Modeling Solute Transport Through Geosynthetic Clay Liners Permeated with Inorganic Solutions

GCLs are employed in containment applications, where both advection and diffusion need to be evaluated as possible migration mechanisms of contaminants. Permeation column tests were carried out on a GCL using two synthetic multispecies inorganic solutions of different ionic strength and containing equimolar concentration of heavy metals (Pb, Zn, Cu). The hydraulic conductivity (k) of the GCL to inorganic solutions increased by one order of magnitude relative to permeation with water. The solute breakthrough curves were interpreted using the software Pollute (R), which allows modeling solute transport in case of variable transport parameters and nonlinear equilibrium sorption. The experimental data were best fitted by assuming effective diffusion coefficients of solute species increasing with time.