The former Dry Cleaner site was located in Redwood City, California, contaminated by tetrachloroethylene (PCE). Affected soils also contained low levels of PCE degradation byproducts, such as trichloroethylene (TCE), and were presumed to have an approximate extent of 384 square feet (16’ x 24’ area) to a depth of 10 feet beneath the building. The remediation goal was driven by vapor intrusion risk requiring final levels to be below commercial soil gas screening criteria.
GEO’s patented GTR™ system was used for In Situ Thermal Remediation (ISTR) to significantly accelerate PCE mass removal by heating affected soils and/or groundwater to target temperatures of 100°C. The C3 Technology refrigerated vapor condensation process was utilized to compress, refrigerate, and condense >99.9% of the PCE and TCE from the vapor stream. The combination of ISTR and C3 technology enabled volatilization of PCE from subsurface soil and groundwater, and condensation of PCE above ground rather than transfer to the atmosphere or onto activated carbon destined for landfill.