Building demolition and in-situ stabilization with in-situ chemical oxidation of tetrachloroethylene impacted clay
PROJECT SUMMARY
Site soils generally consisted of sandy clay with intermittent sand seams. High concentrations of tetrachloroethylene (PCE) were found in the soil and soil gas of the subject property and adjacent properties. A remedial design was necessary and driven by two exposure pathways: the volatilization to indoor air pathway (VIAP) and a long-term precautionary measure to address residential drinking water protection. The response activities chosen included a two-fold process involving excavation and disposal of non-hazardous surficial soils, followed by in-situ stabilization (ISS) and in-situ chemical oxidation (ISCO) via blending and soil mixing of remediation chemicals into the 3-22’ below grade treatment interval. Post remediation site soils are now reduced in PCE concentration by 75-80% and residual PCE is bound in a homogenous monolith of lower hydraulic conductivity soil with an unconfined compressive strength of 25-50 psi.
PROJECT HIGHLIGHTS
· Hazardous substances inventory and removal
· Asbestos Containing Materials (ACM) and Lead Based Paint Survey
· Removal of ACM, decontamination and removal of dry cleaner equipment, building demolition and air monitoring
· In-Situ Chemical Oxidation utilizing sodium persulfate –oxidant and sodium hydroxide
· The In-Situ Stabilization utilizing Portland cement rendered the soil buildable almost immediately, with an unconfined compressive strength of 25-50psi
· 75-80% reduction in PCE concentrations, with the residual mass being stabilized in place
