Role of Geotechnical Properties in the Dynamic Aspects of Methane Migration in Biocovers

Abstract

Controlling methane emissions from landfills has been a significant concern over the last decades. Researchers have identified the use of landfill cover with oxidative capacity (biocover) as a promising solution to mitigate these methane emissions. However, the geotechnical conditions in a biocover can affect the methane fluxes and the pressure buildup inside landfills. In this paper, the effect of the porosity, degree of saturation, and absolute permeability of the biocovers on the atmospheric methane flux and pressure buildup inside landfills is studied. Numerical modeling with TOUGH3 EOS7CA was carried out to assess the methane migration (one dimensional) and methane oxidation in biocovers. Simulations revealed the role of geotechnical properties in controlling the dynamic outflow of methane and inflow of oxygen in the biocover. The relations between methane migration and pressure development are also established, and the effect of geotechnical properties in these aspects is quantified. The importance of coupling these factors for improving the efficiency of a biocover is highlighted. An absolute permeability in the order of 10−13 m2 and a degree of saturation less than 0.5 is suggested for achieving optimal performance. The role of atmospheric pressure and temperature on the atmospheric methane emissions is also described.