Lower Potomac STP - Lorton, Virginia Wastewater Treatment Plant

Lower Potomac STP is a major wastewater treatment facility located in Lorton, Virginia, serving a population of approximately 354,000. It is part of the regional wastewater infrastructure for Fairfax County and the greater Washington, D. C. metropolitan area. As a large-scale plant serving over 150,000 people, it operates under the U. S. Clean Water Act, which requires secondary treatment as a minimum. The plant's designed capacity is 1.00 (likely in million gallons per day), indicating it is sized to handle significant flows. The facility is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Virginia Department of Environmental Quality. The plant discharges into the Potomac River, a major tributary of the Chesapeake Bay. The Chesapeake Bay is the largest estuary in the United States and is ecologically sensitive, supporting diverse aquatic life and important fisheries. The plant's operations are critical to protecting water quality in the Potomac and the bay.

The plant discharges into the Potomac River, which flows into the Chesapeake Bay, the largest estuary in the United States. The Chesapeake Bay watershed is ecologically sensitive, supporting diverse aquatic life including oysters, blue crabs, and migratory fish. Nutrient and pollutant loads from wastewater treatment plants are a key concern for bay health, and the plant's performance is important for meeting regional water quality goals.