Biofiltration of Methane Fugitive Emissions from Landfills Using Scum from Municipal Wastewater Treatment Plants (Wwtp) as Alternative Substrate

Abstract

Biofilters have been recognized as key technology in the mitigation of greenhouse gases (GHG) emitted by landfills. This study aimed to evaluate the methane (an important GHG) oxidation efficiencies of two experimental biofilters at the municipal landfill of Guarapuava (Brazil) under normal conditions (control column), just using landfill cover soil with low organic matter content, and improved, exploiting dried scum from municipal wastewater treatment plant (SWWTP) mixed with the cover soil (enriched column, with a high organic matter content). The influence of parameters such as the methane inlet loading rates (22 and 44 gCH4.m− 2.d− 1), temperatures, methane concentration in the raw biogas, carbon/nitrogen ratio and moisture content of the packing materials on the oxidation of methane was also evaluated during 25 campaigns. The campaigns with the lowest methane loading rates applied to the biofilters showed the best methane oxidation efficiencies (98.4% and 89.5% in the enriched and control columns, respectively) as compared to campaigns with a higher load (92.6% and 82.6% in the enriched and control columns, respectively). In addition to the loading rates, the methane oxidation efficiencies were highly influenced by the organic matter content and C/N ratio of the packing materials evaluated.