Philippines - Manila Second Sewerage Project : environmental impact assessment (Vol. 6 of 27) : Initial Environmental Examination of Project no. 4 ; San Lorenzo village, Makati City

Metropolitan Waterworks and Sewerage System Manila Water Company, Inc. E94 Volume 6 Initial Environmental Examination of the Community Sanitation Project Manila Second Sewerage Project IBRD 4019 Project No. 4 San Lorenzo Village Makati City, Philippines Prepared by: Manila Water Company, Inc. 489 Katipunan Rd, Balara, Quezon City December 2001 IN N ti _ _ ftn l  TABLE OF CONTENTS PAGE NO. Executive Summary 7 1.0 PROJECT DESCRIPTION 11 1.1 BASIC PROJECT INFORMATION 11 1.2 PROJECT LOCATION 12 1.3 PROJECT RATIONALE 12 1.4 DESCRIPTION OF PROJECT PHASES 15 1.4.1 Pre-Operational/Construction Phase 15 1.4.1.1 Construction Plan 15 1.4.1.2 Total Surface Development Block 15 1.4.1.3 Estimate of Total Area to be Opened for Civil Works 17 1.4.1.4 Major Openings and Construction Activities 17 1.4.1.5 Types of Equipment to be Used 19 1.4.1.6 Source of Construction Materials and Facilities 19 1.4.1.7 Support Services and Facilities Requirements and 19 Availability 1.4.1.8 Estimate of Total Cut Soil Volume 19 1.4.1.9 Total Manpower Requirement 20 1.4.2 Operational Phase 21 1.4.2.1 Project Operation Schedule and Duration 21 1.4.2.2 Process Technology and Activities 21 1.4.2.3 Waste Production Scheme 22 1.4.2.4 Manpower Requirement 24 1.4.3 Abandonment Phase 24 2.0 BASELINE ENVIRONMENTAL CONDITIONS 25 2.1 STUDY METHODOLOGY 25 2.2 LAND 25 2.2.1 Land Resource Utilization 25 2  2.2.2 Physiography and Geology 25 2.2.3 Vegetation and Wildlife 25 2.2.4 Land Acquisition Assessment 26 2.3 WATER 26 2.3.1 Inventory of Water Bodies 26 2.3.2 Water Quality (Surface/Ground) 26 2.4 AIR 28 2.5 PEOPLE 28 2.5.1 Population/Beneficiary 28 2.5.2 Project Affected Persons 28 3.0 PROJECT ALTERNATIVES 28 4.0 IMPACT ASSESSMENT 29 4.1 IMPACT IDENTIFICATION 29 4.1.1 Impacts During Construction Phase 30 4.1.2 Impacts During Operation Phase 32 4.2 IMPACT PREDICTION AND EVALUATION 33 4.3 UNAVOIDABLE AND RESIDUAL IMPACTS 35 5.0 ENVIRONMENTAL MANAGEMENT PLAN 35 5.1 IMPACTS MITIGATION/ENHANCEMENT PLAN 35 .2 ENVIRONMENTAL MONITORING ACTION PLAN 40 6.0 COMMUNITY CONSULTATION PROCESS 42 3  LIST OF FIGURES NO. FIGURE PAGE NO. 1 Location Map of San Lorenzo Village 13 2 Existing Drainage System Layout 14 3 Proposed Implementation Schedule 16 4 Proposed Sewer Collection Layout and STP 18 Location 5 General Treatment Process Scheme 23 6 Photograph of STP site 27 4  LIST OF TABLES NO. TABLE PAGE NO. 1 Analysis of Sample of Septic Tank Effluent Quality 15 2 Estimates of Soil Excavation Volumes 20 3 Influent Flow Characteristics 21 4 DENR Effluent Parameters for Class C Waters 22 5 Sources and List of Potential Environmental 29 Impacts Typical Noise Emissions of Construction 6 Equipment at Various Distances from Source in 31 dB(A) 7 Sludge Production of Various Wastewater 33 Treatment Processes 8 Summary of Assessment of Environmental 34 Issues/Impacts 9 Environmental Management Plan 35 10 Environmental Monitoring Action Plan 40 1 1 Institutional Monitoring 41 5  LIST OF ANNEXES Manila Water Company STARRT Card for Monitoring Construction Works 2 Wastewater Quality Monitoring Schedule Environmental Compliance Certificate (ECC) NCR-2001-06- 3 25-112-211 4 Manila Water PCO Format 5 Sample Monitoring Sheet for Effluent Quality 6 Endorsement from the Barangay Captain 7 Draft MOA among SLVAI, Ayala Corporation and Manila Water Company  EXECUTIVE SUMMARY The proposed project for San Lorenzo Village is one of the twenty-three (23) sub- projects of the Community Sanitation Project Phase 1, which is a component of the World Bank-assisted Manila Second Sewerage Project (MSSP). The project is intended to reduce the current wastewater pollution discharged to the Tripa de Gallina by the seven hundred and twenty (720) residential units and one (1) college (Assumption College) located within the village. The project involves the construction of a sewerage system using combined sewage and drainage flows collection and treatment. Specifically, the project includes the construction and installation of: (i) an underground centralized sewage treatment plant (STP), (ii) three thousand four hundred and seventy (3,470) meters of sewer mains and appurtenances, (iii) twenty six (26) interceptor chambers, (iv) one (1) underground lift station and (v) eighty (80) sewer service connections. A Memorandum of Agreement (MOA) among the San Lorenzo Village Association, Inc. (SLVAI), Ayala Corporation and Manila Water Company is being processed. The Barangay Captain of San Lorenzo has favorably endorsed the project. In conformity with the requirements of the Department of Environment and Natural Resources (DENR), an Environmental Compliance Certificate (ECC) NCR-2001-06-25-112-211 pursuant to P.D. 1586 was secured for the project. I. BASELINE ENVIRONMENTAL CONDITIONS San Lorenzo Village was developed in the 1960s by the then San Lorenzo Company, Inc. (now Ayala Corporation). The village is situated in the eastern portion of Makati City in Metro Manila and is bounded by Antonio S. Arnaiz Avenue in the north and northeast, Amorsolo St. in the west and Epifanio de los Santos Avenue (formerly Highway 54) in the south. The village has a total land area of 58 hectares, 87% of which are residential areas, 6% are commercial areas, 4% is occupied by Assumption College and the remaining 3% are parks, playgrounds and common areas. Floral population within the village constitutes ornamental plants and trees. Faunal population is limited to household pets. The area is characterized by a relatively even distribution of precipitation during the year. Like in most parts of Metro Manila, the village has two distinct seasons: the dry season during the months of November to May and the wet season during the months of June to October. 7  There is no existing sewerage system in San Lorenzo Village. The wastewater is partially treated by individual septic tanks and discharges to the drainage system which flows to a canal leading to Estero Tripa de Gallina in Pasay City, Parafiaque' River and ultimately to Manila Bay. II. ENVIRONMENTAL IMPACTS AND MITIGATING MEASURES Potential Environmental Mitigating Measures Impact CONSTRUCTION PHASE 1. Poor quality of . Manila Water Company will monitor the supply and installation construction contract to assure quality of equipment and construction. Site Managers and' Engineers with experience in construction management shall approve all materials and equipment to be used and installed at the site. * The contractor will be required to post a performance bond for the Design and Construction Contract of the sewerage system. 2. Air pollution . Efficient construction planning and work scheduling (suspended particulates, . Formulation of appropriate work plans, work scheduling, work odor and fumes, vehicle specifications and work methodologies emissions e.g. C02, CO * Provision of properly maintained storage area for keeping NO,) stocks of construction materials and equipment . Prompt and fast removal of excavated materials or dredges spoils from construction site . Sprinkling of water on dust generating mounds resulting from earthmoving activities and civil works. * Control of motor vehicle emissions . Dust accumulation will also be prevented through proper washing of construction vehicles prior to departure from the site . Development and enforcement of strict health and safety pollution control regulations specific for the project site - Good housekeeping of workplace and construction affected areas - Use of Protective Gear by all workers 3. Water pollution due to . Provide temporary drain systems and storage facilities for wastewater, oil excavation soils, fuel and oils needed for equipment leakage/spills . Cautious and sensible planning for construction and post- construction phases of the project . Provision of a routine chemical and oil spill clean-up plan * Formulation of a monitoring program 8  4. Noise pollution from . Establish temporary sound barriers around the work site operation of construction . Proper scheduling and phasing of high-noise activities equipment . Use of appropriate mufflers and sound proofing for construction machinery, equipment and engines . Use of Personnel Protective Equipment by-all workers 5. Temporary disruption of . Public information campaign posting schedule of construction traffic flow within the a Provision of a liaison officer from the SLVAI to assist in the village information dissemination regarding inevitable changes in schedule of vehicular operations . Provision of temporary alternative routes, including visible traffic warning signals . Scheduling of delivery materials and removal of excavated material during non-rush hour periods OPERATIONAL PHASE 1. Environmental hazards . Carefully designed post-construction maintenance, due to accidents, man- contingency and monitoring programs made or natural . Well designed plan for detection of accident or natural events disasters e.g. accidental including precautionary and remedial measures to be spills, fire, seismic observed activity, earthquakes, . Provision of preventive and remedial procedural manuals at heavy rain/flooding and workplace design failure a Adequate plans for environmental rehabilitation and restoration of site and removal of temporary structures and facilities installed during the construction phase 2. Water Pollution (effluent . Wastewater discharged by the STP shall conform with the discharge) Effluent Standards set forth in DENR Administrative Order 34 and 35 for Class C waters . Regular monitoring of wastewater effluent by the Manila Water Company Central Laboratory . Regular check on sewer mains to prevent discharge/seepage of untreated wastewater to the environment 3. Noise Pollution (STP . Use of appropriate mounting for machinery to minimize equipment, lift station) vibration a All mechanical/electrical equipment shall be installed inside enclosures . Motors shall be provided with soundproofing devices . Maintenance of greenbelt zones and vegetation with appropriate tree species 4. Solid Waste . Regular collection and disposal of solid waste collected in the (in the interceptor interceptor chambers and generated within and by the STP chambers and generated . Disposal of generated sludge will be in accordance with within and by the STP) established procedures of relevant authorities (disposal of sludge for use as soil conditioner) 9  5. Odors (organic and sulfur . Maintenance of greenbelt zones and vegetation with compounds coming from appropriate tree species raw wastewater and . Provision of landscape which will improve the aesthetic of the during desludging of area by planting green strips using appropriate plant or tree `septic tanks) species- * Use of .'acuum trucks for desludging of septic tanks * Provision of odor control mechanisms (deodorizer / adsorbent / masking agent) to prevent malodorous emissions 6. Maintenance and * Regular asset condition monitoring by Manila Water Company Operation of the System personnel Poor maintenance of * Regular maintenance works for the STP and lift station mechanical equipment equipment (pumps and motors), sewer network, interceptor (pumps and motors) chambers and septic tanks . Connections . Adequate training of STP and lift stations operators * A liaison officer from the SLVAI will assist the STP and lift station operators in assuring the facilities' efficient operation * Provision of adequate maintenance equipment and spares for the sewerage system facilities Ill. ENVIRONMENTAL MONITORING PLAN Environmental monitoring will be the responsibility of Manila Water Company. Construction Phase Compliance with Manila . At STP site and its * On-the-spot daily inspection Water Company health and perimeter and monitoring will be safety policies (dust . Other excavation sites implemented by the Health emissions, good (sewer mains, and Safety Dept. of Manila housekeeping, noise, odors) interceptor chambers, Water Company using the - lift stations and service Safety Task Analysis Risk connections) Reduction Talk (STARRT) * Equipment and Card (Annex 1) materials storage area Traffic . Ingress and egress to the construction sites * Daily 10  Ooerational Phase Effluent Water Quality * Influent . Annex 2 describes in detail the for parameters tike pH, 5-day * Samples from schedule of wastewater quality BOD, COD, Total coliform, Treatment stages monitoring suspended solids, and oil and . Effluent grease Odor . STP site and . Daily perimeter Sludge accumulation/clogging . At STP site . Weekly * Sewer network * Septic Tanks 1.0 PROJECT DESCRIPTION 1.1 Basic Project Information Name of Project : SAN LORENZO VILLAGE COMMUNITY SANITATION PROJECT MANILA SECOND SEWERAGE PROJECT Address : San Lorenzo Village, Antonio S. Arnaiz Avenue, Barangay San Lorenzo, Makati City, Philippines Contact Persons Leonor C. Cleofas Manager, Engineering and Project Management Office Metropolitan Waterworks and Sewerage System Ground Floor, Engineering Building, MWSS Complex, 489 Katipunan Road, Balara, Quezon City 1105 Tel No. (632) 920-5413; (632) 920-5521 to 40 locals 3570/3569 Telefax: (632) 922-2568 Ma. Fiorelia De Los Reyes-Fabelia Wastewater Project Development Manager Manila Water Company, Inc. 489 Katipunan Road, 1105 Balara, Quezon City, Philippines Tel No. (632)981-8147; (632)926-7999 loc2032 Fax (632) 981-8106  1.2 PROJECT LOCATION The proposed project for San Lorenzo Village is one of the twenty-three (23) sub- projects of the Community Sanitation Project Phase 1, which is a component of the World Bank-assisted MSSP. The service area covers the residential units along the streets of Amorsolo, Rocha, Melantic, Tampingco, Zaragosa, Zulueta Circle, Hidalgo, San Lorenzo Drive, Garcia Villa, Joaquin, Apostol, Tolentino, Balmori, Briones, Ponce, Arguilla, Lippay, Abelardo, Zipper, Juan Luna and Hernandez and one college (Assumption College). The project site is easily accessible from Antonio S. Arnaiz Avenue. Figure 1 presents the location map of the project. 1.3 PROJECT RATIONALE In Metro Manila, untreated/partially treated domestic wastewater is the major source of pollution of inland waters. Most residential houses in Metro Manila treat their wastewater by means of septic tanks, which do not provide adequate treatment to satisfy the DENR requirements for wastewater effluent standards. Moreover, majority of septic tanks in Metro Manila is not properly maintained. This situation has led to the deterioration of Manila Bay, the Pasig River and other inland waters. There is therefore an urgent need to establish collection and treatment methods that will help reduce the pollution load to inland waters. The provision of an efficient and cost-effective sewage collection, treatment and disposal is the primary objective of the Community Sanitation Project under the MSSP. This project specifically aims to address the problems of inadequate wastewater treatment and disposal in San Lorenzo Village. Figure 2 shows the current system in the Village where individual septic tanks discharge polluted effluent into the drainage lines. Inadequate treatment of wastewater in septic tanks is indicated by the analysis of the effluent of one of the septic tanks in the area (see Table 1). The project will help reduce public health risks and environmental pollution from untreated/partially treated domestic wastewater by providing a sustainable sanitation and sewerage facility. It will also serve as a good illustration of proper sanitation especially to the neighboring communities near Estero Tripa de Gallina. 12  Figure 1 Location Map 13  Figure 2 Manila Water Existing Drainage System Layout 14  Table 1 Analysis of Septic Tank Effluent Quality from San Lorenzo Village Limit(s) Septic Tank DENR-EMB Effluent pH' 6.5-9 7.40@24.30C Suspended solids, mg/L 70 40 Dissolved Oxygen, mg/L - 0.50/24.10C Biochemical Oxygen Demand 50 (BOD5), mg/L -_-,_. Chemical Oxygen Demand, mg/L 100 349' 1.4 DESCRIPTION OF PROJECT PHASES 1.4.1 Pre-Operational / Construction Phase 1.4.1.1 Construction Plan The project is scheduled for bidding in December 2001. Construction is expected to commence in March 2002 and project completion is targeted in October 2002 (240 calendar days). Figure 3 shows the implementation schedule for the project. Manila Water Company will undertake the project implementation. 1.4.1.2 Total Surface Development Block The service area is approximately 53 hectares and is estimated to have a current residential population of 4,300 and student population of about 4,000. The project will serve 720 residential units and one college within the village. Any increase in population is not considered because there are no further planned development within the village that would significantly affect the quality and/or quantity of wastewater discharges. 15  Figure 3 Proposed Implementation Schedule for the SAN LORENZO VILLAGE Comunity Sanitation Project Week Nlo. 1 23 4 56 79 1 819O1 11 122 1 41 1 5 6 l 71 8 1 9 12 0 21 1212312425 2 6127128129 303113213334 35 Pevmts and Clearios Fll l0000T TF OrdeaI rebn Equipm en Excavation for Mabin Reactor___ _ __ _________ Fonnmr, Steehua and Pounng -- - - - - - - ______ _ - | |||| Install Beduica and numbing Testing, Acptanze and Tumover_es 16  1.4.1.3 Estimate of Total Land Area to be Opened for Civil Works Civil Works will include the construction of an underground STP, twenty six (26) interceptor chambers and one (1.) lift station and installation of sewer mains and sewer service connections. The STP will be located in a 480 square-meter area in the village park which is being [eased by the SLVAI from the Ayala Corporation. Sewer mains totaling 3,470 meters in length will be opened for civil works. Figure 4 shows the proposed sewer network collection system layout. 1.4.1.4 Major Openings and Construction Activities The complete sewerage system will include the following components: * 26 interceptor chambers with land requirement of 6.25 m2 each * 1 underground lift station with land requirement of 4 m2 * 3,470 meters of sewer mains with diameters ranging from 150 to 300 mm * 38 sewer manholes * '80 sewer service connections * Underground STP with a design capacity of 1,152 m3/day and land requirement of not more than 480 m2 The civil works to be implemented are as follows: For STP/Lift Station For Interceptor Chambers/Sewers * Site clearing * Pavement cutting * Earthworks * Shoring and removal - excavation and handling * Excavation and handling - dewatering * Dewatering - backfill and compaction o Pipelaying - lean concrete/gravel bedding * Backfill and compaction * Concrete Works * Testing pavement restoration - shoring and soil protection * Clearing/miscellaneous activities - formworks - concreting * Electro-mechanical - internal and external pipeworks - mechanical installation - electrical installation * Site restoration * Clearing/miscellaneous activities 17  Figure 4 Manila Water Fg r _0 Proposed Sewer Collection Layout and STP Location 18  1.4.1.5 Types of Equipment to be Used The civil works contractor will provide equipment which include, but is not limited to, the following: * backhoe/loader * dewatering equipment * concrete mixer/concrete pump * welding machine * compactor * jackhammer and air compressor * generator * dump trucks 1.4.1.6 Source of Construction Materials and Facilities The following alternative type of pipe materials will be permitted for sewer mains: * UPVC Pipe * Polyethylene * Fiberglass Pipe * Ductile Iron Pipe * Cast Iron Soil Pipe The contractor can choose from any of the above pipe materials. 1.4.1.7 Support Services and Facilities Requirements and Availability Support services and facilities will be tapped from the available utilities on site. Arrangements with the SLVAI and/or any other party will be made by the contractor. 1.4.1.8 Estimate of Total Cut Soil Volumes Table 2 presents the estimated dimension, depth and excavation volume of each project component. 19  Table 2 Estimates of Soil Excavation Volumes Estimated Average Average -omponent.t -. Dimensions . Excavation Depth Excavaton (sqCrnm pon (m - - Volume- (cu. in.) STP site 270 4 1080 Sewer, 150 mm 0.45 x 160* 1.5 . 108 Sewer, 200 mm 0.50 x 2820 * 2.0 2820 Sewer, 250 mm 0.55 x 310 * 2.5 426 Sewer, 300 mm 0.60 x 180* 3.0- 324 26 interceptor 3 x 3 4 936 chambers Lift station 2.5 x 2.5 5 31 80 sewer service 0.45 x 3 1.5 162 connections 0_45_x_3_____162 TOTAL 5,887 * Estimated dimension of sewer main excavation (sq.m.)= [(pipe diameter + 0.3) x total length of pipe required] 1.4.1.9 Total Manpower Requirement The project will be bid out based on World Bank procedures. The winning bidder will provide contractual work for a period of around 240 calendar days. The contractor will provide skilled and unskilled workers to carry out the scope of works as detailed in the bid documents. The general scope of works includes: * site clearing * installation works for the sewer network including lift station and interceptor chambers * detailed engineering design and construction/installation works for the STP and its appurtenances * landscaping of the STP site and its vicinity * abandonment activities (road restoration, etc.) * STP start-up operations 20  1.4.2 Operational Phase 1.4.2.1 Project Operation Schedule.and Duration Completion of construction is expected by October 2002. Start-u'p operations will begin immediately after project completion. 1.4.2.2 Process Technology and Activities The project will be bid on the basis of performance specifications for the STP Treatment Process: * Domestic wastewater flows were computed on the basis of a per capita water demand of 200 liters per day and a 70% wastewater discharge. The combined sewage and drainage flows were regulated at 150% of the dry weather flows. * The influent flow characteristics were based on typical laboratory analyses of a sample of septic tank effluent as well as samples from the other project sites. The influent quality assumptions are shown in Table 3 below: Table 3 Influent Flow Characteristics TSS BODS COD Oil and (mg/l) (mg/I) (mg/I) Grease (mg/I) pH 100 200 350 50 6-9 TSS Total Suspended Solids BOD5 = 5-day biochemical oxygen demand at 200C COD = chemical oxygen demand * Wastewater discharged by the STP shall conform with the Effluent Standards set forth in DENR Administrative Order 34 and 35 for Class C waters as shown in Table 4. * Wastewater treatment will reduce the BOD5 from 200 mg/L to 50 mg/L, at the minimum. This illustrates an STP treatment efficiency of at least 75%. 21  Table 4 DENR Effluent Parameters for Class C Waters .- -_ Color . PCU 150 PH .__ .__:_ 6-9 COD mg/L 100 Settleable solids mg/L 0.5 5-day 20