WATERTOWN — The city may have to spend at least $3 million to correct some issues with contaminants at its water treatment plant.
For the past few years, the city has been under a consent order by the federal Environmental Protection Agency to submit a Corrective Action Plan to comply with maximum levels of a pair of disinfection byproducts at the Huntington Street filtration plant.
The two byproducts are known as total trihalomethanes, or TTHM, and haloacetic acids, or HAA5.
Water customers have periodically received postcards in the mail notifying them of the disinfection byproducts exceeding acceptable levels at the plant.
To try to resolve the issue, water treatment plant operators conducted a pilot test by adding activated carbon to filter contaminants from the water, and “it has showed promise,” City Manager Kenneth A. Mix said.
However, more tests have to be conducted to see if the activated carbon — also known as activated charcoal — works and decreases the level of disinfection byproducts, he said.
Earlier this month, the City Council agreed to hire GHD Consulting Services, Syracuse, to design a filter system for the plant that keeps the byproducts at acceptable levels.
The Syracuse firm will be paid $33,900, plus an amount not-to-exceed $10,000 for a pilot study required by the state Department of Health.
The city’s proposed $56.5 million budget for 2022-23 will include a capital project that could cost at least $3 million to implement the corrective action.
“We really don’t know how much it’s going to cost,” Mr. Mix said, adding that it will depend on how much has to be done at the treatment plant.
Depending on how deep the activated carbon is placed in the plant’s filters, and whether it works, the city might have to replace the plant’s filtration tanks with larger ones, Mr. Mix said.
To keep the contaminants at acceptable levels, the city might have to use activated carbons on a yearly basis.
“And activated carbons are very expensive,” he said.
Chlorine is used at the plant to kill parasites, bacteria and viruses in the water drawn from the Black River.
The TTHM and HAA5 byproducts are produced when chlorine or other disinfectants react with naturally occurring substances in water. The byproducts can also be caused by stagnant water at the end of the system.
A notice issued to city residents in early 2022 said the average TTHM level for 2021 was 89.8 micrograms per liter, above the EPA’s maximum contaminant level of 80 micrograms per liter.
The city’s 2021 water quality report notes the TTHM violation, and an average 55.8 micrograms per liter of HAA5, which is below the EPA’s threshold of 60 micrograms per liter.
The EPA lists the two contaminants as having “potential health effects” from long-term exposure, including an increased risk of cancer from both TTHM and HAA5, and central nervous system problems from TTHM.
Mr. Mix insisted the situation doesn’t pose immediate health hazards because the levels “are just above” the allowable amounts.
The Development Authority of the North Country is also facing a consent order to correct the contaminant issue because DANC purchases water from the city and it contains the two byproducts at higher levels than are allowed.
Councilman Patrick J. Hickey was unaware of the extent of the issue or that the city will have to proceed with a capital project with such a large cost associated with it.
He only learned about it on Friday when DANC Executive Director Carl E. Farone told him about it in an email.
“I was shocked,” Councilman Hickey said. “I had no idea.”
DANC met with the EPA last week to talk about how the authority will handle the issue, according to the email to Mr. Hickey.
Concerned with what was happening, DANC officials met with city staff about it last year and urged them to do something about it to resolve the issue for the authority.
The water that DANC purchases from the city is used by Fort Drum, Pamelia, LeRay and Champion.
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