基于滤饼层截留的高藻水超滤嗅味物质强化去除与不可逆膜污染控制效能及机理

For algae-laden treatment using ultrafiltration (UF), a key problem yet to be solved is to simultaneously improve membrane fouling control and rejection of taste and odor compounds. To this end, an innovative idea is proposed to utilize retention capacity of the cake layer formed by algal cells and metabolites during filtration. On one hand, physico-chemical and structural characteristics of the cake layer will be determined and correlated with retention of taste and odor compounds, so that the interfacial interaction among membrane surface, cake layer and pollutants can be better understood. Then, a combined filtration of the cake layer and UF membrane can be established to enhance the rejection of taste and odor compounds. On the other hand, a novel backwashing strategy, which imposes moderate breakage to the cake layer, is raised for algae-laden water treatment using UF. Both response of algal cell breakage to operational conditions and relationships between cake layer breakage and irreversible fouling will be investigated to understand mechanisms for irreversible fouling control by cake layer retention. Overall, this project will be performed via an integrated research approach with four basic aspects, i.e. minimization of cell breakage, improved retention of taste and odor compounds, effective control of irreversible fouling, and optimization of UF processes and their running. Breakthroughs can be anticipated in key scientific issues including transfer routes for taste and odor compounds in the interface of ‘cake layer-membrane’ and mechanisms for cake layer retention. Moreover, based on utilization of cake layer retention, integrated UF processes and optimized running strategy can be developed for more efficient treatment of algae-laden water. Finally, this project can provide fundamental support for drinking water security and efficient operation of UF processes when algae bloom occurs to source water.

如何控制膜污染并提高小分子嗅味物质去除效能是超滤膜法高藻水处理领域亟待解决的关键问题。申请人提出以“利用滤饼层”为导向的研究思路，开展高藻水超滤过程中滤饼层特性表征及藻类代谢产物去除特性研究，揭示膜-滤饼层-污染物交互界面作用过程与机制；构建滤饼层协同强化超滤除污染技术，强化藻源嗅味物质的去除效能；开发基于“滤饼层适度破坏”的优化反冲洗技术，阐明藻细胞破裂对运行工况的响应机制以及滤饼层破坏程度与不可逆膜污染之间的内在联系，明确滤饼层对不可逆膜污染的抑制机理。本项目以“藻细胞破裂控制-嗅味物质迁移规律解析-不可逆膜污染抑制-工艺模式与运行优化”为技术主线，重点突破“滤饼层-膜”微界面中嗅味物质迁移规律以及滤饼层截污机理等关键科学问题，开发基于滤饼层截留的高藻水超滤工艺模式与优化运行技术，为水源高藻期的饮用水安全保障和超滤工艺高效运行提供基础性支撑。

饮用水安全保障和水处理工艺节能降碳是环境工程领域当前的国家重大需求。本项目严格执行预定的研究计划，以“藻细胞破裂控制-嗅味物质迁移规律解析-不可逆膜污染抑制-工艺模式与运行优化”为技术主线，开展了基于滤饼层截留的高藻水超滤过程中嗅味物质去除与不可逆膜污染控制研究。开发了基于流失细胞分析的藻细胞破裂评价方法，发现藻细胞破裂主要与细胞活性及其所处生长期密切相关，证实了在超滤净水工艺典型运行参数范围内藻细胞破裂低于5%。开展了超滤过程中藻类代谢产物去除效能研究，发现藻毒素、2-MIB和土臭素等代谢产物去除率与可逆阻力之间呈正相关关系，揭示了滤饼层具有强化截留藻类代谢产物的作用。开发了基于亚铁活化高锰酸盐的适度预氧化技术，发现新生态铁锰氧化物的吸附与絮凝作用，可以强化嗅味物质截留并抑制藻类胞外有机物在膜表面直接沉积，同步强化了嗅味物质去除与不可逆膜污染控制。开发了超滤适度反冲洗技术，发现降低反冲洗强度可减少滤饼层的破碎程度，强化藻细胞絮体在膜池底部沉积，减少藻细胞在膜表面反复沉积；超滤适度反冲洗技术成功应用于万吨规模超滤工艺水厂，可在不增加基建和设备的前提下降低超滤系统运行费用15%。构建了基于超滤/纳滤的饮用水应急处理技术，提出了“并列运行，提升水质；串联运行，应对突发”的优化运行模式，论证了超滤纳滤双膜工艺在解决藻类爆发以及其他突发水源污染方面的可靠性。综上，课题研究成果为水源高藻期的饮用水安全保障和超滤工艺高效运行提供基础性支撑。