Greenhouse gas emission from windrow pile for mechanical biological treatment of municipal solid wastes in tropical climate

Methane emission characteristics of a full-scale windrow pile for municipal solid waste (MSW) treatment in Thailand were investigated. Surface emission rate, in-pile methane gas content and waste characteristics were observed over 14 months period. The results revealed average surface methane emission rate of 5.32 g/t dry wt./day, being largely fluctuated between 0.05 and 27.13 g/t dry wt./day. The methane emission from MBT windrow pile, during which 75% of organic wastes were decomposed, were comparatively lower than those reported for landfills and windrow composting operations. The precipitation affected gas emission especially during the initial phase of waste decomposition with gas production lag time ranged between 0.34 and 0.55 years. Positive correlation between methane emission rate from waste pile and precipitation was observed during methanogenic stage or gas rising stage when organic content in wastes was still high. The open windrows operated in tropic climate could facilitate a high degree of waste stabilization but they were not effective for the reduction of moisture from MSW required for utilization as refuse-derived fuel.