Planning, Design, and Startup of a Large, Innovative Membrane Bioreactor Facility

The planning, design, and startup of the Broad Run Water Reclamation Facility (WRF), a new 41,600-cubic-metres-per-day (m³/day) (11-million-gallon-per-day) facility owned and operated by Loudoun Water in Ashburn, Virginia, is discussed. Located in suburban area near Washington, DC, in the Dulles Area Watershed, and upstream of a drinking water supply in the Potomac River, the facility sets a new world-wide technology standard for environmental protection and water reclamation. The Broad Run WRF uses a membrane bioreactor (MBR), followed by granular activated carbon (GAC) treatment and ultraviolet (UV) disinfection and is the first large-scale application of this combination of treatment technologies in the world. The facility is designed to meet stringent discharge limits, including a total nitrogen (TN) limit of 4 milligrams per liter (mg/L), a total phosphorus (TP) limit of 0.1 mg/L, and a chemical oxygen demand (COD) limit of 10 mg/L. The MBR, operated in a 5-Stage Bardenpho configuration and modified to save aeration energy by recycling the highly oxygenated return activated sludge (RAS) of the MBR to the first aerobic stage, is also one of the application points of alum for phosphorus removal. The facility is one of the largest operating MBR installations in the United States.