Brightwater: The Design Challenges of a 39 mgd (150 MLD) Membrane Bioreactor
Many Membrane Bioreactor (MBR) facilities have been constructed in North America, however to date the largest operating MBR facility in Traverse City MI has had a maximum month capacity of 8.5 mgd (32 MLD). The Brightwater MBR plant, now under construction in King County, Washington, is designed to have a maximum continuous capacity of 39 mgd (148 MLD), with a peak MBR treatment capacity of 57 mgd (216 MLD). The design of this facility, the largest under construction in the world, faced many challenges associated with the design and control of such a large facility. One challenge was the control and treatment of peak wet weather flows in excess of the MBR capacity by chemical-enhanced primary clarification. A second challenge was the implementation of a competitive procurement process for membrane equipment for the facility. Foam management, aeration system design, and internal recirculation system sizing were also key design issues.