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Riverside Park Water Reclamation Facility

The Riverside Park Water Reclamation Facility is the community's oldest and largest water recycling facility. The facility recycles about 34 million gallons of wastewater a day and returns the cleaned water to the Spokane River.

The facility is allowed to discharge treated water into the River through a permit (PDF 352 KB) granted by the Washington State Department of Ecology. We must comply with many local, state and federal regulations, which define standards for our effluent.

We consistently produce high-quality effluent and have won several awards for operations and maintenance excellence and beneficial use of remaining biosolids. The facility also routinely passes multiple inspections required by the Department of Ecology.

The Riverside Park facility can handle peak flows up to 150 million gallons a day, and runs that wastewater through a number of processing steps:

  • Preliminary: Rocks, grit and larger debris are removed.
  • Primary: At this step, solids settle to the bottom, and oils and grease float to the top. The solids and oils removed.
  • Secondary: Here, smaller dissolved and suspended particles are separated and removed from the water.
  • Disinfection: Then, the water is disinfected before it is released to the River.
  • Solids: Meanwhile, digesters are used to process all removed solids, oils, and suspended particles. Final, processed solids are dewatered and spread on fields where livestock grain is grown. We handle about 6,500 tons of this a year.

We continuously monitor all aspects of the plant's operations to ensure proper processing of wastewater. We take samples of the water multiple times a day, analyze them in our lab, and make tweaks to the process to keep things running smoothly.

We have made many upgrades to the facility since it was first built in 1958 to keep up with advancing technology, water quality standards, and odor control for surrounding neighbors.

Next Level of Treatment

Planning and design work is under way to add additional treatment at the plant. This tertiary treatment level is often referred to as the Next Level of Treatment. We will use membrane technology to further reduce pollutants, like heavy metals, PCBs, and phosphorus, and improve the quality of the water released to the River. Two types of membrane filters are being tested now.

We are required to add this new technology to the plant to meet requirements for reducing phosphorus going into the river. Phosphorus essentially acts as a fertilizer in the river, encouraging the growth of aquatic plants that compete for oxygen with fish.

We are working with the Department of Ecology to finalize our plans for this project. We are also considering the impacts of this work in coordination with other work to improve the health of the Spokane River. Read the full Next Level of Treatment Engineering Report and Wastewater Facilities Plan Amendment No. 3 (PDF 10.3 MB) for additional information.

Construction on this project, with an estimated $126 million construction cost, is expected to begin in late 2016. The City is required to be in compliance with phosphorus standards for the plant's effluent by March 2021.


Treatment Plant Facts

Report a wastewater or stormwater problem: 509.625.7900

Avg Amt of Wastewater Processed Daily – 34 M Gallons

Capacity at the Facility's Headworks – 150 M Gallons

Solids Resulting from the Process in a year – 6,500 tons

Interesting Use for Digester Gas – Creating steam heat

Original Year Built – 1958