Assessment of technical efficiency and economic viability of existing composting ventures and survey of the legal, policy and institutional framework regarding biowaste reuse

Five composting units located in Metro Manila [Philippines] were studied to assess their technical and economic viability. The units are:a) Pasig City Market, b) Barangay (Bgy) [village] Holy Spirit, Quezon City, c) Bgy. Concepcion Uno, Marikina City, d) Bgy. 169, Caloocan City and e) Paref Woodrose School, Inc., Muntinlupa City. Two laws of the country form the legal framework for the set-up of solid waste management (SWM) system of the units studied: RA 9003- The Ecological Solid Wastes Management Act of 2000 and RA 7160- Local Government Code of 1990. The latter gives the authority for the local government units-provincial and municipal/city governments- to implement RA 9003. It empowers the barangays (the small political unit of the country) to put RA 9003 into action. The barangay captain (highest-elected unit head) is tasked to manage solid waste generated by households and institutions under its jurisdiction. The necessary resolutions and strategies for implementation of the law are worked out by the barangays and municipal/city councils. All waste generators are mandated to segregate their wastes into biodegradable and non-biodegradable components. All five units studied are located within the locality they serve. Two of the five units studied utilize food wastes as the main substrates for composting. These are the Paref Woodrose and Brgy. Concepcion Uno. Two others are composting mainly household wastes- Brgy. 169 and Brgy. Holy Spirit. Pasig City uses mainly market wastes as subtrates. Brgy. 169 and Paref Woodrose compost all the biowastes they collect from their constituents since they process less than 0.5 ton wastes per day. Pasig City Market and Brgy. Holy Spirit process 1.0 and 2.5 tons biowaste per day, respectively, while Concepcion Uno processes about 0.3 ton per day. These volumes of waste constitute only about 11% or less of the total biowaste collected in the study sites. Bgy. Concepcion Uno converts most of its biowaste collected into swine feeds (as much as 65%). The percentage reuse from both nonbio- and biowaste for the city market and the three barangays ranges from 9% to 59%. Paref Woodrose reuses almost all its waste generated with negligible amount disposed at dump site. Three units- Brgy. Holy Spirit, Concepcion Uno and Pasig City Market use mechanized rotary drum composters at the initial phase of decomposition. Composting is achieved by piling substrates on paved concrete floors. The other two units- Brgy. 169 and Paref Woodrose use modified window type. All compost samples from the five component units analyzed were free of pathogenic microorganisms, contained minimal amounts of toxic metals and with slight to moderate alkaline pH. Organic matter content was high ranging from 39% to 71%. Except those produced from Brgy. 169, all compost products had high C:N ratio (42-91) and a total NPK content of less than 3%. Compost samples from Brgy. 169 had a mean ratio of 21, a total NPK content of 3% and moisture content of 24%. Only the compost samples from Brgy. 169 pass the standards for compost as soil conditioner set by the Fertilizer and Pesticide Authority (FPA), the government body that sets the quality standards for fertilizers and pesticides sold commercially in the country. The high organic carbon contents of the produced compost from the four units may be due to the large amount of coconut/sawdust (about 20% of the total volume of wastes) incorporated for moisture control and improvement of aeration to reduce foul smell. No nitrogen and phosphorus sources were added. Proper social and technical interventions are needed by these composting units. If they can collect properly segregated biowaste and produce compost that meets the standards set by FPA, they will be able to sell their produce. They can convert bigger quantities of biowaste generated by their constituents into useful products, and consequently, engender a stronger biowaste reuse. In terms of financial viability, results of the study showed that the costs of converting biowaste into compost were greater than the revenue or value of compost. This was attributed to the relatively lower price of compost. This entails a financial gap that must be financed from other sources, if not subsidy from the local government. To increase revenue from composting, there is a need to improve the quality of compost to command higher price and to aggressively market the compost to capture the financial benefits from the activity. On the other hand, if the other direct benefits (including value of recyclables, revenue from selling swine feeds out of food waste) and indirect benefits from solid waste reuse (savings from collection and avoided landfill) are considered, the composting units posted positive economic gains.