Numerical simulation of aeration flow phenomena in bench-scale submerged flat membrane bioreactor

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) 2019, 69(0), , pp.241-254
• Main Authors: Kim, Dae Chun, Chung, Kun Yong
• Format: Article
• Language: English
• Subjects: Aeration; CFD; Flat sheet membrane; MBR; Wall shear stress; 화학공학
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2018.09.014

The aeration rates in the membrane bioreactor is an important management-point that can reduce the maintenance costs and the membrane fouling by changing the reactor flow patterns and the shear stresses in the vicinity of the membrane surface. In the present study, COMSOL, a finite element analysis (FEA) program was used to analyze the velocity distribution, the shear stresses between the membranes and the baffle, and the shear stresses between the membranes in a system in which two flat membrane modules are installed within a bench-scale submerged flat membrane reactor for aeration at the bottom. The diameters and velocities of the bubbles that develop the velocities within the reactor were measured through image analysis and the results were applied to numerical analysis. The shear stresses between the membrane and the baffle showed relatively high values ranging from 0Pa to 0.1Pa at the 1/3 point from the bottom of the membrane module and showed high shear stresses in some of the top part of the membrane module too. However, the shear stresses between the membranes were formed to be lower than the shear stresses between the membranes and the baffle. This is disadvantageous to the reduction of fouling on the surfaces of the membranes where permeation fluxes exist.