Performance of Soil Covers for Mitigation of Methane Emission from a Municipal Solid Waste Landfill

The organic component of municipal solid waste (MSW) degrades after being buried in landfills, and when under anaerobic conditions produces methane (CH4) and carbon dioxide (CO2). Soil covers have been used for reducing CH4 emission from MSW landfills. Field and laboratory studies have shown that the diffusion of oxygen (O2) into the cover soil promotes the microbial CH4 oxidation by methanotrophic bacteria. This paper examines the CH4 fluxes and oxidation efficiencies for soil covers with and without underlying waste using a multi-phase and multi-component numerical model. The numerical modeling of two laboratory soil cover column tests shows that the cover soil properties can have a great influence on the CH4 oxidation efficiency and a proper selection of soil covers is important for minimizing CH4 emission from MSW landfills. Further examination of soil covers overlying waste using the regional atmospheric temperature and rainfall indicates that the use of the regional atmospheric temperature and rainfall results in temporal variability of the CH4 flux and oxidation efficiency. The paper demonstrates the importance of using the site-specific cover soil and regional climatic data for the design of landfill soil covers to mitigate CH4 emission.