By Jeannette Andrade
Philippine Daily Inquirer
First Posted 22:40:00 10/23/2010
MANILA, Philippines—Faced with the herculean task of cleaning up the Pasig River, nongovernment organizations and government agencies are taking baby steps toward resurrecting the biologically dead waterway.
With waste water making up 60 percent of Pasig River pollutants, the United States Agency for International Development (USAID), the Rotary Club, the Metro Manila Development Authority (MMDA), and the city of Manila linked the waterway cleanup to the pollution source.
The recent launching of the waste-water treatment facility at the Sta. Ana Public Market was “a good start,” Manila Mayor Alfredo Lim told Inquirer during the project’s inauguration held recently near the banks of the river. “It will contribute to cleaning up the Pasig River. We have to start somewhere.”
The Pasig River started deteriorating in the 1930s, when decreased fish migration was noted in the waterway. In 1990, the river was declared biologically dead, with domestic and industrial waste water blamed as the culprit.
Waste water from the marketplaces is described by one of the project proponents to be “very highly polluted and of high strength.” The wastewater-treatment facility is anticipated to address seepage into the Pasig River coming from the Sta. Ana Public Market’s sewage system.
Lisa Lumbao, chief of party of the USAID Philippine Sanitation Alliance (PSA), told the Inquirer that the groups involved in the project were initially focused on the clean-up of the river as a whole, a colossal effort as it involves a 27-kilometer stretch of waterway.
“Wastewater from households was the primary contributor to pollution. But addressing this would call for a big project,” Lumbao explained.
She said that USAID, the Rotary Club and the MMDA settled on one project, the success of which would indicate the feasibility of wastewater management along the banks of the Pasig River.
The Sta. Ana Public Market wastewater-treatment facility is anticipated to be a model of future projects in the city with the marketplace touted to be the cleanest and greenest in the locality in the near future.
Lim said the city could replicate the Sta. Ana project at the Quinta and other public markets situated near the banks of the Pasig.
USAID-PSA consultant Carlito Santos Jr., an engineer who designed the treatment facility, said the operational cost of maintaining the facility was much cheaper than the conventional system and is easier to manage.
The system uses minimal electricity for the maintenance of one tank with separate chambers and makes use of naturally occurring bacteria to break down pollutants in the waste water.
The treatment is based on sequencing batch reactor (SBR) technology and works by utilizing one tank for the separate steps in the wastewater-treatment process; conventional treatment plants require separate tanks. It requires only sparing use of air blowers enhanced with fine bubble diffusers, thus saving on electricity and other costs while being more efficient in transferring oxygen to water.
Santos compared the treatment facility to a huge aquarium with a filtration system.
He explained that the treatment works initially with the separation of solid waste through screening. Filtered wastewater flows through the equalization tank, which balances the flow of the water, then undergoes the anaerobic process where organic pollution is reduced by 50 to 70 percent by microorganisms.
The water that comes through the chambers ends up at the sequencing batch reactor where oxygen is introduced. The final stage is disinfection. A small dose of chlorine is mixed with the water before it is discharged into the river.
“The recycled water from the treatment facility could be used for irrigation and for flushing toilets,” Santos said, adding that the public market could save up to 30-40 percent of operational costs.
The Sta. Ana Public Market wastewater-treatment facility is the second of its kind in Metro Manila. The first was set up at the Muntinlupa City Public Market in 2004 where treated wastewater is used for toilet flushing and street washing.
USAID has also introduced the system to Plantation Bay in Cebu and El Nido in Palawan.
Teresita Morante, president of the Sta. Ana Public Market Vendors Association, told the Inquirer that they were looking forward to a cleaner and greener market, with more customers flocking to its spic-and-span stalls.
In the past, it was everyone for himself at the market when it came to disposing waste.
“Now, not only do we have a better system, we can also help in cleaning up the Pasig River in our small way,” Morante said.
Please find the original article here.