Puget Sound was hit with another spill of untreated wastewater, this time from a King County pump station.

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Puget Sound took another hit of untreated wastewater Thursday.

A King County wastewater pump station in West Seattle switched off for 25 minutes during a neighborhood power outage, sending 330,000 gallons of stormwater and raw sewage into Puget Sound.

The 63rd Avenue Pump Station is supposed to send wastewater to an Alki facility for containment until it can be treated.

But instead the power outage, from 4:45 to 5:05 p.m., knocked out the plant. Crews brought over an emergency generator stored at the Alki Station. By that time, power was restored.

The spill was on top of millions of gallons of untreated wastewater bypassed into Puget Sound beginning Feb. 9, after a catastrophic flood at the West Point Treatment plant at Discovery Park in Magnolia.

The flood caused tens of millions of dollars in damage at the plant, which treats sewage from 1.7 million people in the Seattle region and will take many weeks to repair, according to King County wastewater officials.

The damage occurred when a pump station at the plant failed. The cause for the failure is not yet known.

Beaches at Discovery Park are closed, with no date yet for reopening, because of the risk to public health from raw sewage pumped from the plant into the Sound.

The plant sent 260 million gallons of untreated flows to Puget Sound beginning early in the morning Feb. 9 and stopped about 19 hours later, said Doug Williams, spokesman for the county.

Dumping of untreated flows began again about 3:30 a.m. Wednesday because of the wet weather and lasted until about 10:30 a.m., spilling an estimated 6 million to 10 million more gallons of untreated effluent into Puget Sound from an emergency overflow pipe 35 feet below the surface, nearly 500 feet offshore. Most of the effluent is stormwater, but about 10 percent is raw sewage.

The emergency overflows resumed from 4 p.m. Wednesday and continued overnight until about 6:30 a.m. Thursday, when heavy rain resumed. Totals from that bypass event had not yet been calculated.