Modeling Leachate Contamination and Remediation of Groundwater at a Landfill Site

Leachate contamination of an aquifer from a landfill site was simulated using the groundwater flow and transport model SUTRA developed by the U.S. Geological Survey. The model calibration was performed by spatially adjusting the hydraulic conductivity in order to capture the measured hydraulic head spatial variation and then by adjusting the dispersivity and porosity match the measured chloride plume. Based on the simulations it was found that without remedial action the contaminants in the existing leachate plume would remain above acceptable regulatory concentration levels for longer than 2010. The chloride loading of an adjacent stream exceeds acceptable levels under Ontario's Reasonable Use Guidelines. Simulations indicate that a pump-and-treat system using additional two purge wells could remediate the leachate contamination within approximately 10 years from now.