ELLSWORTH STP - Advanced Wastewater Treatment in Grand Prairie Township, Minnesota

ELLSWORTH STP is a municipal wastewater treatment facility located in Grand Prairie Township, Nobles County, Minnesota. Serving a small population of 448, the plant provides advanced treatment to protect local water quality in this rural agricultural region of the upper Midwest. The plant operates under the U.S. Clean Water Act, which requires National Pollutant Discharge Elimination System (NPDES) permits for all wastewater discharges. With an advanced treatment level, the facility goes beyond secondary treatment standards to reduce nutrients and other pollutants, reflecting the regulatory expectations for sensitive watersheds in Minnesota. The treated effluent from ELLSWORTH STP enters local streams that drain into the Rock River, a tributary of the Big Sioux River, which ultimately flows into the Missouri River and then the Mississippi River. This connection to the Mississippi River basin means the plant's discharge contributes to the water quality of a major continental watershed that supports diverse aquatic ecosystems and provides drinking water for millions downstream.

The plant discharges into the Rock River watershed, part of the larger Missouri-Mississippi River system. This region supports diverse aquatic life including game fish species and migratory waterfowl. The advanced treatment helps reduce nutrient loading that could otherwise contribute to hypoxia in the Gulf of Mexico, where the Mississippi River terminates.