MSD Mill Creek Drainage Basin Wastewater Treatment Plant, Cincinnati, Ohio

MSD Mill Creek Drainage Basin is a major wastewater treatment facility serving the Cincinnati metropolitan area in Ohio, United States. With a population served of approximately 428,050, it operates as part of the Metropolitan Sewer District of Greater Cincinnati's network, managing wastewater from residential, commercial, and industrial sources in the Mill Creek watershed. As a large agglomeration serving over 400,000 people, the plant is subject to the U. S. Clean Water Act and National Pollutant Discharge Elimination System (NPDES) permitting requirements. The plant discharges treated effluent into the Mill Creek, a tributary of the Ohio River. The Ohio River flows into the Mississippi River and ultimately to the Gulf of Mexico, making this plant part of a vast inland drainage system. Its operations are critical for protecting water quality in the Ohio River basin, which supports diverse aquatic life and provides drinking water for millions downstream.

The plant discharges into Mill Creek, which flows into the Ohio River near Cincinnati. The Ohio River is a major tributary of the Mississippi River, draining into the Gulf of Mexico. This watershed supports diverse aquatic ecosystems, including fish species such as bass and catfish, and provides habitat for migratory birds. The plant's effluent quality is crucial for maintaining the ecological health of the Ohio River, which serves as a drinking water source for numerous communities downstream.