在线混凝-超滤中膜污染与絮体水动力学的关系

Relationship between membrane fouling and flocs hydrodynamics' in in-line coagulation /UF process

为了解在线混凝-超滤过程中膜污染与组件内部絮体水动力学的关系,采用一种粒子成像测速技术PIV,在线监测混凝-超滤过程中絮体在组件内的流动状况及流体力学特性,并采用SEM对污染后的膜进行了分析表征。结果表明,在0.05 MPa下,随运行时间延长,出现了膜通量衰减现象。同时,膜表面絮体的水动力学性质发生较大的变化,PIV实验发现沿中空纤维膜轴向,上部絮体水动力现象变化较大,中部次之,下部变化最小,对应的SEM照片可以看出膜污染在轴向分布不均,上部污染最重,中部次之,下部最小。

The membrane fouling greatly restricted the membrane life and separation efficiency in the application of removing the natural organic matter in drinking water. It usually requires pretreatment to reduce membrane fouling for improving the removal efficiency of NOM and weakening membrane fouling. And coagulation is the most commonly used cell technology in drinking water treatment as well as the pretreatment of the membrane filtration. Most researches on coagulation /UF focus on the macroscopic separation at present,but they pay a little attention to the fluid hydrodynamics performance and the dynamic process of membrane contamination in the actual operation. So it's very important to find a new method to explore the fluid hydrodynamics around the membrane and the distribution of the fluid velocity field in the reactor,and then we can effectively control the membrane fouling.