Mount Vernon Treatment Wastewater Plant, Mount Vernon, Washington

Mount Vernon Treatment is a municipal wastewater facility serving the city of Mount Vernon in Skagit County, Washington. The plant serves a population of around 31,940 and is situated near the Skagit River, a major waterway in the Pacific Northwest. As a medium-sized agglomeration, it plays a key role in managing wastewater for the local community. The plant operates under the U.S. Clean Water Act, which requires secondary treatment for municipal wastewater. The National Pollutant Discharge Elimination System (NPDES) permits, issued by the Washington State Department of Ecology, govern discharge limits to protect water quality. The plant's designed capacity is 1.00 million gallons per day, indicating it is sized to handle the community's wastewater flows. The plant's treated effluent is discharged into the Skagit River, which flows into Skagit Bay and ultimately Puget Sound. This watershed supports diverse aquatic life, including salmon runs and other anadromous fish. The proximity to the coast (within 50 km) means that nutrient and pollutant management is critical to protect downstream estuarine and marine ecosystems.

Mount Vernon Treatment discharges into the Skagit River, which flows through the Skagit Valley into Skagit Bay, part of the larger Puget Sound estuary. The Skagit River is a vital habitat for Chinook salmon, steelhead, and bull trout, species that rely on clean water for spawning and migration. The plant's location within 50 km of the coast means its effluent can influence nearshore marine water quality, making nutrient removal and pathogen control important for the health of the downstream ecosystem.