Douterelo Isabel, Jackson M, Solomon C, Boxall J
Pennine Water Group, Department of Civil and Structural Engineering, Mappin Street, University of Sheffield, Sheffield, S1 3JD, UK.
Wessex Water, Claverton Down Rd, Bath, Somerset, BA2 7WW, UK.
Appl Microbiol Biotechnol. 2016 Apr;100(7):3301-11. doi: 10.1007/s00253-015-7155-3. Epub 2015 Dec 5.
Biofilm formation in drinking water distribution systems (DWDS) is influenced by the source water, the supply infrastructure and the operation of the system. A holistic approach was used to advance knowledge on the development of mixed species biofilms in situ, by using biofilm sampling devices installed in chlorinated networks. Key physico-chemical parameters and conventional microbial indicators for drinking water quality were analysed. Biofilm coverage on pipes was evaluated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The microbial community structure, bacteria and fungi, of water and biofilms was assessed using pyrosequencing. Conventional wisdom leads to an expectation for less microbial diversity in groundwater supplied systems. However, the analysis of bulk water showed higher microbial diversity in groundwater site samples compared with the surface water site. Conversely, higher diversity and richness were detected in biofilms from the surface water site. The average biofilm coverage was similar among sites. Disinfection residual and other key variables were similar between the two sites, other than nitrates, alkalinity and the hydraulic conditions which were extremely low at the groundwater site. Thus, the unexpected result of an exceptionally low diversity with few dominant genera (Pseudomonas and Basidiobolus) in groundwater biofilm samples, despite the more diverse community in the bulk water, is attributed to the low-flow hydraulic conditions. This finding evidences that the local environmental conditions are shaping biofilm formation, composition and amount, and hence managing these is critical for the best operation of DWDS to safeguard water quality.
饮用水分配系统（DWDS）中的生物膜形成受原水、供水基础设施和系统运行的影响。通过使用安装在氯化网络中的生物膜采样装置，采用整体方法来增进对原位混合物种生物膜发育的了解。分析了饮用水水质的关键物理化学参数和传统微生物指标。通过扫描电子显微镜（SEM）和共聚焦激光扫描显微镜（CLSM）评估管道上的生物膜覆盖率。使用焦磷酸测序评估水和生物膜的微生物群落结构、细菌和真菌。传统观念认为，在地下水供应系统中微生物多样性较低。然而，对大量水样的分析表明，与地表水采样点相比，地下水采样点的微生物多样性更高。相反，在地表水采样点的生物膜中检测到更高的多样性和丰富度。各采样点的平均生物膜覆盖率相似。除了硝酸盐、碱度和水力条件（在地下水采样点极低）外，两个采样点的消毒残余量和其他关键变量相似。因此，尽管大量水样中的群落更加多样，但地下水生物膜样本中出现了极低多样性且优势属较少（假单胞菌属和蛙粪霉属）这一意外结果，这归因于低流量的水力条件。这一发现证明，当地环境条件正在塑造生物膜的形成、组成和数量，因此对这些条件进行管理对于DWDS保障水质的最佳运行至关重要。
