集新型萃取复合膜和专性降解菌技术为一体的萃取膜生物反应器（EMBR）对难降解有机物的去除及其机理研究

Aimed to solve the problem of increasing pollution of refractory organic pollutants in aqueous environment, novel extractive composite membranes with preferential permeation of organic compounds will be developed in this study accompanied with the previous exploration of super-hydrophobic composite membrane in our lab. An extractive membrane bioreactor (EMBR) would be designed and set up integrating novel extractive composite membrane and obligate degrading bacteria, and its removal and mechanism for refractory organic pollutants will be studied. Electro-spinning technology with casting technology will be employed to fabricate the novel extractive composite membranes. Novel membrane properties will be characterized using advanced characterization instruments, and their effects on the behavior of pollutant mass transfer and their relationship with pollutant removal will be investigated. The degradation mechanism in EMBR will be clarified from the aspects of the pollutant transport property through membrane, obligate degrading bacteria proliferation, biofilm thickness and specialties. Effects of membrane properties, biological process and hydraulic conditions on biofilm thickness will be explored, and optimum biofilm thickness will be determined and controlled. Meanwhile, the cleaning methods and stability of this membrane will be explored. Results will provide new solutions on how to remove refractory organic pollutants, pave the way to future fundamental studies on novel extractive composite membrane technology, and provide theoretical guidance and practice basis for this novel EMBR process. Therefore, this study is of significant importance to guarantee the security of water resource.

针对水环境中日益严重的难降解有机物污染问题，结合申请人前期超疏水复合膜的开发研究，本项目拟制备优先透过有机污染物的新型萃取复合膜，设计开发集新型萃取复合膜和专性降解菌技术为一体的萃取膜生物反应器（EMBR），并研究其对难降解有机物的去除行为和机理。采用静电纺丝技术结合刮膜技术制备新型萃取复合膜；利用现代分析技术表征膜的特性，考察其对难降解有机物传质的影响，揭示其与污染物去除之间的关系；从新型萃取复合膜对有机污染物的渗透性能，专性降解菌的生长情况，生物膜厚度和特性等方面阐明EMBR去除难降解有机物的机理；考察膜特性、生物过程和水力学条件对生物膜厚度的影响，优化控制最佳生物膜厚度；同时考察膜的清洗方法及其稳定性。研究结果将为难降解有机物去除提供新思路，为新型萃取复合膜的进一步研究提供理论基础，对适用于难降解有机物去除的EMBR工艺的应用推广提供理论指导和实践依据，对水资源安全保障有重要意义。

近年来，水环境中难降解有机高盐废水排放量日益增加，对水生动植物、人类的健康危害显著。集渗透萃取膜和污染物降解菌为一体的萃取式膜生物反应器（extractive membrane bioreactor，EMBR）是有机高盐废水处理中较为有效的方法。为解决传统EMBR膜材料传质阻力大、传质系数低、生物膜过度附着等限制，本项目采用高压静电纺丝和相转化法等方法制备了新型高通量选择性渗透萃取复合膜，提高了难降解有机污染物跨膜传质系数；设计、构建了新型外置式EMBR，有效缓解了膜污染问题。本项目考察了废水条件（污染物浓度、pH和盐浓度等）、膜性能（膜表面形貌、粗糙度、浸润性等）和运行条件（流量、温度、曝气量等）对EMBR中难降解有机污染物分离与降解的影响。同时，根据污染物的形态变化、中间降解产物，明确了难降解有机物在EMBR中经废水-膜-专性降解菌的具体传质、降解途径及影响因素，并建立了相关的传质膜型。此外，本项目结合难降解有机物的降解路径及产物，微生物群落变化、胞外聚合物释放、关键酶活性、功能基因表达，以及生物膜厚度变化等，阐明了难降解有机物在EMBR中的降解机理。本项目还监测了膜表面上生物膜的生长和厚度，结合对应时间点的污染物传质及降解情况，探究了生物膜厚度对难降解有机污染物分离与降解的影响，并寻找到了最佳的膜清洗方法。相关研究拓展了渗透萃取膜和EMBR的研究领域，完善了渗透萃取膜和EMBR的研究体系，为难降解有机高盐废水处理提供了高效便捷的处理方案，为难降解有机污染物的回收及资源化提供了安全可靠的技术方法，有助于缓解我国水环境中难降解有机高盐废水污染问题，有助于保障我国水资源的可持续利用。