Hallowell to build $10 million PFAS filtration plant by 2027

Following concerns from residents about chemical levels in Hallowell’s drinking water, the Hallowell Water District is working on long-term solutions.

By the end of 2027, the district hopes to build a $10 million facility that will eliminate detectable chemicals, or PFAS, from the city’s drinking water. Exposure to PFAS, even at low levels, has been linked to health problems, including some types of cancer and developmental delays in children.

In April, the EPA set the first-ever nationwide standard to regulate PFAS in public water supplies. By 2029, drinking water systems must contain less than 4 parts per trillion of each of the two most common types of PFAS.

For each of the major types of newly regulated PFAS chemicals, PFOA and PFOS, Hallowell drinking water contains about 7 parts per trillion, nearly twice the EPA’s 2029 standard. When the Hallowell Water District last tested its aquifer in 2023, the overall PFAS level was 14.4 parts per trillion and has reached 18.8 parts per trillion since the district began requiring testing in 2022.

In an April press release, the Environmental Protection Agency said that while PFAS should ideally be completely eliminated from the environment, the lowest possible standard at which this rule could be effectively implemented is 4 parts per trillion.

“This (regulation) reflects the latest scientific research that proves there is no level of exposure to these contaminants without risk of health effects, including some cancers,” the press release reads.

While the state reviews the new EPA rules, its maximum regulatory level of 20 parts per trillion will remain in effect. The state has said it will adopt standards at least as stringent as the 4 parts per trillion in the EPA regulation.

The EPA has estimated that 6% to 10% of the nation’s roughly 66,000 public drinking water systems will have to lower PFAS levels to comply with the new rules. Hallowell Water District is part of that group.

Hallowell draws its public drinking water from two wells tapping the Chelsea aquifer. The aquifer is partially supplemented by the Kennebec River, which contains PFAS levels of up to 25 parts per trillion, according to Zach Lovely, superintendent of the Hallowell Water District.

Lovely says that while natural filtration of water into the aquifer typically traps other contaminants, it is only about 50% effective at capturing PFAS from the Kennebec River.

Lovely, who is also director of the Gardiner Water District, said Gardiner’s drinking water is not as heavily dependent on the Kennebec River and that PFAS levels are well below the new EPA standards.

He said the Hallowell Water District has already raised $8.2 million in grants toward about $10 million to build a PFAS filtration plant. The district hopes to complete construction of the plant by the end of 2027 — two years ahead of the EPA compliance deadline.

After a months-long search for an engineering firm that began last fall, the district hired Wright-Pierce in May to design and build a facility that Lovely said would reduce PFAS levels in Hallowell’s drinking water to undetectable levels.

“We had a number of engineering firms reach out to us with questions, but many of them didn’t have the resources or the manpower to take on the PFAS facility in Hallowell,” Lovely said. “We ended up getting one (proposal) that came from Wright-Pierce, which has a lot of experience with different water districts.”

Wright-Pierce has built several PFAS remediation facilities in New England and is currently overseeing construction of a PFAS treatment facility in Acton, Massachusetts.

The Water District would cover costs not covered by grants or other funding sources through rates paid by customers.

The final PFAS filter plant will have to deal with iron and manganese in Hallowell’s water, which could cause the ion exchange system commonly used in PFAS filtration to degrade more quickly. The plant will require a filtration step prior to ion exchange, adding to the project’s cost and engineering complexity.

“We’re testing four compounds,” Lovely said. “These four compounds are being tested basically to see what would be the best option for the water district to clean up the PFAS, given the characteristics of the water.”

Lovely said the rest of this year will be used to finalize that testing. He said he expects next year will be used for the design process with Wright-Pierce and to begin accepting bids for construction services, while 2026 and 2027 will be used for construction.