Slug bubbling in flat sheet MBRs: Hydrodynamic optimization of membrane design variables through computational and experimental studies

Journal article

Slug bubbling in flat sheet MBRs (FSMBR) is of interest in water treatment industry to effectively control fouling. In this work, a novel bubbling method is used to produce slug bubbles into all channels between every pair of membranes for a large-scale 100-sheets commercial FSMBR. Below the membrane plates, coalescent bubbles formed and these developed into large-sized bubbles, which eventually distributed between channels as a set of slug bubbles. Computational Fluid Dynamics (CFD) was used to predict the bubble size and distribution among different channels, and associated hydrodynamic features. Substantial agreement was observed with the experiment results. The configuration of membrane plate centrally located above the aeration nozzles was determined to have superior hydrodynamic performance of high shear stress on the membrane surfaces. The effect of membrane plate and channel dimensions were studied to identify the optimized design for hydrodynamics enhancement on fouling control. The combination of membrane thickness at 5 mm and channel gap at 6 mm was verified to be the optimal configuration, which would give uniform distribution of slug bubbles and provide high shear stress in the channels. The optimized air flow rate was successfully reduced to 4.7 L/min m2, which corresponds to a 53% reduction compared with traditional usage (10 L/min m2) in industry.

Authors: Wang, B; Zhang, K; Field, R

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Journal of Membrane Science
• Volume: 548
• Pages: 165-175
• Publication date: 2017-11-11
• Acceptance date: 2017-11-10
• DOI: 10.1016/j.memsci.2017.11.024
• ISSN: 1873-3123 and 0376-7388
• Keywords: CFD; coalescent bubbling; flat sheet MBR; fouling control; slug bubble