Sacramento Wastewater Treatment
Plant Upgrades Long Overdue

UPDATE: Water Board Approves Long Overdue Upgrades to Sacramento Wastewater Treatment Plant

On December 8, after a lengthy public hearing that went late into the night, the Central Valley Regional Water Quality Control Board unanimously voted to adopt a permit, with a 5-0 vote, calling for the Sacramento Regional County Sanitation District to significantly clean up its wastewater discharges into the Delta. The Sacramento Wastewater Treatment Plant is the largest discharger of ammonia in the Delta, which, along with pathogens and other contaminants, has been a major threat to fish, the food web and human health in the estuary. The permit calls for the District to treat its discharges to a much higher level for these pollutants, consistent with other major urban dischargers.

The Sacramento Regional County Sanitation District is responsible for dumping roughly 140 million gallons of inadequately treated wastewater every day into the heart of the Delta, the state’s most important and most troubled estuary. To put it into context, the Sacramento region is the single largest source of treated sewage discharged to inland waters in the entire state. Sacramento’s regional sewage treatment plant is also the largest single source of ammonia in the Delta. In fact, the ammonia load has more than doubled since 1985 due to rapid urbanization. It now exceeds 14 tons per day and more than 125,000 gallons each month.

Multiple studies have shown that these discharges have adverse effects on the Delta habitat, specifically ammonia discharges, which have significantly affected native Delta fish populations. The increased discharge of ammonia in Delta waters has been extremely detrimental to the food web that delta smelt rely upon. The United States Fish and Wildlife Services’ biological opinion for Delta water project operations has stated that a reduction of contaminant levels and exposure to toxic algal blooms (which increase with high ammonia levels) are key to promoting the recovery of delta smelt and other native fish populations.

Water quality regulators have required other cities, such as Stockton and Modesto, to upgrade their treatment systems by installing tertiary systems to clean sewage discharges to the Delta. And, tertiary treatment is standard technology employed in wastewater treatment systems throughout the state. The permit adopted for Sacramento’s treatment plant by the Central Valley Regional Water Quality Control Board will place the same type of requirements on Sacramento’s discharges. “The proposed permit significantly reduces potential impacts from the District’s discharge and will ensure protection of public health, aquatic health and the environment,” said Pamela Creedon, executive officer of the Central Valley Regional Water Quality Board.

Wastewater discharge is just one of the many stressors affecting the Delta ecosystem and the native species it supports, but recent research suggests that it could be a principal driver behind the recent pelagic organism decline. When layered on top of the proliferation of invasive species, agricultural and urban runoff, predation, water diversions, and ocean harvest, it undoubtedly contributes to the crisis in our most vital estuary. The Sacramento wastewater treatment plant is uniquely situated to help solve at least one of these factors contributing to the Delta’s ills, and regulators needed to take this opportunity to aid the ailing estuary.

“The Delta has serious ecological problems. All waste discharges to the Delta must be carefully evaluated and any threats to delta water quality eliminated,” said Creedon. “It is time to move the District’s treatment process into the 21st century before allowing it to discharge more wastewater s to our vitally important Delta, which provides drinking water to over 23 million Californians, serves as a prime recreation area, and is habitat to many rare and endangered species.”

The upgrades to Sacramento’s wastewater treatment facility to reduce harmful discharges will not solve all of the Delta’s problems, but it is one important step toward meeting the co-equal goals of ecosystem restoration and water supply reliability.