具有自由端的梳状中空纤维膜-生物反应器中的膜污染控制研究

Membrane Fouling Control in a Free-End Comb-Like Hollow Fiber Membrane Bioreactor

采用具有自由端的梳状中空纤维膜-生物反应器处理污水,考察了其膜污染控制性能.结果发现,如果将膜污染定义为恒压操作下的膜通量下降,膜组件b比膜组件a易获得更大的膜通量,具有更优异的抗污染效果.含膜组件b的MBR在温度为22～26℃,污泥浓度为7 500～10 500 mg/L,曝气量为200 L/h,抽停时间比为9 min/1 min,压力为0.02 MPa的条件下连续运行47d,膜通量维持在4.0～8.0 L.(m2.h)-1,其间不需要任何水力或化学清洗.由于这种膜组件易充分发挥曝气的作用,不易污染,因而所需曝气量较小,并且当抽停时间比从12 min/1 min变化到6 min/1 min,膜通量差别不大.对膜的清洗试验表明,水力清洗+化学清洗+乙醇浸泡是最有效的清洗方法.水力清洗+化学清洗后,较之水力清洗,中空纤维膜表面上的胶团数目和面积大大减少,膜孔变得更加清晰.

A free-end comb-like hollow fiber membrane bioreactor was applied to treat wastewater. The results clearly showed that membrane fouling, defined as permeate flux decline, was greatly influenced by membrane module configuration. The permeate flux decline was much less for module b, demonstrating the superiority of module b over module a. Its permeate flux could be maintained in the range of 4.0 to 8.0 L·（m2·h）^-1 under the operating conditions that temperature was 22-26℃, the mixed liquor suspended solids （MISS） concentration was 7 500-10 500 mg/L, aeration intensity was 200 L/h, suction time/ suspended time ratio was 9 min/1 min and suction pressure was 0.02 MPa. As this novel kind of membrane module resulted in high air scouring efficiency, relatively low aeration intensity was needed for the MBR maintenance. In addition, the permeate flux varied a little when suction time/ suspended time ratio changed from 12 min/1 rain to 6 min/1 min. The performances of several different cleaning methods were tested and the results indicated that water cleaning ＋ chemical cleaning ＋ ethanol soaking had the best cleaning efficiency. SEM images clearly showed that the membrane surface became cleaner and the membrane holes became more visible after water cleaning ＋ chemical cleaning, compared with water cleaning solely.