Mathematical models for organic contaminant transport in clayey soils are developed to investigate the behavior of organic transport in the landfill clay liner system considering coupled effect of consolidation, diffusion and degradation. The bottom boundary conditions are assumed to be zero concentration or zero flux. Degradation and porosity changing of the organic contaminants in the porous media is considered. The bottom concentration and flux of the soil liners can be greatly reduced when the degradation effect and porosity changing is considered. For the case under steady-state, the bottom flux and concentration for the case with t1/2=10 years can be 2.8 and 4.5 times larger than those of the case with t1/2=100 years, respectively. The bottom concentration and flux of the soil liners can be greatly reduced when the coefficient of volume compressibility decreases. For quasi-steady-state and with t1/2=10 years, the bottom flux and concentration for the case with mv=0.02Mpa-1 can be 17.4 and 19.6 times lower than the case with mv =0.5Mpa-1. This may be due to the fact that the true fluid velocity induced by consolidation is greater for the case with high coefficient of volume compressibility. The proposed analytical model is relatively simple, and can be used for verification of more complicated numerical models and assessment of the coupled effect of diffusion, consolidation and degradation on contaminant transport in clay liners.
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