Preliminary study of methane oxidation in landfill cover soil: The effect of moisture content

Abstract

Methane oxidation is one of the important processes to mitigate the emission of methane gas at landfill to the environment. Th is study investigated the effect of moisture content in order to enhance the methane oxidation of final cover soil fro m Taman Medan Du mpsite. Three different PVC soil colu mns contained cover soils with mo isture content of 7%, 12% and 28% were used in this study. The columns were purged with the mixture of methane gas (60% by volume) and carbon dio xide gas (40% by volume) fro m the bottom of the soil co lu mn s. The mixture gas passing through the soil med ia was retrieved fro m the colu mns daily via sampling ports fabricated at every 10cm of the column height. The soil cover was classified as sandy silt contained 56 % of sand, 32 % of silt and 12 % of clay. It also had 12% of mo isture content, bulk density of 0.229 g/cm3, particle bulk density of 0.0304 g/cm3, pH of 7.21, colour of dark yellowish brown, porosity of 86.72% and organic matter of 1.5 %. Gas chromatography analysed the collected gas had showed that methane oxidation effectively occurred in the colu mn with 12% of mo isture content that the average methane oxidation efficiency of the 7 -day experiment was 47.97%. Ho wever, the methane oxidation efficiency in the other two columns with 7 and 28% of moisture content was significantly lower with only 8.93 and 7.87% of efficiency. The analyses also showed highest methane oxidation efficiency, by average, took place at the height of 80cm of those columns.