Friday, July 24, 2009

Sewer rehab to address odor problem

Relief from the "rotten egg" smell that permeates the Ridgeway Street area of Warrenton and into surrounding neighborhoods is on the way.

Warren County Public Utilities Director Macon Robertson said that construction on sewer system improvements should begin around the first of September, with completion expected in four to six months.

Earlier this month, the county commissioners awarded the $247,257 construction contract to H.G. Reynolds.

The project is funded by the N.C. Rural Center, whose board is meeting on Aug. 26 to vote on obligating money for the improvements.

Roberson explained that the offensive smell is caused by turbulence in the current sewer line churning the hydrogen sulfide gas that creates the "rotten egg" odor. The upgrade to the pump system at Soul City would create a high velocity of flow in sewer mains that would prevent the formation of the gas and make for a smooth transition to the wastewater treatment plant in Warrenton.

In addition to the planned construction, the smell has been addressed through the use of various chemical additives.

"We've been battling it endlessly to try to resolve it. We've tried various chemical applications to try to mask it," Robertson said.

He and his staff recently performed a pilot study on chemical use to eliminate hydrogen sulfide formers, but Robertson said that determining the amount of chemicals used versus the levels of hydrogen sulfide is a "magical balance."

In theory, the improvements could move the odor somewhere else, Robertson said, and the odor may not be gone forever due to mechanical failures or excessive flow for whatever reason.