Sørensen Lasse, Bentzen Thomas Ruby, Skov Kristian
Department of Civil Engineering, Aalborg University, Sofiendalsvej 11, DK-9000, Aalborg, Denmark E-mail:
Aalborg Forsyning Kloak A/S, Stigbords Brygge 5, 9400, Nørresundby.
Water Sci Technol. 2015;72(10):1810-6. doi: 10.2166/wst.2015.401.
Membrane bioreactor (MBR) systems are often considered as the wastewater treatment method of the future due to their high effluent quality. One of the main problems with such systems is a relative large energy consumption, compared to conventional activated sludge (CAS) systems, which has led to further research in this specific area. A powerful tool for optimizing MBR-systems is computational fluid dynamics (CFD) modelling, which gives researchers the ability to describe the flow in the systems. A parameter which is often neglected in such models is the non-Newtonian properties of active sludge, which is of great importance for MBR systems since they operate at sludge concentrations up to a factor of 10 compared to CAS systems, resulting in strongly shear thinning liquids. A CFD-model is validated against measurements conducted in a system with rotating cross-flow membranes submerged in non-Newtonian liquids, where tangential velocities are measured with a Laser Doppler Anemometer (LDA). The CFD model is found to be capable of modelling the correct velocities in a range of setups, making CFD models a powerful tool for optimization of MBR systems.
膜生物反应器（MBR）系统因其出水水质高，常被视为未来的污水处理方法。与传统活性污泥（CAS）系统相比，此类系统的一个主要问题是能耗相对较大，这促使了在该特定领域的进一步研究。优化MBR系统的一个有力工具是计算流体动力学（CFD）建模，它使研究人员能够描述系统中的水流情况。活性污泥的非牛顿特性在这类模型中常常被忽视，而这对MBR系统非常重要，因为与CAS系统相比，MBR系统在高达10倍的污泥浓度下运行，会产生强剪切变稀液体。针对在旋转错流膜浸没于非牛顿液体的系统中进行的测量，验证了一个CFD模型，其中用激光多普勒测速仪（LDA）测量切向速度。结果发现CFD模型能够在一系列设置中对正确的速度进行建模，使CFD模型成为优化MBR系统的有力工具。
