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Numerical simulation of scaling-up for AEC-MBRs regarding membrane module configurations and cyclic aeration modes

Yang, Min, Liu, Mengmeng, Yu, Dawei, Zheng, Jiaxi, Wu, Zhichao, Zhao, Shuguang, Chang, Jiang, Wei, Yuansong
Bioresource technology 2017 v.245 pp. 933-943
aeration, dynamic models, energy, fouling, hydrodynamics, mathematical models, membrane bioreactors, shear stress
The airlift external circulation membrane bioreactors (AEC-MBRs) have been attracting attentions due to their capabilities of nutrient removal with lower energy demand and smaller footprint. The gap between laboratory study and full-scale AEC-MBRs regarding hydrodynamics needs to be addressed. In this study, impacts of seven design variables and cyclic aeration modes on hydrodynamics were studied for the scale-up of AEC-MBRs with computational fluid dynamics modelling. The results demonstrated that shear stress on membranes was 14.7% higher in full-scale MBR with only 15% of SADm of lab-scale MBR while it showed an overall higher sensitivity to the design variables in lab-scale MBRs. Cyclic aeration modes created a sinusoidal pattern of shear stress and generated more fluctuations and were expected to reduce more irreversible fouling. When a shifting frequency of 5s/5s was applied in AEC-MBR, 50% of aeration energy was reduced and yield water with good quality was harvested.