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Republic of the PhilippinesLocal Water Utilities Administration

SEWERAGE AND SANITATION PROJECTWATER DISTRICT DEVELOPMENT PROJECT

WORLD BANK

ENVIRONMENTALLUZON

ASSESSMENTREPORT

CAGAYAN DE ORO CITY

MINDANAO

CAGArANDE ORO

August 1997

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 16Section II Environmental Pollution 20

Chapter 3 PROJECT DESCRIPTION AND ANALYSIS OF ALTERNATIVES 27

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

Chapter 4 ENVIRONMENTAL IMPACTS 47

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

Chapter 5 ENVIRONMENTAL MANAGEMENT PLAN 52

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

Appendices

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

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I

EXECUTIVE SUIqMARY

Introduction

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

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

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

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

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better sanitary conditions will thus be achieved in the areas served by the sewerage andsanitation systems. This will reduce water-borne pollution and water-logging within thecities and in the surrounding water bodies, thereby bringing health benefits to localpopulations. The construction of the systems will protect shallow groundwater aquifersfrom contamination.

Environmental Assessment Requirements

This Environmental Impact Assessment Report for Cagayan de Oro has been prepared inaccordance with the Presidential Decree No. I586 otherwise knovwn as the EnvironmentalImpact Assessment Law and Department of Environment and Natural Resources (DENR)Revised Administrative Order Nos. 36, the Revised Water Usage and Classification/WaterQuality Criteria and Revised Effluent Regulations of 1990 respectively; and World Bank'sOperational Directive 4.01 on Environmental Assessment. The revised Administrative Order36 for Environmental Impact Statement System issued in 1996 is comprehensive and iscompatible with the World Bank's Operational Directive 4.01. It outlines the procedureto be followed by environmental critical projects (ECPs) and projects to be located inenvironmental critical areas (ECAs). in preparing environmental impacts statement(EISs)'. ECP and ECA are defined in the AO. It should also be noted that that localordinances and regulations governing projects of such nature have been taken intoconsideration in preparing this report. Similar EIA reports are being prepared for the other 4cities.

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

Selection of Priority Cities

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

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

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

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

Overall Project Approach

The proposed project follows a demand-based approach in the sense that facilities will beconstructed only if they conform with the preferences of local stakeholders, and servicesconform to their respective willingness to pay. The stakeholders represent the differenttiers of organizations from the City or Municipal Council and Barangay (part of the formalLGU system), to the more informal purok, neighborhood and household levels. Duringproject 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 basicdecision-making process is as follows:

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

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

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

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

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

For the sanitation compone ts, the entire city has been included in the project area, withfinal selections being made on the basis of demand. On-site treatment systems through theconstruction of VIP (ventilated improved pit) latrines, pit latrines, pour flush toilets andseptic tanks will also be constructed if there is demand from property owners. For thoseproperties with uncertain land tenure (as in squatter settlements), the project will financethe construction of communal toilets, to be managed by non-governmental organizations(NGOs) and/or the private sector. The specific locations of these facilities will be drivenby the willingness to pay for the services by beneficiaries at the barangay level, provided ofcourse that these are technically feasible.

Analysis of Alternatives

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

Minimize overall pond area required

Minimize odor production

Meet DENR effluent quality criteria. including fecal coliform reduction

Minimize sludge production rate

Maximize potential to use surroundinig land for recreational purposes

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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

SLze of Central 1.000 heulares 400 hetares 120 helares 95 hedtares 50 hectaresBusness 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 cityrisk 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 fishwastewater recreaticnal untit for and estuarine area and rapid farmingpollutio purposes recreational eutrophicatic

purposes because of fecalocmtaminaticm

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

Cagayan de Oro City

Impact During Construction Phase

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

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

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

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

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

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

Ecological Effects. As there are no rare, endemic species of flora and fauna in any of theproiect 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 facility will have minimal impacton the air quality of the area. Aside frorn the occasional odor nuisance. it is not projectedto have adverse effect at all.

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

Socio-economic. The provision of sanitation facilities in the project cities wouldundoubtedlv benefit the general populace of these areas. Thle occurrence of epidemic-scale diseases caused by cuirent unsaniitary conditionis will be reduced. T'his will result in amore healtlhy and productive populatioln.

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

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

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

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Table 1: Mitigation Actions

Construction Phase

Potential Impact & Risks Mitigation Action

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

Air Pollution * Careful construction planning and work phasing, specificationsand construction methods to reduce the 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 forsuspended 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 civillikely result in a decrease in air works.quality. * Good housekeeping for all construction affected areas and

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

Water Pollution and Soil Erosion * Provide temporary drainage and storage facilities for excavationsoils, 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. avoidtion 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 equipmentm. * 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 beFlow located along secondary streets.

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

* Coordinate with the local traffic management office and the PNPTraffic Management Command: Clear directional signs and barriers in case traffic rerouting isneeded.

* Public information campaign.

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Operation Phase

Potential Inpact & Risks Mitigation Action

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

* Breakdown or malfimction of the including precautionary and remedial measures to besewer 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 facilitiesraw sewage will have to be installed during the construction phase.dumped directly. l

Water Pollution * Upgrade laboratory facilities of the Cagayan de Oro City WaterDistrict (COCWD) to be able to undertake wastewater analysis.

* The effluent discharge may well * Following the bubble concept, wastewater discharged into theaffect the condition of receiving Cagayan River shall, in the long-term, conform to the waterbodies of water and the effluent quality standards established by the Department of Environmentdischarge 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 Qualityconditions (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 theCagayan River shall be timed based on tidal conditions. Theadoption of the AIPS process for the treatment plants shouldresult into attainment of effluent standards.

l Noise would be at about 65-85 . Establishment of buffer zones and noise zonesldBA. principally coming fromseptage trucks unloading at thetreatment 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 theunloading 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.

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Monitoring and Implementation Arrangements

Construction Phase

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

Noise will measured at the same locations as TSP. Lc41 and Lgo values will be measmi d andrecorded.

Operation Phase

Receiving water quality will be monitored by the DENR through its regional officeswhich is monitoring the status of Cagayan River on a periodic basis. The PMO willcollect information on present conditions, observed changes in pollution loads etc. Itshould be noted that all the pollution load will not be removed but the proposed sewerageinfrastructure will greatly reduce the problem. Once the plan becomes operationaL thetreatment 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 effluentdischarges. Daily representative values of PH, 5-day BOD, COD, Total Nitrogen andTotal Phosphorus will be measured during the start-up penod. Once the plant operationsstabilize, weekly measurements (24-hourly basis) will be taken.

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

Implementation of the Monitoring Plan

The PMO. with the assistance of LWJUA-CPSO and consultants to be engaged in theproject. would monitor compliance with the ECC and carry out the requisite datacollection. Monitoring reports would be submitted to DENRJEMB and the World Bankperiodically. While respective responsibilities for the various mitigation activities havebeen identified, the PMO will ensure that the requirements are complied with; in addition,feedback firom communities. city officials. NGOs, etc. will be pro-actively sought throughthe city public affairs programs. regular monthlv meetinpgs of barangay captains and othermethods. Finally, DENR. througlh its planned PPA svstem, would also periodicallymonitor and audit compliance with the ECC, assisted by independent contractors.

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

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Table 2Summary of Responsibilities and Timetable

for the Monitoring Plan

Activity ResponsibUity Start Completion

Secure ECC clearance from DENR. CPSO-LWUA Decemiber 1996 Sptemnber 1997

CoUect reference ambient air parameters City PMU. with DENR September 1997 June 1998around the proposed treatment plant sites at regional officeprojecs cities

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

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

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

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

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

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I

1. INTRODUCTION

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

The provision of a cost-effective centralized wastewater colection, treatment, and disposal isthe primary objective of the proposed Water Districts Development Project (WDDP). Theproposed project wiDl assist the local governments of Dagupan, Calamba (Laguna), Cagayan deOro City. Davao City and Cotabato City, in finding solutions to the problem of sanitation.

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

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

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

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

Overall Approach of the Proposed Project

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

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

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

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

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

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

f Itv irumesnmtal .-I.A:weA.ne,1 IRepor C (agaan e Ol ()ro ( 13

construction of VIP latrines, pit latrines, pour flush toilets and septic tanks will also beconstructed if there is demand from property owners. For those properties with uncertainland tenure (as in squatter settlements), the project will finance the construction ofcommunal toilets, to be managed by NGOs and/or the private sector. The specific locationof these facilities will be driven by the willingness to pay for the services by beneficiaries atthe barangay level, provided of course that these are technically feasible.

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

(a) Minimize overall pond area required

(b) Minimize odor production

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

(d) Minimize sludge production rate

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

Environmental Impact Assessment

This Environmental Impact Assessment Report for Cagayan de Oro has been prepared inaccordance with the Presidentital Decree No. 1586 otherwise known as the EnvironmentalImpact Assessmentt Law and Department of Environmenit and Natural Resources RevisedAdnministrative Order Nos. 36, the Revised Water Usage antd Classification/Water QualityCriteria and Revised Effluenit Regulationis of 1990 respectively; and World Bank'sOperational Directive 4. 01 on Environtmental Assessment. The revised Administrative Order36 for Environmental Impact Statement System issued in 1996 is comprehensive and iscompatible with the World Bank's Operational Directive 4.01. It outlines the proceduresto be followed by environmental critical projects (ECPs) and projects to be located inenvironmental critical areas (ECAs), in preparing enviromnental impacts statement(EISs)'. ECPs and ECAs are defined in the AO. It should also be noted that that localordinances and regulations governing projects of such nature have been taken intoconsideration in preparing this report. Similar EIA reports are being prepared for the other 4cities.

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

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This report has been prepared by a team of local consultants under the aegis of the Local WaterUtilities Administration (LWUA) and the Cagayan de Oro City Government. Much of thework relating to the environmental impact analysis was undertaken as part of the feasibilitystudy done by C. Lotti and Associati Consultation with the community is an on-goingprocess. The sanitation component of the project will be executed in a participatory manner,and detailed guidelines have been spelled out.

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2. BASELINE ENVIRONNMNT - CAGAYAN DE OROCITY

Introduction

This chapter is in two sections. Section I profiles the existing environmental situation inCagayan de Oro City and Section II analyses water pollution impacts (historical) ofuncontrolled sewage discharge.

Section I - Existing Environment

2.1 Land Resources and Use

Cagayan de Oro City is located along Macajalar Bay on the central coast of NorthernMindanao and serves as the capital of the province of Misamis Oriental as well as theregional center of Region X - Northern Mindanao. The city is about 780 kilometerssoutheast of Manila and 190 kilometers northwest of Davao City. [Figure 2.1]

Cagayan de Oro City is the major urban center of Northern Mindanao with a total landarea of 48,886 ha. It is among the developed urban settlements in the country with anannual growth rate of 5.5%, twice the national average of 2.7%. The urban area which isapproximately 2,335 ha, lies along a narrow coastal band expanding southward into thecitys western flank. The poblacion, or the city center, occupies approximately 400 ha. Itlies adjacent to the eastern bank of the Cagayan River. High density residential andcommercial development characterize this area.

Urban development has mainlv followed a linear pattern adjacent to the National Highwaywhich is basicallv the main transport artery to the rest of Mindanao. The natural limitingfactor in the development and growth of the City is the topography of the area.

Development has been confined to the coastal strip, however. recent developments havebeen made southward of the city and in the westem side of the Cagayan River. The mostextensive urban land-use outside of the poblacion is medium-density residential areas. Thecenter of industrial development, on the other hand, is located at Puntod, Bayabas andTabon.

As of 1992, agricultural lands occupy 72.58% or 35,481.46 ha of the total land area.(CPDO) Coconut and corn are the predominant crops cultivated. These mixed cultivatedareas are usuallv associated witlh grasses. This is a manifestation of the present trend to

I knx uro,menta/.-lx / Repf irn (Caga van i doro (,IfY 16

utilize grasslands for agriculture. Table 2.1 shows the Land-Use by Zoning Districts ofCagayan de Oro City. [Figure 2.2]

Table 2.1Land-Use by Zoning District

Cagayan De Oro City

Zoning District Area in PercentAgricultural 81.90Residential 12.39Parks, Plazas and Open Spaces 2.00Industrial 1.68Commercial 1.26Institutional 0.77Total 100.00

Source: City Planning and Development Office, Cagayan de Oro City

2.2 Physiography and Geology

In. general the city is dominated by rolling and steep terrain. The lowlands represent anarea of about 3,536 ha. Most of these lowland landscapes are broad alluvial plains. Asthe most extensive land management unit (LMU), they occupy about 82 % of the lowlandareas. 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. Themost 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 haor about 38.2% of the upland areas. These areas in general have well drained, acidic, anddeep. clayey soils. The remaining upland areas are mostly low hills that have sloping landsand relativelv shallow degraded soils. The hilly lands of about 16,818 ha are lands wheremost soil erosion and degraded grasslands are located. The highlands of about 1,416 haare 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 soilmanagement and conservation program.

About 13. 166 ha are lands below the 18% limit prescribed for the alienable and disposablelands. In general, the area is dominated by steep and rolling lands with slopes greater than18% slopes. TIhese areas 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 greaterthan 30% represent an area of about 2.762 ha (Louis Berger International. Inc.. 1992).nThe two sites being proposed by the City Government for the wastewater treatment planta-e situated along the banlks of the Cagayan de Oro River. The Bgy. Nazareth site and the

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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 withinbuilt-up areas and are adjacent to developed residential communities. It is estimated thatthe 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 avery short dry season which lasts from one to three months only. As is common in thecountry the Northeast Monsoon prevails during the months of November to Marchexhibiting maximum intensity during January and February. It is a relatively cold and lesshumid air mass as it originates from the intensely cold anticyclone over continental Asiaduring winter. From June to September the Southwest Monsoon dominates the area. Thisair mass is warm and extremely humid and originates from the Indian Ocean crossing theequator and enters the country from the southwest. The North Pacific Trades are generallydominant during April and May.

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

The mean annual relative humidity at the site is 80% which is a typical maritime tropicalvalue. The lowest mean monthly value of 76% was recorded in April, the driest monthwhile the highest is 83% during the month January. Appendix 2 shows the climatologicalnormals 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 ofapproximately 1,521 square kilometers. The receiviing body of water for the effluent ofthe wastewater treatment plant is the Cagayan River. It should be noted that as perDENR Classification, 1993, Cagayan River is classified as Class A. As pointed out by theRegional Office of the DENR- 10. discharging of effluents are discouraged in Cagayan deOro River as said river is utilized as source of potable water supply. Table 2.2 shows thelatest analysis of water samples taken at Cagayan River.

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Table 2.2Results of Physical and Chemical Analysis

Cagayan de Oro River, Cagayan de Oro City

Parameters March 4,1996 May 1,1996

Color, units 15 15Odor, T. 0. N.Turbidity, ppmTemperature, Co 27 28pH 8.18 7.15Dissolved Oxygen, mg/L 7.8 7.5BOD5, nigL <1.0 <1.0Settleable Matter, ml/LTotal Solids, mg/L 116 130Suspended Solids, mglL 14 38Total Dissolved Solids, mg/L 88 118Grease and Oil, mg/LTotal Coliform, MPN/100OOmlAlkalinity, mg/L as CaCO3 0.0 40Chlorides, mg/L 50.0 1.0

2.5 Vegetation and Wildlife

Two sites are being made available by the City Government for the Wastewater TreatmentPlant, the Bgy. Nazareth site and the Bgy. Consolacion site. Both sites are along thebanks/easement of the Cagayan de Oro River. The sites are within well developed areasas such floral and faunal communities are severely inhibited and highly influenced byhuman 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 totalpopulation of Cagayan de Oro in 1995 at 397.920. The total urban population isestimated at 372.337 persons with density of 17.03 persons/hectare. Recent developmentaad growth in the City is conicentrated in the urban areas located away from thePoblacion-along the coastal and national higlhway. This is primarily due to the lack of landto cultivate. accessibility. and attraction to developed areas.

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Section II - Environmental Pollution

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

2.7 Existing Sanitation Conditions

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

* Even though water-sealed toilets are considered the "standard" sanitaryfacility, 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 ultimatelydrain to Macajalar Bay, thus increasing bay water pollution; and,

* Although more than 60 percent of the households have septic tanks, theirdesign and construction are a cause for concern. The leaching chambers ofmost septic tanks have unlined bottoms allowing effluent to seep into thegroundwater. the principal source of the City's water supply. High fecalcoliform couwts for groundwater samples in a previous wastewater feasibilitystudy 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 seriousconsequences for human health in Cagayan de Oro. Amoebiasis is endemic, occurringmost frequently in the western areas of the city: Carmen, Patag, Kauswagan, Bulua andBavabas. It is particularly common in areas where the squatter population is high. Theregional office of the Department of Healtlh estimates that the city experiences about 130-150 cases of medicallv-confirmed amoebiasis per quarter.

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Table 2.3: Waterborne disease in Cagayan de Oro, 1992-1994

1992 1993 1994

Rate Rate RateNumber (/100,000) Number (/100.000) Number (/100,000)

MorbidityDiarrhea 2562 696 2065 539 2924 733Amoebiasis 396 108 215 56 418 105Typhoid Fever 234 64 232 61 246 62

MortalityDiarrhea 8 2.17 2 0.52 8 2.0

nAmoebiasis 7 1.9 7 1.83 3 0.75Typhoid Fever 5 1.36 6 1.57 1 0.25

The overall incidence of diarrheal diseases is also quite high. The Office of the CityMayor reports that in 1995, the City Health Office provided medical services to 11.211people 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 indicatorfor our analysis, because medical experts agree that 75% of all typhoid cases are directlyattributable to water pollution. The data in Table 2.4, provided by the RegionalEpidemiological Surveillance Unit (RESU) of the Department of Health, highlight thesame western hot spots. Patag and Bulua have a very high incidence of typhoid. followedby Carmen, Kauswagan and Bayabas.

Table 2.4: Reported Cases of Typhoid, 1995

TyphoidBarangay CasesPatag 33Bulua l sCarmen 4Gusa 4Kauswagan 4Bayabas 2Lapasan 2Nazareth 2!BalulangtBonbonsBugo_i !ICamaman-anL PuntodITablonl

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2.9 Existing Environmental Conditions in Cagavan de Oro

MacaLalar Bav - The coastal waters of the Macajalar Bay show signs of high stress due toits 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 domesticwastewater 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 andheavy metals render the bay unfit for shellfish culture. High fecal coliform counts renderthe bay unfit for swimming, bathing and other water contact recreational activities.

Groundwat r - Cagayan de Oro clearly has a major problem with contamination of watersupplies. . ible 2.5, based on sampling at different points in the city, shows that thegroundwater is heavily contaminated. All 11 samples far exceed the maximum allowablelimit 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 | 3,700Coliforms

Caga an River - serves as the sewage outlet for several populous barangays in the centralpart of the city: Nazareth, Carmen, Kauswagan, Poblacion, Consolacion. Puntod, andMacabalan. Analysis of water drawn from the river at Carmen Bridge (immediately behindCity Hall) suggests a high level of organic/fecal contamination. Table 2.6 providesevidence on average contamination of the river during the past few years.' These readingsgenerally 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 areason the western side of Cagayan de Oro are thought to be more highly degraded thaneastern beach areas; our data generally support this perception. Raagas Beach is locatedin Bonbon. fronting Kauswagan on the north. This beach area extends from Bayabas toMacabalan, interrupted by the mouth of the Cagayan de Oro River. The area is settledthickly by squatter colonies. The data in Table 5 suggest that Raagas is heavilycontaminated by sewage, both from adjoining settlements and from the Cagayan de OroRiver. Recreational beach use in this area has decreased significantly over the past 10vears.

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

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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 StandardBeach Sample Years Coliforms DeviationRaagas Beach, Bonbon 1991- 1995 10,515 23,570

Chali Beach, Gusa 1994 46,245 65,707

Acuna Beach, Tablon 1994 760 764Family Beach, Agusan 1994 1920 2234

Chali Beach in Gusa is located to the east of the Cagayan de Oro River, and is also thesite of several squatter settlements which have probably contributed to the high level offecal contamination. Tablon and Agusan, the locations of Acuna and Family Beachesrespectively, are even further east. There are no substantial squatter settlements in theseareas. The eastern parts of the coastline are said to be cleaner, partly because their use forrecreational purposes is more tightly controlled and partly because neighboring settlementshive lower populations.

There is undoubtedlv a general relationship between the level of contamination at eachbeach and the size of the unsewered population in neighboring barangays. It is alsoreasonable to assume that the problem is worse near the mouth of the Cagayan de OroRiver and three contaminated drainage creeks. One approaches from the south ofCamaman-an. passes behind the Lim Ket Kai Center and discharges into the MacajalarBay. Another is located to the west of Bulua and discharges into the sea. The third flowsfrom 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, weadopted the conservative assumption that these readings were only 24,000.

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2.11 Reduced Opportunities for Commercial Development

Accelerated high-rise construction and sharp increases in property values haveaccompanied the installation of sewerage in the Makati district of Manila and the centralbusiness district of Jakarta. Indonesia. In some Latin American cities, central-cityproperty values are reported to have increased by as much as 20% after sewerage wasinstalled. It would not be surprising to see similar results in Cagayan de Oro if seweragewere installed in the Poblacion district. The city of Cagayan de Oro is well-positioned tobecome a commercial hub for its region, and the municipal leadership clearly aspires tothis role for the municipality. Rapid expansion of high-rise commercial activity inPoblacion 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 themunicipality's drains and water courses. These deficiencies are the major contributingfactor for the poor environmental conditions of Cagayan de Oro.

Health-related problems related to sewage contamination and inadequate sanitation are ofuncertain magnitude, but are an important consideration for the city leadership.Waterborne and other sanitation related diseases continue to be a major public healthproblem in the country. In Cagayan de Oro, amoebiasis is endemic and occurs mostfrequently 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 600cases of medically confirmed amoebiasis per year, particularly in areas where the squatterpopulation 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 ofdiarrheal diseases may be indeed quite severe.

Tle City's water bodies appear to be in seriously deteriorated conditions. Fecalcontaminationi of the groundwater and Cagayan River has been observed. Pollution of theMacajalar Bav is closely related to drainage from the neighboring population. Adverseenvironment conditions exist in Cagayan River and three drainage creeks feeding into thebay. due to organic pollution from untreated wastewater discharged into them. Pollutionreduction will then depend on the proportion of the local population whose sewage aretreated or safely removed from septic tanks. Fishing productivity, in the bay waters hasdeclined. but sewage contamination has not been a significant factor (as was noted inDavao Citv and the other cities).

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

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3. PROJECT DESCRIPTION AND ANALYSIS OFALTERNATIVES

Introduction

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

Section I - Project Rationale and Objectives

Chapter 2 describes the existing environmental situation Cagayan de Oro City, andillustrates the worsening health impacts caused by the uncontrolled discharge of sewage.There is negligible piped sewerage in the city. There are no treatment and disposalfacilities for septage removed from septic tanks. Septic tank overflows and soakawaysenter the drains and the groundwater.

The proposed project is. therefore, aimed at addressiing the problems of inadequatesanitation and sewerage in Cagayan de Oro by providing sustainable sanitation andsewerage facilities, thereby reducing public health risks and environmental pollution fromwastewater sources. The project is designed also to provide a learning experience forfuture expansion of sustainable sanitation services for the city as well as for other urbanareas. 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 theenvironment.

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

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as well as 36 communal toilets city-wilde. The sanitatioll works were based upon anidentified deficit of sanitation facilities of 19%0. The choice between individual andcommunal facilities will be driven by technical feasibility and demand by key stakeholdersand not by tenure status. The location of the individual as well as commiunal toilets is notdefined yet and will depend on the consultation of potential beneficiaries. The areas to beserved by the communal toilets may include public areas such markets and low-incomesquatters or blighted areas.

The possibility to construct on-site facilities is site specific. As thi- majority of squattersare located on government owned property, that is, along river be ks and shoreline it isunlikely that communal toilets, with on-site disposal will be technically feasible. In theselocations communal toilets will only be feasible if there can be a direct discharge to aproposed sewer. The sizing of the facihty is dependent upon the depth to groundwater,the permeability of the ground and the availability and 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 arrangementsfor 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 tothe local community the facility is serving through a leasing arrangement;

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

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

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

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

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

- availability of water supply;

- availability of power supply:

- area not prone to flooding.

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* 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 50,300Communal Toilets- Construction 6.59 9,000- Land 3.60Total Sanitation 73.09

Construction and land costs include 5% physical contingencies. The cost of engineeringhas not been considered on the assumption that the design and construction supervisioncan be handled directly by the City's concerned department due to the simplicity of thestructures.

B. Operation and Maintenance Cost

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

Implementation Schedule

It has been assumed that the 6.882 on-site sanitation facilities and 36 communal toilets willbe constructed during the five-year project period. Therefore, an average of 1,372 on-sitefacilities and 7-8 communal toilets would be constructed annually including the requiredtime for conisultation and 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 individual properties. It includes the collection and treatment of"domestic" sewage only and not for any 'industrial" waste discharge.

The sewage is collected and transported through a network of underground pipes, orsewers, to a wastewater treatment plant (WWTP), where the sewage is treated to producean effluent that can be discharged to a receiving water body (river, sea, etc.). Sewageflows along the sewers by gravity, that is, the pipes are laid at a slope or gradient which issufficient to ensure that the sewage will flow without causing blockage.

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

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

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

The transportation sewers can be considered as the "'main roads", with the collectorsewers 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 limitations for 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'sdrainage system:

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

* biological degradation of rivers and Laguna de Bay which havc been found to bepolluted with human excreta and positive for fecal coliforms. Disposal of septictanks effluent to the drainage sister contributes to aggravate this pollution problem.

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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'sdrainage system;

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

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

The identified Initial Service Area (ISA) comprises a total of 53 barangays with an area of9,808 ha and a total population of about 289,360 in 1995 projected to increase to about531,570 in 2015 (see Appendix 11. I - Table 11.1.2). The ISA is bounded on the north bythe Macajalar Bay, on the west by Barangays Bulua and Canitoan, on the east byBarangay 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 FeasibilityReport) which can provide the highest impact in terms of improvements to theenvironment as well as to the social and economnic conditions of the City. The areasincluded are:

* the Poblacion's -center where commercial and institutional establshments, such as,hospitals, and offices are located;

• the barangays that are highly urbanized and densely populated adjacent to thePoblacion.

The Stage I Service Area has a land area of 192 ha with a population of about 27,830 in1995 projected to increase to about 30.080 in the year 2001 (starting of operations) and toabout 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 servicearea population. At the starting of operations, in the year 2001, the system will serveaoout 18.050 users, with 3.002 connections, projected to increase to about 20,570 users in2015 with 3.422 connections.

The figure that 60% of service area population will connect to the system is based on theassumption that 85% of the population (year 2015) would be connected to the COCWDwater supply system, and of those, 70% would be connected to the sewer. Expansion ofthe system would be dependenit upoIn the number of sewer connlections and the sewage

',1rnMmO11tU/ . INSeASfl7t Report: ( galvan de ()O ( 'it' 31

flow from each connection. The capacity of WWTPs and pump stations would have to beincreased once the 60% design flow is reached. This may or may not correlate to theactual connected population.

Potential Treatment Plant Sites

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

* take advantage on the availability of small parcel of lands with minimalnumber of settlers, if not totally vacant;

* divide the system into smaller catchment areas considering the potentialtreatment 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, downstreamof the Consolacion site previously identified in the Feasibility Report. The previous site isa reclamation area and, therefore, concerns were raised as to the suitability of the site andthe cost of reclamation.

The land value quoted by the City for the new Consolacion and Nazareth sites isP3.000/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 processoptions 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 pondfollowed by facultative pond(s). Each pond is defined as follows:

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

/nr7lwir*mcl .-lx nc.fle( sI?eJ)(port. (caga an ile Or () ('Uv1 32

effectively decrease the land requirements of subsequent facultative andaerobic ponds and the accumulation of large sludge banks in subsequenttreatment ponds is avoided.

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

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

The design criteria for the process is as follows:

* Anaerobic Ponds- Dual ponds. depth of 4.0 m; side slopes of 3: 1; rectangular with length of 1.5

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 tobe applied to residual BOD in effluent from anaerobic ponds.

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

- Pond volume to be determined by the higher value.

- Estimated BOD removals of 70% of influent BOD (overall BOD removalsestimated at 90%/6).

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While providing a treatment system that has a reduced land take (compared toa complete facultative lagoon system) and utilizes no mechanical equipment,there are concerns as to its ability to operate satisfactorily. Concerns raisedinclude:

* Anaerobic Pond

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

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

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

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

* Facultative Pond

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

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

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

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

2. Modified Lagoons

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

The modified lagoon system is an integrated, multi-stage biological reactor systemtreating municipal, agricultural and industrial wastewater. The reactors may berelatively deep and constructed of compacted earth as open surface pond areas.The biological reactor has discrete and isolated biological zones integrated into asingle unit; a deeper anaerobic cell(s) at the bottom of the reactor, sludge blanket

1,i'nvirmnmewtal s svesmesnt Report. (C'qvan a ()ru ('it\ 34

suspended over the deepened zone and an overlying aerobic zone comprised ofaerobic bacteria, algae and a saturated oxygen media provided by a combination ofalgae and surface aeration.

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

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

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

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

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

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

EMtlronnmenial ..lsseswysent Ie?tuwl ( Caga\van c1e Orn ('itl DO

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

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

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

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

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

The design criteria for the process is as follows:

* Basic Design: Three ponds in series to meet coliform requirement< 1.000/l OOmi

- Primarv Facultative with anaerobic cells

- Secondarv Facultative with following anaerobic cell

- Tertiary - maturation pond

h.' lsf Environmentl . Lvsses smeiitu9l Reporl: C gqva sle Oi-o CifY (1[ 306

* All systems designed with parallel facultative ponds.

* Detention period: Primary pond - 5 days

Secondary pond - 3 days

Tertiary pond - 3 daysNote: 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 becauseof reduced area requirements.

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

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

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

Berm width - 3.64 m in all cases.

3. Mechanical Activated Sludge Plant

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

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

- Primary Settling Tanks

- Aeration Tanks

- Final Settling Tanks

- Anaerobic Sludge Treatment

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

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

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4. Recommended Treatment Process

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

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

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

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

Comparison of Alternatives

The alternative schemes identified are briefly described as follows:

AlternativeScheme Description

I The system will drain the sewage of the whole area to the WWTP (modifiedlagoon system) located at Consolacion site.

2 The system is divided in two areas: the sewage flow of Area North will drainto the WWTP (modified lagoon svstem) located at the Consolacion site;while the sewage flow of Area Southl will drain to the WWTP (modifiedlagooni svstem) located at the Nazareth site.

Lni-oonnional7 I. lss:ssmen(.' 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 twoalternatives are as follows:

Alternative WWFP Connected Total Flow BOD LoadingSchemes Location Population (cuamld) (kg/d)

Consolacion 20,564I - Sewage 4,113 823

- Septage 183 915Total 4,296 1,738

Consolacion 16,519- Sewage 3,304 661- Septage 183 915

2 Total 3,487 1,576Nazareth 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 onthe basis of costs derived from the Feasibility Report (DMJM. 1995) and other relevantstudies and data gathered by the consultant. For further information, reference should bemade to the Feasibility Report.

J:,ivirr,ntne,J71 .-ISNL.'XXSmf Reporrt ('agaL an tie Oro (;ty 39

Comparison of the two alternatives is as follows:

(i) Capital Cost

Capital Cost of AlternativesFacility (P million)

_ _ _ _ _ _ _ _ _1 2SEWERAGEI Collection 49.97 49.972. Property Connections 32.13 32.133. Transportation System 21.60 21.50

4. Pumping Station 2.50 _

5 Force Mains 0.486. Punp Station (Land) 0.24 _

7. WWTP 22.11 25.018 WWTP (Land) 120.00 150.009. 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.) asdevelopedfrom two study areas in Davao and Dagupan. Collection sewers proposed are"condominial ", that is, they are routed through private property to optimize the sewerlength and minimize cost of connection to the transportation sewer. Property owners haveto be consulted and agree to the condominial sewer design.

3 The cost of a house connection to a sewerfor an existing property, requiting theabandoning 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 seweragesVstem.

(ii) O&M Costs

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

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

201 246I 2 95 3.40

A1n jronnwll .IssVe..meJn1 RepOrt ('agaqan tle O1 O (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:

NPVAlternatives (P million)

1 179.202 203.32

(iv) Conclusion

The above NPV shows that Alternative I is the most economic (by about 12% over theother) and, therefore, is recommended for implementation. The recommended alternativeis for a collection and transportation sewer network, in the Poblacion area, discharging toa single WWTP located at the Consolacion site. The WWTP would use the modifiedlagoon treatment process and would treat both sewage and septage. The treated effluentwould 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 communalsanitation facilities; (ii) sewerage systems in Poblacion; (iii) maintenance equipment. toolsand spare parts for the operation and maintenanlce of installed sewerage infrastructures;and (iv) institutional support.

Sanitation Facilities

The sanitation component will include the construction of about 6,882 facilities includingVIP latrines. pour-flush toilets and other type of toilets with septic tanks/soakage pits aswell 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 andseptic tank". The demand for on-site facilities will. therefore, be established by publicconsultation concerning rented dwellings and owner occupied houses. Communalsanitation facilities to be provided under the project may be either on-site or off-site,connected to the sewerage system, depending on technical feasibility. The choice betweenindividual and communal facilities will be driven by technical feasibility and demand by keystakeholders. and not by tenure status. However, in slum areas and squatter settlements,the demand will be ascertained not onlv fiom the tenanits. but also from land owners andfrom local government officials representing public interest. The communal toilets will be

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constructed in areas where, through public consultation, there is an established demandand willingness to pay for the senrice.

Sewerage System

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

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

A modified lagoon system will be used for the treatment of both sewage and septage. Itsprincipal unit is a deep vertically integrated pond with an anaerobic pond below afacultative pond system. The geometry prevents turnovers, thereby minimizing odorproblems as well as sludge accumulation.

The project proposes the construction of sewerage facilities in the Poblacion of Cagavande Oro City. In the Poblacion. the Stage I sewerage system will cover a service areapopulation. 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 dischargesewage to a single vertically integrated pond system designed to treat both sewage andseptage. The treatment plant is located at the Consolacion site and the treated effluentwill 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 to400 mm;

* one pump stations with a capacity of 955 cu.m/d and a land requirement of 81 sq.m;

* a force main witlh a 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 tothe year 2015 will be constructed by the COCWD.

AUzli'r(Emfl'n/a1 .-Ixsw.cvmept l Cagor: (gqa m7an Lie 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 ofthe sewerage and pumping facilities. Spare parts for critical equipment will also besupplied.

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

Institutional Support

The project will include: (i) consulting services for detailed design, consultation ofbeneficiaries and construction supervision; and (ii) training of COCWD staff responsiblefor 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 thetraining of staff for the operation and mainteniaince (O&M) of the sewerage systems andparticularly of ponding systems. The consultant will have to prepare an O&M manual andtrain the operators on basic ponding treatment concepts as well as familiarity with theO&M manual. The training program should also include an overseas visit to a countrywhere 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 beenestimated at P327.12 million (US$ 12.45 million) excluding price contingencies andinterest 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. Byincluding price contingencies and interest during construction. the total project cost isP459.22 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

Construction of Facilities 69.49

Land 3.60

Price Contingencies 14.36

Interest During 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 During Construction 87.56

TOTAL PROJECT COST 459.22

Section V - No Project Scenario

Chapter 2 has vividly described the worsening environ-mental and health situation resultingfrom poor sanitation and uncontrolled discharge of sewage and wastewater. Though theproposed project will cover only a small portion of the population, the project is seen asan important and significant first step of a long term program to provide the City ofCagayan de Oro the sanitation and sewerage infrastructure it urgently requires. Theproject is anticipated to contribute to the gradual improvement of the city's environmentand improvement of the conditions of its Cagayan River, its groundwater and MacajalarBay.

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Figure 3.1

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J~~~~ •3~~~~~~"~ONOIASO

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4. ENVIRONMENTAL IMPACTS

Introduction

This chapter has three sectLions. Section 1 describes the beneficial impacts of the projecton the environment. Section I1 identifies and evaluates the different impacts of theproposed project on the environment. Section m summarized the environmental impacts.

Section I - Beneficial Impacts of the Project

The implementation of the sewerage and sanitation project for Cagayan de Oro is foreseento result in positive impacts, namely:

0 Health and Environment Benefits

On the short term, it is expected that the implementation of the sanitation and sewerageproject for the city of Cagayan de Oro will improve the public health conditions especiallythe target beneficiaries. The provision of sanitary toilet facilities is anticipated to decreasethe possibility of human contact with excreta which leads to a reduction of water borneand sanitation related diseases. This health benefit is most significant not only because ofthe health implications but also because the project will mostly be advantageous to lowiiicome groups which could not afford proper sanitation facilities.

Project impacts include the improvement of water quality particularly of the CagayanRiver and other water bodies currently observed to be contaminated with fecal coliformdue to wastewater discharged into them without treatment. The effect of the project onthe river though will be long term and not immediate like the health impacts.Furthermore, it should be emphasized that parallel improvements in solid wastemanagement. drainage and industrial pollution control will have to be implemented toenhance environmental impacts, otherwise effects on water quality become marginal atbest. If the water quality of Cagayan River is improved, it is expected that to some extent,water qualitv at Macajalar Bay particularly near the mouth of the river will likewiseimprove.

En v'ironmn aiental.%ssesNen7t RJepor t: (agavcar o f Urf (cio tv7

Also a potential benefit is the protection from the risk of pollution, from septic tankoverflows, of groundwater which is the main source for domestic water supply for manyhouseholds in the city including the local water distiict.

* Increase in Productivity and Income

On the long terrm basis, the reduction of the incidence of water borne and sanitationrelated diseases is foreseen to result to increased productivity of usually affectedhouseholds. Since people become indisposed due to illness, the time lost is a potential forincome generating activities. The associated benefits include reduction in medical expenseswhich 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 forpeople to live in and to do business attracting local and likewise international investorsinterested to put up commercial and busmess ventures and establishments recognizing theadvantages of having a clean and healthy environment. Consequently, there will beincreased job opportuniti.s reducing the unemployment rate.

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

An improved and cleaner environment likewise bring in local and foreign tourists alikethereby enhancing the city's ability to benefit from activities and businesses generated bythe tourist trade.

* IncreasedPropern Values and Commercial Attractiveness

The city's poblacion, the initial area to be served by the sewerage system, has a strongadvantage in when it comes to property valuation and commercial attractiveness because itcontains the Cagayan de Oro's central business district. Sewerage in the district wouldallow construction of high-rise office buildings, positively leveraging property values andtax collections. In addition, the central business district is the most visible area forpotential investors. A conservative impact estimate suggests that a sewerage projectcould be self-financing in the central business district.

1:;fjHmr'flntal .-IveXeVnic',t R?epfwt: C(agaxcm Lie ()Or ( Citl 48

Section H - Project Implementation Impacts

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

Construction Phase

A. Air Qualitv

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

B. Water Quality

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

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

C. Noise

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

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

D. Ecological Effects

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

j 71z(at1cs1a/-l X>"^}IL7RZeport: (Cagqva ti e ()so O'tY 49

Operation Phase

E. Air Quality

The operation of the wastewater treatment facility shall have minimal impact on the airquality of the area. Aside from the occasional odor nuisance, it is not projected to haveadverse effect on the air quality. Odor production at the AIlPS treatment plants iscontrolled 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 implementation of the project will be beneficial to the general environment ofCagayan de Oro and its surroundings. The current practice of discharging untreated do-mestic waste into nearby bodies of water would thus be reduced or eliminated. Diffusioneffects -- the adoption of the modified lagoon system (or AIPS) treatment process shouldattain high rates of BOD, TSS, and coliform removals. Discharge to the receiving bodiesof water should therefore pose no significant pollution risks. However, to furthereliminate this risk, proper studies would be conducted on the mixing and dilution beforelocating the outfall. In the unlikely event that projected removal rates appear to beunattainable, the treatment system particularly the maturation ponds can be designed forlarger capacities and/or longer detention times to further enhance removal efficiencies andthereby negate the risks of polluting receiving waters.

H. Socio-economic Aspects

The provision of sanitation facilities in Cagayan de Oro would undoubtedly benefit thegeneral populace of these areas. The occurrence of epidemic-scale diseases as a result ofunsanitarv conditions slhall be minimized. This will make for a more healthy andproductive population.

I. Sludge Disposal and Management

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

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

Ati:r(ronertral. %I,e%sovs-ent Recpmri: (C'g,-vai dtie (re) (il .50

The oldest plant in operation treating domestic wastewater in the city of St. Helena inCalifornia, USA, has not had to remove bio-solids for nearly 30 years. (Recent testings ofthis system have indicated that sludge is well-digested and very stable.) Owing to itsstability, the sludge/residue, if desludging does become due, can be disposed of, witharrangements with the municipality, at the municipality's sanitary landfill. Because of itsrelatively stable nature, desludged material could even be barged to the open sea fordisposal 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 onlyminimal adverse environmental impacts. Moreover, there are socio-economic impacts thatwill essentially be beneficial, and will provide employment and livelihood opportunities tothe population of surrounding communities as jobs will be generated during the projectimplementation. In the long-term, better sanitary conditions will result in the project areas.Consequently, an improvement and enhancement of the existing environmental conditionsin the project areas shall be experienced.

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

[JIlT A cdcIN ih 4 dcc

1 nvireontoa I u 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

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

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

* Construction equipment and soil is exposed to the environment.vehicles may cause higher * Provision of adequately and properly maintained storage forsuspended particulates, odors and construction materials and equipment.fumes emissions - 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 civillikely result in a decrease in air works.quality * Good housekeeping for all construction affected areas and

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

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

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

* Maintenance of adequate drainage system.

* Notse from operation of construc- * Erect temporary sound bamers around the work sites; avoidtion 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 equipmentl _ 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 beFlowh located along secondary streets.

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

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

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

. Public information campaign.

Anl zronnmeL'taI .I i.xexsme'nt Report. ('agaQan cle (ro ( 'Y .52

Operation PhasePotential Impact & Risks Mitigation Action

* Environmental hazards due to * Carefully desigred post-construction maintenance, contimgencyaccidents 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 facilitiessewage will have to be dumped installed during the construction phase.directly. l

Water Pollution * Upgrade laboratory facilities of the Cagayan de Oro City WaterDistrict (COCWD) to be able to undertake wastewater analysis.

. The effluent discharge may well * Following the bubble concept, wastewater discharged into theaffect the condition of receiving Cagayan River shall, in the long-term, conform to the waterbodies of water and the effluent quality standards established by the Department of Environmentdischarge 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 Qualityconditions (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 RioGrande de Mindanao shall be timed based on tidal conditions.The adoption of the AIPS process for the treatment plants shouldresult into attainment of effluent standards.

. Noise would be at about 65-85 . Establishment of buffer zones and noise zones.dBA, principally coming fromseptage trucks unloading at thetreatment 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 theunloading 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 staffRegulatorv:. 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

Construction Phase

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

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

Operation Phase

Receiving water quality is to be monitored by the DENR through its Regional Officewhich has been periodically monitoring the status of the Cagayan River and estuarinewater quality. The PMO will collect information on present conditions, observed changesin po,lution loads etc. It is to be recognized that all the pollution load will not be removedyet it is also expected that the proposed sewerage infrastructure will greatly reduce theproblem.

Once the plan becomes operational the Treatment Plant Operator, vis-a-vis the Cagayande Oro City Water District would have to set-up a laboratory and institute a monitoringprogram to measure the effluent discharge. Daily representative values of PH, 5-dayBOD, COD, Total Nitrogen and Total Phosphorus wil be measured during the start-upperiod. Once the plant operations stabilize, weekly measurements (24-hourly basis) willbe taken.

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

EM-Ironmem1tali AIsfsessent Report. ( o,savat tie On () ( n 54

Section m -Implementing Arrangements

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

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

Summary of Responsibilities and Timetable for the Monitoring Plan

Activity Responsibility Start Completion

Secure ECC clearance from DENR. CPSO-LWUA Decaber 1996 September 1997

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

Ensure that the bid documents include provisims for niti- PMO January 1998 August 1999gatiou wmder the responsibilitv of the catractor: reviewcitractors 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 2000situationis

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

Conduct user cxisultatims and information campaign. Project City PMU. with Januarv 1998 June 2000assirtance 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/kn i.' (), ftp. 55

Appendices

1. Bibliography

2. Climatological Normals 1961-1995 from the PAGASA Station inCagayan de 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 IBIBLIOGRAPHY

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

C. Lotti & Associati, 1996. Updating Feasibility Reports for Sanitation Investments in FiveCities, 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 DisposalSystem, Cagayan de Oro, Misamis Oriental, Volumes I and IL March

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

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

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

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

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

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

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

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

I

Appendix 2CLIMVIATOLOG ICAL NORMALS

(1961-1995)

Station 748 - Cagay'an de Oro Cit%

Latitude 0("29'N

Longitude 124"3X'EElcvation 6.0n mcters

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 ningJ 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- 9 65.1 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 1 3 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 3TYPICAL NOISE EMISSIONS OF CONSTRUCTION EQUIPMENT

Typical Sound Pressure LevelsEquipment at 15 m from Source

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

I I

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

Equipment 30 60 120 240 metersmeters meters meters

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

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

Class Area Day Morning/Evening Night

AA Hospital/School 50 45 40

A Residential 55 50 45

B Commercial 65 60 55

C Light Industrial 70 65 60

D Heavy Industrial 75 70 65

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

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

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

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

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

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

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

Oswald. W. J., Advanced Integrated Wastewater Pond Systems. 1990 ASCE Proceedings, Am. Soc. ofCivil 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,LRecirculation of algae bearing water from the High Rate Pond to the Facultative pondprovides an oxygen-rich cap on the facultative pond. This oxygen quickly oxidizesreduced gases emerging from the fermentation pit thus mitigating odors.

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

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

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

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

T-he St. Helena plant treats domestic wastewater at a peak capacity of 2 MGD.Performance data indicate that for the period of 1990 to 1995: average influents of BODof 290 mg/l and TSS of 263 mg/l were treated to 24 mg/l BOD (92% removal) and 34mg/l TSS (87% removal), respectively. A treatment plant in Hollister, California, USA,with capacity of 2 MGD, exhibited similar removal efficiency, reducing an influent BOD of194 mg/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 Systems Treat Wastewater Inexpensively", USEPA Small Flows, Oaober, 1990

Appendix 6. TIhe .-fdanced Integrated Pnid vs;!:temI(.41 PJof if astetater Treatment 2

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

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

In terms of costs, Oswald compares the cost of a conventional treatment of S 50 to $700per 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 betterto secondary and tertiary treatment.

* Energy efficient -- the design provides for reduces oxygen requirements on thefront 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 theponds. In Hollister (CA, USA), the treatment plant is practically within "sniffingdistance" of a golf course and residences in the area.

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

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

Appendix x6 7he. I3 ancel int.grated Pond S wm,.-1IIXN of aste water 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 ASCEConvention Proceedings, Am. Soc. of Civil Engineers, New York, 1990

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

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

>lppendtx6. T he -Idvuancecl Integrated Pond Svstem(.-IIPS) oMff astewvater Treatment 4

ADVANCED INTEGRATED POND SYSTEM(AIPS)'

Natual, Biological Wastewater Treatrnentfor

Municipalities, Agriculture and Industiy

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

y noyva;ve and Alternative,EnviroAnmentaly Sound and Low Cost

SolutionsFor Wastewater Treatment

Into the 21st Century

1340 Arnold l)rive, Suile 1 10Martinez, tCA 94553510-228-5SOI Fxv 51U-228-5804

I

SOA, Inc. Martinec

AIPS Ihighlights

I'ficient pollution controlEftJictive organic reduction and nutrient removal for secondary and tertiary treatment.

Energy Efriciency with AlPS

The initegrated, multi-stage anaerobic and aerobic reactor design reduces oxygen requirements

(atnd lenergy requirements) on thefront end of the svstem. St. Helena vs wastesliater 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 odorsOJdors are controlled naturally. Wuiery Treatment Plant is within 300feet of a convalescent

hosphial in tie City of St. Helena, California.

No daily 1)io-solids bandlngSt. Hleletas Of WW has not removedsludge in 30years ofcontinuots operation;for industrial

plants sludtge removal every 7-10years. depending on waste characterittics.

*PIond buiker 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

1i en.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 .4 NI)

operalion & maintenance costs and long term replacement.

Martin-- St') 2'S-Kgnt Fax: 510-228-584 1

., IGC M 0 j,; 0 !1aruiia, CA

All'S' 'echnology t --

All'S utilizes conipacted earthen construction practices to reduce construction costs. The systemioptimizes naltiu-al biological processes to reduoe power requirements and need for cheinical additives.The design concept is to minimize bio-solids productior rather than to maximize acration soiids andas a resillt minimize power requirements and *olids management. '

All'S is an iniegraledl, multi-stage biological reactor system treating municipal, agricultural andin(dustrial wastewater. The reactors are relatively deep and constucted as an open surrace pond ofconilacted earth. The biological reactor has three discrete and isolated biological zones integrated into a)a'single unit: deep anaerobic pit(s) at the bottom of the reactor, a sludge blanket suspended within thedeelp pit, and an overlying aerobic zone comprsed of aerobic bacteria and algae and oxygenated byphotosynthesis, supplemented by horizontal mechnical aerators when needed.

In niost cases, thc primary reactor is followed bya second reactor operating in series, witli the capabilityto itcir-culate, dependinig on site specific conditions. Recirculation provides flexibility and sliockaborl)tion abilities for variable hydraulic or organic loadings, or where there is thc potential for toxicSpikes*.

The iniluieiit vastewater enters the deep anaerobic pit at the bottom of the reactor where setlable solidsare deposited arouid the inlet and where acid fennentation and methane generation occurs. The risinggases and up-welling of wastewater flow through the thick anaerobic sludge blanket that is fonnedwithin the deep pit. T'he overlying aerobic zone is compnrsed of aerobic bacteria and algae and keptoxygeiialet by borizoittal surface aerators and photosynthesis. The aerobic zone reliably controls o(lorsa.nd soluble wastewater components undergo aerobic oxidation and fiuther degradation. 'lie horizontalaerators also cicate a ciircular motion over the whole surface area; the bacteria and algae circilate overthe far end of the reactor where a second deep anacrobic pit is locatedw The horizontal velocity of thereactor is redti ced while circulating over the secondpit and the aeration solids are settlei by gravity intothis pit where the solids are decomposed and stabilizBd.''

Solids at the bottoin of the deep anaerobic pits remains for very long periods of time, continiouslydeconiposing. 'hits. biosolids minimization is accomplished. The oldest plant in operatioin, treatingdomiestic w;tstewater, has not had to remove biosolids for nearly 30 years. Seasonal tuinover ol the lponcis is prevented by isolation of the deep anaerobic pits. AlPS's design featuires and cell geometrymaituini the integrity of the system thereby suppressing turnovers.

A PI is ;1ppi olria te f'or wastewater applications for nornal flow situations as well as wher e there arcvariabIe liydi auilic I lows and organic loadings, particularly where there may be limited industrial pre-t-eatneni an, souirce control of toxic contaminants and heavy metals. AIPS desigin elenienis proviideflowiahiiatioiu, buff'er capacity and recirculation capabilities to achieve secondaiy and advancedtreaitnitnt for n itoticipahities, agriculture and industry.

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

Inc. blartincz CA

AIPS Technology

AIPS utilizes compacted carthen construction practics to reduce construction costs. The systemopbimizes natural biological processes to reduce power requirements and need for chemical addilives.The design concept is to minimize bio-solids production rather than to maximize aeration solids andas a result minimize power requirements and solids management

AIPS is an integrated, multi-stage biologic I reactor system treating municipal, agricultural andindustrial wastewater. The reactors are reia vely deep and constructed as an open surface pond ofcompacted earh. The biological reactor has three discrete and isolated biological zones integrated intoa'single unit deep anaerobic pit(s) at the bottom of the reactor, a sludge blanket suspendid within thedeep pit, and an overlying aerobic zone comprised of aerobic bacteria and algae and oxygenated byphotosynthesis, supplemented by horizontal mechnical acrators when needed.

In most cases, the primary reactor is followed by a second reactor operating in series, wilh the capabilityto recirculate, depend(ling on site specific conditions. Recirculation provides flexibility and shockabsorption abilities for variable hydraulic or organic loadings, or where there is the potential for toxicspik%es.

Thlie influent vastewater enters the deep anaembic pit at the bottom of the reactor where settlable solidsare deposited around the inlet and where acid fermentation and methane generation occurs. The risinggases and up-welling of wastewater flow through the thick anaerobic sludge blanket that is formedwithin the deep pit. The overlying acrobic zone is comprised of aerobic bacteria and algae and keptoxygenated by horizontal surface aerators and photosynthe'is. The aerobic zone reliably controls odorsand solubile wastewater components undergo aerobic oxidation and further degradation. The horizontalaeratois also create a circular motion over the whole surface area; the bacteria and algae circulate overthe far end of the reactor where a second deep anaerobic pit is located. The horizontal velocity of diereactor is reduced while circulating over the second pit and the aeration solids are settled by gravity intothis pit where the solids are decomposed and stabilized

Solids at the bottom of the deep anaerobic pits-remains for very long periods of time, continuouslydecomposing. Ihus, biosolids minimization is accomplished. The oldest plant in operation, treatingdomestic waslewater, has not had to remove biosolids for nearly 30 years. Seasonal tumover of thieponds is prevented by isolation of the deep anaerobic pits. AlPS's design features and cell geometrymaintain the integrity of the system thereby supprcssing turnovers. t,

AIPS is appropriate for wastewater applications for normal flow situations as ,vell as where there arevariable hydiailic (lows and organic loadings, particularly where there may be limited industrial pre-treatment andi source control of toxic contaminants and heavy metals. AIPS design elements providteflow equalihatinoi, buffer capacity and recirculation capabilities to achieve secondary and advanct dtreatment for mniilcipalities, agriculture and industry.

MartinC7: 51-22F-5XI)1 Fax: 510-228-5804 2

SOA, Inc. Martinez2,

Acceptance and Support.

Al]PS is a state-of-the-art pond-based wastewater treatment system.

* Proven* Reliable* Inherent Buffer Capacity for hydraulic and organic shock loading andi toxic spiking* Advanced Microbiology* Energy Efficient* Minimizes Sludge Production/Management/Handling* Maximizes Natural Photosynthetic Oxygenation* Minimizes Power Requirements>.

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

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

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

* Califomia Water Resources Control Board supports AIPS technology.* Califomia Water Quality Control Boards' supports AIPS technology.

AIPS Plant Overview:

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

* City of Hollister, California Wastewater Treatment Plant

* Hollister Industrial Wastewater Treatment Plant (Cannery Wastes)

* lndustrial - Winery Wastewater Treatment Plants, Califomia

* Rodney Bay Wastewater Treatment Plant, St. Lucia, West Indiies

Martinez: 51j-223-5OI Fax: 510-228-5804 3

i ," ~ ~~~~~~ ~~- N. 2 :'i: v!t " 'd,j"v S Wiat v ,1t$: 4 >

./ AAPS ,s zn integrated rnufl-staga bNological readcr systein ireatingmuL,ic,pa;. agricu,itural and indus,rial wasteviaters. Tihe reactors

Pr-:aif:ng Winds __., consist c,ftthee discrete andisolated biosagica zones: dee1anaerobic pits at the bottom of the reactor. a siudge b:annxet lsusneneleoa over the deep pit and an over!vin aerobic zoneccm o.rnsed of 3erctic tactaria and aigac .vt:e issuaturadwith ox'c2en produced by algae and mechanicat aerators.

All weather rmadwav All weather roadway

/ \ Ae.obic zone Aci dt r

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

SeWn \ zoa1 ulets

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

Rawwaser lnflu \ ~~~~~~blanket Anaerobic3

zone /4 .AemobtOxidation2. Phsoetrfiec Oxygena00on3. Organic Acid Formabon&Mthane Fermemato~n

SOA, Inc.1340 Amold Drive, Suite 110 Martinez, CA 94553 510-228-5801 Fax: 510-228-5804

Rerripiniea tsip;riuing 3wfie,xt and t l-"t--or Sx Si/ion Peuoplth Pr,( Cdines i, s -u -i;tippJlLllyg Water and EF S ,

avYilig the EnvIirovnlient AD%ANCED INTEGRATEDWASTt^'ATEl

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

ABSTRACT

By incorporating special environments for methane fermentation and- photosinthetic oxygenation, advanced integrated ponding systems attain high

degrees of primary and secondary treatment and significant degrees of tertiary andquaternary treatment of sewage and organic industrial wastes. When properly

Ftoctceditnqs of seleCted sessions from the 1990 ASIE Convenition designed in appropriate locations, the systems virtually eliminate sludge disposal.minimize power use, require less land than conventional ponds, and are much more

Sponsored by lhe reliable and economical than mech3nic3l svstems of equal c3pacity.Environniental Enigiru_ering DivisionIrtigst4onasnd Drainage Division!r *, .. .. . .Waitr Iesources Planning and Management Division. As is well known to Environmental Engineers. wastewater treatment to theof 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 solidsproduced during aeration of the primary effluent (secondary treatment). Such

- San r'ranclsco. Calllorn - - treatment traditionally has been done in reinforced concrete and/or steel structuresMlovember 5-8. 1990 with materials moved by motorized pumps and aeration provided by mechanical

means. Sometimes for economy and simplicity in small communities, ponds areEdiled by Udai f Singh and Otto J. Ilelweg used to replace mechanical systems. The greatest advantages of ponds are theirCII2M fILL Memphis Slate University ~~~~~simiplicity, economy, and reliability; their greatest drawbacks are their high landC112M 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 become less effective with age. Our research, devoted to maintaining theadvantages of ponds while mitigating their drawbacks, has led to the developmentof Advanced Integrated Wastewater Pond Systems (AIl;PS). These require muchless capital, energy, operation and maintenance than mechanical systems andrequire less land, produce less odor, and fill in or age much more slowly thanordinarv ponds. In this paper I wish to introduce AIWPS as a system worthy ofconsideration for many waste treatment applications. Due to space limitations.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 aseries of at least four ponds, each designed to rcst perform onc or more oi -he

'Professor of Environmental Engineering 3nd Public Health, Department of CivilPlubtished by the Engineering. 659 Davis Hall, University of California, Berkeley. California 94710Antrtiic,n Sixicty of Civil Erqineti s34fS .ail 4 .'I i Street4 new 'u. flew 'us 10l7-2.zd

4. . .

SUPPIA1NG; WATER AND SAVING ENVlRONN1tNT

ii:iii treatment orocesses isee Fieure i3. First is a Facultative pond 'vith an _c__

aerobic surface and nn extremelv ano-ic internal pit far sedimentation and : .. c t 't. t'

fermentation. Anierohic microbes in the pit are protected ty surroundir.r wva!! or I **-.

,erms from the intrusion of .old surface water containing dissolved oxygen. Raw jr.4....s rni

sewage is introduced directlv into the pits where sedimentation and methane aoI- \

.'crmentation occur. Overtlow velocity in the pits is maintained so low tsee Figure

Z) that suspended solids removal approaches 100% and biochemical oxygen detmard at

t 2OUt removal approaches 701%. The overflow velocities of one or two meter; per J

3 ar, !les- than the settin; velo:ities of helminth ova and parasite zvsts so most YSCT r-' L 4 M.A.

o- ths e remria :n :he pit and consequently are permanently remo.ed trom ins SJ;P Z Rs

effluent. *

I tihattti - \ /sL =1010=6 CMMNWWAsa sVW" =nILimm

t \A s n

a -rntt_?._ 6 e MM ft ___ . .N _

& dm7inttttL _ IL 00*Wt d` 74_

a1 m,as.qa sCm.mme aM101 I 0 &1 0.0

I s it M\

L ft

btV

.20 30 40 90 T006 so 10

SOC -. 1000 amO WO0O 90

''__.______.___-_i_____i_______________________'__________ Plpar, 2. £112 Ota±tt.lin.- Por SedSiaag2t±ol

-~' > S 7-, 1 5 Pcrforacj Showing AIWPS 0Verflow Rates

nP1g 5. An £dwateu Iatgxet. atewater

loodinIg syut" (3eoa.ktic) .

?At9 11

Another potential benefit of anoxic pits is conversion of chlorinated . SEDIMENTATON Or ALGAL-8ACTEPIAL SO5S

hydrarbons to forms that may be biodegradable in sn aerobic environment FROM A PADDLE WHEEL MIXED mGim RATr POND.

(Bouer and McCarty, 1983). toibem ge pi* Volt unLits reduci.g _

,ironmne.6se mert there to pont where only ash remains, hence -warnms Pot L As".1troo orv W.9M

; p l s * - z _ In t-elena, tifSornia GATI M s7r PEVNr

arst AIWP) sludge removal has not been required for over 25 years. A >NO VFWtLUEM StPERArANr SErtLo

second AIWPS at Hollister. California. evidences little sludge build up after twelve

yeanr. JAN 220 IS

MAS io 20 or

Tne second pond of an ATWPS serieS is a paddle wheel mixed shallow '24o 45 t

raceway called a High Rate Pond. In such a pond microalgac grow profuselv WAS 253 2 .1

releasing oxygen from water by photosnthesis. This oxygen is immediately JUsa 320 3 Stl

avaiiable to bacteria to oxidize most of the soluble and biodegradable BOD JULL 300 20 93

remaining in the effluent from the facultative pond. Algae prouced during -W 23C 30 5?IV 220 is :

paddle wheel mixing are highly settleable (see Table 1) (Eisenberg, 1981) and. 1 1 2 ' I5 s

after asgal removal by sedimentation. or disolved air flotation IKrol'ta and Wang. *4 123 a to

1984). the remaining water has a BOD that is generally less than 20 mg/liter. I: Ss 10 to

Recirculation of algae-bearing water trem the High Rate Pond to the Facultative SD 90.

Pond provides an oxygen rich cap on the facultative pond. This oxygen quickly IM . J ___ _2_ *

oxidizes reduced gas emerging from the fermentation pit thus mitigating odors. * 24 MM. Se.noum,n

AII Elwiberq ttlsI)

76 SUPPLYING WATER AND SAVING EN, iRONSMENT .;TEGRATED POND SYSTEMS 77

1600 i -\aters emrcgonz fro.- the ,et:iing ponds are sufriciently low in BOD andsuspended solids ro percouiae readii into the ground or to be used for irrigation

._ They will. hoAe er. iikCis Lurtaiie r. NiPN greater than 1000 per 100 ml andI hence mra requirc z'-.-eo.-! str:;e prior to use. The fourth pond of an A IWPS_; 1[400 often called a %Jatururron pond has the dual purpose of added disinfection andC. tttragC for irrigation. The use of pond efriuents for irrigation is more fully

discussed elsewhere (Oswalid. 1989: Pahren. 1985; Sheikh and Cooper, 1984i. Arecent publication b%y the World Hta!th Organization outlines major concerns andt

i1200 safety t'actors related to the use of wastewater for irrigation (Shuval. 1989).trn -Nzr A;c; din, to Shuv:^ and others the ma;or danger in developing countries is0 ~ ~ ~ ~~~t~ trinsmission of heiminth OV3. This is s irtually precluded by the uise or 'our ponds0 b in sers;e Added ion the needi for four ponds in series should be an admonirion5 100o Focultative Ponds in - against short circuitinS which can orny be avoided by alternating surl'ace andCs Series SO Percentiles submerged intakes in pipes transferring water from one pond to another.cn After Ramani e!. a. 1975

.2 00t0 : TTABLE 2

P2'R--01PMANCE OF ADVANCED INTEGRATEDS 600 rWASTEWATER PONDSO : ~ :.- .. ~ -- a: ' ... ~- :' -i 6ST. MELENA (AnE( ual Means) (1)

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 .,. Mu.B .223 I? II200 ~~~ ~~~~~~~~~~COD Moll 439 [124 74 So 32 9

TOTAL C soI2 6 4 (6 6 0 7Z ~~~~~~~~~~~~~~~~~~~TOTAL N Mott 40 TO 13 i 4 900 INF PONDI POND2 POND3 POND4 TOTAlIO Moll 14 1 I 12 8 5 64

rAgure 3. Total ChromiuMt RtemoVal Due 'o Algal (1) Atist Meten 1970 H0LLISTER (Annutl Means) (2)

PARAMMA UNITS STATION PercentCrovsh. aasc Sedi:sentxaion Zn Itte *> -od PARAMETER J UNIS t I 2 AIO * 'ecn

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

The third rond of the AIATS weries provides for sedimentation of algae in (2) AIlS? MzK4#r1 (iq9l8lthe effluent of the high rate pond. As nrinted above a paddle wuee; mixed nign File (3t Ee Coltpond tends :.. selc: for algtf that 2are sett/!able vwhpn not in a mixing field(Nurdogan. 191! Hall, 1p11 Algae which 5ettle tend to hibernate and thus do ApDxrxirns (ReOne l'irne Varies With Season)not immedinlelv decormpose or produce nuisance. In fact if two settling ponds inparallel are used. oae or the o:her ctn b- drained annd dried every three or four Station Key t- lnsEuent Seo te * ol1slels Sorttin Pond Effluent Isy-cars to remos- :0on:cntrated 2lgal lUds"ges Dried afiMIal 51ge is rich in nitrogen, S K FaItunh Sts Sw Pphosphorus. and potash and hence is an excellent fertilier for fast growing plants D-e octirgeo To NFtufsl Savii Pat.-ols o.niMietting and Pin.nc 19S674 . There is li."le ch-ance that dried alase wOuld contain 3. Miengi etit Pono B Tsherge Ts No SvtseI G 'luy.ercttrinfectious of;anisnr but to be safe it thould only be us edon ornamcentals and 4- Setting Pono B 's. ThereIsNoSurcertuctcrops neo eten ra3 ICalifornii state. 19't; Gunnersoft et 21. 1984). S- Malutation Pond,

SUt'lLYING WATER A.ND SAVING ENVIRONIENT .XL!" rE'RBD '.'N rB RLSY s TIO\) SYStM -7

the 3erobic surfacoe saters. the huhhl?th.n hemr e .crqe nti the n r oartc 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 :t int luent se5wge. In mis 3waN the entire raw 3ewtee tiloW s o a-!ed :sroueh tl9C-C an2 H _!tister (NIosuera. 19881- It is clear *'rom these data that the m3t or :..Ium. of intenze anosic .tiitv ;,here rorh insoluble and soluble O!Sat m3t:erfraction of BtDO remo%ai occurs in the facultsti0e punds aud. froin the St. lielena is ad,3sorhed and conierred to cirbin dioude water. metha:ne anti rnrwen gasdata. 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 _nrownl{^-^*lictes h.h nlatile diisnlvpd solidLs nrivinate frnm a paner -i-53mation 3ljnt umt'tt floJ Oubltve rb!atte- X': s 'r, S eh: 't- r n - lifd r -rsitning hevond the f'tu1Xtitjve !nri his'' -ire t"'od rFa r V rn .1- *.W' ~-*'-'e L;i- *__ :;r __ - - *'.-^; h ; t*C-ts manaerobic and aerobte degradation. Th- high p-e ponds winth ras. lsti bar a .ho t:mparted cte o tr,sanr.hene re dc!rremose a sreast deasl of BOD but contribute oxygenation to the facultative ponds with rJgS. plastic bags and % th eomp3cted slud or rit ands henanc asid n removal of nitrogen. pnosphorus and carcon. Followving algal removal r torus management including tati sate pretreatment. freauent sluaee removalthe degree of pollutant removal in AIWPS is equivalent to that ot mechanical 2nd Jtner tntenanca. In nhe case 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 andremoval (Table 2, St. Helena). removal of heavy metals il-igure it and a deree ot' advantsges Ji UAiSB reactors are realzed in advanced 1'acultative p. .id -iih fewfail sale disinfection (Table 2. Hollister) (also see Sarixaya and Sartei. 1987). of the disadvantages and with lower costs.

The helmintN ova remo%.al projected for fermentation Pits is of particularAnterest in developing Countries where millions of children are weakened by

Neither lfollister nor St. Helena are Complete AIWPS because they lack parasites and consequently fall prey to childhood diseases.paddle wheel mixing in the high rate pond. Also residence times in the high rateponds are excessive, exceeding the time required to accumulate sufficient solar The economy of AIWPS results from a number of factors be%ond operationenergy to release sufficient photosynthesic oxygen to meet the ROD. The high rate and maintenance. For example, consider the cost of reactor volume: reinforcedpond in Hollister is mixed with screw pumps and in St. Helena with propellar concrete reactors such as settling tanks and digesters 3re 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 areTable I is from paddle wheel mixed experimental 1/4 acre t0.1 hectare) ponds at ' ' iTK fo cosf less tha,5S w (I990Yernm' -- a hundred-fold less. By usingRichmond, and indicates the excellent natural algal removal that results from artlhwork ponds. large reactor volumes can be created very economically. Thegentle mixing. The interrelationship between paddle wheel mixing and 31lgae ' microbes involved in treatment are, of course, unaware of the cost of their reactorsedimentation was first noted in high rate pond studies in the Philippines (Oswald : and, provided the environment is suitable and constant, perform as well in,et al.. 1978) and was confirmed in extensive subsequent studies at Richmond yearhwork ponds as they would in the most elaborate digesrer Ako since thcj I(Eisenberg. 1981). Both Nurdogan (1988) and Hall (1989) have studied the reasons - 4ostsa little. earthwork digesters (fermentation. pits) can be made large enough to :for improvement in algal sedimentation following paddle wheel mixing. Nurdogan nttrmit complete digestion and thus the elimination of day by day sludgtbandlinp l'has found a natural selection for larger algae which settle in a quiescent field and - or many years. -1Hall h3s emphasized the natural filaments produced by algae and their tendency tocause agglomeration of cells with consequent improved sedimentation. Both CQNCLUSIQNphenomena appear to be important in natural separ3tion. Neither is related to thephenomenon of auto flocculation that occurs due to high pH in poorly mixed Development of economical and reliable AIWPS is timely because of theponds resulting in precipitation of calcium carbonate. magnesium hydroxide, and problems small communities now have with financing their treatment systems.calcium phosphate. This type of precipitation. as welt as thermal stratification. is The past trend. under government and state subsidies. has been toward complexprevented by continuous mixing at a linear velocity of about 1/2 foot per second 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 sewage trearment are being decreased orThe 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 hectuare Por Jay and re-uts in the upgrading of 3 communit:y's wastewater treatment system. Based on ourrelease rom rater of more than tOO kg of dissolved ux-s5en per hectare per dav-- experience a3tSt. Helena an i Hoilister. AIMPS, when properly desgiieu. a,re notthat ;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 Formechanical aeration which normally transfers one kilogram of oxygen per kwhr communities in the sunny uart of the world. AIWPS can provide a new oDoorIunit'tSmith 197 3). The energy savings is thus more than 10 fold. tc ha%e adequate, sin7ple, reiiaole and nuisance tree waste water treatment with

it,gnific3nt opiportunitirs , r rectamation ano ens,ironmental enhanccmne't and at aThe phenomena that occur in the fermentation pits of facuitative ponds are price most communmt*es sthould be able to atford.

somewhat unique 3nd deserve consideration. Quiescent sedimentati:n is onh thefirst reaction. Apparently then, in the intensely anosic volume in a Pit surflaes ACK.NOWLEgC\IFNTof all sorts of solid particles that settle from raw sewage become pupulated by acidforming and methane producing bacteria. As gas .s released on their surfaces, the I am indebted to Rose Ann Nitzan for typing this manuscript and tosolid particles become buoyant and tend to rise due to the attached gas bubbles. If Patrick Oswald for preparing the tables.the pits are sufficiently deep (S-6 meters). the gas hubbles expand as they rise andusually will 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 o*ues i 1964 i casiewater ei luent reude urIul' 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 p 4 S P.eri..rhal)ogen:zd aWph:ari f :omrnounds undher rr)erharI, g c',P.s niarerworks .Assuciarun Reieirul rou.--fc don. 6666 Quin,:-. a I:. !enveer,

;' , !'t'rrloentfl Nicr,obilloity. -5. r'p. 1IS6 C-oicrad`o, USA 30'35.vz ; ;,v,C IS -e i '.astowater mcClamrt3tn crit-,ia, An e'pt !r-.m r . ih. ; i :'IS R_::a rrl frr F .74 el (r1l te?ines in Hum.rin ;'t~tey He1lth

C. .~i] \ ii. ,t8n: 2t r3ti e Cod?e. T tle '. Li v iin ;. D I 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 p '8 -I't U Sssc 1 n t.Ci..f

8erlele\ vav. Berkelev. CA 94704. USA. S" :zerl2nd.E' en,'t [flrn M1. (I98I) Prouuctivity Harvettabiiii n7d f~rn1r. _Z" .f 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, National Eni Kes (rem. Cinc:nnli P, h: u *:olUnmirrsii of Cjlitornia. Derkelev, CA. Swi:zenburum .Mlike. ed. 119851 Anaerobic rreatmenr of Sewage' No. E.E

Gunrer'n, C. G.. I. i1. Shu.al. and i. Arloscraf (!'i: He.Ph * 33.5-5. Proceedinas ott a Seminar \'orkshop neid June _.--'3. itws*tewater irrigation ind their control in deveit'pivg *.untries, pp. 1576-l502, Untiersitv of Nlassachussetts at Amherst. Amnerst. Nlassaciusetls uu;'a3.in Future of WVater Reuse in Water Reuse Snmposihm 111. proceedings. Vol. 3.American Waterworks Association. Research Foundation. 66o6 QuincvA%enue, Denver, Colorado. USA 80235.

H31. T. W. O1955) Bioflocculation in high rate algal ponds--implementation of aninn,vati.e wastewater treatment technology. Ph.D. dissertation. Universitn ofCalifornia. Berkeley.

Kroft3. Ni.. and L. K. Wang (1984) Development of innowative flotative filtrationsystems for water treatment tirst-rull sandfloat process in U.S. parts A,B.C. p.1I'25- 1:64 in Future of Water Reuse, W3ter Reuse Symposium Ifi. vol.. 3.American Waterworks Association Research Fourdat'ion. 6666 W.' Quincv Ave.. , atDenver, 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 /dayDissertation, 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) Performance of Advanced Integrated Ponding Systems. pg. 78 Discussion 4 h line Photosynthetic oxygenMaster of Engineering Thesis, Sanitary and Environmental Engineerine, ' o- ge-Unm'ersitv of California. Berkeley, California. pp. 1-84.

Nurdogan. Y. 11988) .Microalgal Separation from High Rate Ponds. Ph.D.Dissertation. University of California. Berkeley.

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

Oswald. W. J., E. W. Lee, B. Adan and K. H. Yao (1978) New WastewaterTreatment Method Yields a Harvest of Saleable Algae. WHO Chronicle. 3'.348-150.

Oswald. W'. J. (1988) Microalgae and Wastewater Treatment. Chapter 12. pp. 305-3'S. in \iceroalg:l Bitechnology. Borovitzka and Borovitzka Ed. CambrdigeUni'et,,n Press. U.K.

3su tlJ. 'A J. 19g9) Use of Wastewater Effluent ;n A iculturr De.! nization2:. 52-S0. Elsevier Science Publishers, B. V Amsterdam. Netherlands.

Oswald. 'W. J. 11990) A S\llabus of Waste P'nd F indamentals. EnvironmentalEngineering and Public Health, University of California, ierkelev.

I'ahren. H. R. 119S51 EPA's Research Program on Health Effects of WastewaterRFuse fer Potable Purposes. Chapter 10 in Artificial Rech arge ofGcound,Jster. TaKashi Asano Ed. pp. 319-'8.S Butterworth.

Ramant. R.. and W. J. Os-ald 1973) Studies of pond perfrrmance and pilot Mgaeseparation at Napa sanitation district, report by CSO International tO Napasanitation district, 950 Imola Ave. West, Napa. CA 94558.

Sarikava. H. Z.. and A, M. Saatci (1987) Bacterial die:.off in waste stabilizationponds, Journal of En%ironment Engineering, Vol. 113. No. . p. 366-82, Env.Eng. Div. American Society of Civil Engineers.

Page 4 Small FHo

Ponding systems treat wastewater inexpensivelyby, Edwin W1.. Let, PA.E

(low rsnot, lIi. auth.irhe of ifirtfotlyg aticle iz a self-emrnployed consuti 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,enal engineer with the 1US Bureau ofReclamtion in :JIqSacramento. (ittifernia. and as a itntiryta engineer with the lVorld Htalth Organization Vin thePhilipp,n,s. lie reetivedhis hichelor'sand maser degree in lte llsaniateryergl,ne?ring from the Un erjidy a( Cuiifnrnia aBtr,Aety.

Ihct integrated ponding system is a low-cost adyvnced waste treatment process for . A rmmnicipal sewage. organic industijal waste, And orpnic agricultural waste The lsnsmpic_ly. economy. and ret lamation potentisl ol the Advanced Integotsed Ponding SystemAIPS) make it sttractive to those contmunities wishing to transfoan polluting ovalies Iolasset5 St minin,al cost, IL5w capital cust. high eliability. aid low opepatito and maisseeance cust favot the use of AlPS over conventional seconda and tadvumcetd wstcsrment wherever clitn le and latd availabtlily pemuli

*s shown in Figure .an AIPS involves a selected equenc of ponds. Each pondo i:ientifically designed to accomplish. by natural means. oe more nit eations k _ In aged processes lcading up to advamned lerels of waste teatmet The staging of An derilew af a AIPS to lllter, CoUse'nia that sun-es a town at! 16AJO0 pe.pt.tegrirmto is selectcd to meet the objectives o the site spedeic project Sca=ry The 27evm pond anr J&a at giS lr reat t taio milUnis edastt of srtotieoter p.-stmnent can be achieved with adrep (acultative pond follbw ed po AL da wndiut nro .1 u r ,stAient removal ttnd biortaiss rel mastion can be achdeved wish selected insegon of ecifirtclly designed poods- construetion costs resut mainly fron thite minimnization of use of rtinforced cunc,ele

idge and grease removal are accrnplished in deep facollWise potds wvih special built- sotmtes by wsing fonned atath.deep pit ditgemrs. to ,c,miol n-tri and alsin prtial okidtlon n these pods supple- Lower operation and maitktena nceteis euht it ... :-niasy oxygen can t- iotstl,,ced by recirculaling higlty.oxygentated effluet fmm * Elimiasitoodday-by-dayildudgthandling: Integrated pondbsiaedsiLned toPllow, rloly ,fcirc,ttated Sigal Inv th units terned high-tate ponds." the scndary tetaint sludge in dh deep in-piid iligesicts fot oaiay yets. Sludge velunr iss o(fthe systrm. bliurt c 5inc slgae in the high-esse ponWduscslar energyestinulta. thereby seduced to s mibtnitunt in prolonged digesii. llihe residul sludge is

iuAly accotnplish i4itgusysutetic oxygent production. high pl disinfection, nd ntrient relatively inertn d ts volunm Is sniall. Ditosal is not a msajr oerationalsoval facitet is in tile Itigli -rate polrI use osygen produced by algae ti oxidize all but probim moat refrackory ogalnic sribatsnces. Following osidatiot in the high-sate pond, both * Decreased energy requiremcnts: Energy needs for aeration. sludge handling. stUse and bacteria biotitass siould he sepwarted fixn the efflue, distison are decreased. Each pound of .ticro.gse eatlesa 1.6 pmil rk*.fosygct.

which I diasved in water aid titus tniteJistt I r avrailable for bncteril uxidutionaI-bacterial separations ame accomplished in tertiary ponds specialy designed to pemstit of waste orSanic matier. An acre of algal culltire will prodiuce 200 lbs. of useableral sedimenatiaon of algae produced in the high-rate pondc Natlsal sediittenUliett Is disolved oxygen each day, equivalen tu Its XA) horsepower hours n,l menlalisalIcrated bya self-inditcd hiofllrcculation process- Rewneral adnetaaooldpotliett aert io. ibe snaxx_ eergy requieutteoit is l/ID kilowatt-hour pet kiliogr3m ftigae biomass nay be needed for seeding Ito thpe riptai Wr pond or high rate pod DOD.age of treated water (Oc controlled teuse Is provided in qatesary pod calld Decr_sed egy rs r sludge handling: Since ludge is rctained In specialturations or siorage ponds." Storsge aft mst designed pil digester tut rentains there inderiiitely, daily iransfra P sludtge Is not'Sot aqusaic life ifdesittl i cr wsfii i s alsoIs s;ttelenals .tecessary an denergy needs fowr sliodge transfer ast eliminated. Also. becauseed for use for gruundIxier recharg. inigstlottoraxgero gol cowurses. ar doigstionproceedrs oeryeas otite hstiisgsmdmisingofludgetenntsinin wciinho11taSbif . - ~ requited, futer reducing energy requitesents.

Decrtased manpower requiLemens Mi,iration of ectro-ntehattu 1ends tothe integrated seqnesv:e at designed to utillee naturalideconpoaltot equpmntIntegralatnfte sysuten esign Thlisaso minilittzrstrcclutiicasses. W . Os. a id. pittO.. University of Califonie at Berteley. has tstudied these persnni rquired to operate and inairttain equspnsent.ssrs ands develoked the systcm during wmnr thin 40 ytears o reseaCiL The effluetf llealth-ressted risk reduction dvantagles of Integrated ponds include:y cttsined In such poioling systen), is cotnpatrbl to the tffluent derived fromnpsent plau ineotlxoalilag complc, sdvased tmeauntst stag1s costing sevcea trne is hbcteria. and virse in effluent stueamst li. ii is accomplisetd by pircSding ltwi.

detention periods for sludge in the pit digestres, short circuit aifegutids. high pl I

mance of All'S can be expected to mduce pollutants in the following rngesr levels in seconduy ponds. astd efficient separtion prncesses.*Mlnisisatlton or eliminasin of the nee fit ch rehmic.tl dishi,aecuioit of eltlteints

BOD 95-97% with a resultanl incase in reliability and a decrease ut eott. The potetlital ItaraitsCOD 9t)95% of mutagen. tetutogen. and cacinogen prtductitin in tie finaul cflutnt by conm ft-

Totad Nitogen 90% tional disinfecion processes can be avoidedTotal Phophotrus 60S - Removal of heavy mntasu through co-precipitalion tnd sedimentation.MPN - E. Coli 99999%. With egard to environental Impact. the major objection to wste stabilization ponds of

t advantages of integrased ponds over conventional treatment processcs teult conventional design has been the production of odors Sl cessain times of the year, theirfrom lower consuruction costs nd lower opertio n maintenance cost Low large land requiemwents. and the presence of suspended algae in their effluents. Alps

USEPA Small Flows Oct. 1990

October 1990 Page 5

TCHNOLOGY

KEY TO NUMBERS ON FIGURE BELOW1. SCREENING & GRIT REMOVAL 7. PADDLE WHEEL MiXER 13. Al.GAE HARVEST

2. DISTRIBUTOR 8. HIGH RATE POND 14. LOW LEVEL TRANSFER

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

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

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

6. LOW LEVEL TRANSFER 12. SETTLED ALGAE RETURN it SUPPlEMENTARY AERATION

Ir3

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

tonic hese objections to a considerable extent becauns they awe designed so mWinize E s fil(ton toago ponds AMe oten suitable for aquiculture develetoprs and iarilgadoe.ie of the land for pcmds. to avoid obectionabl edon. and to s e olga. of dowaje crops beeau:

They xwe Ism o paitte ova and dependably low in coliforff and odth eiericland occupied by proJperly designed ponds will: bace dis high pH dis infection in the primary an.d high-sale pod end lolg

Provide opcn space jud xsenhic vwiew. coaided eesuW in conrma sy e dett ; in de sy'planning. * They are kmw in tlmge aid dploaporus and will not over-ferlize.

Pesmit development of aquaculture And welAnd habitat* Be exsily aund inetpensi,ely reclaimable. ustJaly t a hihly apprciaed lad Mleougac rcd i megraed ponds have geati potensisl for:value should future devebpmnts kead to aiternt vte Itaput neoamuet tathidx. - Developesurt t as a bigh-pmetin feed suppleanctut for li. chickets. swisne and

,uwuimLs::tionable odors atc avoideA in intlgrated ponds byr * Use as a lRiid or solsd fcitilizer for rapidly-growing crp:* Assuring the onsct do lIaline fenrcnttloIn.w tdetewaodotemisesn t h tkte * Use as x sua or Methane fkrnmntation;primary ponds of the syisein. by conmrolled sit-up pitc t * Extrctiaor oiLpata randcolltids.* Psevi 'int xt rVIti nryeen. is ell ta algal teediny, thnvot5h releaios Itno hlyh-sate pond elltent to the auslace of tihe ptimary pond, whhenewer low distslved To s *ze.aproply desgned Advanced lntegited Pnding System can puvi&deroxygen levels in the primxtay ponds indicate a need. wvse mageme and reclmthon that Is mnore rliabl, economical, and envinmae-

tally-osusd dtcA conventlarnd aysens* .harvesting is psmotc,l by:

Natural biofloccsslstioit of aIgac in properly dsigned and nmicd high-etae ponds. ReIfrenexs* iligh utnenrcmovalsthaenhaucesedintensationandwrerdaddition Ilgal Osawid, WJ (1987) Large-ScakAlgaeCultureSystems; EngineeringAittecta. Ingrowth in receiving tatrs. Micro-Algl Blotechnloty. Cpte 1. Dotrowitxka. hi. ass Dormwitci. L csli. Canx-

lvinced waste trmatment process should be considered for use by: brdge Univerity Pmss. New York.Any comninnity involved either in developing new waste teaset ndt dspoa Oswald. WJ. (19U1Tlse Role of Algae in Lquid Waste Treatment and Reclamatioo

systems or in upgrading tlteir present tratment system. Chter 12. pp 255-2 lin Ukrolgae andl irsnaaffairs. C.A. amb ad IR. Waal-* Communities in and or emi-mrid auets desiring to pracwice wastewater reclamn nd eds. Cambridge Ultivetity Pess. New Yosk.tion.

Organk industries requiring Independent wate dispossa systems. Oswald. WJ. (1989) Innroduction to Ad&anced Integrated Wastcwatcr Ponding Systems.Animal feed los. dairtes and poultry [anra requiring WAste management nd Depautment of Civil Engineeing. University of Califomia. Berfciey.

lumrenr mcycle.Communities wbih sufficient amounts of availoble lad.

11 -1's V~Altemative VVastew ater~~ ~Treaftment:

Advanced IntegratedF1 j~!r. . i-Pond Systems

td.s lii !|1 XAdvanced in concept and simple in design, a neit: waslevwaler treatment[ j t P, d l~~echniology may offer a solution for cDmmulitilses be?svt tty iitelnsifying

cost constraints and water quality regulations.

Why not build a sewage treatment thinking. In '4 ii tviihr,al plants, forfacility that tiseS much lICt energy examnli, aclal is ,i it l1, nii cI nstimesthan a ctinvetnlional one and prodtices 6(r,, or-nmiiol 'Ilt e i -I t rical energy* no odors, especially if construction, usedln hi a'\l alslor Ite.alment. In con-operation, and tnaintenance costs are trast, mi( roalg wt in an All systemalso dramnatically lower? lThis queition provide dissolvI, c, s -g#n throughmay otccir to many who have visited photosyWihv-s;, ¾.uhlli;antially reduc-the Wastewater Treatntent and lKcla- ing ele rical -aI n iuntpFion. Not sur-niati< n IlaI,nt in St. ielena, California, prisinglv. Iles- S'.sttms ale optimalparticularly to visitors from c nmmu- for sunbcIt' tntnitrmil cs.nities feeling pressure front federala . nd state e'ivirotimelital regulations. 'At St. I Ilvlen. t*Ve plroven this

,, , 1 ,,e . ift, ,,,,; r , technology witha ire nat-tkable qualityI 1 .. f f f Uliase I on the concept of Advanced of treatint I*t." ¾V *torge Milanes,

( ,t't :{.x . w1?'s. ?h-rE3Mt/ dI E .tt 't¢ , Integrated l'ond (All') systems (see chief opetatItr -It t(ie plait. 'The eco-,rit ri'.', lii; 1

P4 fsti tLrte ,r*, ('rit ,* 5 for description), the St. I Iclena nomics i ut wh.t il tal In put one ofm ,itd .m Il it rathlr this it ill p lant marks a radical departure from these toge hell- ju!.t imakes good finan-

tr'rC f f .,. to 1f. conventional wastewater treatment cial sense. I his shouild really be thetechnolo;v (if i oi'c foIr smaller com-

~~~4 ~~munities, of 2iMO tt to I AXI people."

"All' Ictdnitilvv,v i tw, limited toa .. t,~~~~~~~~~~~ ~ ~ ~ ~ ~small I osiommultthi-' hiiw. '.er. Cost

.*7 { tI.~. -¢ 4 a tcompaiH(ons 'A iith other treatment'.i. 4 7w*e'<t metlxt etid to [ilis(r AIP svstems

in manyv Lirger (-nimimimities a' wvell,"says SahiLy Wilkter, I I;i t, tor otspeci.l PI q. 1t 1ti)r . h' , I' t tnil)

.~~~~~~~~~~~~~~~~~~1111 .. 1 dti,1"1pl- li

., ,'~ ','" ^,uonsructlion ano tnergy ostsISol11 5,,lzlt,uilEI s1t1t1Mainlenance CostsA 11 I 1111int should ~ ~ A prreperriy dieSi)'11VLl All'pl I tt

c,1t51s1i1ilel about! o - G(od financial sense begins wilh sioutildi (onSUnle iboit iineI-quarter tofauility costs. Iksause soIlar aefatud one-fifthi lie energy (if a conventional

quirter to (ric-ft fth tie ponds are built of formed earth rather mechanical wastlewater treatmentI than o(f reinforced concrete, ihev cost plautit This translates directly into

eflt11Y tY|f (VIui'cl'tionial albluttI (X times less to build per cost savings. One significant sourcectibic foot of containment than do of savings lies in tising solar energy

~IXT{k(,IwgtlFUIXI Wa(1s lt'71't?IC I conventional treatinent plailt reac- ratlher thaln ele-ti icai eunergy for aera-ncaI,nei,t ,~ ,*~* t(rs. The total pond area needed is tion. (Convenlioial plants aerate by

truilUlilen)t pw]ant. ThZis nmuchI larger thian ;hat neededi for a u5ing; electrical encrgy to bNow or mix

f runtislgiln'ts lXirt 1l1 ielf I conventitonal plant, but ponds should air btihlle; into Ihi u astewater. In annsl sdiret' 1t °! still cost oliiy one-third to one-half as All' sVstei, algite uise solar energy

0X r! ;t S*lttZx,r. i much to build, accordinig lo William and phutosvniih- 'sis th supersattirateOswald, who designed St. I lelena's the wat.' 'vilhil oxygen thatsystem in the early 1960s. Oswald is a microlnes neied tk break down waste.professor emeritlus. at Ihe University

I of California, Berkeley (UC-Berkeley) ';or pcopv wvho) have alwaysand inventor of the AIP system. thoughl in t 'utn; if conventional

treatmennt, il's hi Ld to uiinderstandlProponments of the technology believe that you cmin aenat, without anythat maintenance costs for the new mechalnicl al srq1t-" *;;y.; Oswald.

' plantsate alst lower because suci "Usiig ni' cIwiwc;i auration, youG73tSs of a Conventional Plant plants minimize the use of mechani- need allbot I lil,',tAl-hour of clec-vrs. an AIP Plant cal equipment and require a smaller tricity liii oarh lilogritrn iof dissolved; tClils !n thrtisanTds inventlory( of spare parts and supplies, oxygen. In an AI Vsvstm in a good

K_ 1^;8vris) __ _ _ ____2 | Operation costs are reduced because climate, ou yiuet alowiod 20 kilogranisP 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

Another important advantage of AIP energy."I t . 4.l t -- - - - -- - - - --- - --- plants is tlhe small amount of sludSge* 8! -,- i they prodtice. In these ponids, sludge St. HIel na's pliat still ustes more' --* ! j 1> ---- - ferments tntil niothing is left hut a energy thni am optimal, up-to-date

ii| ; small volumi' of residue. For exam- All' pll voni Thirv liat'sii ! 3 tpie, dtiring 27 years of optralion, St. because St. I Ii'lel-a's plant, designed

HIelena's wastewater treatment plant 30 yeats ago, uses- (conventionalI1 *~: t l has never had tol remove residue. A pumps to circulakte water in thie pond

recent measurement at St. Helena where atalion take's place. Calcula-tO4 1 9fi1 itX E showed that in nearly 3 decades, lss tiolns that no10W sho]v tihC five-to-one

-_ X j g '048Ithian 1 mettr (3.28 feet) of residue had energy advantage of an All; plant

||257 2 accum ulated at the bottom of the are based on designs using paddlei -Rl 1 ~ 'r s v ll 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 operating Lost ing environmental regulations for ini mnlv used in comniercial algac-

I ( invenhinnal panrt tl AfP plant residue dispoisal. gyro% ing operationc. P'addile whieel5l eSOA lrf. Vxi,lw¢p,} CA

!r'u'ce _O_ . PA,rie.' _. _ circoiatiin has htCni incotrporated in

St,rhon aihi r is i iisI rimii 7iiifr l an All' svstem tlhat UiC-Derkelev isna c,ijt,ril.nt pl,11i'. I 7.5 miii, desigiuig for a St. I lelena-sizedlhEro II a 1 ,lEliriu .e,I("."lKl 1p' -,bii-- wastev-ater treatmllent plant itn Cali-

lnll'nl'llwl'l/.C19}lt1"19#"/t.tlRt' t. ~~~~~~fornlia', 'Ceni -,al V all1,N S,t ilelenar,,f ,o I,,i ,,,n,l ,,t r, ,.,n, a is alst- cisideritga (onversion toO,r.tiFif ti, I l'f.iiit, 't<S *Er U paddlet' Wheels.

A& nnr tr itn i,rnlcd I' f'nul pilorl.

Waste water: A nesoutce,Not a Waste

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

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

{ a4 ~:ut. 4 ' shOg d 411tiid Itom their planits.

. a + t i~~~~~~f k,''( I).m llI * stei .l 5 down tox)ic stu

,i,>,* - ~~~~~~~-. _ ! srti.w-, lvv' l~.li" Gt-v't1 'lila UC% t W 5 *~~~~~~~~~~~~~~~~~~GiC1a UC-

f ly~~~~~~~~~~~~~~~~~1'k'e iviifi.f wvIii mtatiwt'' (lt,

"I; ilpfl i IIgf it I COU

iltiilDiZlki}{-.' l v i j \ 2 lt~~~~~~~~~~~~~~K11.;1.lt f1,11 d olgan.ittX i11fi1l

5 h .tiul0 ot' ' l i i' ,,t,.l in latr g it

adiliuin mi- tl f lit-* healvy mtals in'.1 l ttrt I t'. mf / l.t .it illi swewag are' 'w" -il' 'italkd and remain

'sf, "'is jc tfjij n-u'. : frc'isd1 tr While aeralion hyalgae anti soAlar trapped in (lhi Lto ilti.live pond's* c! etvf r n.lr Iiei.u. energy can greatly reduce the elec- diges(.-r flit

tricity consuned by an AlP plant,aiolhitvr so4urce of energy electricity- I:urlHr, ;otit ii(t.k h as nitrogergenerati(oin through combustion of and p !iphoiru, m tts1 dinlamage aquatic;methariv-could eliminate electrical ecosyslmnls int w Ili h effluent maypwer costs completely. Methane can be dischiarg-d All' plants are betterlb prodticed by fermenting algae har- thani coinvettlti..l plants at removingvestted frtmo the plant's settling pond. thest- mitricrnts. Nilr-ogen removal

occlrs inlit) tihe digi.t Aioll hase in theConivenitionial plants typically install facultative pond. If% addition, nitro-large tanks known as digesters, in gen anid phosphoruis are taken upwhich sliutge and efftlueit solids fer- and cOlixi h', algae in the high-iment to ptotiuct methine. In an All rate pond. ( Oswld ch.a-mpions the useplant. methale from natural fermen- oi algae la vvsled flromn AU plants astatioaim in the digester pit coild be cap- fertili,v*r hec awq I e ntitrienis con-ttiretd al [lie surface (f Ilie facultalive tainmied in algav 1% i mii be releasedp 4m1til. D)velfiping a gittl lcoimni *rcial mott slenv (itan would the water-ietluane capture system loir AlP'sys- soluibl forinis in chemical fertilizersIems is undter wav. The lntvir,timen- antl tlns lt. s lil'lv to return tn

j lt I glltering ad d ( 1I * StIivit lakt.i.l t ll stre ';ans ill uttl off.

Laboratorv (UC-Blerkeley) in Rich-miod, tCalifornia, is working on thatdet'vlnouptnent with thinds from (lie

(Caliilrnia Pn*nrgy Comtmti,.sion anid

tIhe ( alitorn i i sittitoh for I lltergy

Fi il icv

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 rn gil.itimur i; i. cost.,

plants at killi,,g pathlogens becanti,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 W vith Sort t r greg i-co or ery atid tjlf -

otut aill u <lte, t1CtM1en1t, effilenlt ternai l, tlie,ttlicrfl ii,iIII lirrain, oIIfnom a lotr- pond All' plant silouhl i may hax 0 monlc\ to poit irnto UVle stifficielt ti) ineet the most ecc'ent disinfectioii or d isc('lvcd air No( tation

n,na, uron, r1jrovo INi WVorl(d llec;lth Organiization re(oil- arid still oine nutll aiead of the

IIul<itidlons foi ii Iigationi watcr, ii(n- ganve. "c r(oinig to ( )swald. 'th St. t h'l'lcia

, - r mqAc, gon,1 u,,w, a, plnant is highlighting the beneficial

:r-S ASfi,,,,C r ha reuse of its r (clainied water by grow-.t 'vi Of St. Irline,, ing pumpkinis, corn, melons, flowers, ConclUsio,Itrr rrnitte1 P'fai,rt. roses, and more tlian 0.8 hectares

(2 acres) of wine grapes. The St. I Ielhn,a plant has de:non-

strated the All' concept for nearly

t Still, not vI, en lth most enthusiastic 30 years .N-h 'rv than 89i hybrid AII'proponents of' All' systems clainm that plants ar- nov u,llcri -ilo); togeleimets

the basic four-stage system of ponds of the All' Pt(I elt in thu UJnited

t 413 1 lil ' ~~~~alonte cani producee effituiett mee-tillg Statesi and. ( thcr comlinI ic- viArost ofM lil Fitandards for drinkinig water or for them lik ',I !Ient _plant, Ecc"unrestricted" uses such as swimming very liltif lhidgu. Manv of them use ap)(,fls and irrigationi of public parks. combinat i ao of roe" I hniical and solarAn All' system, like otter treatment aeration, a p h ttli, ( (.- 1t lill requires

t| icerts, can only acihieve theses goals less electi io.t il uI, d -.; ( trventionalI vw addilional iteiatnient (e.g., disin- treatment and I lam I a ca than

fectioni, filtraitiot, and solids removal). does a systill -I hI ;1'- t. I lelena's.

- -_ -- - _ As the Lcmoflik of All' cN slelmis

g Adi anced Intefgrated Pond System Concepts In Your Community beconme i. nn vell 1, I1 %I, thowever,theaccept.u( nI ot tii^; I 'o-cost treat-

(o1 ttlr Sv'*teMr elPenllits u Oed in AIP high-rate pond can reduce the need for, or ment cin(nlo)l .u isi 14i', to *foww. In ar'ov I in be tr';nd in conriinclinn substitute for, mechanical aeration equip- political cliroit, ol intui:';ifyirig

fNeii;ionilt viasoe'ialei t mrrint meint. The primary or secondary reactorsm oyy lo reatle a hlihvid system. anid mechianical aeration equipment are regulat*iccoiri ,an *. .:a Ilicnate intJitinO thlnse Alf elemen ts allov's usually the most expensive and energy- wich c I i, nu.uiol*nance,aCthive the Irest of bolh wnlrlds" intensive elements ofaconventional treat- and (pmami * nit; it" increasingly

vlamliniu a wastewater treatnierit ment facility. And because of the long importanit. Ih All't (Ol1t niayn. detention time of organic material in the prove to oit' tIU ir lI t 1li( Inuiology

tacultative pond's digester pit, organic for use biy ni.nv huial .a!;tewater:tnology has been arounid ir material is completely removed from the manager.. U40 Years aid la heen applied in wastewaler. This sludge undergoes con-

1litions ere W ow using sote e ele- tinuous digestioni until only a small vol-lons AIP l nolrgv, us rreaing sonie .le ume of residue remains. Daily sludgeof All' teclnolry,' tliu.i creting removal and disposal are eliminated, thus

tring llscal pressule on toveal goven- achievinig dollar and energy savings.anti the high capital costs of con- Wastewater treatment tiranagers are fac-anl waslevialer treatrnent pLtnis, ing tougher state and tederal regulationsbelieve Interest in AIP concepts is affecting the quality and handling ofircreasing. Yomr commrnunilv may sludge and elIluent from their plants.

it a hybrid appmiachl nakes tIhe Using AIP technology to design hybriden1;e. systems or complete AIP systems can

rnnple. use of a larultative pvrd help your community meet regulationsw you to clonsize or elimlinate lthe aand save dollar s atrd energy-a "win-win"

4 or se,eotidary reactor. Llse o! a stuaton.

4

Ilescripil/on of ant Advanceid Inlegraled Pond Sy stemAn Advarir;.d mlilegrated Pond (AIP) sys- mTlicro llpae 1 he rapill (p owll of a!laolefi consists of four basic types of ponds, also t;ises thie alkalinity of the vater.inlerlinked and working together: killing pathogens Rer:ause tIle algae

Facultative Phond (Pond 1) I ate witThie lacultitive pond consists of ani open oxygeni. somie of lthis ponid's vaeri

pondcontiniij a"digste pit" Seage recirculated to the upoer layer of thlepond containij a "digester pit. tSewage faciultative pond to bolster its oxygenentering thep system is injected at the hot- cotn,hurediigoelnnintom of the digester pit, where sludge ispermnanenitly trapped and consumied by the need for mechanical aerationfernientalion In newer AIP system Settling Pond (Pond #3)designs, in which the water table is low More th.an hali tihe atinae produced inenough. the facultative pond is about the hiiuhl-rate pornl settle out. Sutficient4- to 5-moeters (13- to 16.4-feet) deep. algae sttile in Ith hitlh-rate pond to

i nrf Itittrrill F t 1-r The pond has an oxygen-rich upper layer meet total susireiided solids discharge*'I{^f lUJ?t f.acilifi 9 1I. IYJrnr .jf ai, ni about 1-meter (3.28-feet) deep, which requirennenis

helps to oxidize any malodorous gasesi ~~~~~~~~~~~~rising from the digester pit.Mlrlo od /od n 4Treated water is fol)sed to tl?e sun's

High-Rate Pond (Pond #2) UV ra;s and slored t(l i;rrigalton andWater from the lacultative pond flows to dispo:;althe high-rate pond, where aerobic bacte-ria break down dissolved organic matter.Oxygen is supplied photosynthetically by

)fiagrom of it. Itelena s AIP Syslem

S l~~~~~~~~~Recirculation of 1 I ~~~~~~~~~oxyqpn rich water 1 i t

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

Facultatiwe 2Ipond #11

IPligritsle pond #2 ) t M .

; | | ~~~~~~~~~~~~~mtr ||iaterloz lI MbtuatlOZt \ t.'f 2 __ __ ____ wpond i4 pond \i

Settling pond 93 Ettuent uua Onlydischarge JJ15 dunrim %g/I114 ,)lweather

1 ~~~~~~~~~~~~ ~ ~ ~~To lrigatn,n j

I