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Improved hygiene during pandemic might be to blame for muckier wastewater coming out of Liberty Lake plant

Timm Ott, of the Liberty Lake Sewer and Water District, demonstrates how he takes a sample from the aeration basin at the district’s wastewater treatment plant on Friday, May 8, 2020. Officials at the Liberty Lake plant are concerned about all the soap, hand sanitizer and disinfectants being used to protect against the novel coronavirus. They say more of those products are going down the drain and killing the bacteria needed to treat wastewater before it’s discharged into the Spokane River. (Dan Pelle / The Spokesman-Review)

The constant scrubbing, hand-washing and sanitizing that is protecting people from the novel coronavirus may also be inhibiting the dirty work of bugs in Liberty Lake.

The city’s wastewater treatment plant has noticed thinner bacteria colonies that aid sewage treatment. The phenomenon coincides with government orders to stay home and clean surfaces thoroughly, said BiJay Adams, general manager of the Liberty Lake Sewer and Water District.

“We’re a little at a loss, because we can’t tell people, stop washing your hands or using bleach,” Adams said. “What we’re trying to do now is wait out the storm, if you will.”

Liberty Lake notified the state Department of Ecology, which is responsible for issuing permits for entities discharging water into the Spokane River.

So far, the department has not seen the same levels of waste products remaining in treated water, known as effluent, at other treatment plants, but officials are looking statewide for trends, said Art Jenkins, the department’s wastewater permit supervisor for Eastern Washington.

“They’re seeing higher levels of ammonia and other things that are coming through,” Jenkins said of Liberty Lake. “Their bug population is down. It’s not as healthy.”

Most water treatment plants use a process known as biological nutrient removal to break down human waste and other larger compounds in water before it’s clarified, filtered and disinfected for discharge from the plant.

Adams said officials have noticed a reduction in bacteria called “nitrifiers” – microorganisms that break down ammonia into nitrate, which escapes into the atmosphere as nitrogen gas as part of the treatment process.

The phenomenon has been observed by researchers over the past decade, who were concerned about concentrations of a common bacteria-killing agent called triclosan in treated water, indicating a battle with nitrifiers.

Triclosan can be found in toothpaste, deodorants and cosmetics – as well as the antibacterial soaps and hand sanitizers that have flown off store shelves in recent weeks.

Jenkins called the readings at Liberty Lake concerning, but said they didn’t constitute an emergency. Should the readings continue to spike, the potential damage would be algae blooms in the Spokane River, which could affect fish, plants and other wildlife, but Jenkins noted that Liberty Lake is just one of several sources of discharge into the Spokane River.

“We don’t think this is going to continue. Hopefully there’s answers to these questions as time goes on,” he said.

Other facilities both upstream and downstream have not yet reported issues with their bacterial colonies in the days and weeks since the Health Department and the Centers for Disease Control and Prevention urged everyone to frequently wash their hands, use hand sanitizer and – for businesses that have to remain open – disinfect workspaces frequently.

“Using bugs to treat wastewater is nothing new,” said Mike Anderson, wastewater superintendent for the city of Coeur d’Alene.

The city’s wastewater treatment plant has been operational since 1939 and uses a cleaning method that Anderson called “trickling,” in which water is treated as it passes over plastic filters that bacteria cling to. Coeur d’Alene hasn’t seen any major impact to its bacterial treatment since the pandemic began, Anderson said.

Representatives of plants in Post Falls and Hayden also said they hadn’t seen any noticeable change in their bacteria colonies.

Officials with the state Department of Ecology surmised the issue may be more prominent in Liberty Lake because of its smaller size, and because it has fewer industrial users than larger wastewater systems, like those in the city of Spokane and Spokane County.

Plants also don’t typically test the water coming into their facilities, known as influent, for the presence of soaps or triclosan, making any collection of data now meaningless, Adams said.

“We wouldn’t have any kind of baseline,” he said.

Liberty Lake is working with the Ecology Department on potential approaches that would maximize the cleaning operations of its plant, which became operational in 2017.

State regulators said they appreciated that Liberty Lake officials came forward quickly with their concern, and that they would work with the sewer district to achieve compliance with its permit during the irregular circumstances caused by the pandemic.

“We understand things are strange right now, and we want to work with facilities and businesses to work toward compliance as much as we can,” said Ryan Lancaster, an Ecology Department spokesman.