Role of live cell colonization in the biofilm formation process in membrane bioreactors treating actual sewage under low organic loading rate conditions
Role of live cell colonization in the biofilm formation process in membrane bioreactors treating actual sewage under low organic loading rate conditions
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DOI：
10.1007/s00253-021-11119-y
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发表时间：
2021-01
影响因子：
5
通讯作者：
T. Miwa;Y. Takimoto;M. Hatamoto;Daiki Kuratate;T. Watari;Takashi Yamaguchi
中科院分区：
文献类型：
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作者：
T. Miwa;Y. Takimoto;M. Hatamoto;Daiki Kuratate;T. Watari;Takashi Yamaguchi
摘要膜生物反应器（mbr）膜表面生物膜的形成是膜污染的主要原因之一，是影响膜生物反应器稳定运行的一大问题。为了更好地了解生物膜的发育，需要关于生物膜微生物群落组成的精确信息。然而，对于mbr处理实际污水中活性污泥和生物膜的微生物群落与生物膜形成过程之间的关系研究有限。本研究考察了生物膜形成各阶段微生物群落结构与活性污泥之间的关系，并通过非破坏性观察阐明了生物膜的生长情况。运行两个缺氧/缺氧mbr，并诱导膜污染。两种反应器的渗透性均迅速下降，在膜表面的死细胞调理膜上形成了活细胞微菌落。基于16S rRNA基因序列的主成分分析表明，与活性污泥相比，生物膜从中期到成熟阶段的微生物群落发生了显著变化。未分类奈瑟菌科等特定细菌的丰度在中期生物膜中增加，中期生物膜的多样性指数低于成熟生物膜和活性污泥。这些结果表明，具有定植能力的特定细菌的存在在生物膜的形成中起着至关重要的作用。在生物膜形成的早期和中期，需要针对膜污染的缓解策略来减少MBR膜污染。•将成熟生物膜的微生物群落与活性污泥进行了比较。•在生物膜的中期，活细胞定植在死细胞调节膜上。•微生物多样性在活细胞定植阶段低于活性污泥阶段。
AbstractBiofilm development on the membrane surface is one of the main reasons for membrane fouling in membrane bioreactors (MBRs) and it is a big problem for their stable operation. Precise information on the microbial community composition of the biofilm is needed for a better understanding of biofilm development. However, there have been limited investigations of the relationship between the biofilm formation process and the microbial community of activated sludge and biofilm in MBRs treating real sewage. In this study, relationships between the microbial community structure of biofilm and activated sludge at each biofilm formation stage were investigated and biofilm growth was elucidated by nondestructive observations. Two anoxic/oxic MBRs were operated and membrane fouling was induced. Permeability rapidly decreased in both reactors and live cell microcolonies were formed on dead cell conditioning film on the membrane surface. Principal component analysis based on 16S rRNA gene sequences showed that the biofilm microbial community changed significantly from middle stage to mature biofilm when compared with that of activated sludge. The abundance of specific bacteria, such as unclassifiedNeisseriaceae, increased in middle-stage biofilm and the diversity indexes of middle-stage biofilm were lower than those of mature biofilm and activated sludge. These results suggested that the presence of specific bacteria with colonization ability played a crucial role in biofilm formation. Strategies are needed to target membrane fouling mitigation during early- and middle-stage biofilm formation to reduce MBR membrane fouling.Key points•Microbial community of mature biofilm was approached to that of activated sludge.• In the middle-stage biofilm, live cells colonized on a dead-cell-conditioning-film.• Microbial diversity was lower in live cell colonizing stage than in activated sludge.