MAYNILAD WATER SERVICES, INC. MWSS Compound, Katipunan Road, Balara, E1288 v 12 Public Disclosure Authorized

DRAFT FINAL REPORT

CONCEPT DESIGN Public Disclosure Authorized Project 7 Sewage and Septage Treatment Plant Public Disclosure Authorized

August 2006

Program Management Group Maynilad Water Services Inc. 2nd Floor Engineering Building Old Balara, Katipunan Road, Quezon City Telephone No.: +632.433.6978 Facsimile No.: +632.435.2128 Public Disclosure Authorized Website: http://www.mayniladwater.com.ph

Copyright C 2006 by Program Management Group. All rights reserved. The concepts and information contained herein are the property of MWSI. Use or copying of this document in whole or in part without the written permission of MWSI constitutes an infringement of copyright. Project 7Prototype STP/SpTP 8/17/2006 Page i L Document History and Status l Checked/Reviewed Approved by / Date Revision Date Issued Prepared by by Signature Approved A. S. August Draft Final August 2006 Sampiano M. R. Pedron P.N. Rosete 2006

J.C. S. Iglesia

F. A. Arellano

Distribution of Copies Revision Copy No. Quantity Issued to Draft Final 1 1 MWSI 2 1 DENR 3-: MWSS

Printed : 17 August 2006 Last Save : 17 August 2006 Filename : CD:/Project 7 Concept Design Report Author : A.S.Sampiano Office : Water Sources and Wastewater Facilities Development (WSWFD), PMG Managers : (1) M.R. Pedron, Manager -WSWFD, PMG (2) J.C. S. Iglesia, AVP - Program Planning and Design, PMG Support Group : Environment Managernent Dept., Sewerage and Sanitation Dept. Version : Draft Final

Project 7Prototype STP/SpTP 8/17Q2006 Page ii Table of Contents Executive Summary ...... v Section 1. Introduction ...... 1.1 General Background ...... 1 1.1.] World Bank Mission ...... 1 1.2 Objectve ...... 2 ...... 2 1.3 Limitation of the Study ...... 2 Section 2. Quezon City Communal System and Its Condition ...... 3 2.1 Project 7 Imhoff Tank ...... 5 Section 3. Review of the Pre-feasibility Report ...... 8 Section 4. MWSI Proposed Alternative 0...... 4.1 Design Assumptions and Criteria ...... 10 4.1.1 Service Areas and Land se ...... 10 4.1.2 ProjectedSewage and Septage Volume ...... 10 4.1.3 Wastewater Characteristicsand PolluitionLoading...... 10 4.2 Process Flow for Prototype STP/SpTP ...... 11 4.2.1 Components of Proposed.SpTP ...... 12 4.2.2. ('ompotnents of Proposed.S7P ...... 13 4.2.3 Odor Control acili 4...... 14 4.3 Theoretcal Performance ...... 14 4.4 Improvement in the Level of Service ...... 16 Section 5. Estimated Capital and Operating Costs ...... 16 5.1 Estmated Capital Expenditures ...... 16 5.2 Estimated Operabng Expenses ...... 18 Section 6. Recommendations ...... 19 Section 7. Other Issues and Concerns ...... 20 7.1 Social Acceptability ...... 20 7.2 Traffic Accessibility ...... 20 List of Figures Figure 2.0-1 Location Map of Project 7 and Project 8 ...... 4 Figure 2.0-2 Plan and Section of the Existing Imhoff Tank ...... 5 Figure 2.1-1 Site Layout of Imhoff Tank Facility in Project 7 ...... 6 Figure 2.1-2 Influent/ Effluent BOD Levels against DENR AO 35 Required Standards. 7 Figure 4.2-1 Process Flow Diagram for Proposed Project 7 Prototype STP/SpTP . 12 Figure 4.3-1 Mass Balance Flow Diagram ...... 15 List of Tables Table A Summary of Capital and Operating Cost ...... vi Table 2.1-1 Monthly Billed Volume (cmd) for Sewered Customers in . 7 Table 2.1-2 Monthly Influent Data for Project 7 Imhoff Tank ...... 8 Table 2.1-3 Monthly Effluent Data for Project 7 Imhoff Tank ...... 8 Table 4.1.3-1 Monthly Influent Data for Dagat-Dagatan Septage Treatment Plant . 11 Table 4.2.3-1 Classification and Source of Odor ...... 14 Table 4.3-1 Theoretical Performance of Proposed Prototype STP/SpTP ...... 16 Table 5.1-1 Construction Cost Estimates of the Prototype STP/SpTP ...... 17 Table 5.1-2 Breakdown of Cost per Chamber ...... 18 Table 5.2-1 Estimated Operating Cost of the Prototype STP/SpTP ...... 19

Project 7Prototype STP/SpTP 8/17/2006 Page iii Abbreviations and Acronyms

ADF - Average Daily Flow AO - Administrative Order BOD - Biochemical Oxygen Demand CMSS - Central Sewerage System COD - Chemical Oxygen Demand CST - Communal Septic Tank EDSA - Epefanio delos Santos Avenue EO - End-of-Year GEF - Global Environmental Facility MOA - Memorandum of Agreement MP - Master Plan MTSP - Metro Third Sewerage Project PLC - Programmable Logic Control RAS - Returned Activated Sludge SBR - Sequencing Batch Reactor SpTP - Septage Treatment Plant SS - Suspended Solids STP - Sewage Treatment Plant TSS - Total Suspended Solids UASB - Upflow Anaerobic Sludge Blanket WAS - Waste Activated Sludge

DENR - Department of Environmental and Natural Resources LLDA - Laguna Lake Development Authority LMTP - La Mesa Treatment Plant MWCI - Manila Water Company, Incorporated MWSI - Maynilad Water Services, Incorporated MWSS - Metropolitan Waterworks and Sewerage System NHA - National Housing Authority WB - World Bank

m - Meter(s) m2 square meter(s) cum. - cubic meter(s) mL - Milliliter mg/L - Milligram per liter(s) cmd - Cubic meter per day MPN - Most Probable Number pH - potential Hydrogen Php - Philippine Peso Sqm - Square meter(s) USD - United State Dollar

Project 7Prototype STP/SpTP 8/17/2006 Page in Executive Summary

World Bank has a mission to reduce pollution loading discharges in area. Through the Global Environmental Facility - World Bank Technical Assistance (GEF-WB TA) for Manila Third Sewerage Project (MTSP) under DENR, a consultant has been engaged to conduct a pre-feasibility study for the prototype treatment plant for sewage and septage. Several facilities within the MWSI concession area have been considered and due to its advantages the existing Imhoff Tank facility in Project 7, Quezon City has been recommended to be the pilot project. The existing facility will be rehabilitated and upgraded to accommodate a given amount of septage. The consultant's study also indicates that the facility owner has to invest a certain percentage of the total project cost.

This report presents the results and recommendations of a study to develop an alternative concept design for the proposed prototype sewage/septage treatment plant (STP/SpTP). This study aims to: (a) develop a process flow using state-of-the-art technology; (b) examine potential savings in capital expenditure and operating costs; and (c) assess other issues and concerns on environmental and social impacts of the project.

Major activities of the study involve data gathering, review and updating of water quality data, developing various process flow options, and estimating capital and operating costs for the proposed altemative.

The proposed prototype STP/SpTP will be an underground facility. The treatment facilities have been designed to accommodate an estimated sewage flow of 2,400 cmd from the Veterans Village in Project 7 and an additional septage volume of about 240 cmd from other areas in Quezon City (west) and .

Proposed Altematives of the Prototype STP/SpTP in Project 7, Quezon City

In order to meet its sanitation target at a minimum investment cost, MWSI developed an alternative scheme other than that indicated in the pre-feasibility study, summarized as follows:

1. Pre-feasibility altematives * Sewage (2,400 cmd) + Septage 0% (Ocmd) - full aerobic biotreatment; * Sewage (2,400 cmd) + Septage 10% (240 cmd) - full aerobic biotreatment; Sewage (2,400 cmd) + Septage 5% (120 cmd) - anaerobic-aerobic biotreatment; * Sewage (2,400 cmd) + Septage 10% (240 cmd) - anaerobic-aerobic biotreatment * Sewage (2,400 cmd) + Septage 15% (360 cmd) - anaerobic-aerobic biotreatment 2. MWSI proposed altemative * Sewage (2,400 cmd) + Septage 10% (240 cmd) - full-aerobic biotreatment;

The pre-feasibility alternatives consist of full aerobic biotreatment (SBR) and anaerobic- aerobic biotreatment (UASB+SBR). The existing Imhoff Tank with 2 chambers will be upgraded to 2 balancing tanks to hold the mixture of sewage and filtrate in one tank and screened and degrited septage in the other.

Project 7Prototype STP/SpTP 8/17/2006 Page v For scenarios Al (pure 2,400 cmd sewage) and A2 (Al+ 240 cmd septage), full aerobic biotreatment using 2 fill-and-draw Sequencing Batch Reactors (SBRs) is applied prior to discharge of effluent to Culiat Creek.

The treatment process for scenarios B1 (Al+120 cmd septage), B2 (A1+240 cmd septage) and B3 (A1+360 cmd septage) involves anaerobic-aerobic biotreatment utilizing a UASB or an Upflow Anaerobic Sludge Blanket and an SBR. This process is similar to full aerobic biotreatment except that, the mixture of filtrate and sewage is pumped to the UASB for carbon scrubbing then to the SBR for effluent polishing.

The alternative process proposed by MWSI treats sewage and septage separately. Two (2) SBR's will be used to treat sewage and septage in series. Septage is treated using an equalization tank for pre-aeration before it goes to the SBR (SpTP). The primary effluent is mixed with fresh sewage to increase the amount of micro-organisms before subjecting to a biotreatment in another SBR (STP) for discharge to Culiat Creek

Estimated Capital and Operating Cost

Capital costs consist of civil works, supply and installation of equipment, electrical works, instrumentation and cabling. Operating costs identified are power cost, personnel, chemicals, sludge disposal, maintenance and laboratory works. However, mark-up, engineering and construction management, value added tax (VAT), overhead, and other contingencies have also been included in the study. Table A shows that alternative B3 has the highest estimated capital and operating costs at 272M Php and 44M Php, respectively, while alternative C has the least with about 81M Php and 21M Php, respectively. Thus, a potential savings of about 191M Php in capital expenditures and 23M Php in annual operating costs may be realized with alternative C.

Table A Summary of Capital and Operating Costs

. Capital Cost Operating Cost Alternatives (MPhp) (MPhp) I. Pre-feasibility Altematives (Mixed Treatment) A. Full Aerobic Process A.1: 2400 cmd (Sewage) 114.87 12.69 A.2: A.1 + 240 cmd (1O%Septage) 189.64 38.30 B. Anaerobic-Aerobic Process B.1: A.1 +120cmd(5%Septage) 183.76 23.06 B.2: A.1 + 240 cmd (1O%Septage) 229.84 33.42 B.3: A.1 + 360 cmd (15%Septage) 272.42 43.92 II. Separate STP/SpTP C. Full Aerobic Process C: 2400 cmd (Sewage) + 240 cmd (Septage) 80.97 20.74

Project 7Prototype STP/SpTP 8/17/2006 Page vi Recommendations

MWSS/MWSI recommends that alternative C, full-aerobic biotreatment process, be adopted for the proposed prototype STP/SpTP in Project 7, Quezon City at an estimated cost of 81MPhP, using the 1.3M USD WB grant plus capital expenditures of about 10M Php. An annual operating budget of about 21 M Php has to be allocated, as well.

MWSS/MWSI shall prepare the bidding documents for design and build (B&D) contract for the underground prototype STP/SpTP.

Social acceptability and accessibility are issues that need to be addressed.

Project 7Prototype STP/SpTP 8/17/2006 Page vii 1. Introduction

1.1 General Background

Metro Manila which lies at the northwestem part of the is bounded by Manila Bay in the west and Laguna de Bay in the south. It covers thirteen cities (Caloocan, Las Pinas, , , , Manila, , , Quezon City, Paranaque, , and Valenzuela) and four municipalities (, , San Juan and ).

Metro Manila is a political, educational and economic center of the Philippines. The rise of urbanization in this area resulted to rapid increase of pollution loading in bodies of water, particularly Pasig River, composed of about 75% domestic wastewater and 25% industrial and commercial discharges1.

MWSS was created as a government owned and controlled corporation in 1971, responsible for water supply and sanitation in Metro Manila and portions of Cavite and Rizal provinces. In 1997, its operations were privatized through concession agreements with Manila Water Company, Inc. (MWCI) for the East Zone and Maynilad Water Services, Inc. (MWSI) for the West Zone. Each concessionaire agreed to provide water supply, sewerage and sanitation services to the residents within its coverage area until the end of concession period in year 2022.

1.1.1 World Bank Mission

Several funding institutions, one of which is World Bank (WB), have assisted MWSS in its sewerage and sanitation programs by providing financial assistance for various technical studies and projects focused on the improvement of existing sewerage and sanitation facilities.

WB has a mission to reduce pollution loading discharges in Metro Manila area thru the Global Environmental Facility (GEF) components of the Metro Third Sewerage Project (MTSP). The development objective of the GEF-MTSP is to create an enabling environment to scale up investments in priority areas in sewerage and sanitation in the Laguna de Bay - Pasig River - Manila Bay watershed areas through2:

a. Strengthening of partnerships among stakeholders; b. Upgrading of sector plans and policies based on environmental and economic principles; c. Piloting of innovative financial mechanisms to facilitate private sector investment; and d. Demonstration of the viability of combined sewage and septage treatment in Metro Manila.

I Manila Water Company, Sewerage and Sanitation - Metro Manila 2 Aide-Memoire, GEF-MTSP Preparabon Mission, January 30 to February 7, 2006 Project 7Prototype STP/SpTP 8/17/2006 Page 1of2O In the pre-feasibility study conducted by a consultant for DENR, these objectives have been transalated into 6 components and under Component 5, the existing wastewater facility (imhoff tank) at Project 7 will be rehabilitated and upgraded to accommodate both sewage and septage. The Project 7 Sewage/Septage Treatment Plant (STP/SpTP) will serve as a pilot project which aims to demonstrate the technical, financial, social and economic viability of such project for similar plants within MWSS responsibility in the future.

WB has allocated 5M USD grant for this mission, and of which 1.30M USD has been earmarked for the said pilot project. The grant agreement is between WB and the Department of Environment and Natural Resources (DENR), as the executing agency. DENR will, likewise, enter into a Memorandum of Agreement (MOA) with MWSS for the implementation of the pilot project.

1.2 Objective

This technical study aims to present another feasible alternative for the combined sewage/septage treatment plant, to minimize investment cost and be able to optimize the WB grant allocation. Its specific objectives are as follows:

a. Develop a process flow using state-of-the-art technology; b. Estimate the potential savings in capital expenditure and operating costs; and c. Assess issues and concems on the environmental and social impacts of the project.

1.3 Limitation of the Study

This design concept is limited to the study of the sanitation requirements of MWSI. Water consumption data of sewered customers in Veterans Village have been used to establish the capacity of the combined sewage and septage treatment facilities. The estimated capital expenditures and operating costs are budgetary based on parametric unit costs. A detailed financial/economic analysis to determine FIRR/EIRR is excluded.

Project 7 Prototype STP/SpTP 8/17/2006 Page 2 of 20 2. Quezon City Communal System and Its Condition

MWSI is currently operating four (4) sewerage systems namely: Central Manila Sewerage System (CMSS), Dagat-dagatan System, Makati Isolated System and Quezon City Communal System, serving around 11% (Sewerage program, EO 2005) of the total population under the West Concession Area. In addition, MWSI provides free desludging services to residential and semi-business customers, currently estimated at 19% (Sanitation program, EO 2005) of the total population within the service area.

The Quezon City Communal System serves Project 7 and Project 8 in Quezon City and has around 4,000 sewer service connections for residents, mostly, belonging to medium and high-income groups. Project 7 and Project 8 are bounded by major roads, such as, Epefanio delos Santos Avenue (EDSA), Congressional Avenue, Roosevelt Avenue, West Avenue and Mindanao Avenue. The topography in this area is almost flat with an average elevation of 25m.

Wastewater generated in the area is collected through the sewer system and treated in the imhoff tank going to a communal septic tank in Project 7 and through the communal septic tanks (CST) in Project 8 before discharging to Culiat/Duria Creek. Figure 2.0-1 shows the location of the existing CSTs and Imhoff Tank in Project 7 and Project 8.

The existing imhoff tank is located at 11 Road A. St., Anthony Village, Project 7, Quezon City. It was constructed by the National Housing Authority (NHA) in 1955 and handed over to MWSS for operations and maintenance. The imhoff tank is composed of two (2) open chambers with a dimension of 4.70m (width) x 9.40m (Length) x 7.65m (depth) each and has a design capacity of 1,200 cmd. It drains an area of about 45.6 hectares, which translate to 1,753 service connections (inclusive of service area covered by downstream communal septic tank) at Veterans Village. The facility is operational, however, effluent is not complying with the standard specified in DENR AO 35 for inland water class C. The tank also causes odor problem in the area due to various escaping gases. Figure 2.0-2 shows the plan and section of the existing Imhoff Tank.

Effluent from the Imhoff Tank is discharged downstream to a communal septic tank (CST #22) located at Roosevelt Avenue, which was also constructed in 1955 and handed over by NHA to MWSS. It has a dimension of 4.Om (width) x 10.0rn (length) x 3.0m (depth) and a design capacity of 95cmd. The CST has been suspected to be occupied by informal settlers and/or commercial and institutional establishments.

Similar to the case of CST #22 in Project 7, the CSTs in Project 8 were constructed in 1954 by NHA and handed over to MWSS. There are three (3) existing CSTs located in that area with dimensions of 4.Om (width) x 13.7m (length) x 5.5m (depth) each and has an average design capacity of 540cmd. CST #23 serves 26 hectares; CST #35, 37 hectares and CST #35a, 36 hectares. The existing CST's are operational but occupied by informal settlers and/or commercial and other establishments.

Project 7 Prototype STP/SpTP 8/17/2006 Page 3 of 20 11 ^ I . VE ' Z i TiC

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Figure 2.0-1 Location Map of Project 7 and Project 8

Project 7 Prototype STP/SpTP 8,t17/2006 Page 4 of 20 I 7 -- - -

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Figure 2.0-2 Plan and Section of the Existing Imhoff Tank

2.1 Project 7 Imhoff Tank

The Imhoff Tank facility in Project 7 stands in al,300 m2 lot where portions of the area is currently occupied by a repair shop, a stock shop, an office building and a warehouse. The imhoff tanks are desludged every six months with sludge taken to Dagat-dagatan STP-SpTP for further treatment. Figure 2.1-1 shows the site layout of the facility in Project 7.

The estimated average daily water consumption (billed volume) in the area is about 2,400 cmd, taken from the sewered customers in Veterans Village from 1999 to 2002. Table 2.1-1 shows the monthly billed volume of sewered customers in Veterans Village.

Project 7 Prototype STP/SpTP 8/17/2006 Page 5 of 20 However, record shows that only 1,200 cmd average daily flow (ADF) enters the existing imhoff tank. Discrepancy is mainly due to gradual development in the area from year 1955 to present in which almost fffty percent (50%) of the total households in Veterans Village with individual septic tanks discharge their wastewater to the drainage system.

Figure 2.1-1 Site Layout of Imhoff Tank Facility in Project 7

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MWSI regularly monitors the influent and effluent quality of Project 7 Imhoff Tank 24 hours a day. Samples are taken to the Central Laboratory, located at La Mesa Treatment Plant (LMTP-1), for analysis and results are submitted to Laguna Lake Development Authority (LLDA) in compliance with DENR AO 35.

Project 7 Prototype STP/SpTP 8/17/2006 Pae 6 of 20 Table 2.1-1 Monthly Billed Volume (cmd) for Sewered Customers in Veterans Village

Month 1999 2000 2001 2002 Average

January 2,568 2,311 2,175 2,311 February 2,568 2,837 2,465 2,668 March 2,568 2,390 2,155 2,390 April 2,568 2,370 2,230 2,370 May 2,568 2,472 2,097 2,472 June 1,835 2.603 2,249 2,249 July 2,568 1,362 2,165 2,165 2,166 August 2,568 2,279 2,178 2,178 2,229 Septem ber 2,568 2,663 2,264 2,264 2,416 October 2,568 2,498 2,446 2,206 2,472 November 2,568 2,615 2,553 2,216 2,661 December 2,568 2,465 2,760 2,016 2,516 Average 2,868 2,668 2,418 2,192 2,403

(cm d ) ______

Recent data have been evaluated to determine the characteristics of the wastewater in the area. Average Biochemical Oxygen Demand (BOD), the most widely used parameter for organic pollution that depletes dissolved oxygen in water, is about 106 mg/L, while Chemical Oxygen Demand (COD), those refractory organics that can resist biological treatment, is about 246 mg/L. Ratio of COD to BOD of around 2.32 is within normal characteristic of most sewage in other treatment facilities. Figure 2.1-2 shows the current influent and effluent BOD levels against the required standard of DENR AO 35.

250 -

225 -- hf* 200 -5.T* n -o M AO 35 kM d Om Chu CD 175- -150 - *125 -

.100 / 75 - 50 * * * * * 25 -

Apr- May- Jun- Jul- Aug- Sep- Oct- Nov- Dec- Jan- Feb- Mar- Apr- 05 05 05 05 05 05 05 05 05 06 06 06 06

Figure 2.1-2 Influent/Effluent BOD Levels against DENR AO 35 Standards

Project 7 Prototype STP/SpTP 8/17/2006 Page 7 of 20 Total Suspended Solid (TSS), aesthetically not acceptable that may deplete oxygen levels in water, is around 88 mg/L. Records show that low concentrations of major effluent contaminants are discharged to Culiat creak. Table 2.1-2 presents the influent data for Project 7 Imhoff Tank and Table 2.1-3 presents the effluent data.

Table 2.1-2 Monthly Influent Data for Project 7 Imhoff Tank

Parameter Unit Apr-05 May-05 Jun-05 Oct-05 Nov-05 Dec-05 Jan-06 Feb-06 Apr-06 Average

BODs mg/L 140 150 107 93 125 78 140 70 48 10 COD mg/L 256 465 168 144 215 159 458 151 202 246 TSS mg/L 38 57 58 80 97 88 58 240 78 88 Color 29 14 16 8 19 8 10 15 20 15 Temperature OC 28.9 - - 27.0 27.7 26.4 26.1 26.9 27.1 27.2 pH 7.0 7.3 7.2 7.2 7.3 7.1 7.5 7.3 7.3 7.2 Oil& Grese mg/I 16 26 - 15 12 12 5.2 17 11 14 Coliform MPN/100mL 7.OE+07 8.OE+07 8.OE+07 5.OE+07 3.0E+08 5.0E+07 8.0E+07 3.0E+07 2.2E+08 1.1 E+08

Table 2.1-3 Monthly Effluent Data for Project 7 Imhoff Tank

Parameter Unit Apr-OS May-05 Jun-05 Oct-OS Nov-05 -Dec05Jan-06 Feb-06 Apr-06 Average

BOD 5 mg/L 130 100 80 87 73 83 57 41 81 COD mg/L 382 210 140 109 150 145 467 194 167 218 TSS mg/L 146 30 68 60 52 78 47 196 71 83 Color 29 [ 15 15 12 10 10 10 15 15 15 Tefferature OC 29.9 - - 27.5 27.9 26.7 27.1 27.8 28.1 27.9 pH 7.0 7.2 6.9 7.2 7.2 6.7 7.6 7.1 7.3 7.1 Oil & Grease mg/L 26 25 - 11 8.4 11 5 18 16 15 Coliform MPN/100mL 5.0E+047E+0710 8.0E+07 1.3E+08 2.3E+07 3.OE+07 7.OE+07 5.OE+07 1.8E+07 5.5E+07

Since the treatment facility has been constructed 50 years ago, odor problem has been encountered that presents inconvenience to the residents. Its efficiency of removing organic pollutants decreased from 30-50% to almost 23%. Treatment efficiency for other contaminants, likewise, decreased considerably.

3. Review of the Pre-feasibility Report

A sewerage and sanitation Master Plan (MP) for MWSS service area was updated last 2005 indicating preference for aerobic-anaerobic treatment process. Consequently, WB expressed that it would be beneficial to have a prototype STP-SpTP that will serve as a pilot project for other similar treatment facilities in the future. Two sites under MWCI and five sites within MWSI area have been considered. The facility located at 11 Road A, St. Anthony Village Project 7, Quezon City, which drains about 45.60 hectares of

Project 7 Prototype STP/SpTP 81170 Page 8 of 20 sewerage area, has been selected due to a number of advantages: (a) site is within MWSI concession area; (b) Imhoff Tank has a poorly operating treatment system that pollutes Culiat creek; (c) site has available area of about 1,300 sqm; (d) no informal settlers on site; (e) land is government-owned; (f site covers a significant number of septic tanks in adjacent areas; (g) site is close to MWSI monitoring station; and (h) amount of sewage flow is about 2,400 cmd only.

Five (5) scenarios have been evaluated with each scenario uses an estimated sewage average daily flows (ADF) of 2,400 cmd. Alternatives are summarized as follows:

* Sewage (2,400 cmd) + Septage 0% (0 cmd) - full aerobic biotreatment; * Sewage (2,400 cmd) + Septage 10% (240 cmd) - full aerobic biotreatment; * Sewage (2,400 cmd) + Septage 5% (120 cmd) - anaerobic-aerobic biotreatment; * Sewage (2,400 cmd) + Septage 10% (240 cmd) - anaerobic-aerobic biotreatment * Sewage (2,400 cmd) + Septage 15% (360 cmd) - anaerobic-aerobic biotreatment

The pre-feasibility preferred altematives (Scenarios #2 and #5) involve full aerobic biotreatment (SBR) and anaerobic-aerobic biotreatment (UASB+SBR). Other process components include imhoff tanks conversion to balancing tanks, new sewage inlet works, septage acceptance area, biosolids dewatering system, new chlorination system and contact tank, effluent reuse and odour control. The existing Imhoff Tank with two chambers will be upgraded to two balancing tanks to hold the mixture of sewage and filtrate in one tank, and screened and degrited septage in the other. The existing office space will be converted to a control room and a laboratory. It has been proposed to demolish several old structures to accommodate the new treatment plant.

In full aerobic biotreatment (SBR) for scenarios #1 and #2, screened/degrited septage and waste activated sludge (WAS) from a balancing tank are pumped for dewatering to the biosolid building where filtrate is transferred to another filtrate/sewage balance tank. The mixture of filtrate and sewage is pumped to one of the two sequencing batch reactor (SBR) tanks for biological treatment. The SBR is a fill-and-draw system and requires two or more reactors to operate continuously. WAS from the SBR is retumed to the second balancing tank while the decanted liquid is disinfected before discharging to Culiat Creek.

The treatment system in anaerobic-aerobic biotreatment (UASB+SBR) is basically similar to full aerobic biotreatment, except that the mixture of filtrate and sewage is pumped to an upflow anaerobic sludge blanket (UASB) reactor for carbon scrubbing, then to the SBR for effluent polishing.

The pre-feasibility report identified all altematives that would fit in the Project 7 site. However, the estimated capital expenditures exceed the limit of GEF-MTSP for the said component, thus, cost sharing is proposed in which MWSI is required to shoulder any amount in excess of the grant amount.

Project 7 Prototype STP/SpTP 8/17/2006 Page 9 of 20 4. MWSI Proposed Alternative

In order to meet its sanitation target and avail the WB grant at the least cost, MWSI considered an altemative concept design for the combined sewage and septage treatment using a different approach. MWSI opted for a separate treatment of septage and sewage which are located in the same area. The study focused on activated sludge process for sewage and septage in series.

4.1 Design Assumptions and Criteria

MWSI considered various design assumptions and criteria for the upgrading and rehabilitation of Project 7 Imhoff Tank. Major parameters considered in the study are: determination of service area and land use, equivalent discharges, wastewater characteristics and pollution loading. Proposed desludging sites are also included in the study.

4.1.1 Service Areas and Land Use

The service area for the sewage treatment plant is the Veterans Village, in which most of the residents belong to medium and high income groups. Septage will be desludged from various locations in Quezon City (west) and Caloocan. Specifically, areas serve in Caloocan are: Baesa (AltaVista, Reparo, Rubyville), Bagong Barrio, BF Homes, Brixton Ville, Camarin Areas A and B, Capitol Parkland, Cristina Homes, Ciudad Grande, Del Rey Subd, Fortune Village, North Matrix Subd, Bagbaguin (Villa Ocampo), Zabarte and . In Quezon City, these are: ACF Road, Baesa, Brgy Holy Spirit, , BIR Village, Bitoon Circle, Brgy Commonwealth, Damong Maliiit, Don Fabian, Fairview, Greenfields, GSIS Village, Gulod, Pamahay Homes, Rolling Meadow, San Bartolome, Brgy Sta Lucia, Veterans Village and Villa Verde Subd.

4.1.2 Projected Sewage and Septage Volume

The treatment facilities were designed to accommodate 2,400 cmd of sewage or 100% of the water consumed by sewered costumers in Veterans Village and a daily septage collection of 240 cmd (10% of sewage) from adjacent areas. It is advisable to review the sewer network system to verify the actual amount of sewage entering the treatment facility.

4.1.3 Wastewater Characteristics and Pollution Loading

Based on samples taken and analyzed, sewage characteristics as discussed in section 2.1 show low concentrations of major contaminants compared to other domestic wastewater.

Nitrogen and phosphorous contents, as a general rule used for controlling phytoplankton growth rates that may result to eutrophication in surface water and nitrate contamination

Project 7 Prototype STP/SpTP 8/17/2006 Page 10 of 20 of groundwater, are about 0.10-0.70 mg/L and 1.80-2.64 mg/L, respectively. Additional treatment for nitrogen and phosphorus removal is, thus, unnecessary in this kind of sewage.

Influent data entering Dagat-Dagatan Septage Treatment Plant has been considered and used as reference for septage characteristics. COD to BOD ratio of almost 7.36 would require much stronger oxidant to chemically oxidize organic matter. Total Suspended Solids (TSS), classified according to their particle sizes as non-filterable solid, is about 14,481-51,200 mg/L. Table 4.1.3-1 indicates the concentrations of contaminants entering Dagat-Dagatan Septage Treatment Plant.

Table 4.1.3-1 Monthly Influent Data for Dagat-Dagatan Septage Treatment Plant

Paarmeter Lk*it Ar6 15 J"I-M 6- A& SeP05 Oct0 N.5 Dsc-M J.06 Feb.06 Aerage

131s - nyL 2,478 3,589 z349 1,655 1,853 4,063 3,438 2,471 2,235 3,520 2,68 2,752 COD r- L 23,783 13,953 17,874 15,766 14,120 14,852 23,989 11,364 14,811 29,756 42,629 20,263 TSS ng'L 26,733 39,788 47,15D 35,988 39,500 17,325 51,2C0 3o6o0 43,m 45,467 14,481 35,650 Cobr 1,906 1,983 775 1,5S0 1,175 1,875 1,72B 1,400 1,850 2,375 1,t05 1,606 TenpAe OC 322 33.5 317 30.6 29.9 29.1 30.0 31.0 29.3 29.9 30.1 30.64 pH 72 64 70 7.3 7.3 7.3 7.4 7.2 7.4 7.5 7.4 7.20 Cil&Grese nVL 494 1,017 - 1,872 1,831 2,513 2,65B 1,134 1,579 1,741 3,837 1,863 Colfm M1PNIO'TtI 1.3E+07 1.5E407 32E+07 23E+07 1.E+07 1.6E+07 2.9E407 1.7E+07 2.7E+07 32E407 22E+07 2.2E+07

Nitrogen and phosphorous contents of septage are about 2.0-10.0 mg/L and 5.67-23.66 mg/L, respectively. Nitrogen over phosphorus ratio shows that no additional nitrogen and phosphorus removal is required.

Coliform concentration is about 2.2E+07MPN/100mL in septage and 1.1E+08MPN/100mL in sewage. Coliforms as indicator organisms of the potential presence of pathogens are treated through disinfection.

4.2 Process Flow for Prototype STP/SpTP

MWSI proposed alternative treats sewage and septage separately and is basically a combination of two (2) activated sludge processes. The proposed SpTP consists of bar screen, grit chamber, equalization tank, SBR, aerobic digester and centrifuge. While the proposed STP is composed of bar screen, equalization tank, SBR and chlorine contact tank. An odor control facility is, likewise, incorporated to remove undesirable odor. The primary effluent from SpTP goes directly to equalization tank of STP for further treatment. Figure 4.2-1 shows the process flow diagram for the proposed prototype STP/SpTP.

Project 7 Prototpe STP/SpTP 8/17a2006 Page 11 of 20 SEWAGE

C k coi*ciccrti E ~- fr at \

SEPTAGE- -'. o %'t

i~~ ' -, -C%l-,--'

'AEROHIC j :''EoIgxo j

FILT RATE ItFigure 4.2-1 Process Flow Diagram for Proposed Project 7 Prototype STP/SpTP

Screened and degrited septage, waste sludge from the SBR (STP) and filtrate from the I aerobic digester and centrifuge are stored and pre-aerated for 1 day in an equalization tank. The mixture is then pumped to the other SBR (SpTP) for biological treatment. Waste sludge is then pumped to an aerobic digester to biologically destroy volatile solids before feeding to a centrifuge. The primary effluent from the SBR (SpTP) is mixed to screened fresh sewage in another equalization tank for dilution before it is pumped to the SBR (STP) for biological treatment. Waste sludge produced is pumped back to an equalization tank and mixed with degrited septage. Decanted liquid is finally disinfected using chlorine prior to discharge.

4.2.1 Components of Proposed Septage Treatment Plant (SpTP)

a. Bar Screen/ Basket Screen - It is provided to remove coarse particles that might damage downstream operation or clog weirs, pipes and valves. In addition, it could facilitate downstream operations and improve on the aesthetics of the treatment plant.

b. Grit Chamber - It is necessary to discretely settle heavy sand particles and prevent organic suspended solids from settling. Removal of

Projedt7 ProCotpe StP/SpTP 8/17/2006 hage 12 of 20 inorganic maKlers, such as grits and sand, would offer advantages to downstream operations.

c. Equalization Tank- It should be provided for storage and stabilization of septage by pre-aeration, especially that loading varies depending on the traffic condition within the collection area. It is proposed that septage be retained in the tank for about one (1) day for more effective treatment.

d. Sequencing Batch Reactor (SBR) - The SBR is a fill and draw state-of- the-art activated sludge treatment system. It operates by batch and allows large number of microorganisms to biodegrade organic matters and convert them to useful and stable gases such as carbon dioxide, nitrogen and water under an aerobic, anoxic and anaerobic conditions. It involves combined carbon oxidation and nitrification/denitrification processes in one reactor ensuring total treatment of biological wastes. The various operating modes using programmable logic control (PLC) are: fill, react, settle, decant and idle. Organic pollutants are, therefore, allowed to undergo a complete cycle, from aerobic oxidation to anaerobic degradation. SBR has a removal rate of approximately 85-98% in BOD and TSS, 80-95% in COD, 20-50% in Total P and 20-70% in Total N.

e. Aerobic Sludge Digester - Waste sludge is pumped from the SBR to the aerobic sludge digester to biologically destroy volatile solids. The digester is designed to have a minimum of 15 days solid retention time with course bubble diffusers to aerate the tank. After digestion, volume of volatile suspended solids (digested sludge) is reduced/ oxidized to stable forms by about 40-50%. Stabilized sludge may be returned to equalization tank of septage treatment during low flow concentration to reduce sludge disposal problems.

f. Centrifuge - Sludge from the holding tank and aerobic digester is processed in the centrifuge which separates the solid from the liquid portion of the sludge. The supernatant returns to the equalization tank for further treatment while the solid waste may be reused as soil conditioner.

4.2.2 Components of Proposed Sewage Treatment Plant (STP)

a. Bar/Basket Screen - Functions are similar to that in section 4.3.2a.

b. Equalization Tank - Sewage and treated septage flows by gravity to the equalization tank which is similar to that in section 4.3.2c, except that pre- aeration is not applied to maintain a high level of micro-organisms in the system.

c. Sequencing Batch Reactor (SBR) - Functions are similar to that in section 4.3.2d.

d. Chlorine Contact Tank - Decanted sewage from SBR is further treated with hypochlorite solution to eliminate pathogenic bacteria and coliform

Project 7 Prototype STP/SpTP 8/17/2006 Page 13 of 20 before finally discharging to Culiat creelc The sodium hypochlorite solution is prepared in the chlorine tank and pumped by a chemical metering pump.

4.2.3 Odour Control Facility

Odor problems encountered in various locations within the treatment plant are broadly classified into the following categories:

* High intensity odor areas/facilities * Medium intensity odor areas/facilities * Low intensity odor areas/facilities

The main sources of potential odor are summarized in Table 4.2.3-1.

Table 4.2.3-1 Classification and Source of Odor

Classification Sources, Area, Facility and Equipment High Intensity Screening equipment Odour Septage Equalization Tank * Grit Chamber Meduim Intensity Aric Digeser odour Aerobic Digester Low Intensity Screening Facility Odour SBR Tank I Centrifuge Room

4.3 Theoretical Performance

Theoretically, effluent from the proposed STP/SpTP not only meets the required standard specified in DENR AO 35, but should surpass the prescribed effluent water quality at all times. BOD5, COD and TSS concentrations are expected to decrease to 22 mg/I, 72 mg/I and 30 mg/I, respectively, after treatment. Applying mass balance analysis for all systems shows that processing 2,400cmd of sewage + 24Ocmd of septage will result to about 2,393cmd of treated wastewater, 103cmd biosolids, and 144cmd screened and degrited wastes. Biomass produced daily for possible reuse as soil conditioner contains about 99kg of BODs and 660kg TSS. Figure 4.3-1 presents the mass balance flow diagram for the proposed prototype STP/SpTP.

Project 7Prototype STP/SpTP 8/17/2006 Page 14 of 20 It

2/0261 Od

EOf \ G2 .

- -OdCrbOd&,l oLrd ,.ord S075iCR Cor

: W

I FILTRATE

I Figure 4.3-1 Mass Balance Flow Diagram

H InSpTP, the estimated overall removal efficiency in terms of BOD, COD and TSS are 93%, 94% and 97%, respectively. However, treatment efficiency in STP is lower with approximately 80% for BOD, 80% for COD, and 85% for TSS. Dilution of primary effluent with screened sewage and absence of pre-aeration in the system results to further decrease in concentration of pollution loads causing lesser amount of micro- organism in the reactor. Table 4.3-1 summarizes the theoretical performance of the STPlSpTP.

Project 7Prototype STP/SpTP 8i17/2006 Page15of20 Table 4.3-1 Theoretical Performance of Proposed Prototype STP/SpTP

Septage Treatment Plant Sewage Treatment Plant Parameter Lndit R Eiualzation After SBR Mxhed After SBR DAO 35 Septage (Pre-aeraton) Treatrrent Sewage Eualzafon Treatment

BOD5 mg/l 2,752 963 193 109 109 22 50 COD mg/ 20,263 6,383 1,277 361 361 72 100 TSS rg 35,650 6,417 963 201 201 30 70

4.3 Improvement in the Level of Service

The proposed project will significantly improve Maynilad's level of service in terms of the increase in population served from 19% (EO 2005) to 46% (EO 2008). Furthermore, it will improve the effluent quality complying with DENR AO 35 for inland water class C and clean water act, thus, achieving World Bank's objective to reduce pollution loading to receiving waters. MWSI will eventually be able to avoid penalty payments amounting to 2M Php annually starting year 2010 for non-compliance.

5. Estimated Capital and Operating Cost

In this study, final recommendation will be based on the least capital expenditures and operating cost. The cost shown are budgetary and based on parametric unit costs derived during the course of the study

5.1 Estimated Capital Expenditures

The capital costs have been determined using parametric unit costs represenfing installed costs of all components of the prototype STP/SpTP. The parametric unit costs have been derived from recent projects of various designers/builders of STP/SpTP's with similar work description and specifications.

Project 7 Prototype STP/SpTP Page 1 of 20 Table 5.1-1 Construction Cost Estimates of the Prototype STP/SpTP

Alternative Al A2 BI B2 B3 C Item Description Treatment Procesi SB3R SBR SBR+UASB SBR+UJASB SBR+LIASB S!BR Sewage 2400 2400 2400 2400 2400 2400 -Septage o 240 ' 120 240 ' 360 240 1.0 Land sub-total (item 1) 0 0 0 0 0 0 2.0 CivillBuilding & Construction Mtnt sub-total (item 2) 24,412,805 33,248,290 47,626,886 60,191,847 65,618,660 32,400,000 3.0 Mechanical sub-total (item 3) 43,007,200 81,841,670 64,749,235 81,626,470 103,354,706 19,080,000 4.0 BectricaVklstrunentation/Cabling sub-total (item 4) 7,991,401 13,723,795 12,243,735 15,713,798 18,972,404 6,480,000 5.0 Others sub-total (item 5) 7,000,000 7,000,000 7,000,000 7,000,000 7,000,000 6,000,000 T=b (FlM 82.411.406 135,813,755 131.619.888 164,2115 19445.77t 63,89K0. -- Mrk-up 8,241,141 13,581,376 13,161,986 16,453,212 19,494,577 2,898,000 Eng'g and construction Mgnt 6,592,912 10,865,100 10,529,588 13,162,569 15,595,662 6,000,000 VAT 9,889,369 16,297,651 15,794,383 19,743,854 23,393,492 6,955,200 Contingencies 8,241,141 13,581,376 13,161,986 16,453,212 19,494,577 1,159,200 Grand TolWl ( ) 114,871 ,98 1S9,630 U 13M379 22R840 272.420.077 8097Z02 ______l 11U 7 13 W. 33 272m 4M

Q'ii ToW(MULq J_ 205 3.3 _ 28_ 4.10 4. 1.45

Table 5.1-1 which presents the construction cost estimates for all altematives shows that altemative B3 has the highest project cost estimated at 272M Php while alternative C has the least estimated at 81M Php. The construction costs of pre-feasibility altematives ranges from 42 to 236% higher than the cost of MWSI proposed alternative. Therefore, a potential savings of about 34 - 191M Php can be realized with the implementation of altemative C. Table 5.1-2 summarizes the breakdown of the total cost for alternative C.

Project 7 Prototype STP/SpTP 81171200 Page 17 of 20 Table 5.1-2 Breakdown of Cost per Chamber

DescrptionArnountPhp USD

General Requirents 4,600,000 83,636 Odour Control System - 1,400,000 25,455 Sub-total (1) 6,000,000 109,061 Sewage Treatmet Plant Bar Screen 4,452,515 80,955 Equalization Tank 6,184,049 112,437 SBR 9,894,479 179,900 Chorine Contack Tank 4,947,239 89,950 Sub-total (2) 25,478,282 483,241 Septage Treatment Plant Bar Screen 4,037,646 73,412 Grit Chamber 3,627,294 65,951 Equalization Tank 4,534,118 82,439 SBR 5,440,942 98,926 Aerobic Digester 7,915,583 143,920 Centrifuge 6,926,135 125,930 Sub-total (3) 32,481,718 590,577 Toed N.000 ,162,Is,

Engg & Construction Mgnt 6,000,000 109,091 Contractor Mark Up 2,898,000 52,691 VAT 6,955,200 126,458 Contingencies 1,159,200 21,076 Sfud Tld, 0 27200 1A,472,21

5.2 Estimated Operating Expenses

Operating costs refer to power consumption, chemical consumption, personnel, sludge trucking/disposal, and administrative and overhead costs in operating the prototype STP/SpTP. Actual operating expenses for Dagat-Dagatan SpTP and other STPs were used as basis for altemative C.

Table 5.2-1 presents the estimated operating costs for all alternatives. The table shows that altemative B3 has the highest annual operating cost estimated at 44M Php while altemative C has the least, estimated at 21M Php. A potential annual savings of about 23M Php may be achieved by implementing altemative C.

Project 7 Prototype STP/SpTP 8/1712006 PageIS8of 20 Akernative Al A2 BI B2 B3 C Treatmert Prcess s8R SBR SBR+USB SBRWLASB SBR+.ASB SBR Sewage 2400 2400 2400 2400 2400 2400 Septage 0 240 120 240 360 240 1.0 Variable Operating Cost sub-total (item 1) 7,029,890 24,499,194 13,461,991 20,662,965 27,315,0tt 16,557,001 Pow er 3,081,256 7,880,888 3,617,459 4,648,111 5,278,309 5,371,200 Labour 3,476,200 3,476,200 3,476,200 3,476,200 3,476,200 6,156,000 Chencal 366,159 8,153,506 3,984,178 7,782,978 11,484,519 4,806,00 Sludge Trucking 106,275 4,988,600 2,374,154 4,755,676 7,076,060 223,800 2.0 Rxed Operating Cost sub-total (item 2) 2,371,850 3,867,681 3,632,79J 4,095,443 5,217,355 1,963,00 I intenance 1,811,850 3,307,681 2,792,798 3,535,443 4,377,355 963,000 Laboratory fees 560,000 560,000 840,000 560,000 840,000 1,000,Aa TOWl _ _I_ 3401,74C 23, 875 17,087,7 24,7%408 3253Z443 18,520,0 Overheads 1,410,261 4,255,031 2,562,718 3,713,761 4,879,866 1,852,000 Contingencies 1,880,348 5,673,375 3,416,958 4,951,682 6,506,489 370, - GndTohi (Flp) i22,341 3k25K281 23086,4865 3,23,51 43Wk1M7U 2D,74Z -a OTOW(UpIq) 12.1 3.3 2106 33.A4 43U 207 Qa ndT.hdUSj _ 0.2 O."e 0.41 0. 078 0.3

Table 5.2-1 Estimated Operating Cost of the Prototype STP/SpTP

6. Recommendations

This technical study recommends the following for the proposed prototype STP/SpTP in Project 7:

(a) Adopt altemative C as pilot project; (b) Maynilad to avail of the 1.3M USD World Bank grant and allocate any amount in excess of the grant amount from its Capital Expenditure Budget for Y2007. An annual operating budget of about 27M PhP has to be earmarked from the Operating Budget starting August Y2008; (c) MWSS/MWSI to prepare the bidding documents for a design and build (D&B) contract to facilitate implementation of the project.

Protect 7 Prototype STP/SpTP 8/17/2006 Pap 19 of 20 7. Other Issues and Concerns

The upgrading and rehabilitation of Project 7 Imhoff Tank, though advantageous, poses few impacts on the environment during pre-engineering, construction and operation stages. Major issues and concerns, particularly social acceptability and traffic accessibility, must be given due attention prior to implementation of the project.

7.1 Social Acceptability

Most of the residents in Project 7 belong to medium and high income groups. It is, therefore, important to have an inter-agency coordination and focus group discussions to be able to address their concems, particularly on the entry of several vacuum tankers to the facility. About 24 vacuum tankers are expected to enter the treatment facility daily.

7.2 Traffic Accessibility

Vacuum tankers, mostly 10 cum. capacity, might have difficulty in traversing the roads to the facility considering that Road A is only about 5.5m wide and Alley, about 3.0m. It is also worth to note that passenger tricycles ply this route all the time. In this case, the design capacity of the proposed treatment plant may not be maximized. A well-planned septage collection schedule must, therefore, be ensured to address the issue.

Project 7 Prototype STPlSpTP 8/1712006 Page 20 of 20