Groton — Plans for remediating polychlorinated biphenyls, or PCBs, at the water treatment plant that is undergoing renovations, are heading back to the drawing board.

The Environmental Protection Agency said the plan proposed by the utility’s construction manager to remediate PCBs in the old paint doesn't meet the EPA's standards, according to Mark Biron, Groton Utilities general manager of operations for water and electric. In addition, a pile of 3,500 cubic yards of potentially PCB-contaminated soil, which is covered and contained in back of the operations building, also will need to be addressed, he said.

Construction has been ongoing on the upgrade project to repurpose the water treatment plant, built in 1939 and expanded over the years, while building a new facility, adjacent to the old plant, to treat and process water. Groton Utilities officials said window caulking, paint in the walls and paint on some of the piping in the old water treatment plant contain PCBs. No PCBs were used in the new building.

Biron and City Mayor Keith Hedrick, the chairman of the Groton Utilities Commission, said there is no risk of exposure to PCBs, either to employees during normal operations of the plant, or to users of the water supply.

The project's construction manager is expected to develop a new remediation plan in the next couple of weeks, Biron said, so costs and the exact remediation schedule have not yet been determined.

PCBs in old paint, caulking

PCBs can be found in some paint, caulking, plastics, transformers, electrical equipment, thermal insulation, and tapes, among other items manufactured prior to 1979, when PCBs were banned, according to the EPA.

Biron said Stantec, the construction manager on the project, originally proposed a "risk-based assessment" plan to remediate the PCB-contaminated paint in the old treatment plant, but leave paint in areas above 10 feet that were out of reach of people.

Biron said that after Stantec had submitted its plan, Groton Utilities management had questions about it and contacted a third-party consultant to review the plan. Groton Utilities raised concerns with Stantec and then the utility called a meeting with the EPA. The EPA, state Department of Energy and Environmental Protection and state Department of Public Health toured the facility last month and the EPA clarified that there is no regulatory process for the risk-based assessment and that all the old paint needs to be removed, he said.

Another issue is that soil on the outside of the plant was scraped up and put in a big pile, Biron said. Some of the dirt contained window caulking with PCBs in it, so the proper procedure would have been to sample individual sections of dirt for PCBs and then clean up that section of soil, if contaminated, rather than mix all the soil together in a pile, he said.

The resolution, he said, will be to submit a sampling plan to the EPA. Depending on the level of PCBs, the soil either will be sent to a hazardous waste facility, or, if the levels are below regulatory limits, potentially re-used.

"We have a way forward on that," Biron said. "It's not a threat to the public. We're not exceeding the concentrations in an industrial area."

Hedrick said the pile is covered and contained, so runoff is not an issue.

In an emailed statement, a Stantec spokesperson said: "Remediation plans for this project had been developed according to what has been reasonably expected by the EPA for conditions of this type, with the expectation of an iterative process that would require refinement following regulator review — as is typical for this type of work. In consultation with the EPA, we are proceeding along on a course to complete this work and look forward to continuing to support Groton Utilities in delivering a project that best addresses the needs of the community into the future."

R.H. White, the general contractor for the project, said requests for information should be directed to Groton Utilities.

DEEP spokesperson Kristina Rozek said the proposed plan was not consistent with other PCB cleanup plans approved by the EPA and a revised plan will need to be submitted. She said PCBs in building materials and in soils adjacent to the materials with PCBs are common in these types of municipal water and wastewater facilities, and it's also common for plans to go through a number of revisions before being approved.

EPA and DPH officials were not immediately available for comment.

New remediation plan

Stantec will be devising a new remediation plan, which Groton Utilities will have an opportunity to be actively involved in reviewing, Hedrick said. The plan will next go to the EPA, DEEP and DPH for approval.

Biron said Groton Utilities does routine testing of the water supply and PCBs are nondetectable in the water. He said air sampling and swipes of the walls also came back nondetectable.

As a precautionary measure, stickers were placed on the walls in areas with PCBs in the old plant to serve as a reminder to employees, Hedrick said.

Biron said PCBs only would become an issue if a surface is disturbed. When workers do activities, such as sanding, drilling or grinding materials containing PCBs, it's in a controlled environment. They follow all the Occupational Safety and Health Administration requirements, including wearing protective clothing and protecting their skin, face and eyes, and use a filter to suck up the particles.

The exact cost of remediation of the PCBs won't be known until the new plan is submitted, Hedrick said.

The approved cost of the overall project to upgrade the water treatment plant is $54 million, and the upgrade project will not exceed that, Hedrick said. "In order to achieve that, we are doing engineering determinations to determine which projects will fall out of scope of the current project," he said, "and will be completed in the future through the Capital Improvement Project program and operations and maintenance dollars for the plant."

Hedrick said remediation will be a long-term, phased approach, though the exact timeline will be known once the plan is created. Biron said the new remediation plan is expected in the next couple of weeks.

Biron said that while resolving the issue may cause some construction delays, he believes Groton Utilities will be able to start operations at the facility while continuing remediation. The water treatment facility is scheduled to begin flowing water by the end of the first quarter this year and to be fully operational in the fall or early winter.

Hedrick said the new portion of the plant — once it is ready — will be operational and producing millions of gallons of water a day, while PCBs in the old plant will be remediated.

Biron said the water flows through a closed system, so it is not affected by PCBs or remediation work.

k.drelich@theday.com