Wastewater treatment upgrades could cost Pullman $14.6M

DAN DOUCET, Evergreen opinion editor

The city of Pullman is considering upgrades to its wastewater treatment facility, which could cost $14.6 million, in order to meet state regulations by 2019.

Tom Dupuis, project manager from HDR, Inc., said the existing system puts too much dichlorobromomethane (DCBM), a byproduct of the chlorination disinfection process, into the South Fork of the Palouse River.

Potential alternatives to the current process include ultraviolet light disinfection, which would cost $7.3 million; peracetic acid, which would cost $13.1 million; or a combination of both for $12.9 million. Dupuis recommended the UV light alternative because of its low cost and proven effectiveness. With additional upgrades, he said, this will total $14.6 million.

Kevin Gardes, Pullman public works director, said the city contracted HDR Inc. to prepare a facility plan for the city’s wastewater treatment plant. The plan will account for the next 20 years, which Gardes said is typical for this type of plant. The improvements will help offset the increasing population of the city, he said.

“As the city continues to grow,” Gardes said, “it is prudent to plan for and construct needed improvements.”

The costs vary from $900,000 per year to $4 million per year in order to meet the facility plan’s requirements. Gardes said $15 million has already been spent on the facility over a 10-year period.

The plan primarily focuses on disinfection and solids processing, Gardes said. A key element of the 20-year plan is to update currents and project future flows and loads of pollutants treated at the plant prior to being discharged into the South Fork.

The city also needs acquire a Washington Department of Ecology discharge permit and meet the total maximum daily load standards for discharging, Dupuis said.

WSU currently pays 36.4 percent of the operating costs for the plant, Gardes said, and the city and the university have begun discussing how they will share the cost of the facility plan.

Reporting by Dan Doucet