TerraTherm has recently completed its final progress soil sampling effort of Phase 1 at the Solvents Recovery Service of New England, Inc. (SRSNE) Superfund site in Southington, Connecticut. The site's total target treatment zone covers an area of approximately 74,195 square feet and an approximate volume of 47,298 cubic yards; with Phase 1 and Phase 2 each comprising approximately half the treatment zone. Treatment depths vary across the site from approximately 15 to 32 ft bgs based on the actual bedrock surface identified during wellfield installation. The remediation goal is to remove NAPL in overburden soils (from ground surface down to bedrock, with 'NAPL removal' defined by meeting project-specific soil cleanup goals defined in the Remedial Design/Remedial Action Statement of Work (SOW)).
The contamination at SRSNE is the result of historical practices at the site. According to the EPA website, the site operated as an EPA-approved hazardous waste treatment and storage facility and received various waste industrial solvents that were blended for use as a fuel product. From approximately 1955 until closure of the facility in 1991, used solvents were received and processed to remove impurities. In 1990, the EPA began a remedial investigation (RI) to identify the nature and extent of environmental impacts resulting from the historical operations. The PRP Group (Group) completed the RI and evaluated In Situ Thermal Remediation (ISTR) in the Feasibility Study. ISTR was selected as part of the remedy for the site in a 2005 Record of Decision. The Group is implementing the remedy, and selected TerraTherm to conduct ISTR using thermal conductive heating.
Because of the potentially large chemical mass in the source zone (estimated in the FS to range from 500,000 to 2,000,000 lbs), thermal treatment was divided into two phases; Phase 1 and Phase 2, to flatten and spread the peak removal rate out over a longer duration than would be experienced on a single-phase thermal project.
Operations of Phase 1 continued after progress soil sample results were received in September 2014. At this point, the Phase 1 thermal wellfield had been at or above steam temperature for approximately four weeks. The preliminary data show excellent contaminant removal in all 32 samples. Final confirmation soil samples are currently being collected by the Group's consultants.
To date, approximately 400,000 lbs of contaminant mass have been removed from the wellfield with approximately 250,000 lbs from the Phase 1 area and 150,000 lbs from the Phase 2 area.