ST PAUL STP Wastewater Treatment Plant, Marion County, Oregon

ST PAUL STP is a municipal wastewater treatment facility located in Marion County, Oregon, serving a small community of 354 residents. The plant provides secondary treatment, a standard level for small agglomerations in the United States, ensuring that pollutants are reduced before discharge. With a designed capacity of 249.84 and a discharge volume of 181.70, the plant operates under the regulatory framework of the US Clean Water Act, which requires NPDES permits for all point source discharges. Facilities of this scale typically comply with state-level water quality standards. The treated effluent from ST PAUL STP is released into the local watershed, which ultimately drains into the Willamette River. The Willamette River flows north through Oregon's agricultural and urban areas before joining the Columbia River, a major waterway that supports diverse aquatic life and provides critical habitat for salmon and other species.

The plant discharges into the Willamette River basin, a vital waterway in Oregon that flows into the Columbia River. The Willamette River supports a rich ecosystem, including migratory fish like Chinook salmon and steelhead trout. The surrounding watershed is predominantly agricultural, so the plant's secondary treatment helps protect water quality in this sensitive river system.