PAISLEY STP - Secondary Wastewater Treatment Plant in Paisley, Oregon

PAISLEY STP is a municipal wastewater treatment facility located in Paisley, a small town in Lake County, Oregon. The plant serves a population of approximately 250 residents, reflecting the rural character of the area. It operates under the regulatory framework of the U.S. Clean Water Act, which requires secondary treatment for municipal discharges. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 189.27 m³/day and an actual discharge volume of 75.71 m³/day, the facility operates well below its capacity, indicating room for future growth. As a U.S. facility, it is subject to National Pollutant Discharge Elimination System (NPDES) permitting, which sets effluent limits to protect water quality. The treated effluent is discharged to a local water body, likely within the Chewaucan River watershed, which drains into the Great Basin. This arid region relies on limited surface water, making the plant's role in protecting downstream ecosystems critical. The discharge supports local aquatic life and contributes to the hydrology of the closed basin.

The plant discharges into the Chewaucan River watershed, which flows into the Great Basin, a closed basin that does not reach the ocean. The receiving waters support a variety of aquatic species adapted to the arid environment, including native fish and waterfowl. The plant's secondary treatment helps maintain water quality in this sensitive basin, where water resources are scarce and ecological balance is fragile.