Tumwater approves deal to maintain Palermo treatment lagoon


By Tiziana Piatos

The Tumwater City Council approved an interlocal agreement between Tumwater and the Washington Department of Transportation (WDOT) to maintain the Palermo Treatment Lagoon on Thursday, May 19.

According to City Administrator John Doan at the city’s public works committee meeting, the $100,000 deal will include routine maintenance of the aeration plant and address some of the neighborhood’s landscape issues in the region.

Officially called the Palermo Wellfield Superfund Site, the project began in 1993 when Tumwater discovered two contaminants in the city’s drinking water wells, according to a report by the US Environmental Protection Agency (EPA). The contaminants came from Washington Department of Transportation facilities and a local dry cleaning company. While the wells were decommissioned immediately, the EPA began cleanup of affected soil beginning in 1998.

The city administrator also assured council that he will work with the community development department to ensure that all of our permitting needs are met.

“The levels of contaminants continue to drop. However, they are still present, which is why we must continue to collaborate with them. [WDOT] to ensure our drinking water continues to be safe,” Doan said.

According to Doan, additional work is underway on Palermo Avenue. They are currently working on a treatability pilot project. The workers therefore install several wells.

“These facilities would act as a ‘wall’ and prevent water contamination,” Doan explained. “Right now they’re piloting and seeing if it’s effective for cleaning up in the neighborhood, and it’s safe for groundwater.”

Doan said there were no safety or public health implications.

Groundwater treatment in the Palermo catchment area

Doan said there is a lot of naturally flowing water in the Palermo Wellfield area. The natural flow of water is west to east up the Deschutes Valley – the Deschutes River.

“So as groundwater flows that way, the fumes and move with it,” Doan continued. “Therefore, the wellfield historically captured this plume in the mid-2000s or early or late 1990s.”

Doan said the system installed by the EPA is still working and the venting system captures and treats the plume effectively.

“So any water we actually deliver to our customers is free of any contaminants. Both of these contaminants are what they call Baltimore organics,” the city administrator said.

However, Doan said Palermo’s aeration facilities and treatment system remained in place because of the positive benefits they brought to the region.


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