Winnebago STP - Advanced Wastewater Treatment in Winnebago, Illinois

Winnebago STP is a municipal wastewater treatment facility located in Winnebago, Illinois, United States. The plant serves a population of about 3,500 residents and operates under the regulatory framework of the US Clean Water Act, which requires National Pollutant Discharge Elimination System (NPDES) permits for all discharges. As an advanced treatment facility, it provides a higher level of pollutant removal than secondary treatment, ensuring compliance with stringent water quality standards. The plant has a designed capacity of 1,324.89 million gallons per day and currently treats an average daily flow of 719.23 million gallons, indicating operational headroom. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) and disinfection. The facility is subject to state-level oversight by the Illinois Environmental Protection Agency, which enforces permit limits based on the receiving water body's assimilative capacity. The treated effluent from Winnebago STP discharges into local streams that flow into the Rock River, a major tributary of the Mississippi River. The Rock River watershed supports diverse aquatic life and provides recreational opportunities. The plant's advanced treatment helps protect downstream water quality in the Mississippi River basin, which ultimately drains into the Gulf of Mexico.

Winnebago STP discharges into local waterways that are part of the Rock River watershed, which flows into the Mississippi River and eventually the Gulf of Mexico. The Rock River supports a variety of fish species and is used for recreation. The plant's advanced treatment reduces nutrient loads, helping to mitigate hypoxia in the Gulf of Mexico.