ASTORIA STP - Astoria, Oregon Wastewater Treatment Plant

ASTORIA STP is a municipal wastewater treatment plant located on Lagoon Road in Tongue Point Village, Astoria, Oregon. It serves a population of about 10,400 people in the Clatsop County area, near the confluence of the Columbia River and the Pacific Ocean. As a US facility, ASTORIA STP operates under the National Pollutant Discharge Elimination System (NPDES) permit program, which sets effluent limits and monitoring requirements. The plant's designed capacity is 1.00 million gallons per day, indicating a moderate-scale facility. The plant's treated effluent discharges into the Columbia River estuary, a critical ecosystem that supports salmon runs, migratory birds, and diverse aquatic life. The estuary flows into the Pacific Ocean, making the plant's performance important for both local water quality and downstream marine environments.

ASTORIA STP discharges into the Columbia River estuary, a dynamic mixing zone where freshwater meets the Pacific Ocean. This estuary is ecologically sensitive, supporting endangered salmon species, steelhead trout, and a rich community of invertebrates and birds. The plant's location within 50 km of the coast means its effluent can influence nearshore marine water quality, particularly during low-flow periods.