Lone Rock STP - Secondary Wastewater Treatment Plant in Lone Rock, Wisconsin

Lone Rock STP is a municipal wastewater treatment facility located in Lone Rock, Wisconsin, serving a population of approximately 886 residents. The plant provides secondary treatment, a standard level for small communities in the United States, ensuring that pollutants are reduced before discharge. The plant has a designed capacity of 215.77 volume units and an average daily discharge of 200.63 volume units, indicating consistent operation near its design capacity. As a US facility, it operates under the Clean Water Act, with National Pollutant Discharge Elimination System (NPDES) permits issued by the Wisconsin Department of Natural Resources, which set effluent limits to protect water quality. The treated effluent is discharged into a receiving water body that ultimately drains into the Wisconsin River watershed, part of the larger Mississippi River basin. This downstream system supports diverse aquatic life and provides water for communities and agriculture. The plant's secondary treatment helps reduce nutrient loading and protect the ecological health of these waters.

The plant discharges into a local waterway that flows into the Wisconsin River, a major tributary of the Mississippi River. The Wisconsin River watershed supports diverse aquatic habitats, including fish spawning grounds and migratory bird corridors. Downstream, the Mississippi River carries water to the Gulf of Mexico, where nutrient pollution can contribute to hypoxic zones. The plant's secondary treatment helps mitigate local nutrient impacts.