A Cost-Effective approach to In Situ Remediation of Soil and Groundwater at a Diesel Fuel Spill Site

A bioventing and groundwater treatment system designed to enhance the natural biodegradation of diesel fuel residuals in soil and prevent further groundwater degradation was installed at an underground storage tank (UST) facility in Pittsburgh, Pennsylvania. The combined soil and groundwater remediation system operates by pumping groundwater from a single point within the central area of the plume, exposing petroleum hydrocarbon impacted soils at the capillary fringe to air supplied from a single vertical injection point. Groundwater is treated at the surface by activated carbon and discharged through a permitted outfall to the muncipal sewer system. Based on data collected during the first ten months of full-scale system operations, the addition of ambient air has increased the oxygen supply in the subsurface and significantly enhanced the aerobic biodegradation of diesel fuel residuals in the soil to a depth of greater than 30 feet.