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Landfill gas management in Asia |
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University of Padua IMAGE Department |
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Anaerobic decomposition of MSW in landfill generates large amounts of green house gases and other trace gases. Landfills and dumps contribute an estimated 25% of anthropogenic methane emissions and 20% of total global anthropogenic emissions (Ahn Y.M. et al., 2002). In Asia, about 90% of open dumps without any top cover or preventative measures contribute to methane emissions from the MSW (shallow dump sites with layers of only a few metres of waste generate less gas due to their more or less anoxic status). Biological oxidation of methane by indigeneous bacterial populations can be an inexpensive mechanism for treating waste gas (Hogland W. et al., 2005). However, enhanced biological oxidation of the landfill gas depends on factors such as soil properties, bacterial population, misture content and nutrient supplement. It is therefore necessari to identify appropriate controlling parameters for better landfill gas management under Asian conditions where landfill gas recovery is usually not feasible due to factors of size and economy. The design of controlled and engineered landfills of the future in Asia will have to incorporate elements to reduce methane emissions or to oxidize the methane before it enters the atmophere. |