Evaluation of Various Leachate Recycle Methods on the Methane Production and Nitrogen Control for Landfill Management

초록

Three lysimeters, each filled with 114 kg of solid wastes collected from residential area at the density of 0.7 ton/m3, were operated at different conditions: control(L-control), leachate recycle(L-leachate), and sludge recycle(L-sludge). In L-sludge, sludge from the anaerobic digester treating the produced leachate was recycled for a limited time(from t = 45 to 297 days), then nitrified leachate with extended aeration process was recycled from t = 335 days. In L-leachate, the raw leachate was recycled throughout the experiment. Simulated rainfall, 35% of the annual rainfall of Korea, was added to all lysimeters. Recycle of anaerobic sludge from anaerobic digester treating leachate was effective to reduce the stabilization time, to enhance the methane production per unit solid waste, and to control of leachate quality. Conventional leachate recycle has some marginal effect compared to sludge recycle. The recycle of nitrified leachate would be good option for nitrogen control in leachate, especially for old landfill. Sludge recycle followed by nitrified leachate recycle might become a better alternative to simple leachate recycle for landfill management.