With potential savings that could run in the millions of dollars, the town and its sewer engineers plan to begin dye tests next week on about 160 suspected sources of water from rainstorms entering the sewer system that serves the village’s homes and downtown commercial areas.
“We have a 1-million-gallon-a-day plant,” but the normal flow is below that capacity, about 700,000 to 800,000 gallons a day, First Selectman Rudy Marconi told the selectmen Monday. “When we have a rain event, flow can get up to 3 or 4 million gallons.”
With the state mandating improvements at both town sewer plants — first the village, then routes 35 and 7 — Marconi wants to find and eliminate places from which rainwater enters the system “before we move forward, spending millions more upgrading the plant,” he said.
There’s no cost estimate yet, but the last major plant upgrade was $13 million.
Both plants will have to meet tougher standards for phosphorous and nitrates, and be sized to accommodate anticipated growth.
The testing is expected to start Monday, Dec. 14, and continue for some weeks. Property owners in the village sewer district should be on the lookout for notices warning them when a representative of the engineering company will be coming around.
“The overall program is we’re trying to locate sources of storm water that are entering the sanitary sewer system,” said Jon R. Pearson, from AECOM Engineering, the firm overseeing the plan re-design.
“We did the smoke testing two years ago, and out of that came a number of confirmed sources of storm water, and also a number of what we call ‘suspected sources’ — so we’re now beginning the program called dye testing, which is used to confirm those suspected sources,” Pearson said.
“There are things like roof drains that go into the ground with no visible point of discharge. What we’ll do is put dyed water into those roof drains and watch the sewer system to see if the dye appears. And if it does, that confirms it’s a direct source.
“We’ll also check the storm drains. And if it’s in the drainage system — which is where it should be — it confirms that it’s not a direct source.
“A subsequent part of the program will involve internal building inspections, to see if sump pumps are connected to the sanitary sewer system.”
That is expected to involve “the whole system, approximately 1,700 homes” and will be coming later — it’s a future program.
But the dye tests that start next week involve a smaller number of properties. They’ll be preceded by notices on town letterhead to individual homes, saying to expect the workers coming to do the tests.
“It will be a letter from the town that will be hand-delivered to the properties, a day or two in advance,” Pearson said.
“You’ll be getting a notice in advance that there’s a dye test to be conducted on your property, and then somebody will knock on the door.
“The Police Department will be notified each day where the crews are going to be working,” he added.
The police will have not just neighborhoods but specific addresses the test workers are expected to go to on a given day.
Worker IDs
The workers doing the testing will be identified as working for AECOM or its subcontractor, SDE Civil and Environmental Engineering.
“They will have photo ID and a letter of authorization from the town with them. It’ll identify the firm they’re with — names, photographs, business address,” Pearson said.
The dye testing is expected to start Monday, will generally go from about 8 a.m. to 4 p.m., and will be done Mondays through Thursdays for several weeks.
“The dye test will be conducted only when there’s a property owner present, and the work is outside the house. It’s just putting dye in a downspout, or if you had an area with a catch basin in the back, that drained a driveway, that might be get tested.”
“If no one is home, there will be a door hanger left, asking the owner to contact SDE to schedule a test.
Diana Van Ness, the administrator for the town’s Water Pollution Control Authority, said the details of the program are explained on the town of Ridgefield’s website.
“I have it up on the WPCA website,” she said. “If you go to ridgefieldct.org and then go to departments, and under WPCA. Once you click on WPCA it automatically pops right up.
And if anyone has any questions they can call me.”
The WPCA’s number is 203-431-2734.
A month, more
Pearson said the testing will go on for some time.
“We can’t predict how many people will be home. It may be four to six weeks,” he said.
“If winter actually comes and we get snow, we’ll have to curtail it.”
The “infiltration and inflow” of storm water into the sewer system is a problem the town has long been working to address.
The town has already put a lot of money into installing “sleeves” inside the old pipes and into locating and closing known entry points where storm water gets into the system, Marconi said, but there’s still a lot of storm water getting into the sewer system.
“The numbers are still very high,” Marconi said.
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