$24M upgrade for cleaner water

HAYDEN — The Hayden Area Regional Sewer Board installed a $24 million upgrade on Dec. 13 to meet Spokane River dissolved oxygen total daily maximum load limits standards for 2024.

The investment was necessary because of the Washington Department of Ecology’s legal efforts to improve dissolved oxygen in the Spokane River and Long Lake, also known as Lake Spokane.

“You can’t build plants like this overnight, so they gave us 10 years to come up with the new technology and new equipment to meet the standard,” said Ken Windram, administrator and responsible operator for the Hayden Area Regional Sewer Board.

As part of the upgrade, the sewer board installed two pump stations and two high-density polyethylene storage tanks, about 55 and 45 feet long and 11 feet in diameter, with the larger one weighing 18,000 pounds.

The upgrade was funded by the Idaho Department of Environmental Quality state revolving funds.

Windram said they hope to have substantial completion by December 2022. That will allow two years to fine-tune the plant before the requirement is in place.

To insert water into the river, the plant must meet the parameters for organics, solids, nitrogen and phosphorus.

In December 2024, the new standard will call for 0.05 milligrams per liter of phosphorus.

No prior requirement existed, as the standards were developed between 2000 and 2010 after the Washington Department of Ecology did a study on the total daily maximum load calculations for the Spokane River to meet dissolved oxygen requirements in Long Lake.

An adequate amount of dissolved oxygen is vital for aquatic life to breathe, and helps decompose organic matter in the water and bottom sediments.

An overabundance of nutrients, such as phosphorus and organic matter, causes more dissolved oxygen to be used for decomposition, which reduces the amount available for fish and other aquatic life.

The Hayden sewer plant currently puts out 0.2 milligrams of phosphorus per liter, 97% less than intake. The upgrade allows the plant to regularly put out 0.02 to 0.03 milligrams of phosphorus per liter.

Windram said the new storage tanks help provide stable operations for better treatment.

While the upgrade doesn’t increase plant capacity, it does allow for future expansion if more funding becomes available.

The current system is at 2 million gallons per day rated capacity. The upgraded storage allows 2.4 million gallons.