The project team worked with the city of Spokane to establish a next level of treatment filtration system by adding a tertiary membrane treatment to remove phosphorus. The system improves the quality of effluent released into the Spokane River, thereby enhancing the overall health of the waterway.

The facility is an advanced wastewater treatment plant serving a combined storm and sanitary sewer system for a community of 210,000. And with future UV disinfection, the treated water will achieve a Class A standard, allowing for reuse of the water for irrigation, dust control, industrial processes, enhancing wetlands and recharging groundwater supplies.

A major project challenge was finding parking for 120 construction workers on a very constrained site. Because busing staff to and from the site would have been too costly, the team obtained approval to establish a parking area across the street. The new lot addressed safety issues, and after construction of the treatment facility was completed, it became a safe parking area offering public recreational access to the river.

One of the project’s chief benefits was to increase the removal of phosphorus from the effluent discharged into the Spokane River and increase phosphorus removal to 99% from 90%. The team achieved this by installing a new tertiary membrane filtration system (the largest in the nation at that time) to remove the excess phosphorus.