Effects of Leachate Recycle and Anaerobic Digester Sludge Recycle on the Methane Production from Solids Wastes

초록

Performances of lab-scale lysimeters were evaluated to develop a new landfill system for the recovery of CH4 from solid wastes. Lysimeters were operated at three different conditions : control (L-control),leachate recycle(L-recycle), and sludge recycle(L-sludge). For L-sludge, sludges from leachate-treating anaerobic digester were recycled, whereas raw leachate was recycled for L-recycle. Amounts of COD recovered by CH4 were 0.13, 0.29, and 22.5 kg for L-control, L-recycle, and L-sludge, respectively. With L-sludge, 76% of total COD outflow from the lysimeter was recovered by CH4, and the remaining COD was washed out by leachate. Additional CH4 could be recovered by anaerobic digester with L-sludge. However, 1.4 and 4.2% of total COD outflow was recovered as CH4 from L-control and L-recycle, respectively. Stabilization of organics in L-sludge approached to completion within 430 days, while other lysimeters still produce high COD leachate. Results indicated that the continuous additions of active methanogenic population from anaerobic digester rather than simple leachate recycle would be necessary for the rapid and siginificant CH4 recovery from solid waste.