Montpelier delays costly PFAS fix for wastewater plant

This story by John Dillon first published On November 7th at the Bridge.

The city of Montpelier has shelved an ambitious but expensive plan to upgrade its wastewater treatment plant with technology that would remove hazardous chemicals from sewage sludge “forever.”

Faced with cost estimates ranging from $16.4 million to $32.4 million, the city council opted to move forward only with the preliminary phase of the project on October 23. This option allows the public works department to install equipment to dry sludge, reduce odors in the facility and make other improvements. But councilors delayed plans for more advanced equipment to superheat the waste to almost eliminate levels of per- and polyfluoroalkyl substances (PFAS).

The option the council chose would cost about $21 million. Mayor Jack McCullough stated that the city may install the more expensive technology at a later date. But with another bond vote required to cover the increased cost and the city’s budget already under pressure, McCullough said delaying the project was “almost a no-brainer.”

The decision means the city still has a PFAS problem. The wastewater treatment plant is the only facility in the state to accept PFAS-contaminated leachate from the Casella landfill in Coventry.
Public Works Director Kurt Motyka said an experimental pretreatment system installed in Coventry reduced levels of five different PFAS compounds in leachate by 89% to 94%. But because the chemicals are common in a range of consumer products, some PFAS still find their way into sewage sludge, even without Casella leachate.

Currently the city sends its sludge to Coventry landfill but pays a reduced rate because it also accepts Casella’s leachate. Motyka told the city council that without more advanced treatment, the city’s options for disposing of the sludge will be limited.

PFAS chemicals have been used in a variety of consumer products, from cosmetics to carpets to Teflon nonstick cookware. State and federal regulators have moved in recent years to restrict the use of PFAS as new evidence emerges that they are nearly everywhere in the environment.

In fact, a 2019 study for the state of Vermont found minuscule levels of PFAS in every soil sample tested from 66 sites around the state. Researchers believe these background levels are likely due to atmospheric deposition, as chemicals released by industry are transported long distances by wind.

The compounds are known as “forever chemicals” because they break down very slowly in the environment. They are linked to a number of health problems, including cancer, low birth weight, high cholesterol and damage to the immune system.

“These things are available everywhere,” says John Brabant, a former environmental regulator with the Agency of Natural Resources who now works with the advocacy group Vermonters for a Clean Environment.

Sewage sludge has been a significant source of PFAS pollution. Sludge, known as “biosolids” in the waste industry, was routinely applied to agricultural fields as fertilizer. The state of Maine banned the application of sewage sludge to land after fields and farms became contaminated. Vermont still allows sludge to be applied to land but has strictly limited its application. Massachusetts and New Hampshire are also considering banning the application of sludge to land.

Since 2019, the Vermont Department of Environmental Conservation has required testing of soils to which sludge is applied, as well as groundwater near sites. The state found PFAS levels exceeded state standards in 31 of 138, or 23%, of groundwater monitoring wells. But to date, officials say no drinking water sources have been affected by PFAS from land-applied sludge.

Montpelier’s mud does not spread over the fields. Public Works Director Motyka said that the first phase of the project to dry the sludge will reduce disposal costs as the volume of the material will decrease. He said drying the sludge could give the city other options, such as spreading the sludge on land.

“We could have the potential to apply (sludge) to land by just doing the drying process (that’s the component that breaks down PFAS) without secondary advanced heat treatment. But we would still have to go through the permitting process for that,” Motyka told council.
Whether the city would get approval to spread the sludge without the system to break down PFAS is another question. The state has drafted rules that will limit land application to areas where applied sludge does not exceed background levels in the soil.

“Almost all of our sludge will have PFAS,” said Eamon Twohig, director of the Vermont Residues and Emerging Contaminants Program. “The goal is basically to keep Vermont soil levels at – quote unquote – ‘background’ levels and not increase those levels.”

Advanced thermal processing breaks down the carbon bonds in PFAS chemicals, reducing PFAS to undetectable levels, Motyka said. The state had promised a grant of $2 million for the technology. But Motyka told the council that much more state funding is needed to help the city deal with what is essentially a statewide problem. The city’s wastewater plant treats two-thirds of the waste pumped from septic tanks in Vermont and two-thirds of the septic waste from out-of-state sources, he noted.

“This is a regional problem,” he said. “We’re trying to solve a PFAS problem well beyond Montpelier, so I’m hoping there will be an opportunity to get a lot more grant funding to make this project more feasible.”