MT ANGEL STP - Marion County, Oregon Wastewater Treatment Plant

MT ANGEL STP is a municipal wastewater treatment plant located at 1045 Hayes Street in Marion County, Oregon, serving a population of approximately 3,700. The facility is situated inland, about 50 kilometers from the coast, and discharges into the local watershed. As a small-scale plant, it plays a vital role in protecting public health and water quality in the region. Under the U.S. Clean Water Act, municipal wastewater treatment plants are required to meet secondary treatment standards, which typically involve biological processes to reduce organic matter and suspended solids. For a plant serving around 3,700 people, the expected treatment level is secondary or higher, depending on the sensitivity of the receiving water body. The plant is likely permitted through the Oregon Department of Environmental Quality under the National Pollutant Discharge Elimination System (NPDES). The treated effluent from MT ANGEL STP eventually drains into the Willamette River basin, which flows north to the Columbia River and then to the Pacific Ocean. The Willamette River supports diverse aquatic life, including salmon and steelhead, and is an important ecological corridor in the Pacific Northwest. Proper treatment at this plant helps maintain water quality for downstream ecosystems and communities.

MT ANGEL STP discharges into the Willamette River basin, which flows into the Columbia River and ultimately the Pacific Ocean. The Willamette River is a vital waterway supporting salmon runs, migratory birds, and diverse riparian habitats. The plant's location in an agricultural and rural area means its effluent quality is important for maintaining the ecological health of downstream waters, including nutrient-sensitive zones that can experience algal blooms if nutrient loads are not controlled.