REWEY STP Wastewater Treatment Plant, Town of Mifflin, Wisconsin

REWEY STP is a municipal wastewater treatment plant located in the Town of Mifflin, Iowa County, Wisconsin, United States. The facility serves a small population of 291 residents, reflecting its role in a rural community. As a secondary treatment plant, it provides biological treatment to reduce organic matter and suspended solids before discharge. The plant's designed capacity is 94.64 units, with an actual discharge volume of 53.00 units, indicating operational headroom. Under the U.S. Clean Water Act, such facilities operate under 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 local water body that ultimately drains into the Mississippi River basin. The plant's location in southwestern Wisconsin places it within the Driftless Area, a region known for its spring-fed streams and sensitive aquatic ecosystems. Proper treatment helps maintain water quality in downstream rivers and the Upper Mississippi River.

The plant's discharge enters a tributary of the Grant River or a nearby stream, which flows into the Mississippi River. The Mississippi River is a major ecological corridor supporting diverse fish and migratory bird species. The Driftless Area's karst topography and cold-water streams are sensitive to nutrient pollution, making secondary treatment important for protecting aquatic life and recreational uses.