Baker City no longer piping wastewater into Powder River

Jun. 15—For the first time in more than half a century, Baker City no longer has to discharge its treated wastewater into the Powder River north of town.

The city had piped the wastewater into the river from its four treatment and storage lagoons, about a mile north of town, into the river since the early 1960s.

The destination for that water now is the new storage pond the city had built last year on a 51-acre parcel about seven miles away, east of Interstate 84 and just south of Highway 203 at the eastern edge of Baker Valley.

"Not finished, but we're definitely at a major milestone here," said Michelle Owen, the city's public works director. "To me this is a huge milestone, the fact that we're no longer in the river and we're going into our new storage pond."

The old treatment lagoons — the largest is about 70 acres, and the three others are about 10 acres each — are connected by a pipeline to the new storage pond, which is much deeper — about 20 feet compared with 6 to 8 feet — and thus has a larger capacity.

The pipeline and new storage pond are the major parts of one of the city's largest and most expensive public works projects in the past couple decades, a $5.7 million job the city undertook after the Oregon Department of Environmental Quality (DEQ) mandated that the city eventually cease piping treated wastewater into the Powder River.

DEQ told city officials that treated wastewater could promote algae blooms and otherwise pollute the river.

In 2017, the city entered into a Mutual Agreement and Order (MAO) with DEQ.

The city previously added chlorine to its wastewater to kill bacteria, then used sulfur dioxide to remove the chlorine before the water was released into the river.

Owen said the city will continue to use the lagoons to temporarily store wastewater. Bacteria help break down pollutants in the wastewater, and solid material settles to the bottom. Typically wastewater is stored in the lagoons for about 30 days, although during the winter, when the lagoons are frozen, the city stores the water longer.

Because the treated water will now be piped to the new pond, and used to irrigate non-food crops such as alfalfa rather than discharged into the river, the city no longer has to add sulfur dioxide to remove the chlorine, Owen said.

The chlorine will dissipate naturally before it's used for irrigation, she said.

"We're still treating wastewater at the (old) lagoon and it travels approximately seven miles out to our new storage pond," Owen said.

The city is pumping about three million gallons per day to the new lagoon, Owen said.

Of that volume, about 1.2 million is the water that flows each day from the city's homes and businesses.

The rest is water that was already stored in the lagoons.

Lowering the water levels in the lagoons enables another part of the multiyear project — removing the sludge that has accumulated over decades at the lagoons.

That sludge has reduced the capacity of lagoons, Owen said.

The city will also replace valves in pipes that connect the treatment lagoons.

"Those need to be replaced as part of this project, so we need to bring the water level down so the contractor can actually work on the structures," Owen said.

Treated wastewater can flow from the lagoons to the new storage pond by gravity alone. However, Owen said there are pumps at both ends of the pipeline. The pump at the lagoons allows the city to move a higher volume of wastewater than by gravity alone. She said the city is using that pump now to accelerate the lowering of the lagoons.

The pump at the new storage pond makes it possible for the city to move water from there back to the lagoons, where the city hopes to make the water available to nearby landowners to irrigate.

Water from the new storage pond will also be used for irrigation, Owen said.

"We're trying to get enough water into the new pond so that we can fire up those pumps over there and make sure that everything's working and then we'll be able to go into land application for irrigation," she said.

Testing for that will likely occur within a week or two.

Owen estimates the city will have a permit from DEQ allowing irrigation by August. They are waiting for the pump manufacturer to be available to set that up. Owen estimates that it will be around August before they have the paperwork approved by DEQ to begin irrigation.

In January 2021 the City Council voted to hire Gyllenberg Construction of Baker City, the lowest among 10 bidders, to oversee the project.

Owen said the new storage pond will increase the city's wastewater storage capacity, making the city better able to deal with population growth.

The additional storage also will allow the city to hold water when there's no need for irrigation water.

The city had to choose a pond site more than 10,000 feet from the Baker City Airport, because the water could attract flocks of geese and other birds that can pose a danger to aircraft.

The city bought the 51-acre property in 2019 for $123,000. The city also paid $37,900 for an easement across another property that the pipeline crosses.

In November 2020 the City Council agreed to have the city borrow as much as $7.5 million from the state to pay for the wastewater project. The city will repay the loan over 30 years with a 1.36% annual interest rate, and annual payments on the loan are estimated at $275,000, Owen said.

Based on the contract with Gyllenberg Construction, for about $5.7 million, the city likely won't need to borrow the full amount, which could reduce the annual payments somewhat, she said.