STONINGTON — The Water Pollution Control Authority is requesting $300,000 for a two-year "inflow and infiltration" study of the Mystic treatment sewage plant, in part to pave the way for activating a diversion line that would send more of the town's effluent to its plant in the Borough.
The Mystic plant has been operating close to capacity, while the Borough plant has been running under capacity.
Douglas Nettleton, director of the authority, outline the plan for the Board of Finance at a budget session Tuesday night. He asked for the board for $150,000 for the first year of the "I and I" study, and an equal amount the next. The study would show where water is getting into and out of the system, creating inefficiencies.
He said the town could get a matching grant for half of the cost, or $150,000, from the state Department of Energy and Environmental Protection, but would need to provide the initial $300,000 to receive the grant.
The Mystic plant has recently operated at 79 percent, right below its permit limit of 80 percent efficiency. Nettleton said that last year’s average was 68.8 percent and the plant has averaged 72 percent in the last six months.
“It’s a matter of time before we exceed capacity," he said. “This study will force us to come up with a plan about what to do with additional flows."
Nettleton said the Perkins Farm development will need 40,000 gallons of capacity per day and he knew of two hotel applications in Mystic along Coogan Boulevard that would also require additional capacity.
“Looking at upcoming development, we need to prepare about what to with the additional flow so that Mystic doesn’t go into violation,” he said.
In 1987, a transfer line from Mystic to the Borough plant was constructed and Nettleton said it was time to make the line active. The cost would be $775,000 the first year and $865,000 the second year, totaling $1.64 million.
Nettleton said it was important to activate the “diversion line” so that by the second year, the borough plant could accept 300,000 gallons, which it has the capacity to absorb.
He also said it was important to show DEEP that the town was taking a proactive approach by doing the study of the Mystic plant and not merely moving the capacity problem to the Borough.
One of the contributing problems at the Mystic plant are residential sump pumps, which residents may be using to pump water from their basements into the storm grates, he said.
“Some of those of can pump 50-60-70 gallons a minute,” he said.
Aging infrastructure also plays a role, since many of the pipes were installed in the early 1970s, he said.
Blunt White, a Board of Finance member, asked why Nettleton didn’t access the total of $1.8 million the pollution authority has in four accounts instead of requesting funds from the town.
Nettleton said the $1.8 million represented the town’s emergency fund, which allowed his team to take immediate action during an emergency without coming before the board each time to ask for funding.
“We spent $100,000 on 300 feet of pipe on Holmes Street, and we had to move on it,” he said. “I’d really prefer to grow that fund and stay out of your hair.”
Nettleton’s presentation was one of many that the Board of Finance has heard in preparation for its 2019-20 budget deliberations. The board will present its budget in late April and it will go to a voter referendum in early May.