膜-生物反应器中“污染2阶段”污染特性的研究

STUDY ON MEMBRANE FOULING BY TWO STAGE PROCESS IN MEMBRANE BIOREACTOR

结合膜污染的阶段性发展理论和对膜-生物反应器(MBR)小试多阶段膜污染特点的观察与分析,得出膜过程中污染具有"污染2阶段"的特点,在次临界通量状态下,运行初期膜面首先受到附着能力强、粘性高的小颗粒物质的污染,优势形成的是粘性凝胶层;一但粘性凝胶层形成,颗粒较大的物质即可较容易的黏附于其上,并逐渐加厚扩大形成泥饼层,导致运行压力的快速升高,从而进入"污染2阶段"。针对高压力工况下会加剧膜深度污染的现象,提出"污染1阶段"在线维护性清洗策略,以控制"1阶段"粘性凝胶层的形成,试验结果表明,基于"污染1阶段"膜污染理论的维护清洗可有效避免高压运行工况,降低膜深度污染的可能性。

Combining the theory of multiphase fouling process and experimental observations of multistage on membrane bioreactor （MBR）, the characteristics of two stage fouling mechanisms were summarized. Under sub-critical flux conditions, the membrane surface was fouled by high viscous and adhesive particulate materials firstly, and then colloidal layer was preponderant in fouling. Once colloidal layer had formed, more granules adhered to the fouled surface easily which led to cake layer forming. As a result, the suction pressure increased rapidly and the membrane entered into the second fouling stage. To solve the problem of deep fouling in high suction pressure operating conditions, a ＂The first stage maintenance cleaning＂ strategy was proposed which could control colloidal layer forming efficiently. The results proved that this cleaning strategy could avoid high suction pressure condition and reduce deep fouling potential remarkably.