Gradient packing bed bio-filter for landfill methane mitigation

We assessed the suitability of various biogenic materials for development of a gradient packed bed bio-filter to mitigate the methane (CH4) emission from landfills. Five different biogenic materials (windrow compost-WC; vermicompost-VC; landfill top cover-LTC; landfill bottom soil-LBS; and river soil sediment-SS) were screened. Among these materials, the VC showed a better CH4 oxidation potential (MOP) of 12.6 μg CH4 gdw−1 h−1. Subsequently, the VC was used as a packing material along with wood chips in proto-type bio-filters. Wood chips were mixed at 5-15% to form three distinct gradients in a test bio-filter. Under the three different CH4 loading rates of 33, 44 and 55 gCH4 m−3 h−1, the achieved MOPs were 31, 41, and 47gCH4 m−3 h−1, respectively. The gradient packed bed bio-filter is effective for landfill CH4 mitigation than the conventional bio-filter as the latter shows gas channeling effects with poor MOPs.