Selah S_T Facility Wastewater Treatment Plant, Selah, Washington

The Selah S_T Facility is a municipal wastewater treatment plant located in Selah, Washington, within Yakima County. It serves a population of about 5,100 residents, classifying it as a small to medium agglomeration under US regulatory standards. The plant is situated inland, away from coastal areas, and its operations are governed by the US Clean Water Act, which requires NPDES permits for discharges to surface waters. As a facility serving fewer than 10,000 people, the plant is subject to secondary treatment standards under the Clean Water Act, unless a higher level is required by the receiving water body's designated uses. Typical plants of this scale employ biological treatment followed by disinfection. It is assumed to be in compliance with state and federal regulations. The plant discharges treated effluent into the Yakima River watershed, which flows into the Columbia River and eventually reaches the Pacific Ocean. The Yakima River is a vital water resource for irrigation, recreation, and aquatic habitat in central Washington. The plant's discharge must meet water quality standards to protect fish species such as salmon and steelhead, which are important to the region's ecology and economy.

The Selah S_T Facility discharges into the Yakima River, a tributary of the Columbia River, which flows to the Pacific Ocean. The Yakima River basin supports diverse aquatic life, including salmon and steelhead, and is heavily used for agricultural irrigation. The plant's effluent must comply with water quality standards to protect these species and downstream uses. The region's semi-arid climate makes water quality management critical for maintaining ecosystem health and agricultural productivity.