Charged with ensuring all levels of government help meet the state’s coequal goals of a reliable water supply and a restored Delta ecosystem, the Delta Stewardship Council has voted to support a permit that would 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 Chair 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 to the Sacramento River is more than 10 years old, and Central Valley Regional Water Quality Control Board staff has recommended a new tentative permit that would bring the Sacramento plant up to the same level of treatment required of all other large wastewater discharges to the Delta. Among other measures, it would reduce the plant’s daily discharge of ammonia into the Sacramento River by 13 tons, from 14 to one.
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 into the Sacramento River.
At its October meeting, the Council voted 5-0, with Council Member Don Nottoli abstaining because he also serves on the board of the Sacramento Regional County Sanitation District, to ratify the chairman’s letter, which included the findings of Lead Scientist Cliff Dahm in support of the position.
In a memo, 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 – ranks among the most important of these stressors. Excessive amounts of some nutrients can promote the growth of harmful algae, which can degrade its quality both as a habitat for the Delta’s native aquatic species and as a source of drinking water.
“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 wrote. “It is time to make the (Sacramento plant) a key component of the overall Delta solution by bringing current treatment technology into the 21st century.”
Council Member Randy Fiorini put a related observation in blunter terms: “You’ve been using the Sacramento River to dilute pollution,” he told a plant representative at last month’s meeting.
The tentative permit under consideration requires ammonia removal, also known as full nitrification, which would necessitate the construction of new nitrification facilities and the increased use of chemicals and/or power to remove ammonia from the discharged wastewater. In addition to the ammonia measures, it would require new microfiltration and UV disinfection.
Sacramento wastewater officials estimate that full compliance with the terms of the permit would require about $2 billion in capital costs, which could be partially offset through local partnerships or by state or federal funding assistance. Regulators have proposed a 10-year period for compliance with the new permit.
Both Fiorini and Council Member Hank Nordhoff encouraged the Sacramento Regional Sanitation District to consider the financial benefits associated with selling the cleaner water when calculating the ultimate cost of improved water treatment.
The Central Valley Regional Water Control Board is scheduled to take up the matter at its meeting December 8-10 in Cordova.