Department of Civil Engineering, The University of British Columbia, 6250 Applied Science Lane, Vancouver, BC, Canada.
Water Res. 2010 May;44(9):2703-14. doi: 10.1016/j.watres.2010.01.024. Epub 2010 Feb 12.
In an earlier phase of this study, we compared the performances of pilot scale treatment systems operated in either a conventional enhanced biological phosphorus removal (CEBPR) mode, or a membrane enhanced biological phosphorus removal (MEBPR) mode. In the present investigation, we characterized the bacterial community populations in these processes during parallel operation with the same municipal wastewater feed. The objectives of the study were (1) to assess the similarity of the bacterial communities supported in the two systems over time, (2) to determine if distinct bacterial populations are associated with the MEBPR and CEBPR processes, and (3) to relate the dynamics of the community composition to changes in treatment process configuration and to treatment process performance. The characteristics of the bacterial populations were first investigated with ribosomal intergenic spacer analysis, or RISA. To further understand the bacterial population dynamics, important RISA phylotypes were isolated and identified through 16S RNA gene sequencing. The parallel MEBPR and CEBPR systems developed bacterial communities that were distinct. The CEBPR community appeared to exhibit greater diversity, and this may have been the primary reason why the CEBPR treatment train demonstrated superior functional stability relative to the MEBPR counterpart. Moreover, the more diverse bacterial population apparent in the CEBPR system was observed to be more dynamic than that of the MEBPR process. Several RISA bands were found to be characteristic of either the membrane or conventional biological system. In particular, the MEBPR configuration appeared to be selective for the slow-growing organism Magnospira bakii and for the foam-associated Microthrix parvicella and Gordonia sp., while gravity separation led to the washout of M. parvicella. In both pilot trains, sequence analysis confirmed the presence of EBPR-related organisms such as Accumulibacter phosphatis. The survey of the CEBPR system also revealed many uncultured organisms that have not been well characterized. The study demonstrated that a simple replacement of a secondary clarifier with membrane solids-liquid separation is sufficient to shift the composition of an activated sludge microbial community significantly.
在本研究的早期阶段，我们比较了以传统强化生物除磷（CEBPR）模式或膜强化生物除磷（MEBPR）模式运行的中试处理系统的性能。在本研究中，我们在使用相同城市废水进料平行运行的过程中，对这些过程中的细菌群落种群进行了特征描述。研究的目的是：(1) 评估两个系统中随时间推移支持的细菌群落的相似性；(2) 确定是否存在与 MEBPR 和 CEBPR 过程相关的独特细菌种群；(3) 将群落组成的动态变化与处理过程配置和处理过程性能相关联。首先通过核糖体基因间 spacer 分析（RISA）来研究细菌种群的特征。为了进一步了解细菌种群动态，通过 16S RNA 基因测序分离并鉴定了重要的 RISA 类群。平行的 MEBPR 和 CEBPR 系统培养出了不同的细菌群落。CEBPR 群落似乎表现出更大的多样性，这可能是 CEBPR 处理系统相对于 MEBPR 处理系统表现出更高功能稳定性的主要原因。此外，在 CEBPR 系统中观察到的更具多样性的细菌种群比 MEBPR 过程中的细菌种群更为动态。发现一些 RISA 条带是膜或传统生物系统的特征。特别是，MEBPR 配置似乎对生长缓慢的微生物 Magnospira bakii 以及与泡沫相关的 Microthrix parvicella 和 Gordonia sp. 具有选择性，而重力分离导致 M. parvicella 被冲洗掉。在两个中试处理系统中，序列分析证实存在与 EBPR 相关的微生物，如 Accumulibacter phosphatis。对 CEBPR 系统的调查还揭示了许多尚未得到充分描述的未培养微生物。研究表明，仅用膜固液分离替代二沉池就足以显著改变活性污泥微生物群落的组成。
