This study focused on the development of landfill cover layer to minimize greenhouse gas emission. Unlike conventional landfill cover soil that mainly targeting at minimization of leachate production by preventing the percolation of rainwater into the landfill cell, this proposed cover layer plays an importance role in reducing the emission of methane via microbial methane oxidation process through the conversion of methane to carbon dioxide by methanotrophic bacteria. It also helped eliminating leachate produced from the landfill by evaporating leachate during its irrigation to maintain proper moisture content for microbial activities. This work examined the introduction of compost as compared to sandy loam soil in laboratoryscale soil column experiment to study the microbiological activities in simulated landfill cover soil. Furthermore, the effect of vegetation (S. virginicus and P. repens, tropical grasses) and leachate irrigation on methane oxidation reaction was also studied. Longterm methane oxidation rate was evaluated to study their capability in reducing emitted methane from landfill. Simulated rainfall and leachate irrigation was applied to soil column to maintain proper soil moisture content and providing supplement nutrients. According to the experimental results, it was found that the use of compost as cover material together with leachate irrigation practice could successfully maintain methane oxidation efficiency of 90% for more than 250 days. In vegetated landfill cover systems, both S. virginicus and P. repens could grow well under typical landfill condition where they are exposed to landfill gas and irrigated leachate. Nevertheless, beneficial effect of vegetation on methane oxidation was not clearly seen. Methane oxidation rate in P. repens application case was found higher than S. virginicus but it was comparable to non-vegetated compost with leachate irrigation case.
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