Municipal solid waste landfill performance with different biogas collection practices: Biogas and leachate generations

This study investigated the performance of simulated landfills with different biogas collection practices, including upward biogas collection only (L-T) and both upward and downward biogas collection (L-TB). A simulated landfill was constructed using a stainless steel lysimeter equipped with a compression unit. Upward gas flow was favored in uncompressed MSW when both upward and downward gas flows were allowed (L-TB). By reducing void ratio, the preferential flow direction of biogas was changed to downward gas flow along with gravimetric leachate drainage. In L-T, porched leachate was formed because high flow resistance by countercurrent gas-liquid flow affected moisture redistribution. It was considered that high pressure buildup in gas-filled pores of (LT) enhanced uneven moisture distribution and resulted in inhibiting methane production. The cumulative methane volume produced from L-TB was 2.5 times as much as that of L-T. (C) 2019 Elsevier Ltd. All rights reserved.