Spokane Riverside Park Water Reclamation Facility
Slayden is working on a $125 million upgrade to its Riverside Park Water Reclamation Facility. The upgrade will add a new filtration system at the plant, commonly called the Next Level of Treatment, and will greatly improve the quality of effluent that is released to the Spokane River. It will be designed to treat an average wastewater flow of 50 mgd. The project includes a new chemical facility, new primary clarifiers, a new primary solids pump station and modifications to the headworks, pumping facility and tunnels.
- Will be the largest upgrade at the plant since 1970.
- Will be one of the largest and most effective phosphate removal systems of its kind built in the U.S – removing more than 99% phosphorus.
- The client had a budget of $35 million for Phase 1. Thanks to value engineering and constructability reviews, we found $3.9 million in savings, returning close to $4 million to the client. Phase 1 of the $126 million project is now costing the client $31 million.
Project Impact


- This project is a major initiative to improve the health of the Spokane River. It will increase phosphorus removal from the effluent from 90% to 99%, which, in return, will help the oxygen levels in Lake Spokane, creating a more suitable environment for aquatic life.