A laboratory investigation on the hydraulic trap effect in minimizing chloride migration through silt



The effect of the upward flow (the hydraulic trap effect) on advective-diffusive migration of chloride through silt under two different soil densities and Darcy velocity conditions was examined.  Comparison on chloride concentrations in the receptor reservoirs beneath the silt samples in downward and upward flow tests showed that the hydraulic trap system could significantly reduce the concentrations in the soil and underlying receptor reservoirs and hence, the system could be used in solid waste landfill designs to minimize the contamination potential from landfill leachate. Effective chloride diffusion coefficients were measured on clay and silt samples from Urmia City landfill site in Iran, using the solid waste leachate from the same landfill. The experimental results were in good agreement with theoretical predictions in diffusive and advective-diffusive tests.