Barangay San Joaquin, Pasig City

The total estimated project cost is Php 3.5M.

Meralco's Toxic Waste History

Barangay San Joaquin,

Pasig City

• 1990 The Meralco Diesel Power Plant was demolished to make way for what is now the Powerplant Mall
• 1996 - 1999 The Polychlorinated Biphenyls (PCBs) generated by the old plant was initially treated by chlorination, soil washing, and thermal desorption. A percentage of the pure PCBs were also sent to the UK for incineration.
• November 1999 Meralco secured a temporary storage permit from the Department of Environment and Natural Resources Environmental Management Bureau (DENR-EMB) to transfer the PCBs in their service station in Pasig City.
• Present The PCB tomb is still intact underneath Barangay San Joaquin

What are PCBs?

Polychlorinated Biphenyls were widely used in the 70's as a cooling liquid for transformers and capacitors until the ban on its production in 1979. They do not biodegrade and are considered as a persistent organic pollutant (POP). Exposure to PCB can cause chloracne, rashes, and even cancer for both humans and animals. It could also impede plant growth. PCB contamination can occur through ingesting contaminated plants and marine life.

{ Capeding, Sante, Gacis, Rosanto, Molas }

Objectives of the Service Learning Project

• To be able to produce a permanent toxic waste containment system that could efficiently house the PCB waste underneath Barangay San Joaquin without the threat of leakage and soil and water contamination
• To ensure the health and safety of the people in San Joaquin against the harmful effects of PCB

Details of the Barangay

Barangay San Joaquin

Barangay San Joaquin's Most Pressing Problem?

The existence of a

tomb filled with highly toxic waste the size of four basketball courts underneath their Barangay.

• 13,182 residents as of May 2010
• 45 hectares
• Located on the bank of Pasig River
• Urban poor community
• Only experiences heavy flooding during extreme weather conditions
• 2.5km away from the West Valley Fault

Vertical Cut Off Walls Using Soil -Bentonite

Observations and Interview Results

• The surface of the whole Meralco compound is cemented
• There have been complaints among the residents living near the boundaries of Meralco's compound regarding the toxic waste
• People still fish in the Pasig River, under the Antonio Luna Bridge, a few hundred meters away from the dump site
• Plant and animal life seem unaffected by the PCB waste
• Most of the residents of the community are unaware of the dump site's existence
• NAWASA is the water provider of San Joaquin

A ratio of 96% soil and 4% bentonite clay returns the optimum hydraulic conductivity and strength of the vertical cut off wall. A minimum wall thickness of 2ft is required for toxic waste containment according to the US Environmental Protection Agency (EPA).

Pros: Soil is practically free, soil-bentonite is efficient in restricting lateral transport of PCB

Cons: Bentonite is costly, shipment costs for large volume will take money, the vertical cut off wall is space-costly

IPEN's Findings

• In the 1970s, water from the artesian well near Meralco was used for bathing, but now they only use it to bath the pigs in the nearby pen and for watering the plants.
• The mango trees, are not as robust and tend to get dwarfed. Furthermore, the indian trees grow in reverse.
• Water sampling is done on Meralco on a monthly basis by the LLDA (Laguna Lake Development Authority). According to the interviewee, a pipe is being installed during testing and that they also get water from the tanks to be tested. Meralco always passed the quality standards set.

source: Monitoring Community Exposure to PCBs Located at the Meralco Pasig Central Service Station, IPEN 2006

photo by google images

Vertical Cut Off Walls Using Soil-Geosynthetics

The use of geosynthetics practically solve all the problems with the soil-bentonite mixture while retaining the same good qualities such as the low permeability and high strength property. It can effectively store PCB without any threats of leakage even under severe conditions given that the vertical cut off wall is constructed correctly. Although geosynthetics can be expensive, they are easier to ship and handle, and will take considerably less space.

Meralco's Current Solution

Our Proposed Solution

Vertical Cut Off Wall Made of Soil and Geosynthetics

An underground reinforced concrete tomb with suspected dimensions of (L x W x H) 55m x 30 m x 4m housing 14,000 liters of pure liquid PCB and 5,000 cubic meters of PCB contaminated soil.

Pros: RC has a high compressive strength, long service life, low maintenance cost, is economical, and have good fire resistance

Cons: Cracks develop in concrete, concrete is semi-permeable!

Project Schedule

Action Commitment Plan

Lifetime and Costing

1. Inform the community of the details of Meralco's toxic waste problem

2. Coordinate with the community on how to ask funding from Meralco and/or the local government.

3. Coordinate with a licensed engineer to revise the plans

4. Construct the new soil-geosynthetic toxic waste entombment

5. Conduct PCB detection tests every 10 years and after extreme calamities

Lifetime

PCB Exposure Monitoring in 2006

Alternate Solutions

For a vertical cut off wall made accordingly:

Legend: 1.5mm blue - geotextile; 1.5mm red - geomembrane (K = 1x10-12 cm/s ); 10mm green - GCL (K = 1x10-8 cm/s)

Estimated lifespan is 4750 years, provided that the materials followed the manufacturer's specifications, and only considering the hydraulic conductivity.

Costing Analysis

Conducted by International POPs Elimination Network in 2006

Source: Geosynthetic Lining System for Modern Waste Facilities

Experiences in Developing Asia

The depth of the Tuff formation in Pasig City is at 15m. Two walls will then be constructed with dimensions of 60 m x 15 m, and another two at 32 m x 15 m, and one tap cap of 60m x 32 m. Given the following prices:

Php 9.45/sq.m. Geotextile

Php 22.50/sq.m Geomembrane

Php 67.50/sq.m GCL

Free Soil

The total estimated budget for materials is Php 450,000 exclusive of shipment costs and taxes.

Other expenses are needed in the completion of the project such as:

Permits Php 20,000

Laboratory testing Php 50,000

Sieving (Php 25k/mo) Php 50,000

Excavation (Php587/cu.m.) Php 1,650,000

Compaction (Php 60/cu.m) Php 170,000

Labor Php 1,000,000

(5 months, 25 days/mo, 15 workers)

For a total of Php 2,940,000.00

• Incineration
• Construction of Vertical Cut Off Walls
• Using 96% soil, 4% bentonite
• Using soil and geosynthetics

Vertical Cut Off Walls

Incineration

The combustion of organic substances in waste materials under controlled conditions

Pros: highly effective, PCB is completely destroyed

Cons: high cost of incineration, high cost of shipment, technology banned in the Philippines, only works for pure PCB

Vertical cut off walls can be used as a long-term barrier to impede contaminant transport. It can be done in two ways: (1) soil-bentonite (2) soil-geosynthetics