MBR工程长期运行中的膜清洗效果和膜性能变化

Membrane Cleaning Effect and Membrane Performance Change in MBR Projects during Long,term Operation

为了探究膜生物反应器(MBR)工程长期运行中不同使用年限和清洗方案对膜性能的影响,对3个MBR工程中膜现有清洗效果进行评价,并对膜丝进行机械强度、接触角、红外光谱等方面的测试分析。结果表明,3个MBR工程中的膜经恢复性清洗后,膜表面的有机污染物和无机污染物仍有部分残留,其中运行时间最长(5年)的洋里四期MBR中膜的有机污染清洗效果较差,膜表面絮体纤维残留较多;无机污染元素主要是Ca、Fe,柠檬酸对含Fe元素的无机污染物具有较好的去除效果。膜使用时间增加和膜老化可能造成膜的机械强度下降;膜清洗频率对膜机械性能有一定影响,清洗剂会破坏膜表面的亲水性改性剂,导致膜亲水性能下降。

To explore the effects of different service life and cleaning schemes on membrane performance in membrane bioreactor(MBR) projects during long-term operation, the existing membrane cleaning effect in three MBR projects was evaluated, and the mechanical strength, contact angle, infrared spectrum and other aspects of the membrane were analyzed. Some organic and inorganic foulants still remained on the membrane surface of the three MBR projects after recovery cleaning. Among them, MBR in phase Ⅳ project of Yangli WWTP which had the longest operation time(5 years), had a poor organic fouling cleaning effect, and there were more floc fiber residues on the membrane surface. The inorganic foulants were mainly Ca and Fe, and citric acid had a good removal effect on inorganic foulants containing Fe element. The mechanical strength of the membrane might decrease with the increase of the service time and membrane aging. The membrane cleaning frequency had a certain influence on the mechanical properties of the membrane, and cleaning agent would destroy the hydrophilic modifier on the membrane surface, resulting in the decrease of membrane hydrophilicity.