KOOSKIA WTP Wastewater Treatment Plant, Idaho County, Idaho

KOOSKIA WTP is a municipal wastewater treatment plant located on Lower Battle Ridge Road in Idaho County, Idaho, United States. The facility serves a small population of 828 residents, reflecting its role in a rural community within the state's vast inland region. The plant provides secondary treatment, which is the standard biological treatment process required under the U.S. Clean Water Act for municipal wastewater. Secondary treatment typically involves biological oxidation and sedimentation to reduce organic matter and suspended solids. The plant's designed capacity is 749.51 units, and it currently discharges 832.79 units, indicating operation near or slightly above its design capacity. The treated effluent is discharged into a local waterway that ultimately drains into the Clearwater River, a major tributary of the Snake River, which flows into the Columbia River and eventually reaches the Pacific Ocean. The plant's operations are subject to the National Pollutant Discharge Elimination System (NPDES) permit program, ensuring compliance with water quality standards to protect downstream aquatic ecosystems.

The plant discharges into a local stream that feeds into the Clearwater River, a key tributary of the Snake River. The Snake River flows through the Columbia River Basin, supporting diverse aquatic life including salmon and steelhead. The region's mountainous terrain and seasonal snowmelt influence flow patterns, making consistent treatment important for maintaining water quality in downstream habitats.