Remediation of PCE Impacted Soil and Groundwater Beneath a Shopping Centre in Edmonton, Alberta
Halogenated ethenes such as tetrachloroethylene (PCE) and trichloroethylene (TCE) are among the most common groundwater contaminants. A variety of remedial approaches have been developed to address impacts from halogenated ethenes ranging from monitored natural attenuation to excavation and disposal at off-site facilities. One approach to addressing groundwater and soil impacts from PCE and TCE is in-situ chemical oxidation (ISCO). This approach involves treating the soil and groundwater, usually in-situ, with a chemical oxidant. Various oxidants are available including ozone, hydrogen peroxide, hypochlorites, Fenton’s Reagent, and potassium and sodium permanganate.
At an active commercial mall in Edmonton, Alberta, ISCO was used to treat soil and groundwater impacted by PCE and its dechlorination byproducts, TCE, DCE, and vinyl chloride. The oxidant, potassium permanganate, was delivered passively to the impacted media via a series of horizontal weeping tiles and vertical injection wells that were installed below the existing floor.
The results of the injection program, which was carried out over a six-month period, reduced the soil and groundwater concentrations of PCE by greater than 98%.
The application of the ISCO system allowed the owner of the mall to complete the transaction while providing a 60% cost savings over another recommended remedial approach.