BTEX TPH Remediation Case Study
|
In 2007, Emitters were installed to clean up a former gas station site in Guelph, Ontario. The contaminant plume containing gasoline and diesel occurred in unconsolidated silty sand to a depth of approximately 3 m (10 ft). The initial plume stretched 30 m (100 ft) long and 15 m (50 ft) wide.
Migration towards down gradient receptors was a concern; therefore
a solution that worked quickly and effectively was required to help eliminate the potential for exposure. A total of 14 Waterloo Emitters using LDPE tubing were installed in 4" wells screened at and below the water table. Emitters were placed to form a “fence” along the down gradient property boundary to cut off the contamination plume. Dried air containing 21% oxygen was released through the tubing.
|
|
During the remediation process, Dissolved Oxygen (DO) samples were collected on a monthly basis and groundwater samples for BTEX and TPH were collected quarterly from down gradient wells. Within one month of the installation, DO levels in the monitoring wells increased an average of 880%.
Initial TPH levels were a maximum of 27 mg/L (average 9.6 mg/L) and initial BTEX levels were approximately 11 mg/L. Within six months, results showed that the levels of BTEX and TPH had dropped below the analytical detection limit, meeting the Soil, Ground Water and Sediment Standards of the Ontario Environmental Protection Act, thus enabling the Emitter system to be decommissioned just one year after the installation. Please see Papers & Info for more case studies, papers and resources. |