An experimental investigation was carried out in order to evaluate the compatibility between a commercial GCL and ethyl alcohol (ethanol). The hydration of the GCL prior to exposure was found to play a major role in GCL compatibility with ethanol. Tests results showed indicated that if the hydrated GCL is after hydration by pure ethanol, the GCL hydraulic conductivity may be increased significantly but not dramatically. Conversely, in case of unhydrated GCL, the hydraulic performance is strongly dependent on ethanol concentrations. Concentrated ethanol solutions (>50 %) prevent significant swelling of bentonite and impact dramatically the hydraulic conductivity, whereas diluted concentrations (<25 %) have a minor influence on permeability. The effect of initial contact with concentrated solutions was found to be reversible when the GCL was again permeated with water. It is suggested that controlled re-hydration with pure water may be effective as a potential rehabilitation procedure for GCLs contaminated by miscible organic pollutants.
Geosynthetic Clay Liners (GCLs) are increasingly used as low permeability barriers in geotechnical and environmental applications. The hydraulic efficiency of GCLs depends on the low hydraulic conductivity values attained by the bentonite core when hydrated with water. In some situations, GCLs may be exposed to liquids different than water, potentially impacting the hydraulic performance. As a consequence, for a safe use of the GCLs as liner materials, the compatibility between the bentonite and the expected pollutant liquid to be contained should be verified. The common procedure to assess the compatibility between a given pollutant liquid and a candidate liner material consists in measuring a baseline hydraulic conductivity, using distilled water or an aqueous solution of low salinity (tap water or ÒstandardÓ water) as permeant. Permeation with water is followed by the pollutant liquid of interest, until a new steady-state hydraulic conductivity is attained.
