Big Sandy WWTP - Secondary Treatment Plant in Chouteau County, Montana

Big Sandy WWTP is a municipal wastewater treatment facility located in Chouteau County, Montana, serving a population of 750. The plant provides secondary treatment, a standard level for small communities in the United States, ensuring that effluent meets basic quality standards before discharge. The plant's designed capacity is 681.37 million gallons, with an actual discharge volume of 321.76 million gallons per year, indicating it operates below capacity. As a US facility, it operates under the Clean Water Act's National Pollutant Discharge Elimination System (NPDES) permit program, which sets effluent limits and monitoring requirements to protect water quality. The treated wastewater is discharged into a local water body, likely a tributary of the Missouri River basin, which ultimately drains into the Mississippi River and the Gulf of Mexico. The plant's inland location and small population served reduce its environmental footprint, though secondary treatment is adequate for protecting the local watershed.

The plant discharges into a water body within the Missouri River basin, which flows into the Mississippi River and eventually the Gulf of Mexico. The local watershed supports agricultural activities and provides habitat for aquatic species. Secondary treatment helps reduce organic pollutants and suspended solids, protecting downstream ecosystems from nutrient enrichment and oxygen depletion.