Madisonville STP and CS Wastewater Treatment Plant, Kentucky

Madisonville STP and CS is a municipal wastewater treatment plant located in Madisonville, Kentucky, serving a population of around 27,500. The facility is situated in Hopkins County, part of the western coal region of the state, and plays a key role in managing wastewater for the community. Under the U.S. Clean Water Act, plants of this scale are required to meet secondary treatment standards through National Pollutant Discharge Elimination System (NPDES) permits issued by the Kentucky Energy and Environment Cabinet. These permits set effluent limits to protect water quality in receiving streams. The plant discharges to local waterways that ultimately drain into the Green River basin, a tributary of the Ohio River. The Green River supports diverse aquatic life and is an important ecological corridor in western Kentucky, with sensitive species such as the endangered rough pigtoe mussel found in the watershed.

The plant's treated effluent flows into tributaries of the Green River, which joins the Ohio River and eventually the Mississippi River. The Green River basin is ecologically significant, supporting diverse fish and mussel populations, including several federally listed species. The region's karst topography means groundwater and surface water are closely connected, making proper treatment essential for protecting both aquatic habitats and drinking water sources.