Clallam Bay STP - Secondary Wastewater Treatment Plant in Clallam Bay, Washington

Clallam Bay STP is a municipal wastewater treatment facility located at 441 Frontier Street in Clallam Bay, Washington, United States. The plant serves a small population of 780 residents and operates under secondary treatment standards, as required by the U.S. Clean Water Act for facilities of this scale. The plant has a designed capacity of 302.83 m³/day and currently discharges approximately 454.25 m³/day of treated wastewater. As a secondary treatment plant, it provides biological treatment to reduce organic matter and suspended solids before discharge. The facility is regulated under the National Pollutant Discharge Elimination System (NPDES) permit program administered by the Washington State Department of Ecology. The treated effluent is discharged into the coastal waters of the Pacific Ocean near Clallam Bay. This area supports diverse marine life, including salmon runs and shellfish populations. The plant's proximity to the coast requires careful management to protect water quality and aquatic habitats in the nearshore environment.

The plant discharges into the Pacific Ocean near Clallam Bay, which is part of the Strait of Juan de Fuca ecosystem. This coastal area supports critical habitats for salmon, steelhead, and other marine species. The region's watershed drains from the Olympic Peninsula, with freshwater inputs influencing nearshore salinity and nutrient dynamics. Proper treatment is essential to prevent eutrophication and protect shellfish beds and recreational waters.