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Saturday, February 24, 2024
Feb. 24, 2024

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Sewage flows into Columbia River after power failure at Vancouver treatment plant

City says failure of generators led to accidental flow

By , Columbian politics reporter

Nearly an Olympic-sized pool worth of raw sewage was released into the Columbia River on Saturday.

About 400,000 gallons of untreated sewage left Vancouver’s Westside Wastewater Treatment facility, preceded by 110,000 gallons of partially treated effluent.

The release, according to the city, was due to a rapid series of power surges and failures at the plant between 8:30 to 11:15 a.m.

The surges rendered two standby generators inoperable and caused the remaining generator to overload shortly after it was brought online. Dan Swensen, the city’s engineering and construction services manager, said the backup generator is not equipped to handle the power requirements of the facility, so it shut down almost immediately.

The first release of 110,000 gallons was effluent, which was completely treated except for the final step: ultraviolet disinfectant.

“With effluent, you’re looking at liquid waste,” said Loretta Callahan, Vancouver Public Information Officer. “Basically you’re down to water.”

Raw sewage, on the other hand, contains feces, urine and laundry waste.

The good news, Swensen said, is all trace of sewage should be long gone.

“The volume of the river is such that by now any of the (sewage) has been diluted to a point it’s not a problem and washed down stream,” he said. “There’s nothing really for us to do.”

As a result of the release, the city is instructing residents who recreated in the river Saturday or Sunday west of the treatment facility at 2323 W. Mill Plain Blvd. to disinfect clothing, equipment and pets that could be contaminated. Any fish caught in the river, again west of the treatment facility, should be cleaned and cooked before consuming.

A release of partially or untreated sewage poses a health risk for those who ingest the water, either by accidentally swallowing it or hand-to-mouth contact, said Chuck Harman, Clark County Environmental Public Health program manager.

“If you have partially or untreated sewage, the primary concern is coming in contact with fecal bacteria, which can create sickness,” Harman said.

In addition to the “gross factor,” ingesting the water could lead to gastrointestinal illness causing vomiting and diarrhea, Harman said.

Since several days have passed since the release, Harman said the water in the area now is unlikely to pose a health risk.

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Delayed notification

While the event occurred on a Saturday, news of the release was not made available until late Wednesday afternoon. The cause of that delay, Swensen said, is two-fold.

Swensen said it took until Monday afternoon for staff to “convince ourselves there was a release.”

With power out, the tracking instrumentation was also out, meaning there was no way to track if sewage was actually released.

“We surmised there was a release, but we can’t prove it one way or another,” he said. “We’re erring on the side of caution.”

When instances such as the sewage release do occur, there’s a notification system in place. Regulators, including the Washington State Department of Ecology and Clark County Health Department, were notified first. The Public Information Officer should have also been notified Monday, but Swensen said there was “a little human error” involved.

“To be honest, this happens so infrequently that we had to dust off our protocol and we missed the PIO piece until (Wednesday) morning,” he said.

According to city records dating back to 1995, there has never been a release of raw sewage into the Columbia River. Swensen, who’s worked with the city since 1991, said there hasn’t been a similar instance in at least the last 26 years.

Without power, or surety that sewage was released, Swensen said staff estimated the number of gallons released based on flow rates before power went out. The facility treats an average of 10 million gallons of sewage per day.

Callahan said the city is working with Clark Public Utilities and CH2M, the treatment facility operator, to improve the distribution system and reliability of emergency generators to ensure a second release of sewage does not occur.

The city could face a fine by the Department of Ecology, but as of Wednesday, Callahan said the city had not been notified of any action. A spokesperson for the Department of Ecology could not be reached by press time. Callahan said incident review is a lengthy process and the city will be notified if a fine or other action is levied.

Health reporter Marissa Harshman contributed to this story.

Columbian politics reporter