Fugitive emissions of biogas in coverage liner of compacted soil in a landfill

ABSTRACT Fugitive biogas emissions can represent a significant part of the gas flow in landfills, make the methane (CH4) energy use unfeasible, and also pose risks to the environmental health of the surrounding communities. In this context, this work aimed to evaluate the fugitive emissions and the factors that interfere in the biogas flow in the final landfill liner. The study area consisted of a Waste Cell, with a mass of 62,359.44 t of MSW deposited at the Campina Grande Sanitary Landfill, Paraíba, Brazil. In this Cell, measurements of the fugitive emissions of biogas were carried out, using the static chamber methodology; analysis of the concentration of gases at the soil-waste interface, using Gas Concentration Measurement Devices (CMD); and mapping of the gas emissions in the Waste Cell, applying data interpolation techniques based on Kriging. Flows of CH4 and carbon dioxide (CO2) ranging from 0 to 0.09 and 24.62 to 331.31 g.m-2.day-1, respectively. The percentage of retention of CH4 and CO2 by the liner was high, above 95%, being influenced mainly by the high degree of average compaction obtained for the Waste Cell (91.84%) and by the efficiency of the gas drainage system. The mapping of biogas emissions in the Waste Cell proved to be an important tool in the identification of the areas with the greatest potential for biogas generation and flow through the cover liner.