This story by John Dillon was first published in The Bridge on November 7.

The city of Montpellier has abandoned an ambitious but costly project to upgrade its wastewater treatment plant with technology that would “forever” eliminate dangerous chemicals from its sewage sludge.

Faced with cost estimates that increased from $16.4 million to $32.4 million, the municipal council chose on October 23 to proceed only with the preliminary phase of the project. This option allows the public works department to install equipment to dry sludge, reduce odors at the plant and make other improvements. But councilors delayed plans for more advanced equipment that would superheat waste to virtually eliminate levels of per- and polyfluoroalkyl substances (PFAS).

The option chosen by the council will cost approximately $21 million. Mayor Jack McCullough said the city may install the more expensive technology at a later date. But with another bond vote needed to pay for the increased costs — and the city’s budget already under pressure — delaying the project “all adds up almost like a no-brainer,” McCullough said.

This decision means the city still has a PFAS problem. Its wastewater treatment plant is the only one 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 the levels of five different PFAS compounds in leachate by 89% to 94%. Yet because the chemicals are ubiquitous in a range of consumer products, some PFAS still end up in sewage sludge, even without Casella’s leachate.

Currently, the city ships its sludge to the Coventry landfill but pays a reduced rate because it also accepts leachate from Casella. Motyka told the City Council that without more advanced treatment, the city’s options for disposing of the sludge remain limited.

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

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

These 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.

“This stuff is so pervasive,” says John Brabant, a former Natural Resources Agency environmental regulator who now works with the advocacy group Vermonters for a Clean Environment.

Sewage sludge is a major source of PFAS contamination. The sludge – known in the waste industry as “biosolids” – was regularly spread on agricultural fields as fertilizer. The state of Maine has banned the spreading of sewage sludge after fields and farms become contaminated. Vermont still allows sludge spreading but has strictly limited its practice. Massachusetts and New Hampshire are also considering bans on land application of sludge.

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

Montpellier sludge is not spread on agricultural fields. Public Works Director Motyka said the first phase of the project to dry the sludge would reduce disposal costs because the volume of materials would be reduced. Drying the sludge could also give the city other options, such as spreading the sludge on the land, he said.

“By doing just the dryer without doing the secondary advanced heat treatment – ​​this is the component that breaks down PFAS – we would be able to spread the sludge onto the ground. But for that, we will still have to go through the permitting process,” Motyka told the council.
Whether the city would get permission to land sludge without the system that destroys PFAS is another question. The state has drafted rules that would limit land application to sites where the applied sludge does not exceed background levels in the soil.

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

Advanced heat treatment breaks the carbon bonds in PFAS chemicals and reduces PFAS to non-detectable levels, Motyka said. The state had promised a $2 million grant to finance this technology. But Motyka told the council that much more state funding is needed to help the city manage what is essentially a statewide problem. He noted that the city’s wastewater treatment plant treats two-thirds of all Vermont wastewater — that is, waste pumped from septic tanks — as well as wastewater from outside sources to the state.

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