Next attempt to remediate South Municipal Water Supply Well set to start in June

  • The Peterborough Town House STAFF FILE PHOTO BY BEN CONANT

Monadnock Ledger-Transcript
Published: 11/25/2022 12:48:52 PM

Another attempt to remediate the South Municipal Water Supply Well in Peterborough that was contaminated in the early 1980s will start in June 2023, providing that EPA approvals are granted. 

The well is a Superfund site that was installed in 1952 and provided water to Peterborough for nearly 30 years until 1982, when it was found to contain industrial solvents from New Hampshire Ball Bearings.

Chris Rawnsley, director of safety, environment and sustainability at New Hampshire Ball Bearings (NHBB), recently told the Select Board he has been coming to give these presentations since the late 1980s.

“I’d be much happier to come down and tell you that this isn’t where we are,” he said, adding that it was appropriate to do this now because of the project to remediate the well. “Part of the Superfund process is to update the town every four or five years.” 

Rawnsley said NHBB has done a substantial amount of work over years to remediate the contamination, but that unfortunately the problem still exists. In 2005, he said, it was thought the problem had been remedied, but long-term pump tests showed it hadn’t.

“Since 2010 we’ve been implementing new actions,” he said, referring to a permeable reactive barrier (PRB) installed in 2016 that ultimately didn’t meet its performance goals. “We’re currently designing a new one and will be installing that next spring.”

Superfund designation allows the Environmental Protection Agency (EPA) to clean up contaminated sites and forces the parties responsible for the contamination to either perform cleanups or reimburse the government for EPA-led cleanup work.

The approximately 250-acre Superfund site includes the South Municipal Water Supply Well and nearby commercial and residential properties along Sharon Road, a portion of the Contoocook River and U.S. Route 202, the adjacent wetlands and New Hampshire Ball Bearings.  

Thousands of contaminated sites exist nationally due to hazardous waste being dumped, left out in the open or otherwise improperly managed. These sites include manufacturing facilities, processing plants, landfills and mining sites.

Rhiannon Scott of Geosyntec Consultants was joined by representatives from the New Hampshire Department of Environmental Services and EPA representatives at the Select Board meeting. Scott provided a summary of the most-recent PRB to be installed on NHBB property. 

“The PRB is basically a wall,” Scott said, explaining that it acts as a reactive filter using zero-valent iron (ZVI) which serves as a reducing agent after creating a chemical reaction. “As water passes through the PRB and the ZVI the water interacts – destroying contaminants – and clean groundwater exits on the other side.” 

The PRB that will be installed, she continued, will be 450 feet long and 60 feet deep and will be installed with a large-diameter drill rig that will insert hollow cylinders down to the bedrock. The soil inside the cylinders will be replaced with iron next to sand, Scott said.

A previous attempt that also used iron involved a different installation technique, Scott said.  That technique involved injecting the ground with a drill rig.

“It does work in some geologies but it’s harder to control where iron is being used,” and by 2017 and 2018, Scott said it wasn’t clear whether it was working. Scott said it will take two years to know whether the newest PRB is working.

The Select Board was informed that there will be increased traffic for deliveries coming in to the construction site, but Scott said she doesn’t think this will be significant except on days when the company is mobilizing and demobilizing equipment.

Progress using the latest PRB should be made fairly quickly, Scott said, “But there will be an equilibrium period to change what’s been going on for 40 years.”

Scott explained that contaminated soil will be mixed with the PRB and that the remainder will be sent to permitted facilities that can accept the waste.

Rawnsley was asked by the Select Board what will happen next if the proposed PRB fails.

“I don’t know if we’ve considered that yet,” Rawnsley said. “The town people are important stakeholders and we want them to understand what we’re doing.” 

Selectman Bill Taylor spoke about the ongoing process of remediation and the cost.

“I’m sorry to hear that this has to go on,” he told Rawnsley. “It sounds expensive.”

Rawnsley said, “It is but we’re committed to seeing it through.”

Peterborough’s New Hampshire Ball Bearings sued two companies it contracted after an environmental barrier they constructed in 2014 failed to reduce groundwater contaminants in the South Well Superfund Site. NHBB paid about $13.6 million to construct the barrier, a NHBB representative told the Ledger-Transcript in 2015. 

NHBB’s proposed timeline for the latest attempt to remediate the well will begin with the selection of a construction contractor in February 2023, followed by a final design report submitted to the EPA in March, an anticipated approval by the EPA in April and mobilization of the site in June. 


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