzed in advanced 1'acultative p. .id -iih few fail sale disinfection (Table 2. Hollister) (also see Sarixaya and Sartei. 1987). of the disadvantagesand with lower costs.

The helmintN ova remo%.alprojected for fermentation Pits is of particular Anterest in developing Countrieswhere millions of children are weakened by Neither lfollister nor St. Helena are CompleteAIWPS becausethey lack parasitesand consequently fall prey to childhood diseases. paddle wheel mixing in the high rate pond. Also residence times in the high rate ponds are excessive,exceeding the time required to accumulate sufficient solar The economy of AIWPS results from a number of factors be%ondoperation energy to releasesufficient photosynthesicoxygen to meet the ROD. The high rate and maintenance. For example, consider the cost of reactor volume: reinforced pond in Hollister is mixed with screw pumps and in St. Helena with propellar concrete reactors such as settling tanks and digesters3re likely to cost $350 U.S.. pumps. Both are a waste of energy compared with paddle wheels. The data in . (19901 to S100 USd0990) per ml- On the sther hand. formed earth reactors are Table I is from paddle wheel mixed experimental 1/4 acre t0.1 hectare) ponds at ' ' iTKfo cosf less tha,5S w(I990Yernm' -- a hundred-fold less. By using Richmond, and indicates the excellent natural algal removal that results from artlhwork ponds. large reactor volumes can be created very economically. The gentle mixing. The interrelationship between paddle wheel mixing and 31lgae ' microbes involved in treatment are, of course, unaware of the cost of their reactor sedimentation was first noted in high rate pond studies in the Philippines (Oswald : and, provided the environment is suitable and constant, perform as well in, et al.. 1978)and wasconfirmed in extensive subsequentstudies at Richmond pondsas they would in the most elaboratedigesrer Ako sincethcj yearhwork I (Eisenberg. 1981). Both Nurdogan(1988) and Hall (1989) havestudied the reasons - 4ostsa little. earthwork digesters(fermentation. pits) can be made largeenough to : for improvement in algal sedimentation following paddle wheel mixing. Nurdogan nttrmitcomplete digestion and thus the eliminationof day by day sludgtbandlinp l' has found a natural selection for larger algae which settle in a quiescentfield and - or many years. -1 Hall h3s emphasizedthe natural filaments produced by algaeand their tendency to causeagglomeration of cells with consequentimproved sedimentation. Both CQNCLUSIQN phenomenaappear to be important in natural separ3tion. Neither is related to the phenomenonof auto flocculation that occurs due to high pH in poorly mixed Development of economical and reliable AIWPS is timely becauseof the ponds 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 welt as thermal stratification. is The past trend. under government and state subsidies. has been toward complex prevented by continuous mixing at a linear velocity of about 1/2 foot persecond and expensive mechanical treatment plants, many of which work poorly and are (15 cm per sec) (Oswald, 197). difficult to operate reliably in small communities and developing countries. Now, most government and state subsidies for sewagetrearment are being decreasedor The 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 1,Z rot per .ecund is only 3bour 5 k,hrs per hectuarePor Jay and re-uts in the upgrading of 3 communit:y's wastewater treatment system. Based on our release rom rater of more than tOOkg of dissolvedux-s5en per hectare per dav-- experience a3tSt. Helena ani Hoilister. AIMPS, when properly desgiieu. a,re not that ;S :' kg 'f oxygen per kilowatt hnur (kwhrt. This should be compared w:th oniy economical and effec:is-. but also attractive and nuitance frce For mechanicalaeration which normally transfers one kilogram of oxygen per kwhr communities in the sunny uart of the world. AIWPS can provide a new oDoorIunit' tSmith 1973). The energy savingsis thus more than 10 fold. tc ha%eadequate, sin7ple, reiiaole and nuisancetree waste water treatment with it,gnific3nt opiportunitirs , r rectamation ano ens,ironmental enhanccmne't and at a The phenomenathat occur in the fermentation pits of facuitative ponds are price most communmt*essthould be able to atford. somewhat unique 3nd deserveconsideration. Quiescent sedimentati:n is onh the first reaction. Apparently then, in the intensely anosic volume in a Pit surflaes ACK.NOWLEgC\IFNT of all sorts of solid particles that settle from raw sewagebecome pupulated by acid forming and methaneproducing bacteria. As gas.s releasedon their surfaces,the I am indebted to Rose Ann Nitzan for typing this manuscript and to solid particles becomebuoyant and tend to rise due to the attached gas bubbles. If Patrick Oswald for preparing the tables. the pits are sufficiently deep (S-6 meters). the gashubbles expand as they rise and usuallywill break away from their attachment to the particles before thev reach SL??.7'P7EG V;TER k.ND SAV!':G. ' '.1:) it n(iiRATI:D POtND SN.Si'L.is

5,'&4'h., , R r Cu^ro,. ind R S ln i 1964o*ues i casiewaterei luent reude ur Iul' aw-et-Zen `,,'od 3 studyv. n .. .,u'er. C. J_..and r. iE. \.Car!'y f!981) Tmr ttlrmwti'nl ol I - and carbon Rcuse. W'Arer Reuse S%mcoslum Ill. Proceeijness, Vol pP.eri..r 4 S hal)ogen:zd aWph:ari f :omrnoundsundher rr)erharI, g c',P.s niarerworks .Assuciarun Reieirul rou.--fcdon. 6666 Quin,:-. a !enveer,I:. ;' , !'t'rrloentfl Nicr,obilloity. -5. r'p. 1IS6 C-oicrad`o, USA 30'35. vz ; ;,v,C IS -e'.astowateri mcClamrt3tn crit-,ia, An e'pt !r-.mr . ih. ; i rrl:'IS R_::a frr F 4 7 . el (r1l te?inesin Hum.rin ;'t~tey He1lth C..~i] \ ii. ,t8n:r3ti2t e Cod?e.T tle '. Li v iin ;. DI 3 37Io ou9. State ft - :s Their Use :r l? rs nJ A:tUlcuitu- .; " o Cf H-3!th Services.S?.niiirv i'r in"erlne Scn:non.p I'tp U Sssc '8 - 1 n t.Ci..f 8erlele\ vav. Berkelev. CA 94704. USA. S" :zerl2nd. E' en,'t [flrn M1.(I98I) Prouuctivity Harvettabiiii n7d f~rn1r. .f _Z" Smith. Rohert 11973) Elezric3l Power Consumption for Wasrtealter Treatment. jn1roanlu: in PrdJle Aheel Nixed Hi.h Rate Ponds. ls,.).D Dissertation. EP!I-R8-3--31 p~9, *:oNationalKes(rem. Eni P, Cinc:nnlih: u lUnmirrsii of Cjlitornia. Derkelev, CA. Swi:zenburum.Mlike. ed. 119851Anaerobic rreatmenr of Sewage' No. E.E Gunrer'n, C. G.. I. i1.Shu.al. and i. Arloscraf (!'i: He.Ph * 33.5-5. Proceedinasott a Seminar \'orkshop neid June _.--'3. it ws*tewater irrigation ind their control in deveit'pivg *.untries, pp. 1576-l502, Untiersitv of Nlassachussettsat Amherst. Amnerst. Nlassaciusetls uu;'a3. in Future of WVaterReuse in Water ReuseSnmposihm 111. proceedings. Vol. 3. American Waterworks Association.Research Foundation. 66o6 Quincv A%enue,Denver, Colorado. USA 80235. H31. T. W. O1955)Bioflocculation in high rate algal ponds--implementation of an inn,vati.e wastewatertreatment technology. Ph.D. dissertation. Universitn of California. Berkeley. Kroft3. Ni.. and L. K. Wang (1984) Developmentof innowative flotative filtration systemsfor water treatment tirst-rull sandfloat processin U.S. parts A,B.C. p. 1I'25-1:64 in Future of Water Reuse,W3ter ReuseSymposium Ifi. vol.. 3. American Waterworks Association ResearchFourdat'ion. 6666 W.' Quincv Ave.. , at Denver, Colorado. USA 80235. .--- a a Meron, A. (1970) Stabilization Pond Systems for Water Quility Control. Ph.D. pg. 75 fig 2 ,,lower scale gal/ft /day Dissertation, University of California at Berkeley.pp. 318, p t l l Metting. B., and J. W. Pvne (1986) Biologically Active Comrounds from !pg. '76 3rd,to last line(Me tting and Pyne 1986) Microalgae. Enzyme Microbiol. Technology 8, 386-94. . : Mosquera. J. F. (I988) Performanceof Advanced Integrated Ponding Systems. pg. 78 Discussion 4 h line Photosynthetic oxygen Master of Engineering Thesis,Sanitary and Environmental Engineerine, ' o- ge- Unm'ersitv of California. Berkeley, California. pp. 1-84. Nurdogan. Y. 11988) .MicroalgalSeparation from High Rate Ponds. Ph.D. Dissertation. University of California. Berkeley. Oswald. W'. J. (1978) The engineering aspectsof microalgae. In CRC Handbook of microbiology. 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 Wastewater Treatment Method Yields a Harvest of SaleableAlgae. WHO Chronicle. 3'. 348-150. Oswald. W'. J. (1988) Microalgae and WastewaterTreatment. Chapter 12. pp. 305- 3'S. in \iceroalg:l Bitechnology. Borovitzka and Borovitzka Ed. Cambrdige Uni'et,,n Press.U.K. 3su tlJ. 'A J. 19g9) Use of Wastewater Effluent ;n A iculturr De.! nization 2:. 52-S0. Elsevier Science Publishers,B. V Amsterdam. Netherlands. Oswald. 'W.J. 11990)A S\llabus of WasteP'nd F indamentals. Environmental Engineering and Public Health, University of California, ierkelev. I'ahren. H. R. 119S51EPA's ResearchProgram on Health Effects of Wastewater RFuse fer Potable Purposes.Chapter 10 in Artificial Recharge of Gcound,Jster. TaKashi Asano Ed. pp. 319-'8.S Butterworth. Ramant. R.. and W. J. Os-ald 1973)Studies of pond perfrrmance and pilot Mgae separationat Napa sanitation district, report by CSO International tO Napa sanitationdistrict, 950 Imola Ave. West, Napa. CA 94558. Sarikava. H. Z.. and A, M. Saatci(1987) Bacterialdie:.off in waste stabilization ponds, Journal of En%ironmentEngineering, Vol. 113. No. . p. 366-82, Env. Eng. Div. American Society of Civil Engineers. Page 4 Small FHo

Pondingsystems treat wastewaterinexpensively by,Edwin W1..Let, PA.E

(low rsnot, lIi. auth.irheof ifirtfotlyg aticle iz a self-emrnployedconsuti ing rug er F- o.d also is oafifiaied n,'h Sw-anson. 0swald and Associatr in Mermiez. Cafleortia. lit prrrwu.uly worked jt an environni,enalengineer with the 1USBureau ofReclamtion in :JIq Sacramento.(ittifernia. and as a itntiryta engineerwith the lVorld Htalth Organization V in thePhilipp,n,s. lie reetivedhis hichelor'sand maser degreein ltellsaniatery ergl,ne?ring from the Un erjidy a( Cuiifnrnia aBtr,Aety.

Ihctintegrated ponding system is a low-costadyvnced waste treatment process for . A r mmnicipalsewage. organic industijalwaste, Andorpnic agriculturalwaste The lsnsmpic_ ly. economy.and ret lamationpotentisl ol the AdvancedIntegotsed Ponding System AIPS)make it sttractiveto thosecontmunities wishing to transfoanpolluting ovalies Iola sset5St minin,alcost, IL5wcapital cust. high eliability.aid low opepatitoand maissee ancecust favotthe useof AlPS over conventionalseconda and tadvumcetdwst csrmentwherever clitn le andlatd availabtlilypemuli *sshown in Figure .anAIPS involves a selected equencof ponds.Each pondo i :ientificallydesigned to accomplish.by naturalmeans. oe more nitk eations In _ agedprocesses lcading up to advamnedlerels of wasteteatmet Thestaging ofderilew An af a AIPSto lllter, CoUse'niathat sun-esa townat! 16AJO0pe.pt. tegrirmtois selectcdto meetthe objectives o thesite spedeic project Sca=ry The27evm pondanr J&a at lr t giSreat taio milUnisedastt of srtotieoterp. -stmnentcan be achieved with adrep (acultative pond follbw ed po AL.1 r da, wndiutnro u stAientremoval ttnd biortaiss rel mastioncan be achdeved wish selected insegon of ecifirtclly designedpoods- construetioncosts resut mainly fron thiteminimnization of useof rtinforcedcunc,ele idgeand greaseremoval are accrnplished in deepfacollWise potds wvih special built- sotmtes by wsingfonned atath. deeppit ditgemrs. to,c,miol n-tri andalsin prtial okidtlon n thesepods supple- Loweroperation and maitktena nceteis euhtit ... : -niasyoxygen can t- iotstl,,ced by recirculalinghiglty.oxygentated effluet fmm * Elimiasitoodday-by-dayildudgthandling: IntegratedpondbsiaedsiLned to Pllow,rloly ,fcirc,ttatedSigal Inv th units terned high-tateponds." the scndary tetaintsludge in dh deepin-piid iligesicts fot oaiayyets. Sludgevelunr is s o(fthesystrm. bliurt c 5incslgae in thehigh-esse ponWduscslar energyestinulta. therebyseduced to s mibtnituntin prolongeddigesii. llihe residulsludge is iuAlyaccotnplish i4itgusysutetic oxygentproduction. high pl disinfection, ndntrient relativelyinertn d ts volunmIs sniall. Ditosal is not a msajroerational soval facitetis in tile Itigli-rate polrI useosygen produced by algae ti oxidizeall but probim moatrefrackory ogalnic sribatsnces. Following osidatiot in the high-satepond, both * Decreasedenergy requiremcnts: Energy needs for aeration.sludge handling. stU seand bacteria biotitass siould he sepwartedfixn theefflue, distison aredecreased. Each pound of .ticro.gse eatlesa1.6 pmil rk*.fosygct. whichI diasved in wateraid titus tniteJisttI r avrailablefor bncteril uxidution aI-bacterialseparations ame accomplished in tertiaryponds specialy designed to pemstit of wasteorSanic matier. An acre of algal culltire will prodiuce200 lbs. of useable ral sedimenatiaonof algaeproduced in thehigh-rate pondc Natlsal sediittenUliettIs disolved oxygeneach day, equivalen tu Its XA)horsepower hoursn,l menlalisal Icratedbya self-inditcd hiofllrcculationprocess- Rewneral adnetaaooldpotliett aert io. ibe snaxx_ eergy requieutteoitis l/ID kilowatt-hourpet kiliogr3m f tigaebiomass nay beneeded for seedingIto thperiptai pondWror high rate pod DOD. ageof treatedwater (Oc controlled teuse Is providedin qatesary pod calld Decr_sedegy rs r sludgehandling: Since ludgeis rctainedIn specialt urationsor siorageponds." Storsge mst aft designedpil digester tut rentainsthere inderiiitely, daily iransfra P sludtgeIs not

'Sot aqusaiclife ifdesittl i cr i s alsoIs s;ttelenals .tecessarywsfii andenergy needs fowr sliodgetransfer ast eliminated. Also. because edfor usefor gruundIxier recharg. inigstlottoraxgero gol cowurses.ar doigstionproceedrsoeryeas otite hstiisgsmdmisingofludgetenn tsinin wciinho11taSbif . - ~ requited,futer reducingenergy requitesents. Decrtasedmanpower requiLemens Mi,iration of ectro-ntehattu 1 ends totheintegrated seqnesv:e at designedto utilleenaturalideconpoaltot equpmntIntegralatnfte sysutenesign Thlisasominilittzrstrcclutiica sses.W . Os. aid. pittO.. Universityof Califonie at Berteley. has tstudiedthese persnni rquired to operateand inairttain equspnsent. ssrs andsdeveloked the systcmduring wmnrthin 40 ytearso reseaCiLThe effluetf llealth-resstedrisk reduction dvantaglesof Integratedponds include: y cttsined In suchpoioling systen), is cotnpatrbl to the tffluent derived fromnp sentplau ineotlxoalilagcomplc, sdvased tmeauntststag1s costing sevceatrne is hbcteria.and virse in effluent stueamstli. ii is accomplisetdby pircSdingltwi. detentionperiods for sludgein the pit digestres,short circuit aifegutids.high pl I manceof All'S canbe expectedto mduce pollutantsin the following rngesr levelsin seconduyponds. astd efficient separtion prncesses. *Mlnisisatlton or eliminasin of the nee fit rehmic.tlch dishi,aecuioitof eltlteints BOD 95-97% with a resultanlincase in reliability and a decreaseut eott. Thepotetlital Itaraits COD 9t)95% of mutagen.tetutogen. and cacinogen prtductitin in tie finaulcflutnt by conmft- TotadNitogen 90% tionaldisinfecion processes can be avoided TotalPhophotrus 60S - Removalof heavymntasu through co-precipitalion tnd sedimentation. MPN- E. Coli 99999%. With egardto environental Impact. the major objection to wste stabilizationponds of

t advantagesof integrased ponds over conventionaltreatment processcs teult conventionaldesign has been the production of odorsSl cessaintimes of theyear, their from lower consuructioncosts nd lower opertio n maintenancecost Low largeland requiemwents. and the presence of suspendedalgae in their effluents. Alps

USEPA Small Flows Oct. 1990 October1990 Page5 TCHNOLOGY

KEYTO NUMBERS ON FIGURE BELOW 1. SCREENING& GRIT REMOVAL 7. PADDLEWHEEL MiXER 13.Al.GAE HARVEST

2. DISTRIBUTOR 8. HIGHRATE POND 14.LOW LEVEL TRANSFER

3. FERMEtNTATIONPITS 9. HIGHLEVEL TRANSFER 15.MATURATION POND

4. FACILTATIVEPOND 10.ALGAE SUBSIDENCE CHAMBERS 16.HIGH LEVEL TRANSFER

5. OXYGENATEDWATER RETURN 11.ALGAE SETTLING PONDS 17.WArER REUSE

6. LOWLEVEL TRANSFER 12.SETTLED ALGAE RETURN it SUPPlEMENTARYAERATION

Ir3

Figure 1 Ndvanced Integrated Algal-Bacterial System for Liquid Waste Treatment and Oxygen. Water, anidNuitrienit Recovery or Reuse

tonic heseobjections to a considerableextent becauns they awe designed somWinize E fil(tons toagoponds AMe oten suitablefor aquiculture develetoprs and iarilgadoe .ie of the landfor pcmds.to avoid obectionabledon. and to s e olga. ofdowaje cropsbeeau: Theyxwe Ism o paitte ovaand dependably low in coliforffand odth eieric landoccupied by proJperly designed ponds will: bace dis highpH dis infection in the primaryan.d high-sale pod endlolg Provideopcn space jud xsenhic vwiew.coaided eesuW inconrma sy e dett ; in de sy' planning. * Theyare kmw in tlmgeaid dploaporusandwill not over-ferlize. Pesmitdevelopment of aquaculture And welAnd habitat * Beexsily aundinetpensi,ely reclaimable.ustJaly t a hihly apprciaedlad Mleougac rcd i megraedponds have geati potensisl for: valueshould future devebpmnts kead to aiterntvte Itaputneoamuet tathidx. - Developesurtt as a bigh-pmetin feed suppleanctut forli. chickets.swisne and ,uwuimLs: :tionableodors atc avoideA in intlgratedponds byr * Useas a lRiid or solsd fcitilizer for rapidly-growingcrp: * Assuringthe onsct do lIalinefenrcnttloIn.w tdetewaodotemisesnt htkte * Use asx sua orMethane fkrnmntation; primaryponds of thesyisein. by conmrolledsit-up pitc t * Extrctiaor oiLpata randcolltids. * Psevi'int xt rVIti nryeen. is ell ta algalteediny, thnvot5hreleaios Itno hlyh- satepond elltent to theauslace of tiheptimary pond, whhenewer low distslved Tos *ze.aproplydesgned Advanced lntegited Pnding System can puvi&de roxygenlevels in theprimxtay ponds indicate a need. wvsemageme andreclmthon that Is mnorerliabl, economical,and envinmae- tally-osusddtcA conventlarnd aysens* . harvestingis psmotc,l by: Naturalbiofloccsslstioit of aIgac in properlydsigned and nmicdhigh-etae ponds. ReIfrenexs * iligh utnenrcmovalsthaenhaucesedintensationandwrerdadditionIlgal Osawid,WJ (1987)Large-ScakAlgaeCultureSystems; EngineeringAittecta. In growthin receivingtatrs. Micro-AlglBlotechnloty. Cpte 1. Dotrowitxka.hi. assDormwitci. L csli.Canx- lvincedwaste trmatment process should be considered for use by: brdge UniverityPmss. New York. Anycomninnity involved either in developingnew waste teaset ndtdspoa Oswald.WJ. (19U1TlseRole of Algae in LquidWaste Treatment and Reclamatioo systemsor in upgradingtlteir present tratment system. Chter 12.pp 255-2lin Ukrolgae andlirsnaaffairs. C.A. ambad IR. Waal- * Communitiesin and or emi-mridauets desiring to pracwicewastewater reclamn ndeds. Cambridge Ultivetity Pess. NewYosk. tion. Organkindustries requiring Independent wate dispossasystems. Oswald.WJ. (1989)Innroduction to Ad&anced Integrated Wastcwatcr Ponding Systems. Animalfeed los. dairtes and poultry [anra requiring WAste management nd Depautmentof Civil Engineeing.University of Califomia.Berfciey. lumrenrmcycle. Communitieswbih sufficient amounts of availoblelad. 11-1's V~Altemative VVastewater

~~ ~Treaftment: Advanced Integrated F1j~!r. . i-Pond Systems

td.s!|1lii XAdvanced in conceptand simple in design, a neit: waslevwaler treatment [ t jP, d l~~echniologymayoffer a solutionfor cDmmulitilses be?svttty iitelnsifying costconstraints and water quality regulations.

Why not build a sewage treatment thinking. In '4ii tviihr,al plants, for facility that tiseSmuch lICt energy examnli, aclal ,iis it l1, niicI nstimes than a ctinvetnlional one and prodtices 6(r,, or-nmiiol 'Ilt e i-I t rical energy *no odors, especially if construction, usedlnhi a'\lalslor Ite.alment. In con- operation, and tnaintenancecosts are trast, mi( roalg wtin an All system also dramnaticallylower? lThisqueition provide dissolvI, c, s -g#nthrough may otccir to many who have visited photosyWihv-s;,¾.uhlli;antially reduc- the WastewaterTreatntent and lKcla- ing ele rical-aI iuntpFion.n Not sur- niati

"All' Ictdnitilvv,v i tw,limited to

a~ .. t,~~~~~~~~~~~~ ~ ~ ~small I osiommultthi-' hiiw. '.er. Cost .*7tI.~. { -¢ 4 a tcompaiH(ons 'A iith other treatment '.i. 4 7w*e'

speci.l PI q. 1t 1ti)r . I'h' , t tnil)

.~~~~~~~~~~~~~~~~~~1111 .. 1 dti,1"1pl- li ., ,'~ ','" ^,uonsructlion ano tnergy ostsIS ol11 5,,lzlt,uilEIs1t1t1Mainlenance Costs A11 should I 1111int ~ ~ A prreperriydieSi)'11VLl All'pl I tt c,1t51s1i1ilelabout! o - G(od financialsense begins wilh sioutildi(onSUnle iboit iineI-quarterto fauilitycosts. Iksause soIlar aefatud one-fifthi lie energy (if a conventional quirter to (ric-ft fth tie pondsare built of formed earth rather mechanicalwastlewater treatment I than o(freinforced concrete, ihev cost plautitThis translatesdirectly into eflt11Y tY|f (VIui'cl'tionial albluttI (Xtimes lessto build per costsavings. One significantsource ctibic foot of containmentthan do of savings lies in tising solarenergy ~IXT{k(,IwgtlFUIXIWa(1slt'71't?IC I conventionaltreatinent plailt reac- ratlherthaln ele-ti icaieunergy for aera

-ncaI,nei,t,~ ,*~* t(rs. The total pond areaneeded is tion. (Convenlioial plantsaerate by truilUlilen)t pw]ant. ThZis nmuchIlarger thian ;hatneededi for a u5ing;electrical encrgy to bNowor mix f runtislgiln'tslXirt 1l1 ielf I conventitonalplant, but ponds should air btihlle; into Ihi u astewater.In an nsl sdiret'1t °! still cost oliiyone-third to one-halfas All' sVstei, algite uisesolar energy 0X;t r! S*lttZx,r. i much to build, accordinig lo William and phutosvniih-'sis th supersattirate Oswald, who designedSt. I lelena's the wat.''vilhil oxygenthat system in the early 1960s.Oswald is a microlnes neiedtk break down waste. professor emeritlus. at Ihe University I of California, Berkeley(UC-Berkeley) ';or pcopv wvho)have always and inventorof the AIP system. thoughl in t 'utn; if conventional treatmennt,il's hi Ldto uiinderstand lProponmentsof the technologybelieve that you cminaenat, without any that maintenancecosts for the new mechalniclal srq1t-" *;;y.;Oswald. ' plantsatealst lower becausesuci "Usiig ni' cIwiwc;i auration,you G73tSsof a ConventionalPlant plants minimizethe useof mechani- needallbot I lil,',tAl-hourof clec- vrs.an AIP Plant cal equipmentand requirea smaller tricity liii oarh lilogritrniof dissolved ; tClils!n thrtisanTds inventlory(of spare partsand supplies, oxygen. In an AI Vsvstm in a good K______2 1^;8vris)| Operation costs are reducedbecause climate, yiuetou alowiod20 kilogranis P.13; j j,the plants can be run with smaller (44 pound() of oxygen pcr kilowatt- staffs. hour, IeeCutl% our unergy is essen- -- I j 0------1 | tially free. I hat energy is solar Anotherimportant advantageof AIP energy."

I t . 4.l t - plants------is - tlhe- -small --- -amount--- of sludSge *8! -,- i they prodtice.In theseponids, sludge St. HIel na'spliat still ustesmore ' * -- ! j 1>- --- - fermentstntil niothingis left hut a energy thni amoptimal, up-to-date ii| ; small volumi' of residue. Forexam- All' pll voni Thirvliat's !ii 3 tpie,dtiring 27years of optralion, St. becauseSt. I Ii'lel-a's plant, designed HIelena'swastewater treatment plant 30 yeatsago, uses-(conventional I1*~: t l hasnever had tolremove residue. A pumps to circulaktewater in thiepond recent measurement at St. Helena where atalion take'splace. Calcula- tO4 1 9fi1showeditX E that in nearly3 decades, lss tiolns that no10Wsho]v tihC five-to-one -_ X j g '048Ithian1 mettr (3.28feet) of residuehad energyadvantage of an All; plant ||257 2 accumulated at the bottom of the are basedon designsusing paddle

i 1 -Rl ~ s v 'rll digester pit. ibis represents a wheels flor circulation. P'addle wheels capital Arnual sLibsta.iiial l betellit in ltieirs of Ini_t- are now it prt% (t Iet inology com- rost operatingLost ing environmental regulations for ini mnlv used in comniercial algac- I ( invenhinnalpanrt tl AfP plant residue dispoisal. gyro%ing operationc. P'addilewhieel 5leSOA lrf. Vxi,lw¢p,}CA !r'u'ce _O_ . PA,rie.' _. _ circoiatiin has htCniincotrporated in St,rhon aihi r is i iisI rimii7iiifr l an All' svstem tlhat UiC-Derkelev is nac,ijt,ril.nt pl,11i'. I 7.5miii, desigiuig for a St. I lelena-sized lhEro II1 a,lEliriu .e,I("."lKl1p' ,bii-- wastev-ater- treatmllent plant itn Cali- lnll'nl'llwl'l/.C19}lt1"19#"/t.tlRt't. ~~~~~~fornlia','Ceni-,al V all1,N S,tilelena r,,f ,o I,,i,,,n,l ,,t r, ,.,n,a is alst- cisideritga (onversion to O,r.tiFifti, I l'f.iiit, 't

A'i . t,,stil (if ' ki,l-i,nd. I1'vilcrlregot-

r~~~~~~~~~~~~~~~~~~~~.s.oIi Ii ifvtigitirniiiLi1lnl

4 { a ~:ut. 4 ' shOg d 411tiidItom theirplanits.

f ly~~~~~~~~~~~~~~~~~1'k'e iviifi.f wvIiimtatiwt'' (lt, . a + t i~~~~~~fk,''( I).mstei * llI .l down5 tox)icstu

,i,>,* - ! _ srti.w-, lvv' l~.li" Gt-v't1 'lilaUC ~~~~~~~-. "I;ilpfl i IIgf it COU I % t W5 *~~~~~~~~~~~~~~~~~~GiC1a UC-

iltiilDiZlki}{-.' l v i j \ 2 lt~~~~~~~~~~~~~~K11.;1.ltf1,11 d olgan.ittX i11fi1l

5' h.tiul0 l ot'i ,,t,.li' inlatr g it

adiliuin mi- tl f lit-* healvymtals in '.1ttrt l It'. mf/ l.t .it illi swewagare' 'w"-il' 'italkd and remain 'sf, "'is jc tfjij n-u'.: frc'isd1tr While aeralion hyalgae anti soAlar trapped in (lhi Lto ilti.live pond's * c! etvf r n.lr Iiei.u.energy can greatly reducethe elec- diges(.-rflit tricity consuned by an AlP plant, aiolhitvr so4urceof energy electricity- I:urlHr, ;otit ii(t.k h as nitroger generati(ointhrough combustionof and p !iphoiru,tts1 mdinlamage aquatic ;methariv-could eliminate electrical ecosyslmnlsint w Ili h effluent may pwer costscompletely. Methane can be dischiarg-d All' plants are better lb prodticedby fermentingalgae har- thanicoinvettlti..l plantsat removing vesttedfrtmo the plant's settling pond. thest-mitricrnts. Nilr-ogenremoval occlrs inlit) tihedigi.t Aioll hase in the Conivenitionialplants typically install facultativepond. If%addition, nitro- largetanks known as digesters,in gen anidphosphoruis are takenup which sliutge and efftlueit solids fer- and cOlixi h', algaein the high- imentto ptotiuct methine. In an All rate pond.( Oswld ch.a-mpionsthe use plant. methale from natural fermen- oi algaela vvsledflromn AU plantsas tatioaimin the digester pit coild becap- fertili,v*r hecawq I e ntitrienis con- ttiretdal [lie surface(f Ilie facultalive tainmiedin algav 1%imii be released p 4m1til.D)velfiping a gittl lcoimni*rcial mott slenv (itanwould the water- ietluane capturesystem loir AlP'sys- soluibl forinisin chemicalfertilizers Iems is undter wav. The lntvir,timen- antl tlns lt. s lil'lv to return tn j ltI glltering ad d (1I * StIivit lakt.i.l t ll stre ';ansill uttloff. Laboratorv (UC-Blerkeley) in Rich- miod, tCalifornia, is working on that det'vlnouptnent with thinds from (lie (Caliilrnia Pn*nrgy Comtmti,.sion anid

tIhe ( alitorn ii sittitoh for I lltergy Fi ilicv AlI' MVStt'O-'s .li'.0 eYxceed ct vliitio(n'iial "iut tihc 111stioill ill Inwotrog inCn a- prinwiav mid -4eMtndary tieatnment ingly strimt;''it rngil.itimur i;i. cost., plantsat killi,,g pathlogensbecanti,w ,f I says Gicrnt "If y on'%c -.,d 2(Ult',to latlural disinfection by highi alkalinity 300', of votir costs oll the front frid, andt ultraviolet (UV) exposurc Wilh Wvith Sort t r gregi-co or ery atid tjlf - otut aill

IIul

1 , - rmqAc, gon, u,,w, a, plnantis highlighting the beneficial :r-S ASfi,,,,Cr ha reuse of its r (clainiedwater by grow- .t 'vi OfSt. Irline,, ing pumpkinis, corn, melons, flowers, ConclUsio,I trr rrnitte1 P'fai,rt. roses, and more tlian 0.8 hectares (2 acres) of wine grapes. The St. I Ielhn,aplant has de:non- strated the All' conceptfor nearly t Still, not vI,en lth most enthusiastic 30 years.N-h 'rv than 89i hybrid AII' proponents of' All' systems clainmthat plants ar- nov u,llcri -ilo);togeleimets the basic four-stage system of ponds of the All'Pt(I elt in thu UJnited

t 1413 lil ' ~~~~alontecaniproducee effituiett mee-tillg Statesi and.( thcr comlinIic- viArostof Mlil Fitandardsfor drinkinig water or for them lik ',I !Ient _plant, Ecc "unrestricted" usessuch as swimming very liltif lhidgu. Manv of them use a p)(,fls and irrigationiof public parks. combinatao i of roe" hniicalI and solar

An All' system, like otter treatment aeration, a p h ( (.-ttli,1t lill requires icerts,t| can only acihievetheses goals less electiio.t il uI, d -.; ( trventional I vwaddilional iteiatnient(e.g., disin- treatment and I lamI a ca than fectioni,filtraitiot, and solids removal). doesa systill -I hI ;1'- t.I lelena's.

- -_ --- _ As the Lcmoflik of All' cN slelmis g Adianced Intefgrated Pond System Concepts In YourCommunity beconme i.nn vell 1,I1 %I,thowever, theaccept.u(nI ot tii^; I 'o-cost treat- (o1ttlr Sv'*teMrelPenllits uOed in AIP high-ratepond can reduce the need for, or mentcin(nlo)l .u isi 14i', to*foww. In a r'ov I in betr';nd in conriinclinn substitutefor, mechanicalaeration equip- political cliroit,ol intui:';ifyirig fNeii;ioniltviasoe'ialei t mrrint meint.The primary or secondaryreactors moyy lo reatlea hlihvid system. anidmechianical aeration equipment are regulat*iccoiri,an *..:a Ilicnate in tJitinO thlnseAlf elements allov's usuallythe mostexpensive and energy- wich c I i, nu.uiol*nance, aCthivethe Irestof bolhwnlrlds" intensiveelements ofaconventional treat- and (pmami* nit; it" increasingly vlamliniua wastewatertreatnierit mentfacility. And because of the long importanit.Ih All't (Ol1tniay t n. detentiontime of organicmaterial in the prove to oit'tIU ir lI 1li( Inuiology tacultativepond's digester pit, organic for use biy ni.nv huial .a!;tewater :tnologyhas been arounid ir materialis completelyremoved from the manager.. U 40 Yearsaid la heenapplied in wastewaler.This sludge undergoes con- 1litionsW ere ow usingsote e ele- tinuousdigestioni until only a smallvol- lonsAIP l nolrgv,us sonierreaing.le umeof residueremains. Daily sludge of All'teclnolry,' tliu.i creting removaland disposal are eliminated, thus tringllscal pressule on toveal goven- achievinigdollar and energy savings. antithe highcapital costs of con- Wastewatertreatment tiranagers are fac- anlwaslevialer treatrnent pLtnis, ing tougherstate and tederal regulations believeInterest in AIPconcepts is affectingthe qualityand handling of ircreasing.Yomr commrnunilv may sludgeand elIluent from their plants. it a hybridappmiachl nakes tIhe UsingAIP technology to designhybrid en1;e. systemsor completeAIP systems can rnnple.use of a larultativepvrd helpyour community meet regulations w youto clonsizeor elimlinatelthe aandsave dollar s atrdenergy-a "win-win" 4 or se,eotidaryreactor. Llse o! a stuaton.

4 Ilescripil/onof ant Advanceid Inlegraled Pond Sy stem An Advarir;.dmlilegrated Pond (AIP) sys- mTlicrollpae 1he rapill (powll of a!lao lefi consists of four basictypes of ponds, also t;ises thiealkalinity of the vater. inlerlinkedand working together: killing pathogensRer:ause tIle algae FacultativePhond (Pond 1) I ate wit Thielacultitive pond consists of aniopen oxygeni.somie of lthis ponid's vaeri recirculated pondcontainij pondcontiniij aa"digste "digester pit.pit" tSewageSeage faciultativepondto theto upoer bolster layerits oxygenof thle enteringthep system is injectedat the hot- cotn,hurediigoelnnin tom of the digesterpit, wheresludge is permnanenitlytrapped and consumied by the needfor mechanicalaeration fernientalionIn newerAIP system SettlingPond (Pond #3) designs,in whichthe water table is low Moreth.an hali tiheatinae produced in enough.the facultativepond is about the hiiuhl-ratepornl settle out. Sutficient 4- to 5-moeters(13- to 16.4-feet)deep. algaesttile in Ithhitlh-rate pond to i nrf Itittrrill F t 1-r Thepond has an oxygen-rich upper layer meettotal susireiided solids discharge *'I{^f lUJ?tf.acilifi 1I. IYJrnr .jfai, ni about 1-meter(3.28-feet) deep, which requirennenis 9 helpsto oxidizeany malodorous gases i ~~~~~~~~~~~~risingfromthe digesterpit.Mlrlo Treatedwater odis fol)sed /od to tl?ensun's 4 High-RatePond (Pond #2) UVra;s andslored t(l i;rrigaltonand Waterfrom the lacultativepond flows to dispo:;al the high-ratepond, where aerobic bacteria breakdown dissolved organic matter. Oxygenis suppliedphotosynthetically by

)fiagromof it. Itelenas AIPSyslem

S l~~~~~~~~~Recirculationof 1 I ~~~~~~~~~oxyqpnrichwater 1i t

! , 5 5 _ $41Xll*s~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~4

Facultatiwe 2I pond#11

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1 ~~~~~~~~~~~~lrigatn,n ~ ~ ~~Toj I