Employees with King County’s sewer utility are working diligently to determine the cause of an overflow that occurred last night at the West Point Treatment Plant in Seattle’s Magnolia neighborhood.
“This situation is unacceptable,” said Christie True, director of King County’s Wastewater Treatment Division. “Finding out why it occurred is the first step toward taking corrective measures so we can prevent it from happening again.”
An estimated 10 million gallons of untreated wastewater was discharged through an emergency outfall about 500 feet off of West Point spit into Elliott Bay for nearly three hours before treatment plant operators were able to stop it about 1 a.m.
The overflow began as employees prepared the plant for high flows during last night’s rainfall. Standard operating procedures during wet weather entail readying an emergency bypass gate that can open automatically to prevent flooding inside the plant that could harm workers and damage equipment. Instead of being put on standby, the bypass gate was activated, resulting in the overflow. The cause of the gate failure is under investigation.
To protect public health and safety, the county posted the beach as closed, took water quality samples, and told health and regulatory agencies about the overflow.
Employees from the county’s environmental lab will monitor water quality in the area for the next several days.
The West Point Treatment Plant came online in 1966 and treats an average of 130 million gallons of wastewater a day for Seattle and several other cities and sewer districts in north and central King County. The plant can treat up to 440 million gallons of stormwater and wastewater during heavy rains.
Additional information about the West Point plant and the Wastewater Treatment Division is available on the Web at http://www.kingcounty.gov/