MABR膜材料选择优化及微流场对生物膜性能的影响

发布时间：2018-03-20 19:45

本文选题：MABR　切入点：曝气膜材料　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：MABR是一种具有广泛应用前景的利用透气膜进行曝气的新型有机废水处理工艺,它有效的将生物膜和膜分离技术相结合,凭借能耗低、效率高、占地少、污泥少等优点,逐渐成为污水处理的新工艺。曝气膜材料特性及MABR反应器内流场特征对MABR的运行效能有重要的影响。首先,本文通过对PVDF和PP中空纤维膜材料的表面形态、生物相容性、脱氮除碳及膜污染等进行研究,比较材料特性对生物膜及MABR运行的影响,提供选择适合MABR膜材料的原则和依据,以提高MABR运行效率。研究表明:PVDF纤维膜材料相比于PP纤维膜材料具有较强的生物附着性,在挂膜启动过程中能够更快的附着微生物膜,加快系统的启动速度。通过观察两种膜表面生物污染情况,PVDF膜纤维表面呈鱼鳞状结构,有效保护了膜孔不被微生物完全堵塞。PP纤维膜表面较为平滑,导致了较为严重的膜污染和较低的氧传递速率。水质的处理效果中,选用PVDF纤维膜的MABR膜组件COD和TN的去除率分别为94.2%和77.6%,均高于PP纤维膜组件(85.3%和61.4%)。实验运行末期,曝气膜孔被严重污染,生物膜内溶解氧的分布差异致使RPVDF体系内具有同步硝化反硝化和短程硝化反硝化共存的脱氮过程,而RPP体系内的脱氮过程趋向于以短程硝化反硝化过程为主导。其次,本文在课题组前期对MABR反应器内流场模拟优化基础上,对流场区域进行划分,研究了组件中不同流场对局部纤维上微生物种群特性及生物膜的影响。微流场对生物膜密度、厚度及种群分布都有显著的影响且各个阶段的影响各不相同,初期由于生物膜尚未成熟,尤其是进出口区域受剪切力及溶解氧影响较大,氨氧化菌(AOB)及亚硝酸盐氧化菌(NOB)分布不均匀,随着反应的进行,反应器各个区域的种群分布较为均匀,但由于膜污染较为严重,氧传递速率较之前下降较快。当反应器稳定运行后,生物膜分层较为明显,AOB逐渐成为优势种群,反应器向有利于短程硝化反硝化的方向进行。本研究通过对两种纤维曝气膜材料MABR性能的分析比较,认为PVDF曝气纤维更适于做膜曝气生物膜反应器的曝气膜;初步探明了 MABR内微流场对生物膜传氧速率和生物膜微生物群落结构形成的作用机制。
[Abstract]:MABR is a new organic wastewater treatment process with widely application prospect. It combines biofilm with membrane separation technology effectively, with the advantages of low energy consumption, high efficiency, less occupation of land, less sludge, and so on. The characteristics of aerated membrane materials and the characteristics of flow field in MABR reactor have important influence on the running efficiency of MABR. Firstly, the surface morphology and biocompatibility of PVDF and PP hollow fiber membrane materials are studied in this paper. Nitrogen and carbon removal and membrane fouling were studied to compare the effects of material characteristics on the operation of biofilm and MABR, and to provide the principle and basis for selecting suitable MABR membrane materials. In order to improve the running efficiency of MABR, the study showed that the membrane material of MABR had stronger biological adhesion than that of PP fiber membrane, and could attach microbial membrane more quickly during the start-up of the membrane. By observing the biofilm of two kinds of membrane surface, PVDF membrane fiber surface was fish scale structure, which effectively protected the membrane pore from being completely blocked by microorganism. PP fiber membrane surface was smooth. In the treatment of water quality, the removal rates of COD and TN of MABR membrane with PVDF fiber membrane were 94.2% and 77.6, respectively, which were higher than that of PP fiber membrane module (85.3% and 61.4%) respectively. Because of the serious contamination of aerated membrane holes and the difference in the distribution of dissolved oxygen in the biofilm, the simultaneous nitrification and denitrification and short-cut nitrification and denitrification co-exist in the RPVDF system. The denitrification process in RPP system tends to be dominated by short-cut nitrification and denitrification process. Secondly, based on the optimization of flow field in MABR reactor, the flow field is divided. The effects of different flow fields on the microbial population and biofilm on local fibers were studied. The microflow field had significant effects on the density, thickness and population distribution of biofilms, and the effects were different in different stages. In the early stage, the biofilm was not mature, especially in the import and export areas, which was influenced by shear stress and dissolved oxygen, and the distribution of AOB and NOB were not uniform. The population distribution in each region of the reactor is more uniform, but the oxygen transfer rate decreases more rapidly because of the serious membrane fouling. When the reactor runs steadily, the biofilm stratification becomes the dominant population gradually. The reactor is in favor of short-cut nitrification and denitrification. Through the analysis and comparison of MABR properties of two kinds of fiber aeration membrane materials, it is concluded that PVDF aerated fiber is more suitable for aeration membrane of membrane aeration biofilm reactor. The mechanism of microflow field in MABR on biofilm oxygen transfer rate and biofilm microbial community structure was preliminarily investigated.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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