A closure-based in-situ chemical oxidation (ISCO) remediation was conducted at a former gas station in Southern Alberta to address BTEX, F1, F2, and PAH contamination in 6,630 m³ of impacted soil, bedrock, and groundwater, including off-site impacts beneath residential properties. Due to infrastructure constraints and vapour risks, a Remediation Train® approach was implemented, starting with a soil vapour extraction (SVE) and air sparge system, followed by a ISCO program with a 3-meter injection radius. Nested injection wells targeted various depth intervals, with careful scheduling around residential activity. Over 45 days, 1.6 million liters of 10% EHP (enhanced hydrogen peroxide) was injected using TRIUM’s ChemOx® process, achieving daily blend volumes of >35,000 L. The treatment successfully met regulatory groundwater quality guidelines, managed vapour risks, and was recognized as an industry-leading process by consultants, with no negative impact on the community.
Historical operations in the area had impacted soil and groundwater, extending off-site beneath residential properties. Infrastructure currently in place greatly limited the remedial strategies available. Soil comprised of sands/gravels. Vapour mitigation and management were critical to managing risk to neighbours.
A Remediation Train® approach was utilized with a soil vapour extraction (SVE) and air sparge system initially applied followed by an in-situ chemical oxidation (ISCO) program.
The ISCO program is based on 3 meter injection radius of influence to increase contact certainty between the oxidant and the contaminants. Injections were conducted using nested injection wells to target various depth intervals. Injections had to be planned around residential schedules and incorporate “children playing” in backyards.
Over 45 days, injected 1.6 million litres of blended 10% EHP (enhanced hydrogen peroxide) oxidant. Blending is site specific following TRIUM’s ChemOx® process, with blend volumes of >35,000 L per day being achieved.
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