MERIDEN — A more than $38 million project to upgrade the city’s wastewater treatment plant on Evansville Avenue is about three-quarters complete, city officials said.
The project began in 2019. Its scope is two-fold: to reduce the levels of phosphorus in treated wastewater pumped into the Quinnipiac River and to reduce the overflow of untreated sewage that gets discharged into the river following significant weather events.
In 2018, the city received a U.S. Environmental Protection Agency administrative order that found the city non-compliant with its wastewater discharge permit because of overflows.
According to the order, the EPA found that on eight separate occasions over a more than four-year span — between February 1, 2013, and October 31, 2017 — the city discharged untreated sewage from the Harbor Brook Pump Station at levels that exceeded the amount the city was allowed to discharge under its federal and state-issued permit.
Under the permit, the National Pollutant Discharge Elimination System, the city is authorized to discharge a maximum daily limit of 50 milligrams per liter of untreated wastewater. The EPA order cited one occasion in February 2016 when the city’s discharge had reached 202 milligrams per liter — more than four times the allowable limit.
Meriden officials said such discharges occurred during significant storms when the plant is inundated with stormwater, thus causing the untreated wastewater to overflow into the Quinnipiac.
The city did not receive a financial penalty under the EPA’s order. The order required Meriden officials to develop and submit an inflow and infiltration control plan to both EPA and the state, detailing how the city would address the violations.
Richard Meskill, the city’s public utilities director, anticipates the entire project will be completed by May 2022. The phosphorus reduction component of the project is scheduled to be completed by this December.
Meskill explained officials from both EPA and the state Department of Energy and Environmental Protection approached the city about developing a plan to address the overflow issue.
The city’s plan involves diverting that untreated sewage into two concrete digesters located at the Evansville Avenue facility. Meskill explained those digesters, which have the capacity to hold up to 2.5 million gallons of sewage, currently sit empty.
“They haven’t been active for a number of years. They’re not needed at this point,” Meskill said. “We found an alternate use for it, basically.”
Officials plan to divert the flow of untreated sewage into those digesters during a storm. The untreated sewage, instead of flowing into the river, would be stored in those digesters.
“After the storm event subsides, we would begin reversing the flow,” Meskill explained. “... That would help alleviate any potential overflow.”
Other municipalities in the Meriden area have recently undertaken steps to upgrade their water pollution control facilities to comply with stricter phosphorus discharge regulations.
In 2019, the Wallingford Town Council approved the appropriation of $60 million wastewater treatment upgrades intended to reduce phosphorus discharge. In 2018, officials in Southington approved bids on a similar project to upgrade that town’s wastewater treatment plant.
Frank Russo, manager and chief operator of Meriden’s water pollution control facility, explained the portions of the upgrades related to phosphorus reduction are 50% funded through the state’s Clean Water Fund. Other portions of the project are funded through a low interest loan.
Steve Volpini, chairman of the city’s Public Utilities Commission, described the upgrades as a “big undertaking.”
“The government, the EPA, has demanded lower and lower amounts of phosphorus,” he said, noting the new system to lower phosphorus levels does so in a “non-chemical way.”
State Rep. Mary Mushinsky, of Wallingford, sits on the state legislature’s Environment Committee. Mushinsky described the water that flows through the Quinnipiac as being about 50% effluent — “which is why it has to be cleaned,” Mushinsky said.
The state grant and the low interest loan for phosphorus removal are in recognition of the cost, Mushinsky explained.
“You want to have the river capable of supporting fish and recreation. It’s never gonna be drinkable,” Mushinsky said. “Those days are long gone. But you want to have it at least clean enough for fishing and water recreation. That’s the purpose.”
“Because it is a small river with a dense population along it, the extra step has to be taken,” Mushinsky said.