EVALUATION OF REMEDIATION METHODS ON GROUNDWATER CONTAMINATION IN A SHALLOW GLACIAL AQUIFER FROM COAL STORAGE

Ball State University (BSU) kept a large coal reserve until the installation of a ground-source, district-scale geothermal system was completed in 2014. Environmental and regulatory concerns in the 1990s prompted BSU to improve its coal storage area, however prior to these improvements in 1996, BSU’s coal reserve was in direct contact with the ground leading to decades of polluted storm water runoff and leachate into shallow groundwater of a glacial till aquifer system.

 

Research in the 1990s including electrical resistivity, seismic profiles, and water samples from shallow wells was conducted to determine the extent to which pollution had spread, and results indicated that pollution had followed a drainage ditch to the west, as well as a plume of higher-conductivity groundwater travelling to the northwest from the coal pile. Conductivity and sulfate values as high as 1,107 µS/cm and 170 mg/L were measured in the aquifer at that time. Current research using water samples and improved electrical resistivity tomography has measured conductivity and sulfate values as high as 1,388 µS/cm and 740 mg/L respectively, while electrical resistivity profiles show areas of lower apparent resistivity (30 ohm-m for 6 meter electrode spacing) in the same locations as those measured more than two decades ago. This evidence confirms that pollution is still present in the shallow subsurface, and that the passage of time may have had no discernible effect on removing the pollutants.