ALCOSAN STP Allegheny County - Pittsburgh, Pennsylvania Wastewater Treatment Plant

ALCOSAN STP Allegheny County is a large wastewater treatment plant located in Pittsburgh, Pennsylvania, serving an estimated population of 1,865,470. As one of the largest treatment facilities in the region, it plays a critical role in managing municipal wastewater for the greater Pittsburgh area. The plant operates under the regulatory framework of the US Clean Water Act, which requires NPDES permits for discharges. For a facility of this scale, advanced treatment is typically expected to meet stringent effluent limits, especially given the environmental sensitivity of the receiving waters. The treated effluent from ALCOSAN STP is discharged into the Ohio River, which flows into the Mississippi River and ultimately to the Gulf of Mexico. The plant's operations are vital for protecting water quality in the Ohio River basin and downstream ecosystems.

The plant discharges into the Ohio River, a major tributary of the Mississippi River system. The Ohio River supports diverse aquatic life and serves as a drinking water source for millions. Downstream, the Mississippi River drains into the Gulf of Mexico, where nutrient pollution can contribute to hypoxic zones. Effective treatment at ALCOSAN helps mitigate these impacts.