The Sacramento region will proceed with removing ammonia from its sewage effluent, settling a key dispute in a legal battle over protecting water quality in the Delta.
In the settlement reached Friday, the Sacramento Regional County Sanitation District agreed it no longer will fight the terms of a state permit, issued in 2010, that requires the capital region to remove ammonia and nitrogen from its urban wastewater. The district's board is led by elected officials from throughout the region.
The regional treatment plant near Elk Grove processes effluent from 1.4 million people in the capital area. That mixture is then pumped into the Sacramento River near Freeport at the rate of millions of gallons every day.
This effluent is the largest single source of ammonia entering the aquatic environment of the Sacramento-San Joaquin Delta; scientists say it has contributed to an altered food chain and potentially the decline of native fish species.
The sanitation district has contested the science behind this claim. But it agreed to drop its opposition to the treatment requirement in the lawsuit, originally filed against the state in 2011.
Stan Dean, district engineer, said the agency always planned to cut ammonia by 50 percent. Going to 100 percent is "not the end of the world for us," especially after seeing results of an $18 million pilot treatment project.
"It's a very good business decision for the sanitation district, and it's a very pragmatic thing to do, and it puts an end to this war over should we or shouldn't we remove ammonia," Dean said. "We're just going to move forward and do it."
Ken Landau, assistant executive officer of the Central Valley Regional Water Quality Control Board, which imposed the rules and became the target of the lawsuit, called the settlement a "big plus" in that it allows both parties to focus on solving the ammonia problem.
"Rather than litigating, we will be working with them on the science of building this treatment solution, and that's a big win for both," Landau said.
The sanitation district agreed to meet the original deadline to remove ammonia, which is May 2021.
The district, however, is not giving up its fight against other permit terms that require the wastewater to be filtered. This so-called "tertiary" treatment step was also ordered in 2010 to remove pathogens, such as giardia and E. coli, and other pollutants. The lawsuit will remain active on this front.
Whether the district ultimately wins or loses on filtration, the settlement gives it two more years to meet the filtration requirement. That new deadline is May 2023.
The sanitation district estimates the filtration and ammonia removal together will cost $1.6 billion, to be funded primarily by ratepayers. Dean said ammonia removal alone might cost half as much, still a huge investment because it requires major renovations at the treatment plant.
"Essentially, we're going to replace our existing secondary wastewater treatment process with a new one," he said.
The settlement still must be approved in Sacramento Superior Court. Other parties to the lawsuit include a number of water agencies that rely on Delta water diversions and support the state's treatment order, including Metropolitan Water District of Southern California and Westlands Water District.
Contact The Bee's Matt Weiser at (916) 321-1264. Follow him on Twitter @matt_weiser.