Riverhead Town’s $24 million sewage treatment plant upgrade, for which work began in April 2014, is now expected to be completed by Aug. 31 — four months later than initially estimated.
The state Department of Environmental Conservation allows the plant to operate with interim discharge limits that are less stringent than normal during the upgrade, but those limits can only be used from November to April, said sewer district superintendent Michael Reichel.
“That’s because dissolved oxygen levels are higher in the winter,” he said.
The town had the option of operating with less stringent interim discharge limits either this winter or last winter, but by the time contracts were signed and equipment to start the job was ordered, it was too late to use them in 2014-15.
Once the upgrade is completed, the sewage treatment plan will be state of the art. It will allow just 30 to 40 pounds of nitrogen per day to be discharged into the bay, as opposed to the current 170 pounds per day.
The existing plant, which cost about $8 million to construct and began operating in 2000, was also considered state of the art when it was built, Mr. Reichel said. The federal Environmental Protection Agency enacted newer, more stringent guidelines for nitrogen removal shortly after it was constructed.