BIOFILTRATION OF METHANE IN LANDFILL BIOGAS: A FIELD STUDY

Abstract

The release of landfill biogas (LFG) into the atmosphere as fugitive emissions (through the cover layer) is quite representative. Given the high potential of biogas in the greenhouse effect (GHG), the study of different technologies for its use in energy production has been increasingly studied. In addition to the biogas recovery to the energy purposes, use of biosystems (biocovers, biofilters, etc.) in cover layers aimed at optimizing the biotic consumption of methane, the main component of biogas in terms of global warming potential (GWP), has also been widely evaluated as a system complementary in GHG mitigation. Thus, the present study evaluated the performance, in terms of methane oxidation efficiency, of a biofilter filled with conventional landfill soil enriched with scum from a domestic wastewater treatment plant. This "improved" biofilter, with high organic matter content (»4.5%) in the upper portion of the bed, was compared to a "control" biofilter, containing only conventional landfill soil and therefore with low organic matter content. (»0.5%). Both biofilters were fed with a loading rate of »44 g_CH4.m^-2.d^-1 over nine monitoring campaigns. Parameters as methane concentration in raw biogas (LFG), moisture and temperature of biofilter beds were also related to the methane oxidation efficiencies. The average efficiency of methane oxidation in the improved biofilter was 95.2%, compared to the control biofilter (84.7% efficiency), confirming the effectiveness of WWTP scum as a cover layer soil amendment in GHG mitigation.