EPA Research Partner Support Story: Suitable groundwater remediation
Partner: New Hampshire Department of Environmental Services (NHDES)
Challenge: Suitable groundwater remediation technologies at the South Municipal Supply Well Superfund Site
Resource: Technology transfer and technical support for permeable reactive barrier & thermal remediation
Project Period: 2009 – Present
The South Municipal Water Supply Well Superfund Site located in Peterborough, New Hampshire, includes the New Hampshire Ball Bearings (NHBB) property, adjacent wetlands, commercial/residential properties, and the South Municipal Water Supply Well. Installed in 1952, the South Well provided water to Peterborough for nearly 30 years. In 1982, concentrations of volatile organic compounds were detected in the South Well at levels above 100 parts per billion and use of the well discontinued. Initial groundwater and soil cleanup actions at the site included in-situ vacuum extraction and groundwater pump-and-treat using air stripping and carbon adsorption. In 2010, revised groundwater remedies were initiated to include a combination of two treatment technologies: 1) thermal remediation within targeted source areas, and 2) in-situ groundwater treatment using a zero-valent iron permeable reactive barrier (PRB).
"EPA ORD personnel have provided invaluable technical support to the South Municipal Well government team.” – NHDES Waste Management Division, Kenneth Richards
NHDES and EPA Region 1 (New England) first requested EPA ORD technical assistance in 2009 for information on innovative remediation technologies, including thermal, enhanced bioremediation, and PRB applications. Technology transfer efforts by ORD personnel resulted in recommendations on bench-scale studies, site characterization and monitoring requirements, and implementation of the thermal and PRB remedies. In 2014, the PRB was installed along the alignment of the former Boston & Maine Railroad (B&M) line to intercept and treat groundwater contaminants emanating from the eastern NHBB property line. Thermal remediation using Electrical Resistance Heating technology was completed in 2016. Approximately 5,000 pounds of tetrachloroethylene (PCE) were removed from the subsurface. ORD personnel continued to provide technical assistance to the NHDES and EPA Region 1 teams by helping to determine the effectiveness of the thermal and PRB remedies, and in determining the location of other source areas that require treatment.
Groundwater data show that the original PRB failed to meet specified treatment criteria. A new PRB has been designed and installed. Current ORD technical support efforts include assistance in interpreting site groundwater data; recommendations on pilot study designs for characterizing groundwater flow and enhanced biodegradation potential.
Additional information can be found on the South Municipal Supply Well Superfund Site profile.