Nassau County officials on Friday touted their new proposal to send treated wastewater from the Sandy-damaged Bay Park plant to an ocean-outfall pipe at their Cedar Creek facility in Wantagh through an unused aqueduct as a way to keep nitrogen out of the Western Bays.

At a news conference, County Executive Edward Mangano, flanked by county and state legislators, detailed the plan, which would be an alternative to building a $450 million ocean-outfall pipe at Bay Park.

“This holds great promise for our collective goal of cleaning up the Western Bays,” Mangano said.

The county plans to issue a request for proposals for an engineering firm to conduct a two-phase study, he said.

The first phase would determine the condition of the aqueduct, which was built around the turn of the 20th century to transport water from Long Island to Brooklyn, and whether it could be used to carry the effluent.

In the second phase, engineers would determine how to connect the Bay Park and Cedar Creek outfalls to the aqueduct.

advertisement | advertise on newsday

The county has been searching for money for constructing an ocean-outfall pipe at Bay Park for years, but hasn’t been able to secure funding to cover it.

But the new plan, which would send the treated effluent to the Wantagh pipe through 10 miles of the historic aqueduct under Sunrise Highway, would cost much less, potentially clearing the way for a solution to the problem of getting the nitrogen-rich effluent out of the Western Bays.

While it is still unknown exactly how much the alternate proposal would cost, Mangano estimated it at $200 million to $300 million.

“It’s a major savings,” he said. “You’re not building what amounts to a five-mile pipe.”

The roughly 50 million gallons per day of effluent from Bay Park, which serves 500,000 people, goes into Reynolds Channel in the Western Bays — a series of waterways that are part of the South Shore Estuary Reserve. Nitrogen in the effluent has caused severe environmental damage there, harming fishing, water quality and the marshes that state environmental officials have said are critical to buffering the area against severe waves during storms.

Norma Gonsalves, the Republican presiding officer of the Nassau County Legislature, called the plan “a creative new approach to our environment.”

“I believe it’s a step in the right direction,” she said. “This proposal has the potential to solve both the environmental and the financial problems associated with the Bay Park plant.”

State Sen. Todd Kaminsky (D-Long Beach) said the issue of diverting effluent out of the Western Bays went beyond partisanship.

“It’s not a Republican issue, it’s not a Democratic issue,” he said, adding that he would “fight like a bulldog” to secure state funding for the plan.

“I feel like we’re well on our way,” he said.