Williamsport West STP - Municipal Wastewater Treatment in Williamsport, Pennsylvania

Williamsport West STP is a municipal wastewater treatment facility located at 1 Arch Street, Williamsport, Lycoming County, Pennsylvania. The plant serves a population of about 12,374 residents, placing it in the small-to-medium agglomeration category for US wastewater infrastructure. As a US-based plant, it operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permitting. For facilities of this scale, secondary treatment is the standard requirement, with additional nutrient controls possible depending on the receiving water body's sensitivity. The plant's treated effluent discharges into the West Branch Susquehanna River, which flows into the main stem Susquehanna River and ultimately reaches the Chesapeake Bay. This watershed is ecologically important, supporting diverse aquatic life and contributing to the bay's nutrient management efforts.

The plant discharges into the West Branch Susquehanna River, a major tributary of the Susquehanna River, which flows into the Chesapeake Bay. The Chesapeake Bay is a large estuary that supports critical fisheries and migratory bird populations. Nutrient loading from wastewater plants in this basin is a key concern for bay health, driving regulatory focus on phosphorus and nitrogen removal.