Compost quality economic viability of five biowaste composting ventures in Metro Manila [Philippines]
2008
Cuevas, V.C., Philippine Univ. Los Baños, College, Laguna (Philippines). Inst. of Biological Sciences | Sumalde, Z.M., Philippines Univ. Los Baños, College, Laguna (Philippines). Dept. of Economics | Valencia, S.A., Philippine Univ. Los Baños, College, Laguna (Philippines). Dept. of Chemical Engineering | de Guzman, C.C., Philippines Univ. Los Baños, College, Laguna (Philippines). Crop Sciences Cluster
The compost quality and economic viability of five urban biowaste composting ventures in Metro Manila, Philippines were studied. The study sites which were chosen to represent the composting of biodegradable waste collected from the market, household and school included: a) the Pasig City Market; b) Barangay(Bgy) Holy Spirit, Quezon City; c) Bgy. Concepcion Uno, Marikina City; d) Bgy. 169, Caloocan, City; and e) Paref Woodrose School, Inc, Muntinlupa City. Compost from Bgy 169 passed the Fertilizer and Pesticide Authority (FPA) standard for compost on soil conditioner. Chemical analysis showed that the compost had a C:N ratio of 21 and contained 39% organic matter, 1.08% total N, 0.81% P as P2O5 and 1.58% K as K2O. It was free of pathogenic coliforms and had no traces of the toxic metals Pb and Cd. Its Zn content was 103:67 ppm, way below the allowable limit of 1000 ppm. However, the other four composting ventures had poor compost quality with a C:N ratio over 40 but the composts were also relatively free of pathogenic coliforms and the toxic metals Pb and Cd. Financial analysis showed that the direct costs of producing compost ranged from PhP 1,515- PhP 13, 654 per ton, which were greater than the income or value from the compost produced. This could be due to the relatively low price of the product because of its poor quality. Composting entailed a financial gap that ranged from PhP 551- PhP 10,946 per ton, which must be bridged from other sources, if not subsidized by the local government. However, if indirect benefits such as the value of savings from avoided landfill and collection costs are considered, the composting activities are economically or socially beneficial due to positive economic gains.
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