Quantification of Diffusive Transfers in Multicomponent Geosynthetic Clay Liners

Multicomponent geosynthetic clay liners (GCLs) have recently been introduced to the market to perform sealing in landfills, dams, dikes, ponds, etc. As they are combining a GCL to a coating or film, their hydraulic properties are falling between geomembranes (GM) and GCLs. In order to evaluate the importance of performing the experimental quantification of the diffusion of phenolic compounds in multicomponent geosynthetic clay liners, which will be a time consuming and expensive operation, a preliminary modelling was undertaken. The objective of this paper is to present the results of this modelling performed based on the quantification of the diffusion in geosynthetic clay liners, polyethylene films and geomembranes in order to evaluate the performance towards diffusion of a multicomponent geosynthetic clay liner. Diffusion was quantified for 2,4-dicholophenol, 2,3,5,6-tetrachlorophenol, and pentachlorophenol. Results show sensitivity to the thickness of the film or geomembrane used in conjunction with the GCL, more important than to the nature of the phenolic compound under study. The protection at field scale by a multicomponent GCL would thus not be ensured with the same level as with a more classical composite liner containing a geomembrane, which remains the best performing solution towards diffusive transfers.