Franklin STP Wastewater Treatment Plant, Franklin, Indiana

Franklin STP is a wastewater treatment facility located in Franklin, Johnson County, Indiana, serving a population of about 22,627. The plant is situated inland, approximately 50 kilometers from the coast, and discharges treated effluent into local waterways that ultimately drain into the Mississippi River system. As a medium-sized agglomeration, the plant is expected to meet secondary treatment standards under the U.S. Clean Water Act, which requires removal of at least 85% of biochemical oxygen demand and suspended solids. The facility is regulated through the National Pollutant Discharge Elimination System (NPDES) permitting program, administered by the Indiana Department of Environmental Management, ensuring compliance with water quality standards. The plant's discharge contributes to the protection of the White River watershed, which flows into the Wabash River and eventually the Ohio and Mississippi Rivers. This system supports diverse aquatic life and provides drinking water for downstream communities. Proper treatment at Franklin STP helps maintain the ecological health of these regional water bodies.

Franklin STP discharges into the White River watershed, which flows through central Indiana before joining the Wabash River, a major tributary of the Ohio River. The Ohio River then drains into the Mississippi River, ultimately reaching the Gulf of Mexico. The White River supports diverse fish populations and provides habitat for migratory birds, making effective wastewater treatment critical for maintaining water quality and ecosystem health in this inland basin.