The City of Snoqualmie is projected to increase in population to over 18,000 people in the next 20 years, necessitating a major upgrade to the treatment plant and river bank outfall.

The city had an engineering report and design documents prepared for these improvements on a fast track time schedule. The engineering report for the project evaluated alternate processes for nutrient removal , eventually selecting a low speed "Carousel" oxidation ditch configuration for anaerobic / anoxic / aerobic treatment. The city began planning work in early 1994 and design work in early 1995. Construction was completed on the wastewater pumping, transfer, and treatment facilities in 1997.  The plant was then upgraded again in 2003 increasing the capacity.
 
The new 3.0 mgd treatment plant includes mechanically cleaned bar screens, vortex grit removal, secondary treatment by a modified Bardenpho process for advanced nutrient removal, traveling hood effluent sand filtration, and ultraviolet disinfection. Sludge disposal is by wastage to existing facultative stabilization ponds. Effluent disposal is based on discharging secondary effluent to a new Snoqualmie River outfall in the winter, and Eagle Lake for golf course irrigation in the summer.  All water sent to Eagle Lake meets Class A Reclaim Water Standards.

Fallsgro Biosolids
Available to Residents (free)

The City of Snoqualmie’s Water Reclamation Facility, with the addition of Fallsgro biosolids production, is now capable of recapturing wasted nutrients and transforming them into a slow release nutrient-rich organic soil enhancer. The city has received clearance by the State of Washington Department of Ecology to make its Class “EQ” (Exceptional Quality) biosolids product available to the public. The product can be used in gardens and areas that require fertilizer.

Biosolids Fact Sheet