The Colossus Water Recycling Plant (CWRP), which is currently under construction in Memphis, Tennessee, is a state-of-the-art advanced treatment facility that will produce up to 13 MGD of high-quality reuse water. The CWRP will be the largest flat plate ceramic membrane bioreactor (MBR) in the world. The facility will receive effluent from the City of Memphis T.E. Maxson Wastewater Treatment Facility typically discharged to the Mississippi River, provide advanced treatment to meet both State of Tennessee reuse water standards and end-user water quality requirements, and distribute reuse water to at least two end-users: the Colossus Supercomputer Data Center and the TVA Allen Combined Cycle power plant. T.E. Maxson WWTF treats wastewater with a large industrial component, leading to significant diurnal and seasonal variation in effluent quality. In addition to its highly variable influent loading conditions, the City of Memphis is currently upgrading T.E. Maxson with enhanced treatment processes and additional improvements are planned in the near future. These improvements are anticipated to improve T.E. Maxson effluent quality over the next decade. Therefore, a robust process modeling effort was undertaken for the CWRP to simulate an adaptable treatment process necessary to produce high quality reuse water and achieve end user requirements consistently. This presentation will provide a brief background of biological treatment modeling then focus on the modeling and design of CWRP’s core biological treatment process using BioWin™ wastewater treatment process simulator. The process modeling effort during the design of the CWRP was used to establish key design elements including treatment reactor size and operational characteristics, pumping, aeration and mixing criteria, and chemical feed requirements. After establishing these design parameters considering the variable influent loading conditions expected at CWRP, various sensitivity analyses were performed—including potential inhibition from the industrial influent component of T.E. Maxson—ultimately resulting in a flexible and adaptable treatment process at CWRP.