Cocopeat biofilter secondary treatment system - School wastewater story from Philippines
Implementation of cocopeat biofilter secondary treatment system in Philippines
“We are very proud of our environmental record here at our high school, and this cocopeat wastewater system is one more step in the greening of our school”, says Mrs. Madeline Ann L. Diaz
Madeline is the school principal of the Science High school in Muntinlupa City, Philippines. Since the beginning of 2012 a cocopeat secondary treatment system treats the wastewater of around 870 students. The effluent is disbursed to a tree planting area, where it is hoped that the nutrient-rich effluent gives a jump-start to the mahogany saplings planted around the school.
In the course of a project on the efficiency of low-cost materials to treat wastewater for reuse in developing country settings, RTI International installed a cocopeat biofilter secondary treatment system at the Science High School, as well as at the Putatan Elementary School in Muntinlupa City.
The installation and the run of the project:
Cocopeat, the dust from crushed coconut shells, is a waste byproduct of coconut processing that can be used in the development of low-cost wastewater management systems to improve sanitation. Cocopeat is used in the construction of biofilters, which treat septic tank or digester effluent so that it can be used safely for agriculture and landscape irrigation, or discharged into the environment. As wastewater passes through the biofilter, suspended solids are trapped, and organic matter is consumed by the microbes living in the filter, resulting in a significant reduction of pollution constituents in the final effluent.
"The biofilter is simply a wood box sealed with fiberglass and fitted with an underdrain system to collect the treated effluent", explains Jet Pabilonia, Project Administrator and Chief Environmental Officer for Muntinlupa City. "The box is then filled with cocopeat, and covered with a layer of about 6 inches of coco coir (fibers). It took us about three weeks of labor to construct the system. We are especially excited about this technology as it requires such a small space. We only had about 20 square meters available to us for the construction of the system".
O&M for this system is minimal. Depending on flows, the cocopeat should last at least a couple years (given the pilot nature of these studies, we still aren't really sure how long it can last, but at least a year or two for sure, quite possibly much longer), whereafter the old peat should be shoveled out (into the garbage or compost) and replaced with fresh peat. It could be adequate to simply change the peat whenever the septic tank is desludged. The pump adds a bit more complexity to the situation if it breaks down, but given its very low usage and simple setup, it will likely outlive the rest of the unit! That means, the school can always contact the Muntinlupa environment office if any support is needed. A pump could also be avoided by excavating the biofilter into the ground, thus the septic tank effluent could just flow into it by gravity.
The system installed for the Putatan Elementary School will serve around 2,000 students and 78 teachers. The pour-flush toilets discharge to a septic tank equipped with a small pump that feeds effluent to the biofilter.
According to school principal, Rhodora V. Mandap, "the cocopeat wastewater project will help us to realize our dream of developing a green campus filled with plants for the enjoyment of our pupils and staff. We will use the treated water for our ornamental plants, which should do quite well with this rich source of irrigation water". "Our students are also very much engaged in the project", said Mandap during the launching ceremony. "Our second graders worked up a song and dance routine entitled: Science, Technology and Low Cost Wastewater Treatment Systems". Dressed as microbes, the students sing about how science, technology and sanitation will improve their lives and their school.
Schools represent a bigger challenge than many other sources for wastewater technologies due to their highly variable flows. Systems must be able to function under peak flow conditions, during special events, as well as low flows during weekends and summer vacations. However, the opportunities are equally great as the schools represent an ideal entry point into a community interested in scaling up sanitation through wastewater treatment. As students learn about the technology and benefits of treating wastewater, they can teach their parents, which helps raise awareness and demand for services.
“The location provided an opportunity to provide real sanitation improvement for hundreds of children, while demonstrating and promoting the technology,” Mr Robbins of RTI International said.
Analysis of the water discharged from the system shows that reductions in organic matter, solids and pathogenic bacteria approached 90 percent, comparable to results for constructed wetlands and sewage lagoons. (After 18 months of development and testing, RTI’s cocopeat team has observed that this waste product can be used to successfully remove approximately 90% of the organic matter, solids, and pathogens in domestic wastewater).
The Philippines has continued to lag behind other Southeast Asian nations in terms of the percentage of the population with access to sewerage services. As centralized wastewater treatment remains prohibitively expensive for all but the most densely populated regions, decentralized on-site wastewater technologies are now necessary to meet this need. The project seeks to demonstrate one such low cost wastewater treatment technology, which can be installed by local service providers using locally available cocopeat.
The key lesson of the story:
This case study shows, how important it is to adopt a waste-water project to the the specific features of the project place, in this case to the available local materials, which helps to achieve an environmentally friendly method.
Contribution to the SuSanA sustainability criteria
Environment and natural resources: With locally available materials a water-saving solution is provided by the project.
Technology and operation: The cocopeat wastewater system is a sustainable and an appropriate technology in areas without reliable water supply, where enough local plants-material is available.
Type of project: cocopeat biofilter secondary treatment system
Project period: 2011 -
Start of operation: Putatan Elementary School - Started November, 2011 and still running strong. Muntinlupa Science High School- January 2012.
Address of project location: two schools in Muntinlupa City, Metro Manila, Philippines
Planning institution: RTI International, Muntinlupa City in the Philippines: local city environmental officer
Executing institution: RTI International, Muntinlupa City in the Philippines: local city environmental officer
RTI International is one of the world’s leading nonprofit research institutes, dedicated to improving the human condition by turning knowledge into practice. Our staff of more than 3,700 provides research and technical expertise to governments and businesses in more than 75 countries.
Financially supporting agency: Bill & Melinda Gates Foundation’s Grand Challenges Explorations initiative
Mr David Robbins
Senior water and sanitation specialist at RTI and the project’s director
Water and Environment for Development, RTI International, 3040 Cornwallis Rd, Research Triangle Park, North Carolina
Mr Jet Pabilonia, environmental officer of Muntinlupa City