Experimental Validation of a Hydrodynamic CFD Model of a Hollow Fiber MBR Using Shear Intensity Measurements Nicolas Ratkovich 1 , Blair Fulton 2 , Michaela Hunze 3 , Pierre Berube 2 and Ingmar Nopens 1 1 BIOMATH – Department of Applied Mathematics Biometrics. Ghent University, Coupure Links 653, B-9000, Ghent, Belgium (E-mail: nriosrat@biomath.ugent.be ) 2 Department of Civil Engineering. The University of British Columbia. 6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada. 3 FlowConcept GmbH, Vahrenwalder Str. 7, 30165 Hannover, Germany. ABSTRACT The main drawback of MBR systems is the fouling of the membrane, which is decrease and/or prevented through gas sparging. However, gas sparging practices are based on rules of thumb or a trial-and-error approaches which are tedious, very time-consuming and do not necessarily provide optimal fouling control. Therefore, dedicated experiments are needed to fully understand the hydrodynamics of this two-phase flow. This work focus on the validation of extensive experiments using a pilot-scale hollow fiber GE-Zenon submerged MBR against computational fluid dynamics (CFD). It was found that the order of magnitude from the CFD model is similar compared to experimental data in magnitude based on the shear intensity contours and the overall average. However, some differences in the distribution and magnitude of shear intensity throughout the pilot-scale submerged MBR system were observed. Cumulative frequencies were considered to compare the CFD results and the experimental data. It was found that below the 50 th percentile, the CFD and experimental data was similar (error less than 8 %). At higher shear intensity, the differenced between the simulation and the experimental data increase up to 17 %. These were likely due to the approximations made in developing the CFD model (i.e. rigid membrane modules, no water-air air flow through the fibers). Although further improvements are needed to use the CFD model for optimization, the results from the present study are promising. KEYWORDS Membrane bioreactors, CFD modeling, shear intensity INTRODUCTION To better understand fouling and fouling control in MBR, research has historically focused mainly on characterizing the effects of different fractions of the mixed liquor (e.g. soluble and colloidal particles) on fouling. However, it has been shown that the hydrodynamics near the membrane surface also play an important role in fouling control. That is why, to reduce the fouling, air is introduced in submerged membrane systems to create a gas-liquid two-phase flow 526 Membrane Applications 2010 Copyright ©2010 Water Environment Federation. All Rights Reserved.