COMPUTER MODELING OF GROUNDWATER CONTAMINATION CAUSED BY LANDFILL LEACHATE SEEPS

Solid waste landfill leachate poses a known threat to various environmental media, including groundwater. It forms as rainwater percolates through the wastes sequestered in a landfill, leaching out dissolved organic compounds, nutrients, inorganics, greenhouse and explosive gases, pathogens, etc. This study uses computer modeling to compare the geometry of groundwater contamination plumes caused by subsurface point-source releases (i.e., landfill liner holes or small tears) to those resulting from leachate-seep releases at the surface. The latter allows contamination to move quickly over longer distances in ditches and streams, and infiltrate into the subsurface (to shallow groundwater) all along the way, particularly in areas where natural clay layers have been excavated for landfill construction materials. This presentation compares theoretical contaminant transport modeling results to actual groundwater contamination data at a landfill using per- and polyfluoroalkyl substances (PFAS) compounds as a tracer.