By Carrie Czerwinski, Special to The Day

Stonington — The Water Pollution Control Authority has proposed $3 million in work to repair cracked sewer lines along Route 27.

If approved by the state Department of Energy and Environmental Protection, the WPCA would reline more than 10,000 feet of sewer lines to prevent storm and river water from flowing into the pipes, potentially allowing a moratorium on new sewer connections to be lifted.

Daniel Smith, WPCA director, said Thursday that the DEEP had approved plans and specifications to line sewer pipes along Greenmanville Avenue from roughly Pleasant Street to Willow Street, then onto Broadway Avenue, continuing onto Broadway Avenue Extension, and ending on Edgemont Street at the wastewater treatment plant.

He said the DEEP still needs to approve the construction oversight plan, and he hopes to see the state approve partial funding and a loan for the project.

If approved, the project could go out to bid in late spring and work could begin early this fall.

Smith said, conservatively, the project would take approximately 45 days to complete, and work would most likely take place at night to limit the impact to traffic.

On Wednesday, Smith described the process as putting a large sock into the pipes. The material form-fits to the interior of the pipes, sealing cracks and breaks with a resin-type material, which is then cured with ultraviolet light.

He explained that a 2019 evaluation of the more than 50-year-old sewage pipes found significant cracks that allow large amounts of water to enter the system in the area.

“It’s not exact science. You estimate how much water you think is coming in, and best estimates are 100,000 to 200,000 gallons a day. It’s a significant amount,” he said, noting that much of the infiltration is river water.

He pointed to an area near Elm Grove Cemetery and Precious Memories Place where the main sewer line sits below the level of river, allowing river water to flow into the system through cracks and breaks in pipes.

All of the excess water makes its way to the Mystic treatment plant, where it must be processed as part of the daily permitted maximum of 800,000 gallons.

A 2019 moratorium on new connections to the Edgemont Street facility was partially lifted in 2021 to allow an additional 50,000 gallons of wastewater to enter the system each day, which has not yet been reached.

However, if the reduction in storm water and river water entering the system is significant enough, the moratorium could be lifted more or even completely.

But Smith doesn’t want people getting ahead of themselves and cautioned that any considerations regarding the moratorium are a long way off.

“That will be a little bit more of a process. Once we line, then we will have to reevaluate flows at the Mystic plant, and then the authority would make a decision on lifting the moratorium,” he explained.

Regardless of whether the moratorium is lifted, he noted the repair will have several benefits, including reducing wear and tear on equipment and reducing flow to the plant. Smith explained that lower flows can increase the amount of time wastewater spends in the disinfection channel, enhancing the disinfection process.

https://theday.com/news/728670/stonington-plans-3m-sewer-work-that-could-lift-mystic-moratorium