Characterization of an old municipal landfill (Grindsted, Denmark) as a groundwater pollution source: landfill hydrology and leachate migration

The migration of leachate from an old municipal landfill (Grindsted, Denmark) was investigated by intensive mapping of groundwater potentials and groundwater quality at the downstream borders of the landfill and beneath the landfill. A groundwater mound controlling the migration of the leachate into the aquifer was observed beneath the landfill, especially after the wet season The lateral spreading in the leachate plume was significantly increased due to the water table mound present and the seasonal variations of the mound. Also, a significant vertical transport of leachate in the aquifer was observed below the landfill. Detailed information about the spatial and seasonal changes in groundwater flow directions and location of intensive leaching is needed in order to design a cost effective delineation of the plume in the downstream aquifer and to establish appropriate remediation.