
Previously excavated soil was stockpiled on-site. Contaminants in the soil included BTEX, F1, and F2. A total of 1,900 m3 of low to moderate PHC impacted mineral soil was stockpiled and 600 m3 of heavily contaminated organic/ topsoil was stockpiled separately.
Mineral soils and organic soils were segregated due to high variability amongst the two piles for PHC concentrations. A specialized mulcher was used for the project in order to ensure the greatest contact between the oxidant and the impacted soils.
Mineral soils had a total of three passes with 56,150 kg of 50% EHP (enhanced hydrogen peroxide) applied. Pilot test on the organic soils had a total of three passes and 3,600 kg of 50% EHP (enhanced hydrogen peroxide) applied.
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 litres 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.