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HARTFORD/MIDDLETOWN — Sewage treatment plants on the Connecticut River released millions of tons of partially treated sewage into the river over the last month after heavy rains pushed the treatment plants over capacity.
Middletown Health Department Director Kevin Elak told CT Examiner that partially treated sewage was released into the river three times in September from the Mattabassett Treatment Facility — once on September 13, once on September 25 and once on September 29.
The facility, which serves Middletown, Berlin, Cromwell and New Britain, can handle up to 55 million gallons per day.
Elak told CT Examiner that this was the first time he was made aware of the Mattabassett plant releasing sewage that was only partially treated.
But Art Simonian, executive director of the Mattabassett Treatment Facility, told CT Examiner that this has happened once or twice a year on average, although the recent years of heavy rains have caused it to happen more frequently.
Simonian explained that, normally, wastewater goes through a three-phase process, where solids are separated out and the liquid is aerated and disinfected with bleach. In a partial treatment, the wastewater goes through the first phase — separating out solids — and is disinfected, but skips a secondary phase that aerates the wastewater in order to reduce the nitrogen content. The partially treated wastewater is then mixed with a larger quantity of fully treated wastewater and discharged into the river.
Simonian said that even when the discharge is partially treated, it meets federal and state guidelines for nitrogen content and certain bacteria levels.
“From an effluent quality [and] health standpoint, we’re not concerned,” he said.
Health Risks
According to Simonian, the discharges on September 13 and September 29 all met with federal standards for wastewater discharge. The discharge on the 25th showed an excess of Enterococci bacteria — nearly five times the allowed amount, although that number normalized the next day, and the facility was still well within the required monthly average. Enterococci bacteria can cause UTIs, meningitis and infections in open wounds.
Elak said that everything from chemicals that people use in their toilets to bacteria or viruses that can exist in raw sewage pose health risks — although he said he believed the risk was minimal. He said the health department did notify the local rowing teams and recommend that they stay off the river while the sewage was being discharged.
“I think the risk is pretty low, but the risk is there and we didn’t want to take a chance and have people get exposed to the water during that time and possibly get ill,” said Elak. He added that the rowing teams had been grateful for the alerts.
“I don’t think parents would be too happy if they learned that their children were out in the river during a sewer bypass,” he wrote in an email.
Sal Nesci, Director of the Health Department in Cromwell, disagreed with Elak about the health risks. He said that he’d been getting notifications from both Mattabassett and the Metropolitan District, which serves Hartford and the surrounding communities, for a long time.
“It’s been going on for years, and the reason why there’s no health concerns is because there’s various stages of treatment that the sewage goes through, and what these treatment plants do is they bypass certain stages and they have to stay within certain limits and certain parameters so that whatever effluent is discharged into the receiving body of water still meets the state and federal guidelines for effluent,” said Nesci.
Nesci said he did not notify the public when these discharges happened, because he had been assured that the sewage still met federal guidelines.
“This is a reasonable and customary thing that happens,” said Nesci.
Aging Infrastructure
The Mattabassett facility was upgraded in 2017, and its capacity increased from 80 million gallons to 110 million gallons, but Simonian said the understanding was still that it would only be able to fully treat 55 million gallons of wastewater at a time.
He noted that while Mattabassett is not a facility where stormwater is meant to mix with the sewage, aging pipes in the towns that Mattabassett services will sometimes allow rainwater to leak into the sewage — which causes a problem during heavy rains.
“We have some older pipes that are in the communities that we serve,” said Simonian. “Those pipes sometimes will let clean water leak in, or sometimes people have illegal connections from their stormwater runoff from their roof leaders or catch basins that are tied to there, so that’s where some of the higher flows come from during wet weathers.”
Cities in the district have embarked on projects to fix aging sewer infrastructure. In Middletown, for example, the city allocated $2.75 million in federal coronavirus relief funds toward sewer infrastructure projects with the goal of keeping more stormwater out of the sewage pipes. Joe Fazzino, director of Middletown’s Water and Sewer Department, told CT Examiner that the city has already separated its sewer and stormwater lines, and is currently fixing old clay pipes so that groundwater doesn’t leak into the sewer system.
New Britain is also in the midst of a $90 million replacement of stormwater and sewage lines, which, according to the city, are 100 years old. The project is estimated to require 8-10 phases that will span 20 years — the city is preparing to go out to bid for phase 3 in 2024.
More severe storms
Mattabassett is not the only treatment plant that has had to discharge partially treated wastewater into the Connecticut River because of the heavy rain. And even facilities that are designed to take in both stormwater and sewage have found themselves unable to keep up. The Metropolitan District, for example, which services Hartford and four of its surrounding towns, discharged 450 million gallons of combined stormwater and sewage overflows in September.
Paul Copleman, director of communications for DEEP, said that these combined systems were originally built a hundred years ago, and were cheaper than building separate systems. Since then, he said, many municipalities have done infrastructure work to separate out the stormwater, but that the work was costly and difficult, particularly for the urban centers.
But he said the heavy rains created problems for these systems that could put people at risk.
“Untreated wastewater can contain pathogens, excess nutrients, and chemicals, which is why CSOs [combined sewer overflows] represent a public health and environmental concern,” said Copleman.
Nick Salemi, spokesperson for the Metropolitan District, noted that Brainard Airport in Hartford had received a total of 31.7 inches of rain in July, August and September — the highest amount ever recorded during that period. He said there had also been multiple storms during that time, causing stormwater to flood into the system.
And the storms may continue in future years. Rhea Drozdenko, a river steward with the CT Environmental Conservatory, said wastewater treatment facilities will need to invest in upgraded infrastructure and “green infrastructure” to prevent negative environmental or health effects. For instance, she said, nutrients from sewage and fertilizer can cause harmful algae to bloom in the river, releasing certain toxins.
“As climate change increases wet-weather and heavy rainfall events, we’re going to see increased strains on outdated stormwater and sewer infrastructure,” Drozdenko wrote in an email.
Simonian, with the Mattabassett District, said that in his time working as a civil engineer, the changes he’s seen in the last 15 to 20 years have had less to do with the amount of rain and more to do with the intensity of the storms.
“I wouldn’t say that we’re having, let’s say, twice as much rain on an annual basis as we did before. That’s not true,” said Simonian. “I think it’s more of when we do get events, they seem to be much more severe in terms of how damaging they are and how strong they are. So that part is very hard to design for and very hard to treat for.”
Salemi said the city of Hartford invested $1.5 billion over the last 15 years to improve its system, including a four-mile underground storage tunnel that would take in sewage overflows during rainstorms. People who receive services through the Metropolitan district have to pay a separate fee on their bills for the upgrades.
But Salemi warned that the recent rainfall had pushed all the treatment plants beyond their capacity.
“To be clear, no system anywhere is built to take the amount of rain we recently received,” he said.