Mansfield S_T FAC Wastewater Treatment Plant | Mansfield, Washington

Mansfield S_T FAC is a municipal wastewater treatment plant located at 55 Wall Avenue in Mansfield, Washington, a small community in Douglas County. The plant serves a population of approximately 325 residents, classifying it as a small-scale facility within the state's wastewater infrastructure. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 151.42 megaliters per year, the facility operates under the U.S. Clean Water Act, which requires NPDES permits for all point source discharges. For small agglomerations like Mansfield, secondary treatment is the baseline requirement to protect water quality. The treated effluent is discharged into a local water body, likely a tributary of the Columbia River basin, which ultimately drains to the Pacific Ocean. The plant plays a key role in safeguarding downstream aquatic ecosystems, including fish habitats in the Columbia River system, by reducing nutrient and pollutant loads.

The plant discharges into a local watercourse within the Columbia River basin, one of the largest river systems in North America. The Columbia River supports diverse aquatic life, including salmon and steelhead, and is an important migratory corridor. Downstream, the river flows into the Pacific Ocean, where nutrient and pollutant inputs can affect coastal marine ecosystems. The plant's secondary treatment helps mitigate eutrophication risks in the receiving waters.