MBR复合工艺膜污染及其清洗特征

Characteristic of Fouling and Cleaning of MBR Hybrid Process

采用"A+(A/O)n+MBR"复合工艺,在次临界通量条件下,考察了膜污染发展及清洗特性。试验发现,膜污染随运行时间的变化呈现出阶段性上升的特征,即经过初期缓慢发展和中期较快发展后,出现了膜污染的急剧增加。电镜及能谱分析表明,膜面污染物主要包括沉积于膜面的大量污泥絮体、附着于膜面的致密凝胶层和一些由Ca2+、Mg2+等离子形成的堵塞和吸附于膜孔的无机垢粒。膜清洗及阻力表明,自来水冲洗可使泥饼层大部分脱落,泥饼层对膜污染阻力贡献最大,达到60.71%;NaClO清洗对凝胶层的去除效果显著,有机污染对膜污染阻力为31.44%;HCl清洗去除的无机垢粒对膜污染贡献率仅为7.85%。

Characteristic of membrane fouling development and cleaning in an A＋ （A/O） n＋ MBR process was investigated under the condition of sub-critical flux. It could be concluded that a characteristic three-stage trans-membrane pressure（TMP） profile was observed with an initially extended period of slow and fast TMP rise followed by a sudden transition to a rapid rise. From SEM examination, it was found that contaminants attached on the mem-brane surface comprised large amount sludge flcc and gel layer formed by fine particles and macro-molecular organic substance, especially EPS, and some inorganic particles formed by Ca^2＋ , Mg^2＋, etc. The results obtained by membrane cleaning and resistance analysis showed that fouling caused by cake layer and gel layer and inorganic particles could be removed effectively by tap water washing, NaC10 and HC1 respectively, and their contributes to total resistance account for 60. 71%, 31.44% and 7.85% respectively.