Big Timber WWTF - Secondary Wastewater Treatment in Sweet Grass County, Montana

Big Timber WWTF is a municipal wastewater treatment facility located in Sweet Grass County, Montana, serving a population of approximately 1,650 residents. The plant provides secondary treatment, a standard level for small communities in the United States, ensuring compliance with federal Clean Water Act requirements. The plant has a designed capacity of 1,979.76 megaliters per year and currently treats an annual discharge volume of 643.52 megaliters. As a secondary treatment facility, it utilizes biological processes to remove organic matter and suspended solids before discharge. The plant operates under the U.S. EPA's National Pollutant Discharge Elimination System (NPDES) permit program, which sets effluent limits to protect water quality. The treated effluent is discharged into a local waterway that ultimately drains into the Yellowstone River basin, a major tributary of the Missouri River system. This watershed supports diverse aquatic life and is important for regional agriculture and recreation. The plant's location inland and away from coastal areas reduces direct marine impact, but its discharge contributes to the overall health of the Yellowstone River ecosystem.

The plant discharges into a tributary of the Yellowstone River, which flows into the Missouri River and eventually the Mississippi River system. This watershed supports a variety of fish species, including trout and other cold-water species, and provides habitat for migratory birds. The area's semi-arid climate means that maintaining water quality in these rivers is critical for downstream communities and ecosystems.