【作者】 李伟；

【导师】 李顺义；

【作者基本信息】 郑州大学 ， 环境科学， 2011， 硕士

【摘要】 膜生物反应器(MBR)是将膜分离技术与生物处理技术有机结合的一种高效污水处理新工艺,具有处理效果稳定、出水水质好、能耗低、结构紧凑占地面积小、运行管理简单、剩余污泥少等优点,但膜组件价格高及膜污染问题限制了其进一步的推广与应用。本文采用填料生物反应器与动态膜技术组合的复合式预涂动态膜生物反应器(CPDMBR)处理生活污水。基膜选用廉价的工业滤布,经粉末活性炭预涂后形成预涂动态膜以增强膜组件的过滤性能；在生物反应器中加入填料,提高微生物量,加强系统的处理效果。试验研究了动态膜的最佳预涂液浓度及复合系统对生活污水中污染物的去除效果和机理；探讨了不同运行条件和方式下系统对各污染物的去除率；同时还研究了生物反应器中膜污染的成因,膜通量的变化规律和膜清洗后的恢复情况。主要研究结果如下：(1)筛选得到涤纶短纤维滤布作为膜基材,用粉末活性炭溶液预涂膜,当预涂液浓度为0.70 g·L-1时,形成的预涂动态膜过滤性能较好。(2)抽吸式CPDMBR在HRT9h、DO3.3～3.8mg·L-1的工艺条件下处理生活污水,稳定运行后,浊度的去除率可达100%,COD、TN、TP的平均去除率分别为92.59%、73.51%、81.06%。(3)在重力自流的出水方式下,采用阶梯式压力步长法测定膜的临界压力,在污泥浓度为4.9-5.6 mg·L-1,曝气量为500 L·h-1的情况下,本试验所用动态膜的临界压力范围为25～30 cmH2O,即2.45-2.94 kPa。连续运行试验表明,反应器对污染物的处理效果较好,COD、TN的平均去除率分别为93.75%和67.74%。(4)膜生物反应器中不可避免地存在膜污染的问题。在抽吸式动态膜生物反应器运行过程中,膜污染呈现“2阶段”性。滤饼层阻力是导致膜污染的最主要因素,占总量的78.9%,这种污染属可逆污染,清洗后即可消除；膜孔堵塞与吸附阻力只占17.0%,用高速水流冲洗也可除去,用刷子刷洗膜通量可100%恢复。(5)重力自流式动态膜生物反应器的运行周期约为30天,当曝气强度为600 L·h-1,污泥浓度为4600-5200 mg·L-1时能有效减缓膜污染。预涂后膜的阻力稍有增加。在重力自流下滤饼层仍是造成膜污染的最主要因素,占总阻力的90.4%。膜污染后经水力清洗通量可恢复96%,刷子刷洗后通量几乎可恢复至100%。更多还原

【Abstract】 The Membrane bioreactor (MBR) is a new wastewater technology which combined membrane separation with biological treatment technology. There are lots of advantages on MBR, such as high effluent quality, less energy consumption, smaller footprint and less sludge production and so on. However, the high initial membrane cost and membrane fouling reduced dramatically the widespread use of MBR.In this paper, the domestic wastewater was cleaned by compound precoating dynamic membrane bio-reactor(CPDMBR), which was made up of suspended carrier biofilm and precoating dynamic membrane. The filter cloth was used as the filtration module, which was coated by powdered activated carbon(PAC), and then puting fillers into reactor to improve the efficiency of wastewater treatment. Firstly, the suitable concentration of the PAC dynamic membrane have been investigated in this experiment, secondly, the removal efficiency of pollutants in different operational condition and styles. Last but not the least, the reasons of membrane fouling, and the change of membrane flux, and the membrane cleaning method were also discussed.(1) Based on the selection of filter material, the polyester staple fibre was considered as the better choice. The suitable precoating concentration was 0.70 g·L-1.(2) For CPDMBR with pump suction operation, the optimum operating condition was:HRT 9 h, DO3.3～3.8 mg·L-1. During the stable operation, the CPDMBR has a high removal efficiency of pollutants, the average removal rate of COD, TN, TP and turbidity reached 92.59%,73.51%,81.06%,100.00%, respectively.(3) For CPDMBR with gravity outflow, the critical pressure was about 25～30 cm water head drop, which means 2.45～2.94 kPa on the condition that MLSS was 4.9～5.6 mg.L-1 and the aeration intensity was 500 L.h-1. The removal of COD and TN could amount to 93.75% and 67.74%.(4) In the pump suction operation, membrane fouling could be divided into two stages. The resistance arising from cake formation was 78.9% of total resistance, and the resistance due to pore blocking account for17.0%. (5) The running period was 30 days for HDMBR with gravity outflow. The condition of the 600 L·h-1 of aeration intensity and the 4600～5200 mg·L"1 of MLSS slowed effectively the membrane fouling. The cake layer still was the main reason of membrane fouling, which amounted to 90.4% of the total resistance. The membrane recovery coefficient reached to 96% after hydraulic cleaning, and the flux could be recovered to nearly 100% just by brushing.更多还原