Overview
Edmonds STP serves approximately 73,790 residents in Edmonds, Washington. The plant is located within 50 km of the coast and discharges treated wastewater into the Puget Sound ecosystem.
Edmonds STP is a municipal wastewater treatment plant serving the city of Edmonds, Washington, located in Snohomish County. The plant serves a population of approximately 73,790, placing it in the medium-to-large agglomeration category for the region. As part of the greater Seattle metropolitan area, the facility plays a key role in managing wastewater from a growing suburban community along the Puget Sound coastline. The plant operates under the U. S. Clean Water Act, which requires secondary treatment for municipal wastewater discharges to surface waters. Plants serving populations of this scale in Washington are typically permitted by the Washington State Department of Ecology under the National Pollutant Discharge Elimination System (NPDES). The designed capacity of 1.00 million gallons per day indicates the facility's planned treatment volume. The plant's treated effluent is discharged into the Puget Sound, a major estuary and part of the Salish Sea. This water body supports diverse marine life, including salmon, orcas, and shellfish. The discharge location is within a sensitive coastal environment where nutrient and pollutant loading must be carefully managed to protect water quality and aquatic habitats.
Environmental context
The plant discharges into the Puget Sound, a large estuarine system connected to the Pacific Ocean via the Strait of Juan de Fuca. The Puget Sound watershed includes numerous rivers and streams that drain the Cascade and Olympic mountain ranges. This ecosystem supports critical salmon runs, orca populations, and extensive shellfish beds. Effluent from the plant must meet strict water quality standards to protect these resources from nutrient enrichment and toxic contaminants.
Frequently asked questions
Edmonds STP is located at 200 2nd Avenue South, Edmonds, Washington, United States, in Snohomish County.
The plant serves approximately 73,790 residents in the city of Edmonds and surrounding areas.
The plant discharges treated effluent into the Puget Sound, a major estuary in the Pacific Northwest.
The plant operates under the Clean Water Act, which requires secondary treatment for municipal discharges. It is likely permitted by the Washington State Department of Ecology under the NPDES program.
Plants of this scale in Washington typically use secondary treatment processes such as activated sludge or trickling filters, with disinfection to meet water quality standards for sensitive coastal waters.
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