Computational Fluid Dynamics Simulation to Investigate Diffuser Outlet Factors in Anaerobic Membrane Bioreactors Treating Wastewater

Anaerobic membrane bioreactors (AnMBRs) require biogas recycling to stir the mixed liquid and flush particles away from surfaces for stable operation. With fixed gas cycling rate, diffuser configuration is an important factor that affects stirring flushing performance. This study investigated effect of different outlet diameters on diffusers in AnMBR by using computational fluid dynamics (CFD) analyze gas–liquid flow a numerical model constructed based experimental AnMBR. According CFD results, as diameter increased 2.5 5.0 mm, average velocity 0.15 0.31 m/s wall shear stress (WSS) 0.21 1.10 Pa surface. The increase enhances effect, WSS improves However, when it was further 10.0 0.27 0.22 Pa, respectively, indicating too large leads concentrated distribution, which reduces performance flushing. Furthermore, these results provide basis optimizing configuration, significant promoting practical application wastewater treatment.