College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, PR China.
College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, PR China.
Water Res. 2023 Sep 1;243:120353. doi: 10.1016/j.watres.2023.120353. Epub 2023 Jul 13.
The optimization of membrane bioreactors (MBRs) involves a critical challenge in structural design for mitigation of membrane fouling. To address this issue, a three-dimensional computational fluid dynamics (CFD) model was utilized in this study to simulate the hydrodynamic characteristics of a flat sheet (FS) MBR. The optimization of the membrane module configuration and operating conditions was performed by investigating key parameters that altered the shear stress and liquid velocity. The mixed liquor suspended solids (MLSS) concentration was found to increase the shear stress, leading to a more uniform distribution of shear stress. By optimizing the appropriate bubble diameter to 5 mm, the shear stress on the membrane surface was optimized with relatively uniform distribution. Additionally, extending the side baffle length dramatically improved the uniformity of the shear stress distribution on each membrane. A novel in-situ aeration method was also discovered to promote turbulent kinetic energy by 200 times compared with traditional aeration modes, leading to a more uniform bubble streamline. As a result, the novel in-situ aeration method demonstrated superior membrane antifouling potential in the MBR. This work provides a new approach for the structural design and optimization of MBRs. The innovative combination of the CFD model, optimization techniques, and novel in-situ aeration method has provided a substantial contribution to the advancement of membrane separation technology in wastewater treatment.
膜生物反应器（MBR）的优化涉及结构设计方面的一个关键挑战，即减轻膜污染。为了解决这个问题，本研究采用了三维计算流体动力学（CFD）模型来模拟平板膜生物反应器的水动力特性。通过研究改变剪切应力和液体速度的关键参数，对膜组件的结构和操作条件进行了优化。混合液悬浮固体（MLSS）浓度的增加会增加剪切应力，从而使剪切应力分布更加均匀。通过优化适当的气泡直径为 5mm，可以优化膜表面的剪切应力，使其分布相对均匀。此外，延长侧挡板的长度可以显著提高每个膜上剪切应力分布的均匀性。还发现了一种新的原位曝气方法，与传统曝气方式相比，可将湍流动能提高 200 倍，从而使气泡流线更加均匀。因此，新型原位曝气方法在 MBR 中表现出了优异的膜抗污染潜力。这项工作为 MBR 的结构设计和优化提供了一种新方法。CFD 模型、优化技术和新型原位曝气方法的创新组合为废水处理中膜分离技术的发展做出了重要贡献。
