生物电耦合作用下超滤膜污染缓解机制研究

Membrane fouling is one of the key issues which restricted the further development of membrane technique, understanding the membrane fouling from micro-level could contribute to solving this issue fundamentally. It is well known that the membrane fouling greatly relates to the content of surrounding extracellular polymeric substances (EPS). This project aims to explore the influences of bioelectricity integration on ultrafiltration (UF) membrane fouling during drinking water treatment, which induced by the microbes naturally existed in our aquatic system. The influences of bioelectricity integration on biodiversity of the microbes accumulated on the membrane surface will be thoroughly investigated via molecular biology method, with subsequent exploration of its effects on the metabolic pathways and the metabolites of the microbes. The reaction of biofilm to the environmental factors will also be explored, in order to understand the interactions between the microbes within and outside the biofilm and its influences on EPS secretion. Based on which, the characteristics of EPS under the synergistic effect between bioelectricity integration and environmental factors will be systematically investigated, to understand its adhesion ability on membrane surface and the clogging mechanism. This project will help us to understand the influences of EPS on membrane irreversible fouling radically and thereby propose an effective anti-fouling strategy.

膜污染是制约着膜技术普及应用的关键因素之一，从微观层面上掌握膜污染机制有助于从根本上解决膜污染问题。微生物胞外聚合物的含量与膜污染有着密切的联系。本项目研究基于天然水体中存在的微生物，考察其在生物电耦合作用下对饮用水处理过程中超滤膜污染的影响。通过生物分子学手段研究生物电耦合作用对超滤膜表面富集微生物种群的影响机制，并探究在其影响下微生物代谢途径转变及代谢产物分泌机制。通过对环境因子的控制，探讨生物膜对环境因子的响应机制，考察生物膜内外微生物在环境因子影响下的相互作用机制及对其胞外聚合物分泌的影响。基于此，进一步解析在生物电耦合和环境因子协同作用下微生物胞外聚合物的分泌特性，考察不同分泌物和超滤膜表面的黏附机制及对膜孔道的堵塞机理，从而掌握胞外聚合物对超滤膜不可逆膜污染的影响机制，并提出有效的超滤膜污染防治措施。

膜污染是制约着膜技术普及应用的关键因素之一，从微观层面上掌握膜污染机制有助于从根本上解决膜污染问题。研究首先探明了微生物共存条件下基于原电池的生物电耦合体系对超滤膜污染的影响。研究发现微生物的存在可以强化基于原电池的微絮凝过程中的电子传递，从而在膜滤过程中促进微絮凝过程，降低超滤运行过程中滤膜表面累积的生物大分子含量（降低55%以上），对超滤膜污染的缓解具有积极的促进作用（连续运行1200小时，跨膜压差降低近一半）。进一步的，通过对超滤膜表面生物膜的电势控制，使得超滤膜表面所积累的电活性微生物（如Oxalobacteraceae和Sphingomonas等）的代谢活动显著增强，表现为生物膜与膜电极之间的电子交换能力及生物大分子的代谢能力均得到显著的提升，促使长期运行的超滤膜跨膜压差维持稳定在一个较低的水平，超滤膜污染得到有效控制。此外，针对原水中的天然有机物的去除，研究开发了以生物慢滤为预处理工艺核心的耦合超滤技术，对超滤膜污染缓解及最终出水水质健康均有显著的提升。本研究内容为生产高品质水、低膜污染的饮用水膜法水处理提供了可行的且具有前景的方案，可进一步促进超滤膜在给水领域的应用。