A Vermont waste management company has been testing a system to remove toxic man-made chemicals known as PFAS from wastewater at the landfill it operates in Coventry.
Casella says the on-site treatment system is one of the first of its kind in the country to remove what are known as “forever chemicals” from leachate, the contaminated liquid that accumulates when water runs through waste in landfills. But local environmental advocates have raised concerns the system may be pumping those chemicals into the air, potentially polluting soil and water in surrounding communities.
They say a draft air pollution permit the state recently issued doesn’t do enough to address these risks.
Casella has been developing — and using — this technology at Vermont’s only open landfill for a few years, at the direction of state regulators, without an air quality permit in place. State officials argued the need to remove PFAS chemicals from landfill wastewater was so urgent, the project should proceed before the permit could be finalized.
Now, regulators have announced they do not plan to require Casella to test emissions from the Coventry facility to see if PFAS are escaping into the surrounding air — nor will they set limits on potential PFAS emissions.
That’s sparked more concern from advocates, who are urging people to participate in a public comment period about the permit this month.
“The people in the Northeast Kingdom are entitled to accountability,” said Ed Stanak, who is vice chair of the local environmental group Don’t Undermine Memphremagog’s Purity, or DUMP. “We felt all along, and still feel, that when it comes to that landfill, the state policy by default is out of sight, out of mind. Ship it to the Northeast Kingdom.”
Vermonters send PFAS to the landfill in a near constant stream of manufactured goods — in discarded clothing, furniture, cookware and carpets.
The compounds are very difficult to destroy, and are linked to cancers and other health issues.
Casella sends much of the leachate from the Coventry landfill to get processed at a wastewater treatment plant in Montpelier, where it’s ultimately released into the Winooski River. But wastewater treatment plants can’t filter PFAS out of leachate, so these chemicals end up polluting Vermont’s waterways. That’s why state regulators tasked Casella with developing a way to remove them from leachate in 2022.
Company officials say the pilot is a crucial step towards protecting Vermont’s environment from these pernicious toxins, even as the state begins to ban them from new commercial goods.
“We’re going to be dealing with these compounds for the next 20, 30 years, as people continue to put them into our waste stream,” said Sam Nicolai, Casella’s vice president of engineering and compliance. “So they have to be managed. They have to be dealt with. This system is doing exactly that.”
The system Casella has been testing pumps air into the wastewater and traps the PFAS compounds on the resulting bubbles that rise to the surface, creating a concentrated foam. Locals with Don’t Undermine Memphremagog’s Purity have long argued this has the potential to push the toxins into the air.
Some kinds of PFAS have been shown to travel long distances through the air, depositing in soil and water many miles away. In Bennington, many people discovered their wells were poisoned by emissions from a Teflon manufacturing plant there owned by ChemFab and later Saint-Gobain.
State regulators say they expect that if the Coventry facility does release PFAS into the air, it would be in far lesser amounts. But the federal government doesn’t regulate PFAS in water, soil or air. And while Vermont sets limits on them in drinking water, it doesn’t for air. Absent state or federal standards, regulators at the Department of Environmental Conservation say they have little recourse to require the landfill to test for or address PFAS emissions.
“I can certainly appreciate there are concerns about the unknown,” said Vermont Natural Resources Secretary Julie Moore. “But at the same time, we're trying to balance those with the very real concerns we have about the known, which is the that there are significant concentrations of PFAS in landfill leachate, and absent technology to sort of strip them out and remove them, we're just continuing to perpetuate and circulate them in Vermont's environment.”
Part of the problem, Moore says, is that unlike for water quality, the EPA has not approved a standard test for local regulators to use to measure PFAS in the air, though the agency did issue a draft guidance in 2024.
Some states, including New Hampshire, have already started to use that guidance to regulate air quality for PFAS, including by mandating some businesses test for and limit emissions that come out of their vents. In early August, DUMP submitted a letter to Moore asking the Agency of Natural Resources to do the same at the landfill.
The draft permit announced July 17 would require Casella to investigate and report back to state regulators whether it would be feasible for them to test for PFAS in air emissions from the Coventry facility in the future.
But the permit doesn’t say what would happen if the waste company discovered aerating the leachate is indeed pumping PFAS into the surrounding air.
Beyond that, the state is also requiring Casella conduct a one-time test at the building’s smokestack for a host of other regulated chemicals found in liquid leachate. And Casella will install a carbon filter on one of the vents to control odor.
Vermont’s Department of Environmental Conservation is hosting a public hearing about the draft permit on Aug. 21 from 5-6:30 p.m. at the Gateway Center in Newport. The deadline to file public comment on the permit is Aug. 28.
