King County is still investigating, but it appears that a power surge might have knocked out two pumps and led to the massive damage.

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Damage to the crippled West Point wastewater-treatment plant in Seattle could cost more than $25 million to repair and might have happened after a power surge knocked out two pumps, resulting in major flooding, according to new details from King County.

The cost and possible cause are all part of an ongoing investigation yet to nail down the extent of damage or the source of the trouble.

The details were spelled out by King County with its insurer, whom the county asked on Feb. 24 to wire $10 million for repairs. So far, the insurer has released $5 million, but it may hand over $25 million as soon as this week as the company receives more information from King County on the extent of the damage.

The county is also discussing coverage for losses potentially far higher.

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To speed repairs, the Metropolitan King County Council, on a 9-0 vote Monday, passed legislation to allow contracting to fix the plant without the usual competitive-bidding requirements.

Mark Isaacson, director of the King County wastewater division, said the waiver, good through May 2018, removes a hurdle that can add three to six months to the procurement process.

He promised a root-cause analysis of the plant flooding but said right now the first priority is employee safety and getting the plant back to normal operation.

Early understanding already emerging includes problems with the power supply to pumps that carry effluent from the plant, as well as level-limit switches on raw-sewage pumps that did not activate.

The flooding that crippled the plant occurred during a 10-minute period as sewage and wastewater continued to pour in while workers were trying to start the failed pumps.

A separate emergency gate eventually triggered automatically, shutting down further flow. But by then the damage was done.

On the bidding waiver, Councilmember Kathy Lambert offered an amendment that imposed the May 2018 sunset, as well as reporting requirements to the council. The wastewater-treatment division had asked for the waiver through August 2018.

Lambert said she also wants to know why backup systems at the plant apparently failed. “I have a lot of questions,” she said.

Councilmember Rod Dembowski said it is imperative to speed ahead with repairs.

“It’s an environmental catastrophe every day it is not up and running,” he said of the plant. “I hate to say that, but it’s true.”

A council subcommittee meets in a public session at 3 p.m. Wednesday for a briefing by King County Wastewater on the flood at the plant.

The flood of wastewater in the plant occurred at 2:30 a.m. Feb. 9, when the pumps went out just as the plant was taking in maximum flows during heavy rain and snow melt.

Areas of the plant flooded with an estimated 12 feet of raw sewage and stormwater. Thousands of pieces of equipment were destroyed in the flooding, including an estimated 200 electrical motors submerged in the polluted water.

The motors run pumps and connect switch gear and electrical panels that also must all be replaced, along with hundreds of yards of ruined insulation in hot-water piping.

An additional 20 to 25 power-distribution controls were also damaged. Also wrecked were employee lockers, including all the personal gear inside.

Cleanup began immediately after the disaster and is ongoing. The work includes pumping out the mess and power washing and steam cleaning equipment and surfaces.

Some damaged equipment will be repaired, but much of it is considered a total loss.

Costs also include trucking sludge usually treated at the plant all the way to Renton, where the county runs another regional wastewater-treatment facility.

The West Point plant is running at only half-capacity, operating well below the performance required by its state permit from the Department of Ecology.

West Point is supposed to send wastewater into Puget Sound cleaned to at least 85 percent purity. But right now wastewater is being returned to the Sound only 40 percent clean of solids — or worse.

With its reduced capacity, during high flows the plant has also shunted hundreds of millions of gallons of untreated wastewater directly to the Sound through an emergency bypass.

The plant, located near Magnolia next to Discovery Park, probably won’t be back to operating normally until at least April, managers have estimated.