基于生物滤饼层调控的重力流超滤净水技术与原理研究

Gravity-driven membrane ultrafiltration (GDM) water technology can efficiently remove contaminants in water without changing its physicochemical properties, which meets the demand of low consumption and clean process for the innovation of water purification process. Considering the problems of low flux and poor removal of dissolved pollutants for the current GDM process, the GDM water technology based on control by bio-cake is proposed in this study. The changes of properties and structures of bio-cake on membrane surface in the GDM system will be investigated, by which the formation and evolution of the cake layer is analyzed. Then, the water purification and membrane fouling characteristics of GDM is defined, and the mechanisms of water purification by bio-cake and its synergistic effect with ultrafiltration (UF) membrane are revealed. Further, the effects of physical control measures (e.g. critical flux, intermittent operation and salt washing) on the characteristics of bio-cake in GDM are systematically studied, and these control measures are further optimized. Finally, the mechanisms of pollutants removal and flux stabilization in the GDM based on control by bio-cake are expected to be illuminated, the water purification efficiency and water productivity will be promoted, and a simple, efficient and green water purification technology is expected.

重力流超滤净水技术(GDM)能够有效地去除水中的污染物而不明显改变水的理化特性，符合低耗、清洁的净水工艺变革诉求。本课题针对当前GDM工艺膜通量低及溶解性污染物去除效果差等难题，提出了基于生物滤饼层调控的重力流超滤净水技术，通过考察GDM系统中膜面生物滤饼层的性质与结构变化，解析生物滤饼层形成和演化过程，明确GDM净水特性及膜污染特性，揭示生物滤饼层净水机制及其与UF膜间的协同作用机制；进而系统研究膜临界通量、间歇运行和盐洗等物理调控措施对GDM生物滤饼层作用特性的影响，优化生物滤饼层调控措施，阐明基于生物滤饼层调控的GDM系统中污染物去除与通量稳定机理，强化GDM的净水效能和产水能力，开发出简洁、高效、绿色的净水技术。

为实现低耗、清洁的净水工艺变革，本项目构建了基于生物滤饼层调控的重力流超滤净水技术（简称GDM），结合多种微观表征手段，系统研究了生物滤饼层的微观结构和生化组分特性随时间序列的形成和演变规律，并建立了相应的表征方法体系；通过追踪不同污染物在生物滤饼层-超滤膜微环境的迁移转化规律，揭示了污染物的截留、吸附、水解及生物转化等多路径去除机制，实现了污染物的高效去除和膜污染的有效缓解；考察了GDM工艺对水中铁锰的去除效能，通过抑制和强化“滤饼层”的功能活性，揭示了生物滤饼层的催化氧化除锰机制，并提出了基于活性滤膜基层构建的直接超滤除铁锰技术策略，实现了除铁除锰功能的快速启动；考察了不同工艺参数（如膜材质、运行压力和运行模式等）和原水水质对GDM工艺通量稳定性的影响规律，明确了工艺关键参数、原水水质边界条件及适配性，优化了工艺运行条件，形成了针对不同原水水质类型的GDM技术调控体系；开发了缓速滤池+GDM耦合工艺，解析了污染物在缓速滤池和GDM间的迁移规律和去除路径，DOC、氨氮和AOC的去除率分别提升了约40-50%、50-60%和40-70%，通量提升了约80-100%，研究成果为无药低耗型超滤净水技术的发展和推广应用提供了理论和技术支撑。