Wastewater treatment facility in the Muntinlupa Public Market, Philippines
Public markets pose a challenge for waste management in cities and towns. Local government of Muntinlupa (Metro Manila), with the assistance of USAID, installed a low-cost waste-water treatment plant in the public market. The investment is recovered through a small surcharge in the rental fee that vendors pay for their stall. The practice helped lessen water pollution, saves money by recycling water and maintaining clean standards in the market.
1. Problems addressed
For years the government of the Philippines has been struggling with ways to manage effectively waste water issues and the ever increasing rate of water-borne diseases in urban communities. In 2004 the Philippine Clean Water Act was enacted, mandating all local government units to “share the responsibility in the management and improvement of water quality within their territorial jurisdictions.” This was instrumental in pressuring local governments to address waste water issues that were the cause of much environmental damage: over 90 per cent of all sewage generated in the Philippines is not treated. Water-borne diseases accounted for nearly 31% of all reported illness from 1996-2000 and economic losses from water-borne diseases alone exceed P2.3 billion a year.
Muntinlupa is one of the fastest growing cities in Metro Manila. It has a population of 379,310 (2000) and an annual growth rate of 3.14 per cent. Muntinlupa covers and land area of 4,670 hectares adjacent to the Laguna Lake and is divided into 9 barangays.
Like most cities in the Philippines, Muntinlupa has been faced with health and water related issues for years due to the scarcity of clean water and the ever-increasing amounts of untreated waste water that is released into the rivers that feed into Laguna Lake, the main source for drinking water in Metro Manila. The majority of the population in the city depends upon deep wells for potable water, which is known to be contaminated due to the untreated waste water released.
With the approval of the Clean Water Act, Muntinlupa has been compelled to take necessary actions to comply with the law and provide better services to its people. The law requires that within five years, all subdivisions, condominiums, commercial centres, hotels, hospitals, market places, and public buildings be connected to a sewerage system.
The wastewater treatment facility was constructed by Public Market Cooperative, part of the local government, in coordination with the United States Agency for International Development (USAID) and a specialised firm that provided technical assistance. The facility was part of a broader programme to improve sanitation conditions in Muntinlupa financed by USAID which included an important public awareness campaign on sanitation issues.
A hybrid technology was selected as the most suitable for the circumstances. The collected wastewater from the market enters first the anaerobic baffled reactor where it undergoes several steps where the waste is screened and partially clarified until the BOD level is reduced. Afterwards, the water proceeds through a sequencing batch reactor (SBR) that aerates and settles the wastewater under sluggish conditions, then passes to a settling tank with inclined plates to reduce suspended solids. The water is then filtered through a cocopeat filtration system for the final phase of the process. The treated water is used in the market for cleaning and flushing.
Other technology options were considered as well: sewage lagoons and constructed wetlands were rejected because of lack of space; activated sludge, a technology commonly used for high strength wastewater treatment, was rejected because of its high operating cost. Because of lack of space in the area, the facility had to be built under the parking lot of the market. This fact increased construction costs substantially, as the treatment plant had to be reinforced to sustain the weight of trucks over it. Total construction costs were P6.7 million.
The facility, like the market, now operates 24 hours, 7 days a week and treats 210 cubic meters of sewage per day with a biochemical oxygen demand (BOD) of approximately 600 milligrams per litre. Suspended solids and fats, oil and grease are also quite high.
Muntinlupa City has implemented a “user-fee system” collecting P5.00 per stall owner each day. This payment was approved by the stall owners prior to the construction of the facility. Monthly income from this source will be P216,750, against an operation and maintenance expenditures of P27,000. The facility is managed by two operators and consumes about P15,000 of electricity per month.
3. Key outcomes
Following nearly two years of operation, the Muntinlupa Wastewater Treatment Facility has been able to show the following results:
- The treatment facility has helped to lower water pollution due to an impressive decrease in BOD level of waster discharged into the creeks and rivers systems from more than 600 mg per litre to less than 30. (Note: 50 mg/litre is the acceptable BOD value for the Laguna Lake)
- The facility is instrumental in protecting families in Muntinlupa City from water-borne diseases and helped to ensure higher quality potable water from the deepwells within the community.
- The system helped to maintain clean standards in the market which prevented its closure.
- Due to the availability of recycled water, the market was able to save nearly P25, 000 a month in pumping costs.
- The project has raised public awareness on proper waste disposal, wastewater management, water and sanitation
The facility is able to treat 210 cubic meters of water everyday at an approximate cost of P4.28 per cubic meter. The figures show its efficiency and cost-effectiveness.
As a result of this innovative project, Muntinlupa City has received praise from local organizations, local government units in the Philippines and other countries in Asia that have included study visits to the treatment plant and technical trainings
4. Sustainability and replication
The wastewater treatment facility is an excellent financial investment. With current user fees of P5 per day/per stall it is estimated that the investment will be recovered in 3-4 years only. The facility is expected to remain in operation for at least last 25 years; however the electro-mechanical equipment life span will vary from 1 to 5 years which includes blowers, motors, & pumps. The City of Muntinlupa should ensure there are sufficient funds in hand for emergency situations or breakdowns.
Intergovernmental partnerships with neighbouring cities could help to encourage other communities to set up their own treatment facilities, then share costs for construction and operations.
The Muntinlupa Wastewater Treatment Facility has set standards for other communities to replicate the project as long as they are constructed for small scale usage, since it is relatively small and can only effectively accommodate up to 3,285 cubic meters of water per day. If the facility were be scaled up for larger communities, the equipment might not be able to handle the workload or reach its maximum lifespan of 25 years. Further, setting it up for larger areas will entail bigger construction cost and maintenance expenses.
At present, Muntinlupa City is working with Calbayog City in replicating the wastewater treatment facility, with plans to replicate the treatment facility in Barangay Bayanan which has the second largest public market in the city.
5. Contact information
Lisa Kircher Lumbao
Team Leader, Local Initiatives for Affordable Wastewater Treatment (LINAW)
United States Agency International Development (USAID)
Suite 4022. Golden Rock Building
168 Salcedo Street, Legaspi Village
Makati City 1229, Philippines
Telefax: +632-819-0688 ext. 107
Local Initiatives for Affordable Wastewater Treatment