好氧膜-生物反应器中微滤膜选择的实验研究

Experimental study on selection of microfiltration membranes in aerobic membrane bioreactor

用扫描电镜表面观察和全自动压汞仪测定了2种亲水化改性PVDF微滤膜的平均孔径、孔隙率等基本性能参数。对2种膜的纯水通量,及其平板膜组件在好氧膜生物反应器内污染过程进行分析。结果显示,2种膜污染过程均呈现先缓慢后快速的"二阶段"趋势,第二阶段是膜污染的主导阶段。尽管平均孔径小、孔隙率高的膜本身阻力大、纯水通量低,但其污染速率较低,物理及化学清洗恢复率较高。膜孔径及孔隙率指标是影响其在MBR中运行的污染速率的主要因素,平均孔径小、孔隙率高的膜抗污染能力强。

In this paper,two kinds of hydrophilic PVDF porous MF membranes were investigated by SEM and automated mercury porosimeters to gain the average pore size and porosity.In order to select a preferable membrane,the pure water flux and the fouling process of these two flat-sheet membrane modules during the application in MBR were analyzed.The result showed that the fouling velocity was slow in the first stage,and then became fast in the second stage for both membranes.And the membrane with smaller average pore size and higher porosity had a relative lower fouling rate and higher permeability recovery rate by chemical or physical cleaning,despite of its larger resistance and lower pure water flux.The pore size and porosity of the membrane are the main factors for the fouling rate during the application in MBR,the membrane of smaller average pore size and higher porosity has strong resistance to fouling.