After enormous amounts of rain today in the Western Washington area, the King County Wastewater Treatment Division reported that they had experienced flooding at their West Point Treatment Plant in Seattle, WA.
As a result, they've had to shut down some of their operations and divert 150-200 million gallons of combined stormwater and wastewater to an emergency bypass outfall into Puget Sound since about 2:30 a.m. Thursday morning.
The plant is now operating in emergency bypass mode due to a response of major equipment failure. However, officials at the plant have been bypassing as much overflow sewage waste to other treatment plants in the county as possible.
According to a Treatment Division news release, "The County’s four combined sewer overflow treatment plants have been providing primary treatment to a portion of the flows that are being diverted from the treatment plant. Additional wastewater flows from communities around the north end of Lake Washington are being diverted to the County’s Brightwater Treatment Plant in Woodinville, and South Plant in Renton."
Sewage overflow systems are nothing new to Puget Sound. In the mid-20th century, many sewage systems dumped into Lake Washington, which ended up creating an uproar and environmental movement to make Lake Washington clean again. Now, overflows only release into the Puget Sound after certain thresholds are met. These releases are also regulated by the EPA and permits need to be acquired before releases can occur. In addition, the outflow pipes release into deep portions of Puget Sound; however, more studies need to be done on how this relatively point-source pollution affects the marine ecosystem.
The County is cooperating with the health department in testing for toxicity, and asking the public to avoid contact with the Puget Sound over the next 24-48 hours, in accordance with public health and safety.