Clairton Municipal Authority STP - Wastewater Treatment Plant in Clairton, Pennsylvania

The Clairton Municipal Authority Sewage Treatment Plant (STP) is a wastewater treatment facility located in Clairton, Pennsylvania, a city in Allegheny County along the Monongahela River. The plant serves a population of about 18,761 people, placing it in the medium-agglomeration category under U.S. regulatory frameworks. As a U.S. facility, the plant operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Pennsylvania Department of Environmental Protection. For a plant of this scale, secondary treatment is typically required, with additional nutrient removal if discharging into sensitive waters. The plant's treated effluent is discharged into the Monongahela River, which flows north to join the Allegheny River at Pittsburgh, forming the Ohio River. The Ohio River then drains into the Mississippi River and ultimately the Gulf of Mexico. The Monongahela River supports diverse aquatic life and is used for recreation and drinking water downstream.

The plant discharges into the Monongahela River, a major tributary of the Ohio River. The Monongahela watershed is ecologically significant, supporting fish species such as smallmouth bass and walleye, and providing habitat for freshwater mussels. Downstream, the Ohio River flows into the Mississippi River, which empties into the Gulf of Mexico, contributing to nutrient loading concerns in the Gulf's hypoxic zone.