Philippines - Manila Second Sewerage Project : environmental impact assessment (Vol. 1 of 27) : Main report

WOUPD 1Av e"flpv Republika ng Pilipinas PANGASIWAAN NG TUBIG AT ALKANTARILYA SA METROMANILA Metropolitan Waterworks and Sewerage System MANILA SECOND SEWERAGE PROJECT CE C ORIGINAL ENGINEERING CONSULTANTS CO., LTD. in association with DCCD ENGINEERING CORPORATION   '. l Republika ng Pilipinas */j7jIj PANGASIWAAN NG TUBIG AT ALKANTARILYA SA METRO MANILA METROPOLITAN WATERWORKS AND SEWERAGE SYSTEM I MANILA SECOND SEWERAGE PROJECT WORLD BANK - JAPANESE GRANT AGRFEMET TF 2252-3 PH U ENVIRONMENTAL IMPACT 3 - ASSESSMENT VOLUME I I MARCH 1995 l 0 E C ORIGINAL ENGINEERING CONSULTANTS CO., LTD. in association I with i DCCD ENGINEERING CORPORATION  ENVIRONMENTAL IMPACT ASSESSMENT I TABLE OF CONTENTS 1. EXECUTIVE SUMMARY 1.1 Introduction 1-1 * 1.2 The Proposed Project 1-1 1.3 Existing Conditions 1-3 1.4 Environmental Impact 1-3 1.5 Issues and Concerns 1-6 | 2. POLICY, LEGAL AND ADMINISTRATIVE FRAMEWORK 2.1 Background 2-1 2.2 Policy and Legal Framework 2-1 2.3 Legal and Regulatory Framework 2-1 2.4 Projects Covered by the EIS System 2-1 1 2.4.1 Kalakalan 20 Projects 2-1 2.4.2 Environmentally Critical Areas (ECA) 2-3 2.4.3 Environmentally Critical Projects (ECP) 2-3 | 2.5 Exemptible Projects 2-3 2.6 Institutional Framework 2-4 2.6.1 Lead Agencies 2-4 | 2.6.2 Inter-agency Coordination 2-4 2.6.3 Compliance Monitoring 2-4 2.6.4 Violations and Penalties 2-4 2.6.5 Screening 2-5 2.7 Classification of MSSP Project Components 2-5 I. 3. PROJECT DESCRIPTION 3.1 Introduction 3-1 1 3.1.1 Project Objectives 3-1 3.2 Project Area and Existing Sewerage Systems 3-3 3.3 The Need for the Project 3-4 3.4 Septage Management Plan 3-7 3.4.1 Septage Collection and Hauling 3-9 3.4.2 Barge Loading Stations 3-12 3.4.3 Sea Dumping of Septage 3-12 3.5 Dagat-dagatan Septage Treatment Plant 3-18 3.6 Ayala Sewerage System and Treatment Plant Upgrading/ Rehabilitation 3-21 3.6.1 Existing Conditions 3-22 3.6.2 Proposed Rehabilitation Works 3-24 3.7 Manila Central Sewerage System Rehabilitation 3-30 3.7.1 Existing Conditions 3-30 1 3.7.2 Rehabilitation Work 3-31 3.7.3 Basis of Design 3-34 l  l 3.8 Laboratory Strengthening 3-37 3.8.1 Sampling Schedule and Test Program 3-38 3.8.2 Recommendations for Improvement 3-39 3.9 Implementation Schedule and Costs 3-39 I . 3.9.1 Implementation Schedule 3-39 3.9.2 Project Costs 3-40 3.9.3 Costs of Environment Mitigation Measures 3-40 * 3.10 Photographs 3-40 I 4. EXISTING ENVIRONMENT AND RESOURCE USE 4.1 Geology 4-1 4.2 Hydrogeology 4-1 4.3 Climate/Meteorology 4-9 4.3.1 Climate . 4-9 4.3.2 Temperature and Humidity 4-9 4.3.3 Evaporation 4-13 4.3.4 Rainfall 4-13 4.3.5 Cloudiness 4-13 4.3.6 Tropical Cyclone 4-13 4.3.7 Prevailing Wind 4-17 U 4.3.8 Climatological Extremes 4-17 4.3.9 Atmospheric Stability 4-17 4.3.10 Tides and Currents 4-18 I 4.3.11 Aquatic Resources 4-18 4.4 Topography and Drainage 4-19 4.5 Biological Setting 4-30 I 4.5.1 Flora 4-30 4.5.2 Fauna 4-30 4.6 Air Quality 4-32 J 4.7 Hydrology and Water Quality 4-37 4.8 Noise 4-48 4.9 Land Area and Demography 4-54 * 4.10 Land Use 4-54 4.11 Socio-Economic Aspect 4-57 | 4.12 Industries/Institutions 4-58 4.13 Health 4-60 4.14 Road and Traffic 4-60 4.14.1 Dagat-dagatan Septage Treatment Plant 4-60 4.14.2 Napindan Barge Loading Station 4-64 4.14.3 Estero de Vitas Barge Loading Station 4-64 4.15 Community Resources 4-65 5. PREDICTION AND ASSESSMENT OF IMPACTS 5.1 General Impact 5-1 5.1.1 Impact of Septic Tank Desludging 5-2 I 5.1.2 Impact of Sea Dumping 5-2 5.2 Odor Impact 5-2 5.3 Noise Impact 5-4 5.4 Impact of Other Elements (Air, Water, etc) 5-5  l 6. ANALYSIS OF ALTERNATIVES 6.1 Treatment 6-1 |6.1.1 Collection of Septage 6-1 6.1.2 Treatment Methods 6-1 6.1.3 Criteria for Selection of Treatment Method 6-2 6.2 Sea Dumping 6-3 6.2.1 Sea Dumping Area 6-4 6.3 Lahar Site Disposal 6-4 6.3.1 Characteristics of Lahar Deposits 6-6 6.3.2 Constraints 6-6 6.3.3 Conclusions and Recommendations 6-6 I 6.4 Septage Dewatering 6-7 6.5 Incineration 6-9 6.6 Summary Cost Comparison 6-12 I 6.7 Recommended Option 6-12 6.8 Environmental Considerations 6-13 6.9 Future Environmental Conditions Without the Project 6-17 7. ENVIRONMENTAL MANAGEMENT PLAN 7.1 Mitigation Measures 7-1 .7.1.1 Septage Collection and Hauling Services 7-1 I 7.1.2 Barge Loading Stations 7-1 7.1.3 Sea Dumping of Septage Services 7-2 7.1.4 Dagat-dagatan Septage Treatment Plant 7-3 7.1.5 Sewerage Systems (Ayala and Manila Central) Rehabilitation 7-3 7.1.6 Ayala Sewage Treatment Plant Upgrading 7-4 3 7.2 Environmental Monitoring 7-4 7.2.1 Monitoring Program for Effluent 7-4 7.2.2 Monitoring Program for Collection Vehicle System 7-5 I 7.2.3 Monitoring Program for Drainage Water 7-5 7.2.4 Monitoring Program for Septage and Sludge 7-6 7.2.5 Sampling Schedule and Test Program 7-6 7.2.6 Test Item Number and Sampling Number 7-11 7.2.7 Monitoring for Sea Dumping 7-11 7.3 Contingency Plans 7-11 I 7.3.1 First Aid and Medical Procedures 7-15 7.3.2 Emergency Plan 7-15 7.3.3 Fire Protection Plan 7-15 I 7.3.4 Fire Detection System 7-15 7.3.5 Fire Protection Program 7-15 7.4 Compensation Plan 7-17 8. ENVIRONMENTAL MANAGEMENT AND TRAINING 8.1 Recommendations for Improvement in Laboratory Works 8-1 8.1.1 Roles of Laboratories in Site 8-1 8.1.2 Investigation of Septic Tanks 8-1 8.1.3 Sampling and Testing Staff for Ayala STP and Experimental Plant Laboratory 8-2  l 8.1.4 Proposal for Improving 8-2 8.1.5 Number of Samples and Test Items for Septage Management and Existing Treatment Plants 8-2 8.1.6 Annual Performance of the MWSS Central Laboratory Sewage Research and Analysis Section (SRAS) 8-2 8.1.7 Improvements of MWSS Central Laboratory Capacity 8-2 3 8.2 Training of Staff 8-5 8.2.1 Upgrading of Skills through a Comprehensive Training Program for Sewerage and Sanitation Operations 8-5 9. INTER-AGENCY COORDINATION I PUBLIC PARTICIPATION 3 9.1 Scoping Session 9-1 9.2 Inter-Agency Meetings 9-2 9.3 Public Consultation Process 9-2 9.4 Perception Survey 9-3 9.5 Selection of Survey Sites and Respondents 9-4 9.6 Components of the Survey 9-4 I -1 . l I. l  l APPENDICES Appendix 1 ENFORM 1 Appendix 2 Analysis of Sewage Dumping in an Open Sea Appendix 3 Septage/Supernatant Characteristics (MWSS-ADB Feasibility I Report 1991) Appendix 4 Latest Laboratory Analysis of Septage/Supernatant 1 994 Appendix 5 Wind Direction / Wind Speed Data (January-December 1993, I Port Area, Manila) Appendix 6-1 Dagat-dagatan Septage Treatment Plant: Forecast and Assessment of Odor Impact I Appendix 6-2 Dagat-dagatan Septage Treatment Plant: Forecast and Assessment of Noise Impact I Appendix 7 Communications / Letters Appendix 8 Minutes of Meeting Appendix 9 Public Consultation Attendance List Appendix 10-1 Perception Survey: Survey Forms Appendix 10-2 Perception Survey: Survey Results Appendix 11 Traffic Impact Assessment Appendix 12 1 972 London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Harmful Matters at Sea 3 REFERENCE REPORTS I. Final Reports for MSSP (December 1994) 1) Project Executive Summary I 2) Environmental Impact Assessment: Dagat-Dagatan Septage Treatment Plant (March 1995) 3) Project Description for: I - Septage Collection and Hauling - Barge Loading Stations - Sea Dumping of Septage I - Ayala Sewage Treatment Plant Upgrading - Ayala Sewerage System Rehabilitation - Manila Central Sewerage System Rehabilitation * 4) Institutional Framework 5) Financial Studies 6) Laboratory Strengthening 7) Street Drainage Improvement (Preliminary Design) II. Design Reports and Tender Documents (December 1994) 1 ) Barge Loading Stations 2) Dagat-Dagatan Septage Treatment Plant 3) Ayala Sewage Treatment Plant Rehabilitation 4) Ayala Sewerage System Rehabilitation 5) Manila Central Sewerage System Rehabilitation, 6) Fort Santiago Pumping Station (Basic Design Report only) l  l I Fig. 4-9f Average Monthly Prevailing Wind Direction, Frequency and Speed, Port Area, Manila (1 993) November - December 4-25 Fig. 4-1Oa General Winds and Currents in the Philippines (January-April) 4-27 Fig. 4-1Ob General Winds and Currents in the Philippines (May-August) 4-28 Fig. 4-1Oc General Winds and Currents in the Philippines (September-December) 4-29 Fig. 4-1 la Air/Noise Sampling Stations of Dagat-dagatan STP and Estero de Vitas 4-33 Fig. 4-1 1 b Air/Noise Sampling Station of Napindan Barge Loading Station 4-34 Fig. 4-12 Vicinity Land Use Map 4-55 Fig. 4-13 Percent Distribution by Size of Industry, I Kalookan City 4-59 Fig. 4-14 Percent Distribution by Type of Industry, Kalookan City 4-59 Fig. 4-1 5 Road Network for Dagat-Dagatan STP 4-63 ' Fig. 6-1 Typical Septage Application Lahar Soil Trench 6-5 Fig. 6-2 Truck Mounted Dewatering Device 6-8 Fig. 6-3 Wet Combustion Treatment Flow Diagram 6-11 I - Fig. 7-1 Annual Changes in Supernatant and Settled Sludge 7-10 Fig. 7-2 Sampling Schedule and Test Program for Septage Treatment a Plant (Experimental Plant)  l LIST OF TABLES Table 2-1 EIS System Legal and Regulatory Framework 2-2 Table 2-2 Roles in the EIS System 2-4 Table 2-3 EIS System Classification of MSSP Project Components 2-6 I Table 3-1 Project Costs for Phases 1 and 2 3-42 Table 3-2 Cost Related to Environmental Mitigation Measures (EMM) 3-43 | Table 4-1 Final Borehole Log & Summary of Test Results (BH #1) 4-4. Table 4-2 Final Borehole Log & Summary of Test Results (BH #2) 4-5 I Table 4-3 Final Borehole Log & Summary of Test Results (BH #3) 4-6 Table 4-4 Final Borehole Log & Summary of Test Results (BH #4) 4-7 Table 4-5 Final Borehole Log & Summary of Test Results (BH #5) 4-8 Table 4-6 Data Based from Science Garden at Diliman, Quezon City Period of Records: 1961-1985 4-12 Table 4-7 Estimated Monthly Precipitation, Surface Runoff and Infiltration in Pasig (1 987) 4-15 Table 4-8 Climatological Extremes - Science Garden (1991-1 986) 4-26 Table 4-9 Tide Variation for Manila Harbor and Pag-asa Stations 4-26 ' Table 4-10 Total Suspended Particulates 4-35 Table 4-1 1 National Ambient Air Quality Standard 4-36 Table 4-12 Maximum Air Quality Standards of Other Specific Pollutants 4-36 Table 4-13 SO2 and NO2 Levels 4-37 Table 4-14 Water Quality Monitoring Station at Pasig River 4-37 I Table 4-15 Water Usage and Classification 4-38 Table 4-16 Water Quality Criteria for Conventional and Other Pollutants Contributing to Aesthetics and Oxygen Demand for Freshwater 4-40 Table 4-17 Water Quality Criteria for Toxic and Other Deleterious Substances for Fresh Waters (for the protection of I public health) 4-41 Table 4-1 8 Effluent Standards - Toxic and Other Deleterious Substance 4-41 Table 4-19 Effluent Standards - Toxic and Other Deleterious Substance 4-42 I Table 4-20 Rivers and Creeks in the Manila Bay Region 4-43 Table 4-21 Water Quality Baseline Data (Dagat-dagatan STP) 4-45 Table 4-22 Water Quality Baseline Data for Estero de Vitas I Barge Loading Station 4-45 Table 4-23 Water Quality Baseline Data for Napindan Barge Loading Station 4-46 I Table 4-24 Freshwater Budget for Manila Bay 4-47 Table 4-25 Assessment for Compliance 4-49 Table 4-26 Noise Standards in General Areas 4-49 Table 4-27 Noise Baseline Data (Site A) 4-51 Table 4-28 Average Noise Values 4-54 Table 4-29 Ten Leading Causes of Morbidity 4-61 Table 4-30 Ten Leading Causes of Mortality 4-62 Table 4-31a Road Inventory: Dagat-dagatan STP and Estero de Vitas BLS 4-66 Table 4-31 b Road Inventory: Napindan BLS 4-66  I Table 5-1 Odors at the Dagat-dagatan STP 5-3 Table 5-2 Dispersed Odor Value on the Ground at Downwind Points 5-3 Table 5-3 Forecast of Noise Levels by Noise Type at Dagat-dagatan STP 5-5 Table 5-4a Impact on Other Elements During Septage Collection 5-6 Table 5-4b Forecast and Assessment of the Impact on Other Elements during Septage Collection Operation 5-6 I -Table 5-5a Impact on Other Elements by the Barge Loading Stations 5-7 Table 5-5b Forecast and Assessment of the Impact on Other Elements - -* by the Barge Loading Stations 5-8 * Table 5-6a Impact on Other Elements by the Septage Treatment Plant 5-9 Table 5-6b Forecast and Assessment of Impact on Other Elements by the Septage Treatment Plant 5-10 I Table 5-7a Environmental Impact of Sea Dumping 5-11 Table 5-7b Forecast and Assessment of the Impact on Other Elements by Sea Dumping of Septage 5-11 * Table 5-Sa Impact on Other Elements by the Rehabilitation at the Ayala Sewage TP and Central Sewerage System Pump Stations 5-12 Table 5-8b Forecast and Assessment of the Impact on Other Elements by Rehabilitation at the Ayala Sewage TP and Central Sewerage System Pump Stations 5-1 2 1 Table 6-1 Summary of Cost Estimates for the Septage Management Options 6-14 Table 6-2 Total Cost Summary for the Management Option 6-1 5 Table 6-3 Unit Cost Summary for the Management Option 6-1 5 Table 6-4 Significant Environmental Impacts and Mitigating Measures * (for each option) 6-16 Table 6-5 Estimated Sludge Volume for Cities and Municipalities 6-18 Table 6-6 Summary of the Estimated Number of Accessible Septic Tanks as Projected to Year 2010 6-19 Table 7-1 Daily Test 7-8 Table 7-2 Sampling Schedule and Test Program i-9 Table 7-3 Summation of Total Test items and Sampling Numbers for Septic Tank, Septage Treatment Plant and Ayala STP 7-1 3 I Table 7-4 Sampling/Monitoring Scheme for Sea Dumping of Septage 7-14 Table 7-5 Examples of Emergency First Aid Procedures 7-16 | Table 8-1 Annual Samples and Test Parameters Number at MWSS Central Laboratory (SRAS) 8-3 I Table 8-2 Recommended Personnel 8-4 Table 8-3 Annual Operating Costs of MWSS Central Laboratory 8-5 Table 8-4 Suggested Training Program for SSD Personnel Under the MSSP 8-7 Table 9-1 Result of Perception Survey 9-5  l | ENVIRONMENTAL IMPACT ASSESSMENT * 1. EXECUTIVE SUMMARY | 1.1 Introduction Through a technical assistance from the Japanese Grant Facility administered by the World Bank, the Metropolitan Waterworks and Sewerage System (MWSS) completed in 1994 the plans and detailed design for the Manila Second Sewerage Project (MSSP). The MSSP, initially conceived as a continuation of the MWSS METROSS I projects formulated under the 1 978 Sewerage and Sanitation Masterplan, has significantly deviated from the masterplan concept. The proposed program of the MSSP would address immediate sanitation and environmental problems of Metro Manila, deferring costly investments for separate sewerage system facilities. The program re-affirms the 1 991 ADB pre-feasibility studies recommending the sustained utilization of septic tanks and the use of combined collection system for the metropolis. This is realizing the fact that these tanks, if 1 ooperated properly and desludged regularly could provide the sufficient treatment for the effluent to be discharged to the drainage waterways without any significant adverse impact. Although MWSS has already institutionalized the septic tank desludging program for Metro Manila and its service area, current accomplishments are * well below the programmed targets primarily due to the lack of approved disposal sites. This constraint is addressed by the various projects developed for implementation under the MSSP. This assessment covers the various components under the sewerage project. Detailed studies are given in the separate reports and submittals. In the conduct of the assessment the following reports were prepared: o EIA for Dagat-dagatan Septage Treatment Plant I o Project Description for Sea Dumping of Septage o Project Description for Septage Collection o Project Description for Ayala Sewage Treatment Plant Upgrading I o Project Description for Ayala Sewerage System Rehabilitation o Project Description for Manila Central Sewerage System Rehabilitation o Project Description for Napindan and Estero de Vitas Barge Loading Station | 1.2 The Proposed Project The MSSP aims to improve the quality of sanitation services, reduce environmental pollution and lessen health hazards from wastewater in Metro Manila. These objectives are expected to be realized by a sustained septage management program, rehabilitating/upgrading the existing sewerage 3 systems and improving street drainage. These are to be complemented by 3 1-1  a laboratory & equipment support and institutional strengthening of the sewerage sector of MWSS. Completed under the MSSP including the tender documents are the following project components: (i) Septage Management - Septage Collection and Hauling Services - Barge Loading Stations 3 - Sea Dumping of Septage Services (ii) Pilot Septage Treatment Plant (iii) Sewerage System Rehabilitation - Ayala Sewage Treatment Plant Upgrading Ayala Sewerage System Rehabilitation Manila Central Sewerage System Rehabilitation (iv) Laboratory and Equipment Support The highlight of the present MSSP is a septage management plan covering the period 1 996 to 2010. The initial target is the 1.3 million septic tanks in Metro Manila for desludging at frequency of once every five to ten years. In the long-term, treatment facilities will be provided for the collected septage. However, current data and design parameters for large-scale septage treatment plants are lacking, so that while building a database in the interim period, the disposal of septage will be by sea dumping. The plan aims to collect 1,000 m3/day of septage and dispose these by sea dumping from 1 996 to 1998. The priority targets are the 600,000 septic tanks of households with MWSS water connections. In 1999, the pilot septage treatment plant will be operational and septage collection will increase to 1,700 m3/day. By 2004, sea dumping will be phased out with the operation of three or four treatment plants up to 2010 when collection rates will have reached 3,100 m3/day. In the period 1996 - 1999, major rehabilitation work will be made at the treatment plant and sewerage systems operated by MWSS, aimed to restore these old systems to the design operating efficiencies. This report consolidates the environmental impact assessment study conducted for the above project components and compiled according to the World Bank format for EIA reports. The EIA for the Septage Treatment Plant only covers the facilities for Dagat- dagatan. Outputs from the pilot project will be the basis for the upgrading of the Dagat-dagatan STP and the construction of similar facilities in Las Pinias, Taguig and Quezon City. These new facilities will be the subject of similar El assessments. 1-2  I 1.3 Existing Conditions In 1991, the urban population of Metropolitan Manila (MM) was estimated | at around 8.9 million, of which about 7.4 million, or 82 percent, has access to sanitary facilities in the form of septic tanks for human waste disposal. The remaining 1.5 million were underserved or unserved. Many of the I existing septic tanks of about 1.1 million units, are not well maintained and ineffective in treating the wastes. In particular, because settled sludge has not been removed from the septic tanks for years, the incoming sewage overflow to street drains or nearby waterways. In addition, as the soil is generally clayey and of low permeability, the effluent could not percolate. All these lead to the widespread pollution of Metro Manila's rivers, "esteros" and creeks. The situation is exacerbated by the constrained flow capacity in the street drainage systems caused by breakages and the accumulation of grit in sewers. These system defects result to the stagnation of water flows and frequent flooding during the rainy season. Consequently, the rivers of Metro Manila can now be described as biologically dead. Moreover, as these rivers eventually flow into Manila Bay, which is visibly black and malodorous, the environment of this body of water continue to deteriorate. There is a rapidly rising trend of high counts of coliform in the water quality of Manila Bay, averaging more than 1,000,000 MPN/100 ml in 199 1.4 Environmental Impact 3 Framework - The conduct of the environmental assessment for the MSSP follows the guidelines and procedures set under the Philippine EIS System. Using the system criteria, the services components (septage collection and I sea dumping) of the project are exemptible, while the infrastructure projects (treatment plants, sewerage system rehabilitation, barge loading stations, etc) are not. However, based on scoping meetings and discussions with the I DENR-EMB, only the Septage Treatment Plant will be required an Environmental Impact Statement (EIS), while project descriptions (PD) are adequate for the new barge loading stations and rehabilitation work for the I existing sewerage systems. These EIS and PDs will be required by EMB to process the Environmental Compliance Certificate (ECC) of the Project. I Sianificant Imoacts - The impacts of the Project will emanate from the construction and operation of new facilities (Dagat-dagatan Septage Treatment Plant and Barge Loading Stations), the construction/rehabilitation I work of existing plants and facilities (Ayala Sewage Treatment Plant & Sewerage System, and pump stations of the Central Sewerage System), and the operation of services (septage collection/hauling and septage barging to the sea dumpsite). Significant adverse impacts will be temporary and associated mainly with the construction activities. Adverse impacts (significantly on odor and noise) will be local and generated by the operation of the facilities which will be minimized by instituting proper mitigation measures. In Metro Manila, the beneficial impacts will be the general * improvement of public health situation and better water quality in the 3 1-3  receiving water bodies owing to the cleaner effluent from septic tanks. The upgrading and rehabilitation works on the existing treatment plant and sewerage systems will restore the design operating efficiencies and ensure effluent BOD and SS at the designed levels. The regular desludging of septic tanks is aimed to maintain effective treatment in the tank, thus reducing the BOD loading into public drain and waterways. Previous studies indicate that desludged septic tanks can remove significant amounts of BOD loads at 50-65% and 28-58% respectively for double- and single-compartment septic tanks. Without desludging, a maximum of 10% removal is estimated. Between desludging, it is expected that BOD removal would start at the highest level and decrease progressively until the next desludging. Properly functioning septic tank can remove up to 90% of suspended solid. The total population of Metro Manila in 1990 was about 7.9 million and is estimated to increase to 9.9 million in 2000. At a BOD generation rate of 35 g/c/d, about 346 t/d BOD will be generated in year 2000. With 60% of the population served by septic tanks, about 208 t/d of BOD load is contributed by the septic tanks. With the 28-65% BOD removal rate of desludged tanks, the reduction in BOD load will be about 58-135 t/d which is equivalent to 17-39% of the total BOD generation in Metro Manila. Significant amount of suspended solids will also be removed. The impact is a significant improvement of the sanitary condition of the community and reduction of the pollution level to the waterways. The septage management plan indicates about 600 - 1,700 t/d of septage to be disposed at sea in 1996 - 2000 when the construction of full septage treatment plants are not yet completed. At septage BOD of 5,500 g/m3 and SS of 10,000 g/m3, the equivalent loading at dumpsite will be 3.3-9.3 t/d BOD and 6-17 t/d SS. Given the characteristic nature of the sea dumpsite, the impacts are expected to be insignificant. Odors mainly hydrogen sulfide and ammonia-link gases will emanate from the treatment plants and pump stations. Receptors of these odors are plant personnel and nearby residents. Odor generating areas will be covered and the odor-filled air conducted to deodorizing units (activated carbon towers) to reduce the odor level. Noise impact will be most adverse during the construction periods when heavy equipment are in use. Noise generated by the increased vehicle traffic in the plant or station during construction and operation are insignificant. Noise generated by the operation of pumps, blowers, and other machines during the plants' operation will be properly mitigated. 1-4  l Some 50 - 60 collection vehicles will converge daily to the septage treatment plant or barge loading station. The traffic study indicated that these number of vehicles will not generate adverse impact on the present and future traffic flow conditions in the area. Impacts during construction: air particulates, noise, traffic, garbage, etc are shortlived and can be mitigated by good construction practice and good housekeeping. Mitigation Measures - Septage collection vehicles are suitably equipped for efficient and tidy desludging operation and for unlikely septage spills. Since septage or sewage is characterized by an offensive odor and may attract insects/pests, such projects as treatment plants are perceived negatively by the affected population. This is coupled by the experiences of poor plant maintenance. For the treatment plants and rehabilitated pumping stations, the malodors will be mitigated by installing activated carbon deodorizing units, covering odor generating areas and ducting foul-smelling gases. During construction, the generated loud noises will be lessened by minimizing the simultaneous operation of heavy machines, fencing the construction area, etc. Noise generated by operating facilities are minimized by suitable architectural design including concrete walls and fence, trees for buffer, etc. Though vehicle traffic condition to the plant or stations is not considered critical, the traffic flow will lessened by proper scheduling in the receiving or transfer facility including night operation. Sea dumping will be done only at the designated site and during favorable months, to minimize dumped septage reaching the nearshore areas. Proper monitoring will be made of dumping operation (e.g. spread dumping at well- submerged discharge outlet) as well as the condition of the dumping area. Overall, the impact of the project will be highly beneficial. Visible impact will be the cleaner water in the receiving water bodies. Environmental Monitoring - A monitoring program for effluent, septage and sludge, vehicle collection system, drainage water, septage and sludge, and sea dumpsite will be instituted during project operation. On-going water sampling in the Marikina and Pasig Rivers will be expanded and include the receiving rivers of the Dagat-dagatan STP effluent. Monitoring of Manila Bay need to be continued. An extensive sampling and tests will be made for the septage and sludge from septic tanks to be undertaken during desludging/collection services. Several types of septic tanks will also be monitored to determine the annual changes in supernatant and settled sludge for the purpose of establishing the optimum frequency of desludging. 1-5  l For the environmental monitoring of the sea dumping area, a sampling and test program will be implemented for the dumpsite seawater quality as well * as monitoring weather and sea conditions. 1.5 Issues and Concerns | Some issues and concerns are identified which may cause problems and delays in project implementation. | o The Project, particularly the sea dumping of septage is a new approach of waste disposal as far as Metro Manilans are concerned. Peoples' perception will certainly be adverse without the proper * information. It may be prudent to start soon relevant information dissemination, to minimize adverse reaction from environmentalists or vocal organizations. A well-planned campaign is certainly important and requires resources. o The site of the barge loading stations are public lands but their acquisition may suffer delays if present users have other plans and unwilling to give way. The Estero de Vitas site is presently used as a 1 temporary garbage transfer station, while the Napindan site is an equipment depot, with an expanding housing resettlement adjoining the site. Considering that sea dumping is scheduled in 1996, there is | an urgent need to initiate site acquisition with the concerned agencies. | o The database of septic tanks spatial distribution and conditions as well as septage characteristics needs to be properly built-up with the reliable information. Data gathering, sampling and testing will have to I be properly monitored. The plan for the development of such data- base including specifications of the required design parameters for the septage plant need to be formulated at this early stage. o Monitoring of the environmental impact of the Project is a long-term process and requires a major effort in data collection and analysis. I With likely limited resources in manpower and financial support, it is important to establish the essential data to be gathered by MWSS and maximize collaboration with other agencies with projects related to the environment of Metro Manila. * 1-6  l 2. POLICY, LEGAL AND INSTITUTIONAL FRAMEWORK I 2.1 Background The issuance of National Environmental Policy Act (NEPA) of 1970 in the | USA gave birth to similar legislation in other countries, notably the Philippines. | The Philippine Environmental Impact Statement (EIS) was introduced in 1977. It mandates that all government agencies, government-owned or controlled corporations, and private companies prepare an environmental * impact assessment for any project or activity that affects the quality of the environment. (The Philippine system uses three types of environmental impact statement: an EIS, a project description, or a brief project description. The type of assessment that must be prepared depends on the size, type, and location of a proposed project.) The system has been refined through a number of laws, proclamations, regulations, and guidelines issued since 1977. 1 2.2 Policy and Legal Framework Policy Obiectives - The basic policy objective of the EIS System is stated in the 1978 Presidential Decree 1586, Section 1: 'It is hereby declared the policy of the State to attain and maintain a rational and * | orderly balance between socio-economic growth and environmental protection.' * 2.3 Legal and Regulatory Framework The EIS System is based on a series of presidential decrees, executive orders, proclamations, letters of instruction and corresponding implementing rules and regulations as listed and briefly described in Table 2-1. 2.4 Projects Covered by EIS System There are three general categories of projects that are under the EIS System: Kalakalan 20 Projects, environmentally critical projects and projects located in an environmentally critical area. 2.4.1 Kalakalan 20 Projects Kalakalan 20 projects are countryside and barangay business enterprises I that meet the following criteria: * 2-1  l I TABLE 2-1 EIS SYSTEM LEGAL AND REGULATORY FRAMEWORK LAWIREGULATION YEAR FEATUREIS * PD 1151 - Philippine Environmental 1977 Requires proponents of government and private projects Policy affecting environmental quality to prepare an EIA. PD 1152 - Philippine Environmental 1977 Requires land use management regulating or enforcing Code agencies to consider significant environmental impacts, as well as other aspects, of locating industries. I PD 1586 - Establishes the EIS 1978 Centralizes the EIS system under the NEPC (now EMB) and System authorizes the President and NEPC to proclaim projects and activities subject to EIS System. * Implementing Rules and Regulations 1979 Defines parameters for EIS. of PO 1586 I Proclamation 2146 1981 Proclaims certain areas and types of projects as environmentally critical and within the scope of the EIS system. [LOI 1179 1981 Authorizes NEPC to issue ECC and exemptions. NEPC Office Circular No. 3 1983 Provides technical definitions and scope for environmentally U critical projects and areas. Revised Rules and Regulations 1984 Limits EIS for ECPs; establishes requirements for ECAs, fees, Implementing PD 1586 compliance monitoring system, calls for closure of ECPs operating without an ECC; authorizes NEPC to cancel an ECC for violating ECC conditions or other standards; identfies lead agencies for ECPs and ECAs. EO 192 1987 Establishes the central and regional structure of the DENR, including the EMB, abolishes the NEPC, and transfers NEPC powers and functions to EMB. I DAO 21 - Amendments to Revised 1992 Decentralizes certain functions to DENR regional offices; Rules and Regulations Implementing refines need for public hearings and establishes the concept PD 1586 of multi-sectoral monitoring team and the Environmental Guarantee Fund (EGF). RA 7160 - Local Government Code 199111 Transfers certain environmental management functions to and Implementing Rules and 992 LGUs and provides for positions of Environment and Natural Regulations Resources Officers in provinces, cities and municipalities. DAO 30 - Guidelines for the Transfer 1992 Lists issuance of ECCs for and adjudication of cases involving and Implementation of DENR complaints against projects and businesses under Kalakalan Functions to LGUs 20 (as defined by RA 6810) as functions to be assumed by LGUs. DAO 70 - Guidelines for Programmatic 1993 Establishes procedures to address EIA requirements for Compliance industrial development projects to consider potential overall impacts of existing, planned and future industrial establishments within a specific geographic area and to issue single ECC for each area. 2-2  I* A business entity, association or cooperative engaged in the - production, processing or manufacturing of products or commodities, or other productive services; | * Located anywhere in the country except: - eight cities and nine municipalities comprising Metro Manila - other highly urbanized cities | * Total of 20 employees or less; | * Total asset at the time of registration of R 500,000 or less. 2.4.2 Environmentally Critical Areas (ECA) An ECA is defined as a project site that meets any of the following characteristics: v all areas declared by law as national parks, watershed reserves, | wildlife preserves and sanctuaries; * areas set aside as aesthetic potential tourist spots * areas that constitute the habitat of an endangered or threatened I species of indigenous Philippine wildlife (flora and fauna) & areas of unique historic, archaeological or scientific interest * areas that are traditionally occupied by cultural communities or tribes U* areas frequently visited and/or hard-hit by natural calamities (geologic hazards, floods, typhoons, volcanic activity) v areas with critical slopes * areas classified as prime agricultural lands 3 2.4.3 Environmentally Critical Projects (ECP) An ECP is defined as any type of projects, whether they are new or an expansion in production or physical area: v heavy industries (i.e. non-ferrous metal industries, iron and steel mills, petroleum and petrochemical industries, smelting plants) * resource extractive industries (i.e. large-scale mining and quarrying projects, forestry projects, dikes and/or fishpond development | projects) * infrastructure projects (i.e. dams, power plants, reclamation projects, roads and bridges) 2.5 Exemptible Projects Department Administrative Order 20 of 1992 describes two broad categories of projects that are exempted from the EIS System: | * environmentally critical projects that began operation before 1982, except where their operations are expanded in production or entail new construction and/or new facilities; I * projects that are not defined as environmentally critical, not located in ECAs, and meet the following conditions: - are considered non-pollutive 2-3  - have capitalization of less than 9500,000 I - employ not more than 20 persons. | 2.6 Institutional Framework 2.6.1 Lead Agencies * There are a number of agencies involved in the preparation, review, approval and rejection, compliance monitoring and enforcement of the EIS System. | These roles are defined by the type of project as shown in Table 2-2. TABLE 2-2 ROLES IN THE EIS SYSTEM * PROJECT/ACTIVITY CONCERNED AGENCY Kalakalan 20 LGU, Provincial Governor Environmentally critical project DENR-EMB Environmentally critical area DENR Regional Office, l____________________________ Regional Executive Director | 2.6.2 Inter-Agency Coordination DENR has signed Memoranda of Agreement (MOA) with 30 agencies and government-owned corporations to streamline the EIS system and resolve areas of conflict and overlapping requirements. From these, an inter-agency network was created to facilitate the regular exchange of information on I procedures and guidelines and continually review the process flow, documentation procedures and requirements as well as the forms for streamlining environmental and government licensing and permit structures. 2.6.3 Compliance Monitoring Compliance monitoring is a joint responsibility of the project proponent, EMB, NGOs, LGUs, and the DENR regional offices. The ECC conditions contain a specific schedule under which the proponent must submit a compliance report to the DENR regional office. The EMB or the DENR regional offices may recommend the establishment of a multi-sectoral monitoring team as a condition of the ECC. The multi- sectoral monitoring team may include representatives of: EMB, the DENR regional office, LGUs, NGOs, people's organizations, the media, academe, other government agencies represented at the regional or local level, and the affected communities. The specific composition of the monitoring team and * their responsibilities are listed in a Memorandum of Agreement. 2.6.4 Violations and Penalties There are three types of enforceable violations in the EIS System: 2-4  l o environmentally critical projects found operating without an ECC or ECC exemption; | o projects with an environmentally critical area found operating without an ECC; and o projects found violating ECC conditions. EMB, DENR regional offices, and LGUs have the authority to impose a fine, | require corrective action, or both, for projects found in violation of the EIS System. The maximum fine permitted by law for a single violation cannot I. exceed la50,000. Repeated violations result in the issuance of a cancellation/suspension order and/or revocation of the ECC. 2.5.5 Screening 0 Screening is performed by EMB or the Regional DENR staff in order to determine if a project can be exempted from the EIS process. At the outset of any project, the proponent must obtain a copy of ENFORM 1 from the DENR regional office. This one-page form is used to determine whether the project is an environmentally critical project, is located in an environmentally critical area, or is exempted from the EIS System. The proponent completes the ENFORM 1 (see Appendix 1) and submits it to the DENR regional office. The Regional Office's EIA Division reviews the ENFORM 1 and recommends that the Regional Executive Director (RED) as authorized by the Secretary sign or not sign the form certifying that the 3 proposed project or activity is exempted. The DENR RED notifies the proponent, in writing, within fifteen (15) days of receiving the completed ENFORM 1 on whether the proponent: o must prepare and submit a PD or EIS or o is exempted from the EIS System. The completed ENFORM 1 and a letter of notification are used to begin a file I on the project. The file is kept at the EMB and DENR regional office. 2.5.6 Classification of MSSP Project Components Using the above described EIS System, a classification is made to the project components of MSSP and is shown in Table 2-3. It will be noted I that the projects are aimed at reducing the pollution to the environment by treatment of the waste and its proper disposal. * 2-5  The classification indicates that the two services projects are exemptible. The remaining projects are infrastructure constructions or rehabilitations, which are not exemptible. I Based on the scoping meetings and discussions with the EMB, the proposed Dagat-dagatan Septage Treatment Plant will be subject to an environmental impact assessment study; while project descriptions will be adequate for the *I. remaining projects. These shall be the requirements for the processing of the Environmental Clearance Certificate (ECC) by the DENR-EMB. - TABLE 2-3 EIS SYSTEM CLASSIFICATION OF MSSP PROJECT COMPONENTS * AND DOCUMENT REQUIRED j PROJECT ECA ECP REQUIREMENT REMARKS 1) Septage Collecton and No No PD Services aimed for cleaner Hauling Services environment . | 2) Barge Loading Stations No Infrastructure PD Transferlhandling of septage for Construction sea disposal 3) Sea Dumping of Septage No Not classified IEEIPD Environmental impact at site Services and vicinity to be well monitored 4) Dagat-dagatan Septage No Infrastructure EIA Waste treatment plant to reduce Treatment Plant environmental pollution Constructionl 5) Ayala Sewage Treatment No Infrastructure PD Waste treatment to reduce Plant Upgrading pollution to the environment/ ___________________________________ ._______________ no increase in capacity J 6) Ayala Sewerage System No Infrastructure PD Convey sewage to reduce health Rehabilitation hazards from exposurelwill 3__________________________________ ________________ involve only excavation I 7) Manila Central Sewerage No Infrastructure PD Convey sewage to reduce health System Rehabilitation hazards from exposure/will I involve only excavation ECA - Environmentally Critical Area ECP - Environmentally Critical Project PD - Project Description EIA - Environmental Impact Assessment IEE - Initial Environmental Examination 2-6  | 3. PROJECT DESCRIPTION 3.1 Introduction The Metropolitan Waterworks and Sewerage System (MWSS) is a public corporation mandated by law to own and/or have jurisdiction, supervision and control over all waterworks and sewerage systems in its service area. The MWSS service area covers 1, 1 98 km2 consisting of Metro Manila and I an adjoining city and 10 municipalities. Metro Manila has an area of 636 km2 comprising 7 cities and 10 urban towns. It is bounded in the north by municipalities of Bulacan province, in the east by the Laguna de Bay and I towns of Laguna province, in the south by municipalities of Cavite province and in the west by the Manila Bay. About midway, the area is bisected by the Pasig River whose watershed extends to the Marikina Valley and Laguna de Bay and discharges into the Manila Bay. Metro Manila presently comprises 8 cities (Kalookan, Makati, Mandaluyong, I Manila, Muntinlupa, Quezon, Pasay and Pasig) and 9 towns (Las Pifias, Malabon, Marikina, Navotas, Parafiaque, Pateros, San Juan, Taguig and Valenzuela). Metro Manila is the prime center of culture, commerce, politics and business of the Philippines; it is the seat of the national government. Metro Manila and the MWSS service area is shown in Fig. 3-1. I 3.1.1 Project Objectives Well aware of the inadequacies of its sewerage and sanitation services, the MWSS in 1978-79 prepared a sewerage and sanitation masterplan for Metro Manila. The multi-stage plan consists of a long-term sewerage program and an interim non-sewerage sanitation program. The former proposes separate collection systems, several wastewater treatment plants and the disposal of treated wastewater into the Manila Bay; the latter, was focused on the areas in Metro Manila that lacked sewerage systems and are currently provided with regular septic tank desludging program and an attendant street drainage improvement component. METROSS I, the first of the five-stage packages under the master plan was implemented in 1981-90. Due to financial constraints, the succeeding stages of METROSS were not implemented. In 1991, the MWSS with a grant from ADB conducted a pre-feasibility study which formulated the Second Manila Sewerage Project. The Project consists of the following physical components (in their order of priority): (i) septic I tank upgrading and regular desludging, treatment and disposal, (ii) drainage improvement to reduce and eliminate sewage in streets, (iii) upgrading of the Central Sewerage System, (iv) upgrading of the Ayala Sewage Treatment * Plant and sewer system, and (v) construction of the new South Sewerage System and Bay Outfall. The environmental, institutional and financial aspects of these proposed components were assessed. After the study, these were not pursued owing to the difficulty in obtaining rational subsidies for projects of the system. 3-1  s PROgL ' P-DI \~~hi aig *l~~~~~~~~~~~~~~~~~~~~ I 2'V 3- 4KM I~~~~~~~~~~ 1 \l~s -M cmwm I MANILASY LE A * .LAND MO MNILA-AND PROJEVC AREA A .; ~~~~~PROJECT AREA (METRO MANILA) - O < AND MWSS SERVICE AREA ________PH__ ._ . _ CNSULTANTS: OEC-DCCD I FIG. 3-1 3-2  I~~~ Consequently, in early 1994, t5de MWSS was a recipient of a technical assistance from the World Bank. The grant was aimed in reviewing the 1991 ADB report and to prepare studies/detailed designs for four of the above-mentioned components and additional related studies on the institu- tional/financial aspects and environmental impact assessment of the sub- projects. The goals of these engineering studies are to: (i) improve the quality of sanitation services, (ii) reduce environmental pollution, and (iii) eliminate health hazards from wastewater in sensitive areas. This program has resulted in a package of projects with the following health/ecosystem related objectives: Health Obgectives: o Reduce exposure of population to sewage in and round homes and streets; o Reduce the exposure of population to sewage and industrial wastes on the beaches; o Reduce exposure of population to waste in the esteros and rivers; o Reduce population exposure to disease from consuming contaminated shellfish. Ecosystem Obiectives: o Reduce waste loads to esteros, rivers and Laguna de Bay; o Reduce waste loads to Manila Bay near shore; o Reduce waste loads to Manila Bay offshore. Septage management became the major focus in the 1994 work for the MSSP. The plans and detailed design (including bid documents) were completed for the following components of the project. (a) Septage Management - Septage collection and hauling services - Sea dumping of septage services - Barge loading stations construction - Pilot septage treatment plant construction (b) Ayala Sewage Treatment Plant Rehabilitation (c) Ayala Sewerage System Rehabilitation (d) Central Sewerage System Rehabilitation (e) Laboratory and Equipment Support The abovementioned services and infrastructure projects except item e) are the subject of the present environmental impact assessment. * 3.2 Project Area and Existing Sewerage Systems The project area shown in Fig. 3-1 covers the water supply service area of MWSS in Metro Manila. It does not include the fringe towns included in the MWSS water service area. 3-3  l The location of the various project components is shown in Fig. 3-2. Septage management covers the unsewered areas of Metro Manila which is about 5% of the Metro Manila area. The major sewerage systems consist | of the Central system in Manila covering 2,600 ha and the Ayala system in Makati (700 ha). Several communal sewage collection systems are located in Quezon City and were constructed in housing developments during the 1 960s and early 1 970s. The existing Dagat-dagatan wastewater treatment pond services a 1 50 ha reclamation/urban housing development area located in the border of Caloocan and Manila cities. 3.3 The Need for the Project * The major problem in Metro Manila's sanitation condition is the heavy pollution from the effluent of domestic septic tanks. There are about 1.3 million septic tanks in the unsewered areas of Metro Manila. Considering i their design and usage, these tanks need to be desludged once every 5 to 10 years for them to maintain effective treatment of sewage. The sludge settling in the tank and accumulated from long period of use, fills up the I tank. When wastewater or fecal matter are discharged into an undesludged tank, these are not detained as desired, but shortly flows through. The resulting effluent is essentially an untreated sewage flowing into urban 1 drains and ultimately discharged to nearby bodies of water. During the rainy season, creeks/esteros overflow and the clogged drainage systems cause flooding thus exposing the people to the hazards of polluted floodwater. The problem is aggravated during the dry periods when street drains are fed mainly by discharges from the septic tanks. I Past studies indicate that desludged septic tanks can remove significant amounts of BOD loads at 50-65% and 28-58% respectively for double- and single-compartment septic tanks. Without desludging, a maximum of 10% removal is estimated. Between desludging, it is expected that BOD removal would start at the highest level and decrease progressively until the next desludging. Properly functioning septic tank can remove up to 90% of suspended solids. The total population of Metro Manila in 1990 was about 7.9 million and is estimated to increase to 9.9 million in 2000. At a BOD generation rate of 35 g/c/d, about 346 t/d BOD is generated in year 2000. With 60% of the I population served by septic tanks, about 208 t/d of BOD load is contributed by the septic tanks. With the 28-65% BOD removal rate of desludged tanks, the reduction in BOD load will be about 58-135 t/d which is I equivalent to 17-39% of the total BOD generation in Metro Manila. Significant amount of suspended solids will also be removed. The impact is a significant improvement of the sanitary condition of the community and reduction of the pollution level to the waterways. Providing the proper maintenance to the septic tanks will significantly U improve the sanitation conditions in Metro Manila. Since 1981, MWSS implemented a septic tank maintenance program as part of its sewage/ 3 sewerage operations. The program is undertaken through service contracts 1 3-4  I I R10' 04 210,00CC 290, QOGE 00,.00OE I C~~~~~~~~~~~~~~~~~~~ALO OCAIH CITN( lIZVEk A I I ~~~LOADING STATIO 1 .SETAGE TREATMENT 7, C ISYSTEMREHABITATION to -f LOADING STATION !1 ~~MAIPLA CNT UPRADIN S R 0~~~~SSE REHABILITATIONEABLITTIN w 4 w P^"^riAQuE , ~~~~~~~LEGEND- F X J t / x-z-x ~~~~~~~~~~~~~~Metro Manila I ' ^ ,. 4 - -~ Exist. sewer system City/town limit I~~~~~~~~~~~ gA0e 460 00 I~~~~~~~~~~~~~~~~~~VLI * 1-sLr^ lk _ v \ aSOURCE: JMIVIEMIO MMIREIS R.cwri FIGURE 3-2 LOCATION PLAN OF PROJECT COMPONENTS I 3-5  l and the operation of its own desludging equipment fleet. In 1 993, the I program cleaned some 4,020 septic tanks against an annual target number of 120,000. While many factors and problems contribute to the low performance of the program, the major reasons and constraints are: (a) A considerable time is required to desludge each septic tank because of difficult access (narrow road or distant from road) and obstructed access manholes, most often within the house floor area; (b) The number of desludging crews is inadequate. There were only two 3 contractors in 1993. There are constraints the MWSS organization affecting the program. (c) The capacity and effectiveness of equipment and vehicles used for 3 desludging are basically poor. MWSS and its contractors use tanker trucks with engine-driven or diagram vacuum pumps mounted on trailers, and rigid type suction hoses together with wash water tanker I trucks. These are old and inefficient equipment and could not cope with the high performance necessary to desludge the large number of tanks. I (d) The increasing awareness for clean environment restricted the opening of new disposal sites. Septage disposal have been limited to the Sta. Rosa dumpsite located some 60 km north of Manila. 1 Discharging the septage into the communal imhoff tanks, to main trunks of the large sewerage systems or to the esteros were not an * uncommon practice. The sewerage systems operated by the MWSS are old and in bad state of operating condition. These are (i) the Manila Central Sewerage System m. originally built in 1 900s and its last major expansion and rehabilitation made 1 985, (ii) Ayala Sewerage System and Treatment Plant constructed in the 1 960s, (iii) Dagat-dagatan Sewer System and Wastewater Treatment Pond built in the late 1970s in the Tondo Foreshore reclamation and housing development, and (iv) Several communal sewer systems of the govern- ment's housing development done in the 1960s and 1970s. The Manila Central and Ayala sewerage systems serve a large population and have been recommended for major rehabilitation and upgrading in past studies. The operation of septic tanks requires periodic desludging and satisfactory disposal of septage. The problem of disposal have hampered desludging | operation. The provision of septage treatment plants could not advance due to insufficient data on the number and distribution of septic tanks, and on the characteristics of septage. A strategy was developed in the Septage I Management Plan consisting of (i) a rational septage collection and hauling supported by new equipment to address the lack of equipment; (ii) sea dumping of the collected septage to address the lack of land-based disposal I sites; and (iii) a pilot septage treatment plant to be the basis of design and efficient operation for the future large treatment plants. The disposal of septage at sea in the initial years of the Plan is an interim solution to the I. lack of disposal site and at the same time enable to build-up a reliable database for design and operation. 3-6  | 3.4 Septage Management Plan During the preliminary design of MSSP, the recommended long-term septage management approach was to operate four septage treatment plants (STPs) each servicing a designated collection area and designed to handle the septage volume generated by the projected number of septic tanks for the Years 2000 and 2010. The distribution of septic tanks and the four STPs with the delineated service area are shown in Figure 3-3. The basic input in the preliminary design (Year 2000) are: o Total septic tank to be desludged per year = 910,000 I o Septage collection per day = 3,800 m3/day (240 workdays/yr) o Sludge generation rate = 140 Ipcy o Frequency of desludging = 1 in 5 years The recommended STPs and their design capacities (Year 2000) are: 1 o Dagat-dagatan & Quezon City @ 220 m3/d x 4 modules o Taguig & Las Pifias @ 200 m3/d x 3 modules 1 The major features of the recommended preliminary plan included: o Use of the more versatile vacuum car to efficiently desludge and collect/haul the septage from the 1 .1 million accessible septic tanks; 3 Subdivision of the Metro Manila area into four collection districts and provision of transfer stations for more efficient hauling; 0o Use of "low-technology" treatment process that could be upgraded to suit the long-term program; o Four treatment plants each serving a collection district with a combined capacity of 3,800 m3/day (design year 2000); o Each STP has 4 to 5 modules that could be installed stages to meet the demands for the design years up to 2010; and o Co-disposal of the stabilized sludge output of the treatment plants to existing sanitary landfills. The design parameters for the treatment plants for the preliminary design are summarized in Tables 5.1-1 and 5.1.2 in Appendix 1. The above septage management approach was revised for the final design considering the comments of MWSS and the World Bank review mission of I July. The final septage management plan was developed taking into account the following: I (a) the need to significantly reduce the project costs, (b) the use of sea dumping of septage in the interim period and resolve the lack of inland disposal site, I \ (c) the need to build-up an adequate database on septic tank distribution and septage characteristic for use in the final design, (d) the operation of a pilot septage treatment plant for aimed to provide 1 3-7  KALOOKAN CJTY , 1419,9851 (North) I / > VAENZUELA / I ~\Xs - m_ A 28940 14514 O a/SAN MATEO ;QUEZON CETY (EXISTING SOLID