Numerical investigation of leachate transport into the groundwater at landfill sites

This model can be used for the simulation of contaminant transport in aquifers in any scale. It is established on finite difference-finite volume solution of two dimensional advection-diffusion-linear sorption with first order decay equation. The case study presented in the paper is simulating leachate transport at a 2000 ton/day landfill facility assesses leachate migration away from the landfill in order to control associated environmental impacts, particularly on groundwater wells down gradient of the site. Leachate discharge from landfills is the main route for release of the organic and inorganic contaminants through subsurface, commonly encountered in the refuse. Leachate quantity and potential percolation into the subsurface are estimated using the Hydrologic Evaluation of Landfill Performance (HELP) model. A comprehensive sensitivity analysis to leachate transport control parameters was also conducted. Sensitivity analysis suggest that changes in source strength, aquifer hydraulic conductivity, and dispersivity have the most significant impact on model output indicating that these parameters should be carefully selected when similar modeling studies are performed. The sensitivity of the model to variations in input parameters results in two opposing patterns of contaminant concentration. While higher groundwater velocities increase the speed of plume spread, they also increase the dilution ratio and hence decrease the concentration

Keywords:

Advection- Diffusion- Sorption- First Order Reaction Equation , Finite Volume , Finite Difference , Sensitivity Analysis