Rock Island STP SW Wastewater Treatment Plant, Rock Island, Illinois

Rock Island STP SW is a municipal wastewater treatment plant located in Rock Island, Illinois, serving a population of about 5,040 residents. The facility is part of the city's infrastructure, managing wastewater from the local community in Rock Island County. As a U.S. plant serving a small agglomeration, it is subject to the Clean Water Act and National Pollutant Discharge Elimination System (NPDES) permitting. The U.S. Environmental Protection Agency (EPA) and the Illinois Environmental Protection Agency oversee compliance, requiring secondary treatment as a baseline for municipal facilities of this scale. The plant discharges treated effluent into the Mississippi River basin, which flows southward to the Gulf of Mexico. The Mississippi River supports diverse aquatic life and is a critical migratory corridor for birds and fish. Proper treatment helps protect downstream water quality and ecosystems.

The plant discharges into the Mississippi River watershed, which drains into the Gulf of Mexico. The Mississippi River is a major ecological corridor, supporting diverse fish species and migratory birds. Downstream, the river contributes to the Gulf's hypoxic zone, making nutrient removal important for regional water quality.