The South Municipal Water Supply Well Superfund site is located approximately two miles south of downtown Peterborough. The South Municipal Water Supply Well was installed in 1952 and provided water to the town of Peterborough for nearly 30 years. The New Hampshire Ball Bearings (NHBB) manufacturing facility, located about 1,200 feet west of the South Well, has manufactured ball bearings at the Site since 1957.
In October 1982, a study conducted by DES identified NHBB as a potential source of contamination found in the South Well. Under an administrative order issued by the EPA on July 22, 1986, NHBB agreed to conduct a remedial investigation/feasibility study (RI/FS) under the supervision of EPA and DES. The field studies for the RI/FS began in August 1986 and were completed in March 1989.
EPA's September 1989 Record of Decision (ROD) for cleaning up the Site consisted of cleaning contaminated soils on the property by vacuum extraction and installing a groundwater pump and treat system to clean contaminated groundwater at the Site. A third component of the cleanup plan required excavating contaminated sediments from a small on-site wetland area near the NHBB plant for removal to a permitted hazardous waste disposal facility.
Construction activities were completed in mid-December 1993, with start-up and commissioning of the treatment system in January 1994. Cleanup of the sediments in the wetlands was completed in late fall of 1994. The impacted wetlands were re-vegetated so as to achieve a similar plant density/diversity in comparison to the adjacent wetland. The re-vegetation project was completed in the spring of 1995.
EPA and DES issued an Explanation of Significant Differences in the winter of 1997 that explains a technical impracticability (TI) waiver for the portion of the Site immediately adjacent to the NHBB facility. Due to the presence of contamination in the form of Dense Non-Aqueous Phase Liquids (DNAPL), and the limitations of available remedial technologies, it was deemed technically impracticable to achieve groundwater cleanup goals in the area of the DNAPL in the foreseeable future. There are currently three groundwater extraction wells operating at the Site to contain contaminated groundwater within the "waiver area" on NHBB property. Also, a Groundwater Protection Overlay Zone has been established to facilitate the management of the contaminated groundwater.
DES's Drinking Water Source Protection Program worked with NHBB and the town of Peterborough to provide approval for use of the South Municipal Well as a drinking water source. NHBB and the town entered into an agreement in late spring 2003 to begin reactivation of the South Well. The agreement, in part, established protocols and communication procedures between NHBB and the town in the event that volatile organic compounds (VOCs) migrated beyond capture zones for NHBB's containment system during the pumping of the South Well. A regular preventive maintenance