Soils consist of clays and silts with sandy fill materials over weathered shale bedrock. Bedrock is encountered at 3 feet below ground surface (bgs) and groundwater is present within the bedrock.
Targeted Environmental Media:
 Dense Non-aqueous Phase Liquids (DNAPLs) - Fractured Bedrock
Not identified in the references cited.
Major Contaminants and Maximum Concentrations:
- Tetrachloroethene (0 µg/L)
No technologies selected.
- Chemical Oxidation (In Situ)
Comments:
The in situ remedial technology is called Perozoneý and consists of the injection of gas phase ozone and hydrogen peroxide (aqueous). The two oxidants are introduced into the subsurface through sparge points that are designed to form microscale hydrogen peroxide-coated bubbles of ozone. The injection system functions continuously and between sparge points, repeatedly cycling the injections. The system operated for a 3-month pilot and was then implemented full-scale.
CVOC provincial criteria ý 17 ug/L
Review of groundwater VOC analytical data obtained throughout the 3-month pilot test indicated that the technology had a significant radius of influence and the potential to lower chlorinated VOC concentrations if implemented at the full-scale.
After a year and a half of full-scale application, off-site property objectives were met and PCE within the groundwater on site met the provincial criteria. Groundwater PCE levels were sufficiently decreased in order to implement a risk assessment that indicated further action through limited vapor mitigation measures.
References:
Strajin, Darko. 2011. Treating Chloroethenes in Shallow Fractured Rock. From The 21st Annual International Conference on Soil, Water, Energy, and Air. March 14-17, 2011, San Diego, California.
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