Mitigation of Methane Emission from Solid Waste Disposal Site in the Tropics by Vegetated Cover Soil

Development of a mitigation technique for methane emission from a solid waste disposal site using biological activity in cover soil was investigated. Methane emission rates through clay, sandy loam and vegetated sandy loam (with Sporobolus virginicus) cover soil laid on existing waste pile at a dumpsite in Thailand were studied by using closed flux chamber method. Over 275 days of monitoring, average methane emission rates measured through clay, sandy loam and vegetated sandy loam were 1.31, 1.79 and 0.95 g/m $^2$ /d, respectively. Though methane emission rates fluctuated significantly with time, higher emission rates were detected during the dry period than the high intensity rainfall period. Significant reduction of methane emission was observed in cover soil employing vegetated sandy loam where methane oxidation reaction could be promoted. The application of leachate onto the vegetated cover soil could also enhance plant growth and methane oxidation. The results of this study suggest that methane emission from solid waste disposal sites could be mitigated through application of appropriate topsoil as a bio-filter.