Membrane Fouling in Vibratory MBRs: Impact Distance Complements Wall Shear Stress as a Fouling Predictor

Computational fluid dynamics (CFD) modeling and lab-scale preliminary tests were performed to elucidate mechanisms of membrane fouling control in vibratory hollow fiber membrane bioreactors. Shear stress distribution on the hollow fiber membrane surfaces was estimated analytically and compared with predictions by 3D CFD modeling. During lab-scale testing, transmembrane pressure buildup was recorded for membranes operated under two different vibration regimes designed to affect similar shear stresses at the membrane surface (1.33 and 1.48 Pa). MBR tests showed that the different combinations of frequency and amplitude values with the same shear stress values led to different TMP profiles.