ST MARYS MUN AUTH STP - Saint Marys, Pennsylvania Wastewater Treatment Plant

ST MARYS MUN AUTH STP is a municipal wastewater treatment plant located on Ridgway Road in Saint Marys, Elk County, Pennsylvania. The facility serves a population of about 14,500 people, placing it in the small-to-medium agglomeration category for US inland plants. As a US facility, the plant operates under the National Pollutant Discharge Elimination System (NPDES) permit program established by the Clean Water Act. This regulatory framework requires permits that set effluent limits based on technology and water quality standards. For plants of this scale, secondary treatment is typically mandated, with additional nutrient controls if discharging to sensitive watersheds. The plant's treated effluent is discharged to a local waterway within the Susquehanna River basin, which ultimately drains to the Chesapeake Bay. The Chesapeake Bay is a large estuary of ecological significance, supporting diverse aquatic life and important fisheries. Nutrient and sediment management in this watershed is critical to bay health.

The plant discharges into a tributary of the Susquehanna River, which flows south through Pennsylvania and Maryland into the Chesapeake Bay. The Chesapeake Bay is the largest estuary in the United States, supporting a rich ecosystem of fish, crabs, and waterfowl. The bay has historically suffered from nutrient pollution, making wastewater treatment plants in its watershed subject to stringent nutrient reduction requirements under the Chesapeake Bay Total Maximum Daily Load (TMDL).