Contaminant transport through a soil liner underlain by an unsaturated stone collection layer

Abstract

Chloride and sodium migration in an unsaturated stone collection system underlying a compacted soil liner was examined for three different flow rates ranging between 2.5 and 0.017 m/a. Relatively high and uniform concentrations were observed in the unsaturated stone layer. The groundwater velocity played a significant role in contaminant transport through unsaturated stone even at a flow of 0.017 m/a. Experimental observations were accurately predicted using one-dimensional advective–diffusive–dispersive theory. Transport parameters were reduced by modelling the test data. Key words: soil liner, unsaturated flow, diffusion, landfill, collection system.