RALEIGH, N.C. — When a treatment plant is not meeting its dumping "potential," it can transfer its unused amount to another water system. A treatment plant in Pamlico County agreed to sell dumping rights up the Neuse River to the town of Butner. It would be the largest nutrient transfer ever, which means up to 61,000 pounds of additional pollutants could end up in Falls Lake and the Neuse River.

Falls Lake supplies drinking water to more than 300,000 people, including Raleigh. It is also a haven for aquatic life and recreation.

"This is where the Eno, the Flat River, Knap of Reeds Creek and Ellerbee Creek all come together," said Upper Neuse Riverkeeper Dean Naujoks.

Naujoks said treated sewage from plants already threaten the resource. Increasing the nitrogen discharge limits can only do more harm.

"We just feel it's unacceptable," he said.

Nitrogen is a primary fertilizer that helps your grass grow, but if you put it in water, it makes algae grow.

"Algae blooms deplete the oxygen of water and it's very harmful to aquatic life, but it also causes odor and taste problems," Naujoks said.

Granville County and state leaders said critics are overreacting to the potential environmental impact.

"We really do not perceive this as polluting the river anymore than it's already there," Granville County commissioner Hubert Gooch said. "Otherwise, they wouldn't have allowed it be dumped into the river. It's just moving where it goes in at."

Officials point out expanding the Butner treatment plant is critical to keep up with the explosion of new homes and businesses.

"As a matter of fact, there can be no growth without some additional water and sewer," Gooch said.

"We just don't believe everyone that depends on this lake should have to bear that cost," Naujoks said.

State leaders argue an updated Butner treatment plant will be cleaner and more efficient than other facilities on the Neuse River. They said it will likely discharge far less than has been discussed.

Both sides of the debate want a thorough study to determine sewage impact on Falls Lake. With approval still pending, Raleigh, Rolesville, and the Environmental Protection Agency have all raised concerns.