Flanked by executives from United Water, the firm selected to manage the system, Mangano told more than 50 local residents and plant employees that the system would run more efficiently and with less risk to the environment under a private operator.
He noted that without a private operator, a 32 percent rate increase would be needed by 2015. "We can't just ignore the problems," Mangano said. "They won't just go away."
But neighborhood residents who deal with odor from the Bay Park plant remain skeptical.
"At the forefront it doesn't seem bad," said Rich Brennan, president of the Bay Park Civic Association. "But there are still a lot of questions."
Scott Bochner, of Long Beach, with the environmental watchdog group Sludgestoppers, said the plan "could be a viable option," but that he has concerns about water quality.
With 54 water-quality violations in the past five years, the Bay Park plant was ranked by an environmental advocacy group last year as Long Island's worst.
The proposed deal calls for United Water to run the Bay Park and Cedar Creek plants, 53 sewage pumping stations and 3,000 miles of sewers for at least 20 years. A private financier, Mangano said, would pay the county at least $750 million to fund the transaction, with the money going toward reducing the county's $3 billion debt. The investor would pay for all capital improvements to the plants.
The plan calls for sewer rates to be frozen through 2015, and then capped for the life of the deal at the rate of inflation.
Residents also raised questions about federal charges United is facing in Gary, Ind. The firm and two employees were charged by the Justice Department in 2010 with 26 counts of violating the Clean Water Act for allegedly tampering with daily wastewater sampling methods.
The company denies the allegations. "We feel strongly that the government is wrong," said Brent Fewell, United's chief of environmental compliance.