Modeling of leachate migration in an anti-seepage system for landfill

In order to predict the seepage quality of leachate, and to predict the temporal and spatial distribution of contaminant concentrations, a coupled mathematical model for leachate migration was developed based on the analysis of retardation mechanisms of anti-seepage system constructed by clay-solidified grout curtain (CSGC). Solutions to the coupled equations are accomplished by the finite difference method. The results show that the contaminants are retarded in CSGC by means of precipitation, adsorption or ion exchange that makes pollution controlled. The CSGC has a strong retardation capability for contamination, and the retardation ratio with respect to heavy metals ranges from 70.4% to 94.5%. The migration of contaminant through the CSGC is related with time, and the contaminant concentration increases with longer time and decreases with distance from the leachate source.