ABSTRACT
Decentralized waste treatment facilities are recently highlighted for the treatment of solid waste in rural areas for being cheap, flexible, and reliable. Among them, decentralized composting is most commonly used. Many forms of decentralized composting facilities also develop and apply in developing countries, but the environmental and economical performances remain unknown. Therefore, this study analyzed the environmental impacts and cost of a decentralized composting facility through life cycle assessment and life cycle cost. The functional unit was the construction, operation, and demolition the composting facility. Contribution and sensitivity analysis were also performed to find out the most influential processes and parameters. The facility had a 10-year designed life span and could treat about 5840 t organic waste in its life cycle. The life cycle environmental impacts were 646,700 kg CO2-eq, 8980 kg SO2-eq, -28 kg P-eq, 7.09 × 10-3 CTUh, 0.13 CTUh, and 16,754 kg oil-eq for climate change, terrestrial acidification, freshwater eutrophication, human toxicity cancer effects, human toxicity non-cancer effects, and fossil resources scarce, respectively. The life cycle cost was 1080.925 k CNY. When scaling to treating 1 t organic waste, the environmental impacts were close to those of similar decentralized and centralized composting facilities and the cost was lower than those of centralized biological treatment plants when excluding revenues from compost. According to the contribution and sensitivity analysis, the operation stage had the largest environmental impacts. The composting and compost substitution processes in the operation stage were the most sensitive processes. This study proved quantitatively that the decentralized facility was feasible both environmentally and economically and enriched the study cases for decentralized composting facilities.
