St Leon WWTP - Dearborn County, Indiana Wastewater Treatment Plant

St Leon WWTP is a municipal wastewater treatment facility located in Dearborn County, Indiana, United States. It serves a population of approximately 2,900 residents in the rural community of St Leon and surrounding areas. The plant is situated near State Road 46, about 30 miles west of Cincinnati, Ohio. As a small-scale treatment plant in the United States, St Leon WWTP operates under the regulatory framework of the Clean Water Act, administered by the Indiana Department of Environmental Management (IDEM). Plants of this size typically employ secondary treatment processes to meet National Pollutant Discharge Elimination System (NPDES) permit requirements, ensuring effluent quality protects receiving waters. The plant's treated effluent discharges into local streams that flow into the Ohio River, a major tributary of the Mississippi River system. The Ohio River basin supports diverse aquatic life and provides drinking water for millions downstream. Proper treatment at facilities like St Leon WWTP is essential for maintaining water quality in this ecologically and economically significant watershed.

The plant's discharge enters tributaries of the Ohio River, which flows into the Mississippi River and ultimately the Gulf of Mexico. The Ohio River basin supports diverse fish populations and migratory birds, and its water quality is critical for downstream communities and ecosystems. The region's agricultural and industrial activities contribute nutrient loads, making effective wastewater treatment important for preventing eutrophication in the Gulf.