DSC Finds Science Supports Improved Sacramento-Area Wastewater Treatment

Updated permit would reduce daily ammonia discharges by 13 tons

Oct 28, 2010, 16:37 ET from Delta Stewardship Council

SACRAMENTO, Calif., Oct. 28 /PRNewswire/ -- The Delta Stewardship Council, charged with ensuring all levels of government help meet the state's coequal goals of a reliable water supply and a restored Delta ecosystem, voted Thursday to support a proposal to require more thorough treatment of Sacramento-area wastewater.

"If we're serious about the Delta and its future, we have to start doing things differently – upstream, downstream, and in the Delta itself," said Council Chairman Phil Isenberg. "The science is clear, and so is the need for action."

The NPDES permit that regulates the discharge of treated wastewater from the Sacramento Regional Wastewater Treatment Plant into the Sacramento River is more than 10 years old. The Central Valley Regional Water Quality Control Board has recommended a new tentative permit that in part would reduce the Sacramento County Regional Sanitation District's ammonia discharge from 14 tons per day to one ton per day, requiring an upgrade of its treatment facility.

In recent correspondence to the Central Valley board, Isenberg shared findings by the Council's lead scientist that the proposed permit is consistent with the best available science and is expected to improve water quality and the Delta ecosystem by limiting ammonia discharges that have thus far been left largely to the "assimilative capacity" of the Sacramento River.  The Council voted unanimously to ratify the chairman's letter.

"I ... agree that there is sufficient evidence of total ammonia and nitrogen impairment of the aquatic ecosystem to warrant the limits in the tentative permit," wrote Delta Stewardship Council Lead Scientist Cliff Dahm in the memo that Isenberg provided to the Central Valley water board. "The suggestion by the discharger that there is sufficient assimilative capacity in the Sacramento River to absorb 14 tons of ammonia per day runs counter to the mounting chemical and biological evidence downstream of the discharge."

Dahm commended the regional water board on its "comprehensive assessment" of the issues associated with the Sacramento Regional Wastewater Treatment Plant and noted that there is proof of multiple stressors affecting the Delta ecosystem. However, he said, it is also clear that the current balance of nutrients in the ecosystem – particularly ammonia levels – rank among the most important of these stressors.

At Thursday's meeting, Delta Stewardship Council Member Gloria Gray said that consideration of both specific stressors and their broader implications "goes to the heart" of the state's coequal goals for the Delta.

"The Council has to look at this issue as a whole in terms of what we were charged to do," Gray said before voting in favor of the Council officially adopting the position Isenberg relayed to the Central Valley board.

The Council voted 5-0 to adopt the position, with DSC Member and Sacramento County Supervisor Don Nottoli abstaining.

SOURCE Delta Stewardship Council