State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
Water Res. 2013 Nov 1;47(17):6680-90. doi: 10.1016/j.watres.2013.09.007. Epub 2013 Sep 11.
The biofouling characteristics of a sequential anoxic/aerobic-membrane bioreactor (A/O MBR) were analyzed during the three-stage process (fast-slow-fast transmembrane pressure (TMP) increasing). The results indicated: during the stage 1 (before day 1), the microbial communities in the activated sludge (AS), cake sludge (CS) and biofilm (BF) were similar to each other, and the adsorption of microbes and the metabolic products was the main factor that led to TMP increase; during the stage 2 (between day 1 and day 7), the cake layer begun to form and the TMP continued to rise gradually at a reduced rate compared to stage 1, at this point a characteristic microbial community colonized the CS with microorganisms such as Saprospiraceae and Comamonadaceae thriving on the membrane surface (BF) probably due to greater nutrient availability, and the predominance of these species in the microbial population led to the accumulation of biofouling metabolic products in the CS, which resulted in membrane fouling and the associated rise in TMP; during the final stage (after day 7), the biofilm had matured, and the activity of anaerobes stimulated cake compaction. The statistical analysis showed a correlation between the TMP changing rate and the carbonhydrates of soluble microbial products (SMPc) content in the CS. When the SMPc concentration rose slowly there was a low level of biofouling. However, when the SMPc accumulating rate was greater, it resulted in the more severe biofouling associated with the TMP jump. Furthermore, the correlation coefficient for the TMP increase and protein concentrations of extracellular polymeric substances (EPSp) in the CS was highly significant. The cluster analysis suggested that the AS microbial community remained stable during the three TMP change stages, while the CS and BF community were changed accompanied with the TMP change. The interaction between the microbial communities and the metabolic products lead to the significant correlation between them. The EPSp in conjunction with the SMPc were the main factors that accelerate the membrane fouling. The rapid rise of SMPc triggered a sudden increase in the TMP, while the accumulation of EPSp caused the sustained rise in TMP.
采用序批式缺氧/好氧-膜生物反应器（A/O MBR）进行三阶段（快速-缓慢-快速跨膜压力（TMP）增加）试验，分析生物污堵特性。结果表明：阶段 1（第 1 天之前），活性污泥（AS）、膜生物反应器内污泥层（CS）和生物膜（BF）中的微生物群落相似，微生物的吸附和代谢产物是导致 TMP 增加的主要因素；阶段 2（第 1 天至第 7 天之间），开始形成滤饼层，与阶段 1 相比，TMP 以较低的速率持续缓慢上升，此时具有代谢产物的微生物群落在 CS 中定植，微生物种群中这些物种的优势导致 CS 中生物污堵代谢产物的积累，导致膜污染和 TMP 升高；在最后阶段（第 7 天之后），生物膜成熟，厌氧菌活性刺激滤饼压实。统计分析表明，TMP 变化率与 CS 中可溶性微生物产物（SMPc）含量呈正相关。当 SMPc 浓度缓慢增加时，生物污堵程度较低。然而，当 SMPc 积累速率较大时，会导致更严重的生物污堵，TMP 会突然升高。此外，CS 中 TMP 增加与胞外聚合物物质（EPSp）中蛋白质浓度之间的相关系数具有高度显著性。聚类分析表明，在三个 TMP 变化阶段，AS 微生物群落保持稳定，而 CS 和 BF 群落随着 TMP 变化而变化。微生物群落及其代谢产物之间的相互作用导致它们之间存在显著相关性。EPSp 与 SMPc 是加速膜污染的主要因素。SMPc 的快速增加引发 TMP 的突然升高，而 EPSp 的积累则导致 TMP 的持续升高。
