Location: Winthrop, MA

Project Description

  • Tetrachlorothene (PCE) release to soil, groundwater, soil gas, and indoor air at multiple commercial and residential buildings.
  • Subslab Depressurization System (SSDS) installed under day care center. Soil excavation completed in former dry wells. In-Situ Chemical Oxidation (ISCO) conducted in source area.
  • Soil gas points and vapor monitoring points installed below three buildings. Indoor air and soil gas screening and sampling completed.
  • MassDEP conditional approval required Soil Vapor Extraction Pilot Test and a detailed Feasibility Evaluation in accordance with 310 CMR 40.0860.

Services provided by OHI

  • Conducted Pre and Post soil gas surveys.
  • Conducted Soil Vapor Extraction (SVE) Pilot Tests on two wells adjacent to the building. The test was conducted in 15 inches of water column (IWC) steps. Vacuum influence measurements were collected in 20 points at 15 minute intervals.
  • Influent concentrations, flow rates, vacuums, and pressures were collected for system design. Measurements indicated vacuum control under the building was not feasible given the age and condition of the floor/foundation without completely demolishing rebuilding internal structures.
  • The Feasibility Evaluation demonstrated alternate technologies were more feasible.