The vast majority of Vermont’s trash meets its end at a large landfill in Coventry, the only operating landfill in the state. Leachate — liquid waste from the landfill — is currently treated at a single wastewater facility in Montpelier.
In late April, after discovering levels of E. coli in the plant’s effluent that violated its permit, officials at the Montpelier facility stopped accepting leachate from the Coventry landfill.
From then until now, Casella, the company that owns the landfill, has been trucking most of the leachate produced in the state to Plattsburgh, New York, and the rest to Franklin, New Hampshire.
Chris Cox, chief operating officer at Montpelier’s Water Resource Recovery Facility, said he’s not sure when the city will be able to accept leachate again. His team is working with Casella and the consulting engineering firm Brown and Caldwell to determine the source of the problem.
On April 20, Cox said officials found E. coli levels of 190 colony forming units (CFU) per 100 milligrams, and the permitted limit is 77 CFU. That level remains below what the state considers safe for swimming, which is 235 CFU, Cox said.
Montpellier’s facility uses ultraviolet light to sterilize effluent before it’s released into the Winooski River, which is part of the Lake Champlain watershed.
It seems that a material present in the leachate hindered the effectiveness of the ultraviolet light, Cox said, adding that a material may have absorbed or reflected the light, shielding the E. coli and possibly other bacteria and pathogens.
E. coli is an indicator organism, Cox said, meaning that “if you can really prove that you’re killing E. coli, you’re beyond certain that you’re killing viruses and pathogens that are killed a lot easier than E. coli.”
Officials determined that leachate was the source of the problem because levels of E. coli dropped dramatically soon after the flow of leachate into the facility stopped.
Joe Fusco, vice president at Casella Waste Systems, said he wasn’t aware of problems with the leachate, and the incident has not posed a significant obstacle for the company.
Casella’s pretreatment discharge permit regulates the quality of the leachate leaving the landfill, but it’s difficult to determine whether that permit could be relevant to the incident because officials don’t yet know what caused the problem at the facility.
Components of the leachate are “based on what’s sent to the landfill in the first place,” Fusco said.
Fusco indicated that the facility might accept leachate again in the coming weeks, but Cox said he couldn’t confirm that timeline. He’s waiting on a report from Brown and Caldwell “to explain how we, if possible, will continue to take leachate.”
Part of the city’s budget relies on the several hundred thousand dollars it receives per year to treat leachate. Officials also “feel some responsibility to not just export our waste to other states,” Cox said.
Meanwhile, Jonathan Ruff, environmental manager for the city of Plattsburgh, said city officials didn’t hesitate to assist while Montpelier and Casella determine the nature of the problem. Plattsburgh’s wastewater treatment facility has the capacity to take the leachate, and its method of disinfecting effluent — chlorination — appears to have remained effective.
Plattsburgh receives financial compensation for treating the material, he said, and the Coventry landfill is its backup location for biosolids.
