Charlestown STP - Wastewater Treatment Plant in Charlestown, Indiana

Charlestown STP is a municipal wastewater treatment facility located in Charlestown, Clark County, Indiana. It serves a population of approximately 6,540 people, placing it in the small-to-medium agglomeration category. The plant is situated inland, about 50 kilometers from the nearest coast, and discharges into local waterways that are part of the Ohio River basin. As a US facility, Charlestown STP operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permitting. For plants serving populations around 6,500, secondary treatment is typically required, with additional nutrient controls if discharging into sensitive waters. Regulatory standards ensure compliance with effluent limits. The plant's treated effluent ultimately flows into the Ohio River, a major tributary of the Mississippi River, which drains into the Gulf of Mexico. The Ohio River supports diverse aquatic life and is an important migratory corridor for fish species. Downstream ecosystems include wetlands and floodplains that provide habitat for waterfowl and other wildlife.

Charlestown STP discharges into local streams that flow into the Ohio River, a major tributary of the Mississippi River system. The Ohio River basin supports a variety of aquatic species, including freshwater mussels and fish, and is an important ecological corridor. Downstream, the Mississippi River carries nutrients and sediments to the Gulf of Mexico, where nutrient loading contributes to seasonal hypoxic zones. The plant's location in the Ohio River watershed means its effluent quality can affect downstream water quality and ecosystem health.