Ahsahka STP Wastewater Treatment Plant, Clearwater County, Idaho

Ahsahka STP is a municipal wastewater treatment facility located in Clearwater County, Idaho, within the Dworshak Complex area. The plant serves a small population of 150 residents, reflecting its role in a rural community. As a secondary treatment plant, it provides biological treatment to reduce organic pollutants and suspended solids before discharge. The plant operates under the U.S. Clean Water Act, which requires secondary treatment for municipal facilities. With a designed capacity of 280.12 cubic meters per day and a discharge volume of 75.71 cubic meters per day, the plant has ample capacity for current demand. The regulatory framework ensures compliance with National Pollutant Discharge Elimination System (NPDES) permits, which set effluent limits to protect water quality. The treated effluent from Ahsahka STP is discharged into the Clearwater River basin, which flows into the Snake River and ultimately the Columbia River. This watershed supports diverse aquatic life, including salmon and steelhead, making effective treatment critical for downstream ecosystems. The plant's secondary treatment helps reduce nutrient loading and protect these sensitive habitats.

Ahsahka STP discharges into the Clearwater River, a tributary of the Snake River, which flows into the Columbia River and eventually the Pacific Ocean. This watershed supports critical fish species such as Chinook salmon and steelhead trout, which rely on clean water for spawning and migration. The plant's secondary treatment reduces organic pollutants and nutrients, helping to maintain water quality in this ecologically sensitive river system.