The aim of this study was to check the effectiveness of microelectrolysis for the pretreatment of a municipal landfill leachate with the objective improving its overall biodegradability, evaluated in terms of BOD5/COD ratio, up to a value compatible with biological treatment. The best microelectrolysis operational conditions for achieving the desired COD values were: pH=2.0; granular activated carbon (GAC) =10 g/L; mass ratio of zero iron (Fe0)/GAC=2:1; reaction time=90 min. The BOD5/COD was significantly improved from 0.12 to 0.31, which allowed an almost 85% removal of COD by a sequential activated sludge process. The results show that the microelectrolysis is a promising technology to improve the biodegradability of mature landfill leachate.

Thermally activated natural low-grade manganese ore was used as an efficient and stable catalyst for enhancing the activation of PMS through increased charge transfer, pore size and acidic sites.

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The modified digested sludge (MDS) can be used as landfill biocover that serve to minimize CH4 emissions by optimizing CH4 oxidation. MDS composited by coal ash and digested sludge was studied in this paper. The permeability coefficient and the compressive strength of MDS were tested in full factorial L9(34) experiment using simulation column. Results show that when the mix ratio of coal ash and digested sludge is about 1:1-1.5:1, the permeability coefficient < 10-4 cm/s and compressive strength 50 kPa, MDS can meet the engineering requirements for landfill operation. The optimal conditions of MDS were as follow: mix ratio of coal ash/digested sludge = 1:1, nutrient solution = 0.05 ml/g, thickness of biocover = 400mm, and moisture content of MDS = 40%. The maximum CH4 oxidation efficiency was 88.6% and the volume flow rate of CH4 was 0.75 mmol/(kgd) under the optimal conditions.