Diffusion of organic contaminants in triple-layer composite liners: an analytical modeling approach

This paper presents an analytical solution for modeling the one-dimensional diffusion of organic contaminants through a composite liner, comprising a geomembrane, a geosynthetic clay liner and a soil liner system. The Laplace transformation technique is used to obtain a dimensionless analytical solution to the diffusion of organic chemicals through the triple-layer composite liners. The solution presented is verified against two alternative numerical solutions. The analytical solution is then adopted to provide a series of graphical design charts which can assist with the assessment and design of composite liners. Design examples are included for a composite liner having a geomembrane, a geosynthetic clay liner and a soil liner system. The proposed analytical solution provides a practical and relatively simple tool to assist with the design of composite liners and the validation of numerical models.