A change from ex-situ to in-situ remediation strategy achieves site closure

At a former metals manufacturing facility in upstate New York, historic use of chlorinated solvents had resulted in groundwater contamination with tetrachloroethene (PCE) and trichloroethene (TCE). A pump and treat system had been operational on the site for 10 years, successfully reducing contaminant concentrations, but could not reach the clean up targets required for site closure.

Benchmark, a leading engineering and redevelopment consulting company, quickly developed an in situ approach to achieve the project objectives and facilitate site closure. After evaluating remedial alternatives, Benchmark proposed a new Corrective Action Plan (CAP), specifying the in situ application of PlumeStop® (colloidal activated carbon), Hydrogen Release Compound® (HRC), a controlled-release electron donor, and Bio-Dechlor INOCULUM Plus® (BDI Plus), a bioaugmentation culture containing Dehalococcoides sp. and other beneficial microbes.

in-situ remediation

Case study highlights:

  • Based on successful performance results, a pump-and-treat system was decommissioned in 2020, and the NYSDEC granted the site closure in August 2021
  • By not having to operate and maintain the pump-and- treat system, substantial energy and cost savings were realized in this period
  • Benchmark’s agile site management, making the switch from an ex situ to a PlumeStop in situ approach, saved time and money for their client

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