Henryville STP - Secondary Wastewater Treatment in Clark County, Indiana

Henryville STP is a municipal wastewater treatment facility located in Clark County, Indiana, serving a small community of about 1,545 residents. The plant provides secondary treatment, a standard level for small agglomerations in the United States, ensuring removal of organic matter and suspended solids before discharge. The plant has a designed capacity of 605.66 thousand gallons per day and currently treats an average daily flow of 681.37 thousand gallons per day, indicating it operates near or slightly above its design capacity. As a US facility, it operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Indiana Department of Environmental Management, which set effluent limits to protect water quality. The treated effluent from Henryville STP is discharged to a local water body that ultimately drains into the Ohio River watershed. The Ohio River is a major tributary of the Mississippi River, supporting diverse aquatic life and providing drinking water for millions downstream. The plant's secondary treatment helps reduce nutrient and pollutant loads to these waters.

Henryville STP discharges into a tributary of the Ohio River, which flows into the Mississippi River and eventually the Gulf of Mexico. The Ohio River basin supports diverse fish and wildlife, including several species of freshwater mussels and migratory birds. The plant's secondary treatment helps control organic pollution and suspended solids, but nutrient removal is limited, contributing to downstream eutrophication concerns in the Gulf of Mexico hypoxic zone.