污水再生高压膜工艺中无机-有机-生物膜污染耦合效应与动态作用机制

High pressure membrane filtration processes, such as nano-filtration and reverse osmosis (RO), are important technologies for producing the reclaimed high quality water from municipal wastewater, whereas the membrane fouling has always been the bottleneck of the stable operation of such systems. Up to date, it is vague that the mechanisms of synergistic fouling by inorganic, organic and biological foulants, and improvement is urgently required in current fouling suppression techniques. Thus, it is of great significance to conduct deep relevant investigations on such fields. In this study, RO membrane will be adopted, its dynamic fouling development will be characterized, and the respective contributions of inorganic, organic and biological fouling to the filtration resistance will be identified using advanced physico-chemical and biological analysis measures. Furthermore, the synergistic effect and dynamic mechanisms of interaction among inorganic, organic and biological fouling will be dissected at the molecular level, to reveal the key inorganic ions and organic components causing high synergistic effect of organic-inorganic fouling as well as such key factors with high potential to induce biological fouling. Besides, principles and methods will be investigated to remove those key factors, and new strategies for fouling suppression will be established based on the regulation of relevant key factors. The outcome of this study would be expected to offer significant support both theoretically and technically to the stable operation of high pressure membrane processes such as RO in reclamation and reuse of municipal wastewater.

纳滤/反渗透高压膜工艺是对城市污水进行再生、制备高品质再生水的重要技术手段，然而膜污染是制约系统稳定运行的关键。针对城市污水处理厂二级出水复杂体系中无机-有机-生物耦合膜污染机制不清，膜污染控制对策不力的现状，深入开展相关研究意义重大。本研究将基于先进的物理、化学以及生物学分析手段，以反渗透膜工艺为例，主要研究反渗透高压膜污染动态发展特征，识别无机污染、有机污染以及生物污染对膜过滤阻力的贡献；基于分子水平，深入解析无机-有机-生物之间的膜污染耦合效应与动态作用机制，揭示无机-有机膜污染耦合效应高的关键无机离子和有机组份、生物污染诱发潜势高的关键无机和有机因子；探索这些关键因子的去除原理和方法，建立基于关键因子调控的高压膜工艺膜污染控制新策略。研究结果对于从理论和技术上支持反渗透等高压膜工艺在城市污水再生回用中的稳定运行具有重要意义。

纳滤/反渗透高压膜是对污水进行再生、制备高品质再生水的重要技术手段，然而膜污染是制约系统稳定运行的关键。针对高压膜工艺的膜污染问题，解析了膜污染动态发展过程特征：膜污染形成初期，腐殖酸等在膜表面附着使膜表面疏水性增强；膜污染中期，疏水性蛋白在其上进一步附着；膜污染后期，由于生物污染及其分泌的多糖和蛋白质、以及无机离子的架桥作用，使得多糖成为优势污染物；建立了膜污染的统计学分析新方法。基于该方法定量评价了有机、无机、生物污染物对膜污染的单独贡献以及三者对膜污染的交互作用；以海藻酸钠和偏硅酸钠为多糖和硅的代表，分析了无机-有机膜污染耦合效应和分子作用机制。验证了当二者共存时，膜污染现象加剧。多糖与硅的复合物具有Si-C和Si-O-C吸收峰，表明两者之间形成了稳定的化学键。多糖与硅可自发进行放热反应，二者之间以氢键和范德华力为主要相互作用；发现多段高压膜系统中，膜生物污染的段间差异显著。核心菌种的α-变形菌门的鞘质单胞菌中Sphingopyxis和Sphingomonas两个属，具有较强的胞外多聚物分泌能力和较高的膜污染潜势；针对高压膜污染特征，提出了一款碱性含酶复配清洗药剂，长期清洗效果与传统化学清洗剂相当，虽然清洗过程使部分有机物残留，但所形成的污染层结构疏松，从而可增加对膜通量的恢复效果，有效缓解再污染，是一种温和、绿色的具有可持续性的新型膜污染控制方法。研究结果对于从理论和技术上支持高压膜工艺在污废水再生回用中的稳定应用具有重要意义。