Mechanical failure led to Riverhead Town’s sewage treatment plant dumping improperly treated sewage into the Peconic River on three different occasions last month, according to the Suffolk County health department.
Michael Reichel, the town’s sewer plant superintendent, confirmed Friday the plant exceeded the amount of fecal coliform bacteria it is permitted to discharge into the Peconic on Nov. 26, as well as two other days in November, Nov. 5 and Nov. 19.
The town has not been issued a violation “yet”, Mr. Reichel said.
Another incident occurred in August.
The state Department of Environmental Conservation issued a Notice of Violation to the town Thursday, saying the town had until Jan. 5 to respond with a corrective action plan, said Aphrodite Montalvo, a DEC spokeswoman.
The town could be fined up to $37,500 for each incident, Mr. Reichel said.
While the amount of the contaminated water that was discharged isn’t known, the plant was discharging at a rate of 847,000 gallons per day on Nov. 26, 775,000 gallons per day on Nov. 19, and 873,000 gallons per day on Nov. 5, health department officials said.
The county said the incidents are not considered public health risks because there is an “exclusion zone” around the plant’s outfall discharge pipe under the Rt. 105 bridge, where shellfishing or swimming is not permitted.
The nearest shellfishing bed is 1.8 miles away, Mr. Reichel said.
An incident is considered a public health risk if there is a potential for human contract with raw or partially treated sewage, or by swimming in or consuming shellfish from water affected by the discharge of raw or partially treated sewage, according to the county.
“It does happen from time to time, not that it should,” Mr. Reichel said of the mechanical problem. “It can be due to mechanical failure, electrical failure or human error. This started off with the mechanical failure.”
He notified the state Department of Environmental Conservation and the Suffolk County Health Department through their alert system to let them know.
The mechanical failure, which was the result of a sensor defect in late October, caused a “plant upset” that resulted in the plant failing the fecal coliform test for three of the next four weekly samples, Mr. Reichel said.
“It’s a biological process and it takes time to bring the biological process back and regrow the microbes,” he said.
How the plant functions depends on things like temperature and time of year, and adjustments need to be made to adjust to those changes, Mr. Reichel said.
The plant’s flow cannot be shut off when something like this happens, and the corrective action takes time, he said. In this case, the corrective action involved the town importing a total of about 14,000 gallons of “seed sludge” from plants in Patchogue and Selden, which were properly treated, in order to mix it in with the improperly treated sludge at the town plant that was a result of the malfunction.
That needed to be done before the treated effluent could be dumped back into the river.
“You have to let it sit awhile and see how it reacts,” Mr. Reichel said. “You need seed sludge with microbes in it and they live there and continue to grow, but it takes time for them to develop.”
November was a “really bad month,” he said, in part due to the weather, which bounced back and forth between warm and cold and then warm again.
The Dec. 3 readings for fecal coliform bacteria were within limits, he said, adding the fecal coliform levels were the only category that exceeded permitted limits in November, as other categories like nitrates, suspended solids, and dissolved oxygen levels were okay.
“Sewage treatment plants in general have their problems,” said Kevin McAllister, a marine biologist who heads the non-profit Defend H20. “These exceedances of coliform limits are a problem, particularly if they are reoccurring and you have three separate occurrences in one month.”
He disagrees with the county’s assessment that it is not a public health risk, because the average person may not know the exclusion zone exists.
He added that most people aren’t even aware when a sewage treatment plant malfunctions, as there is no public notification unless someone asks about it.
Mr. McAllister said he is seeking to review all of the discharge reports from the Riverhead Sewage Treatment Plant for the past year.
The mechanical failures come at a time when work is already underway on a new $23.5 million upgrade to the sewage treatment plant that will bring it up to the best treatment level currently available, Mr. Reichel said.
“It will be state of the art,” he said.
The current plant was considered state-of-the-art when it was upgraded for $8.7 million in 2000, but since then, the state DEC changed permit requirements based on recommendations from the federal Environmental Protection Agency that necessitated the latest upgrade.
The work is expected to be done in two years.
The town has received a $8 million county grant for the project, along with $2 million in state money, and $4 million in town sewer district reserve funds. The town will borrow the rest through low interest state Environmental Facility Corporation loans, said Supervisor Sean Walter.
Town officials are hoping to receive additional county funding from its sewer rate stabilization fund, which caps the tax rate increase for sewage treatment plant upgrades at 3 percent, with the county picking up the difference.
A consultant told the town earlier this year that without that fund, the tax rate in the sewer district would increase by about 18 percent.