Analytical model for vapour-phase VOCs transport in four-layered landfill composite cover systems

An analytical model for vapour-phase volatile organic compound (VOC) diffusion through four-layered landfill cover system consisting of a soil protective layer, a drainage layer, a geomembrane, and a compacted clay liner (CCL) or geosynthetic clay liner (GCL) is presented. VOCs transport in the cover system is sensitive to the changes of Sr in the protective layer and CCL rather than that of the drainage layer. When Sr1 = Sr2 = Sr4 = 0.5, in order to meet the EPA standard on benzene concentration, the thickness of CCL should be greater than 200 cm or it should be modified with 2% biochar.