Northport’s $14M sewer system upgrade enters final phase

Northport Village is about to enter the final phase of a long-term sewer system upgrade, expected to cost $14 million by the time all work is complete.

The village has already spent about $10 million to upgrade its sewer treatment plant, reline sewer mains and rehabilitate manhole covers. The improvements in recent years have dramatically cut the levels of nitrogen entering the harbor through the plant.

The third and final phase of the project will replace two sections of old, fragile sewer lines with new pipe to be buried beneath the village’s shoreline.

It’s “highly deteriorated, with occasional leaks, which we repair as they occur,” Deputy Mayor Henry Tobin said in an interview last week. “But the whole pipe has been in danger of serious failure. So it needs to be entirely replaced.”

The two cast-iron, Depression-era pipelines run beneath Woodbine Avenue and along the Northport Harbor bed, which has pipes and a pump station that are submerged at high tide and exposed at low-tide.

“Its life span is over,” said Damon McMullen, village trustee and commissioner of wastewater treatment. “It’s basically turned into graphite, like a pencil. At the molecular level, it’s deteriorating and you can’t line it.”

Both lines will be replaced with one higher-capacity pipeline made of high-density polyethylene. The new, durable pipe will be buried beneath the sand along the shoreline.

While the older lines are 8 inches in diameter, the village will use pipes at least 12 inches in diameter for the project, increasing the capacity of the entire system, McMullen said Tuesday.

The larger size will offset capacity lost when they seal off and abandon about 2,000 feet of the Woodbine line and the current shoreline pipe.

The village will have to go back and connect 16 houses on Woodbine individually to the new pipeline to complete the conversion.

The greater capacity will also make it possible to move more Northport residents off of cesspools and onto village sewer lines, McMullen said. Cesspools can leach nitrogen and other contaminants into the groundwater.

The new underground line will be parallel to Woodbine Avenue, and run roughly between Fifth Avenue and Beach Avenue, McMullen said.

That stretch of Woodbine is where the underground pipeline will be sealed and abandoned.

The latest effort is estimated to cost $4 million, and officials will find out April 1 if they will receive additional state funding for the project, McMullen said.

The village has had financing help from the New York State Environmental Facilities Corporation in the form of $9.03 million in no-interest and low-interest loans. That debt will be converted into a long-term bond later this year, Tobin said.