Effects of the depth of active methanogenic layer on the methane production and leachate quality in a landfill with sludge recycle

초록

Lab-scale lysimeter systems(LSRs) were operated at three different conditions to investigate the effects of the depth of the active methanogenic layer(AML) on methane production and leachate quality. After the development of AML by recycling the sludge from an anaerobic digester treating the produced leachate to lysimeters, the ratios of the total solid waste layer(TSWL) to AML were set to 2, 4, and 8 for LSR-1, 2, and 3, respectively. During the development of AML, the cumulative methane production were 32.4, 34.1, and 28.9 L CH4/kg waste, for LSR-1, 2, and 3, respectively, accounting for 58%-63% of the total COD production from the lysimeters. After the development of AML, the cumulative methane productions of LSR-1, LSR-2 and LSR-3 were 91.0, 90.6, and 53.5 L CH4/kg waste, respectively. Concentrations of COD and NH4+ were generally higher in LSR-3, while no significant differences were found between LSR-1 and 2. Results of the research suggest that the ideal ratio of TSWL to AML was 4 or less for the recovery of methane and the improvement of leachate quality by the rapid stabilization of organics.