A Two-Dimensional Transport Model of Contaminant Through Defected Composite Liner in Landfill

Abstract

The composite liner system, which consists of geomembrane (GM) and geosynthetics clay liner (GCL), is usually used to prevent the toxic landfill leachate from migrating into the environment. However, it is difficult to evaluate the barrier capacity of the liner system, especially in the case of defects and two-dimensional (2-D) scale. In view of this, a 2-D model is developed to discuss the contaminant transport through flawed composite liner, and the semi-analytical solutions are produced with the combination of integral transforms. The soil contaminant concentration profiles generated by this new model are shown in good agreement with the results by lab experiments and numerical simulations, which implies that the current solution can serve as an efficient and easy-to-use estimation tool by replicating numerical results with much more universality. A case study based on diffusion coefficient, defect rate and modeling sizes was conducted to illustrate the concentration and flux profiles under the spatiotemporal domains. Results show that GCL can effectively reduce the pollution level caused by GM failure, and peak values appear in flux curves on the GCL-SL interface, indicating different contaminant risks from aspect of the entire model cross-section.

Keywords: landfill, 2-D transport of contaminant, composite liner, geomembrane, geosynthetics clay liner, semi-analytical solution