Four months after a disastrous wastewater spill in Puget Sound, water quality levels are normal.
Hundreds of millions of gallons of sewage and stormwater spilled from the West Point treatment plant near Discovery Park. Local lawmakers called it a disaster, and it cost King County millions of dollars in repairs.
King County’s Wastewater Treatment Division has been checking the water quality every week, watching bacteria levels, the amount of solids, nutrients, dissolved oxygen and more.
In the days immediately after the incident that caused the spill, some monitoring categories spiked. As of now, lead water quality planner Kimberle Stark said everything looks typical.
“There was a reason West Point outfall was put in the location it was. It’s a perfect location in terms of, there are some very high bottom currents,” Stark said. “So the effluent goes out and kind of moves and just becomes very dilute, very quickly.”
She said even when West Point was not fully functioning, workers were able to chlorinate most of the waste that was pumping into Puget Sound. Stark said that’s another reason there are not longer-term effects from the plant failure.
Even so, Stark said the county will likely do reports for a few more weeks off of the Discovery Park monitoring station. That’s because recent results show higher ammonia levels in the water that’s pumped out of the South Treatment Plant, based in Renton.
That facility received trucks of sewage, mostly solids, when the West Point equipment was under repair. Stark said that led to higher ammonia levels in the water, but still nothing beyond the state’s clean water limit.
King County has hired a consultant to look into what caused the equipment failure. The Washington State Department of Ecology is also tracking water quality.
West Point was operating at full capacity by the end of April.
West Point treats wastewater from homes and businesses in Seattle, Shoreline, north King County and parts of south Snohomish County.