(January 6 WSB photo, Cove Park entrance)
Three weeks ago, warning signs like that one were up at and near Cove Park south of the Fauntleroy ferry dock after a combined-sewer overflow sent a mix of stormwater and sewage into Puget Sound. The King County Wastewater Treatment Division told WSB that an “electrical issue” at the Barton Street Pump Station was to blame. We’ve been asking for more specifics and obtained additional information from KCWTD, which also now says the spill was about half the size first reported. Here’s what we received after our latest followup inquiry to KCWTD spokesperson Akiko Oda:
On Jan. 5, the Barton Street Pump Station experienced a power loss to one of the phases from the inbound utility power line. This caused the variable frequency drives, which control the station’s pumps, to shut down as a protective measure — similar to a circuit breaker. The overflow lasted only three minutes because an on-call wastewater operator arrived on site and was able to manually reset the variable frequency drives and bring the equipment quickly back online. Approximately 1,660 gallons of stormwater and wastewater was released — far less than the initial 3,500 gallons we conservatively reported.
We are working with the vendor of the variable frequency drives to help improve their resiliency to different types of power fluctuations. Our pump control system is complex, and we have to continuously look for ways to update and improve these systems so we can prevent overflows.
The pump station on the north side of the ferry dock was upgraded a decade ago, and electrical work was part of the project.
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