Abstract Membrane fouling is the bottleneck of stable operations for reverse osmosis (RO), which is the key technology for reclaimed water reuse in thermal power plants. The foulant composition, formation mechanism, and key contributors were analyzed in this study. The primary scaling substances are Ca, Mg, Al, Fe, and Si, and Ca accounts for 1.49 wt%. Humic substances, proteins, and polysaccharides are the primary organic constitutes, and among them bio-derivatives were main composition revealed by FTIR, EEM, and SEC. Thus, bio-fouling was believed to be the key contributor together with the results of the SEM and the microbial community analysis. The three leading bacteria were α-, β-, γ-proteobacteria at class levels, 38.11%, 14.19%, and 34.31%, respectively, while starkeya, acidovorax, luteimonas, and pseudoxanthomonas were the leading bacteria at the genus level. Among these bacteria, the one with metabolic processes related to nitrogen fixation and proteolysis showed higher abundance for the high concentrations of nitrogen and protein. Foulants on the endcap and membrane entrance also indicated severe bio-fouling, where Acidovorax presented significant abundance. A Vertical distribution of the microbial community was found in the cross-section of the foulant, in particular, a significant decrease of starkeya (from 48.4% to 4.65%) and acidovorax (from 17.64% to 5.61%) and an increase of pseudoxanthomonas (from 1.04% to 12.89%) from the top layer to the bottom layer were observed. The γ-proteobacteria was recognized as the pioneering bacteria for its significantly higher abundance in the deeper layer. This study helps to elucidate the RO membrane fouling composition and its key contributors, and improves our understanding of the membrane fouling mechanism and a controlling strategy.

中文翻译：

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全规模反渗透废水回收过程中膜污染的特征和形成机制：膜尸检和污染表征

摘要 反渗透（RO）是火电厂中水回用的关键技术，膜污染是其稳定运行的瓶颈。本研究分析了污垢的成分、形成机制和主要贡献者。主要结垢物质为Ca、Mg、Al、Fe和Si，Ca占1.49wt%。腐殖质、蛋白质和多糖是主要的有机成分，其中生物衍生物是FTIR、EEM和SEC揭示的主要成分。因此，生物污染与 SEM 和微生物群落分析的结果一起被认为是关键因素。三个领先的细菌是类水平的α-、β-、γ-变形菌，分别为38.11%、14.19%和34.31%，而starkeya、acidovorax、luteimonas、和假黄单胞菌是属水平的主要细菌。在这些细菌中，具有与固氮和蛋白水解相关的代谢过程的细菌对高浓度的氮和蛋白质显示出更高的丰度。端盖和膜入口上的污垢也表明存在严重的生物污染，其中 Acidovorax 表现出显着的丰度。微生物群落垂直分布在污物横截面，特别是starkeya（从48.4%到4.65%）和酸食菌（从17.64%到5.61%）显着减少，假黄单胞菌增加（从 1.04% 到 12.89%）从顶层到底层被观察到。γ-变形菌因其在更深层的丰度显着更高而被公认为先驱细菌。