by Dakota Antelman | September 12, 2025 | The Concord Bridge

 

Concord’s shuttered state prison could one day provide a little freedom.

As limited sewer capacity constrains new development, local officials are ramping up public discussions about acquiring an old treatment plant at the MCI-Concord prison, which already has federal approval to dump treated wastewater into the Assabet River. 

 

 

Leaders are also weighing ways to bypass the federal government altogether in a two-pronged approach that could net hundreds of thousands of gallons of new daily capacity.

 

 

River experts say they’re concerned, and town consultants want to do more research. But after years of stalled talks with the Environmental Protection Agency, Public Works Director Alan Cathcart says the tandem approach could be the solution to Concord’s sewer shortage.

 

 

“What’s at stake here is the one potential silver bullet the town has,” Cathcart told the MCI-Concord Advisory Board last week.

Public Works Director Alan Cathcart speaks during a recent MCI-Concord Advisory Board meeting.
Photo: Dakota Antelman/The Concord Bridge

 

‘The old college try’

The EPA controls how much treated wastewater municipalities release into rivers. Concord is perilously close to a 1.2 million-gallon-per-day limit at its current plant off Bedford Street.

 

 

Experts say the capacity crunch is a major barrier to new projects because commercial and housing developers have to pay for expensive on-site water treatment when they can’t connect to the sewer.

 

 

Cathcart remembers asking the EPA to raise its cap. “We really did give it the old college try back when I was young and innocent,” he told The Concord Bridge.

 

 

Regulators, he said, had a simple response: “No, thanks.”

 

 

According to EPA spokesperson JoAnn Kittrell, Concord last asked for a 200,000-gallon-per-day permit increase in 2023. She said the agency asked the town for a review to either ensure an increase wouldn’t “significantly lower water quality” or show that an increase is “necessary for important social and economic development.” 

 

 

Kittrell said that as of last week, federal regulators had not heard whether the town had begun the review process.

 

 

 

Though a lobbying solution appears at least temporarily out of reach, MCI-Concord’s aging on-site treatment plant limps along with a permit for 310,000 gallons per day. The state officially offered to convey the plant to the town last year, and conversations quickly got underway. The state would still need some of the plant capacity for its remaining operations in the area, but the rest could be available if the town takes control.

 

 

Officials say the plant is in “rough shape.” Repairs could cost $25 million, and the state recently agreed to put off the town’s decision-making deadline until August 2026 while consultants help evaluate the site. 

 

 

Cathcart has been making the rounds in recent weeks, presenting the wastewater dilemma and prison possibilities to town boards. 

 

 

After one such presentation, MCI-Concord Advisory Board co-Chair Dan Gainsboro said having a second facility could also let crews take part of the system offline for maintenance without disrupting service.

 

 

“That’s a big deal that they don’t really have right now,” he said. 

 

 

As Concordians watch their tax bills and officials consider pricey repairs, Gainsboro said that “it makes a lot of sense” for the town to explore ways to recoup costs from the state or developers.

 

 

MCI-Concord Advisory Board member John Boynton, left, and panel co-Chair Dan Gainsboro review a document. Photo: Dakota Antelman/The Concord Bridge

 

Groundwater discharge

While wastewater plant negotiations have been ongoing, a proposal to reconfigure old sand beds and leach treated wastewater into the ground is new to the public discourse.

 

 

Cathcart estimates the town could add anywhere from 100,000 to 300,000 gallons of additional daily capacity at the prison plant—beyond the 310,000 gallons allowed under the EPA permit—if it adds sub-surface groundwater discharge. Unlike systems that dump into rivers, these are subject only to state oversight. 

 

 

Restoring the sand beds could cost another $3 million on top of the $25 million in prison water treatment plant upgrades. That’s still cheaper than the $10 million required for a theorized groundwater system at the town’s existing treatment plant off Bedford Street.

 

 

Sven Weber, a member of the Public Works Commission and a co-chair of the town’s Land Use Working Group, said 150,000 gallons of sewer flow would cover 1,300 bedrooms’ worth of residential use. 

 

 

For all the cost, Weber said more capacity could lower the number of septic tanks in town, which can leak pollutants.

 

 

“Having 70% of [the] town on septic is an ecological nightmare,” he said, referencing the majority of Concord currently left off the sewer network. 

 

 

 

Kittrell, the EPA spokesperson, said “the matter of the existing septic systems and demand for sewer hookups” could be part of the town’s required “antidegradation review.”

 

A wastewater treatment plant at the MCI-Concord prison property would require extensive repairs but could provide a much needed sewer capacity boost. Photo: Carl Calabria/The Concord Bridge

 

Environmental concerns

Cathcart said the prison plant hasn’t used its full permitted capacity in the last 20 years.

 

 

Asked whether her organization is comfortable with a possible increase in treated wastewater discharges, OARS 3 Rivers Water Quality Program Manager Abby McCarthy said the nonprofit “is concerned about river health in the Assabet River.” 

 

 

OARS is based in Concord and aims to protect the Assabet, Concord, and Sudbury Rivers. Although treatment plants disinfect sewage before releasing it, McCarthy said, wastewater discharge is still a common cause of E. coli contamination.

 

 

Kent Nickols of the Weston and Sampson consulting firm told the Select Board that the town treats wastewater “to a very low level” for phosphorus. McCarthy still flagged concerns about E. coli, phosphorus spikes, and temperature changes from treated wastewater releases that could harm rivers.

 

 

Cathcart said he got into the public works industry to protect water quality and bills himself as “a bent environmentalist.” 

 

 

He’s still frustrated with the EPA and thinks they’ll eventually budge on permit capacity requests like Concord’s. In the meantime, he and others continue considering alternatives.

 

 

“We permit what we can, not what we should,” he said. “What we should isn’t allowed.”

 

 

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