title: Bacterial community radial-spatial distribution in biofilms along pipe wall in chlorinated drinking water distribution system of East China.
abstract: Biofilms in the pipe wall may lead to water quality deterioration and biological instability in drinking water distribution systems (DWDSs). In this study, bacterial community radial-spatial distribution in biofilms along the pipe wall in a chlorinated DWDS of East China was investigated. Three pipes of large diameter (300, 600, and 600 mm) were sampled in this DWDS, including a ductile cast iron pipe (DCIP) with pipe age of 11 years and two gray cast iron pipes (GCIP) with pipe ages of 17 and 19 years, and biofilms in the upper, middle, and lower parts of each pipe wall were collected. Real-time quantitative polymerase chain reaction (qPCR) and culture-based method were used to quantify bacteria. 454 pyrosequencing was used for bacterial community analysis. The results showed that the biofilm density and total solid (TS) and volatile solid (VS) contents increased gradually from the top to the bottom along the pipe wall. Microorganisms were concentrated in the upper and lower parts of the pipe wall, together accounting for more than 80 % of the total biomass in the biofilms. The bacterial communities in biofilms were significantly different in different areas of the pipe wall and had no strong interaction. Compared with the upper and lower parts of the pipe wall, the bacterial community in the middle of the pipe wall was distributed evenly and had the highest diversity. The 16S rRNA genes of various possible pathogens, including Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Salmonella enterica, were detected in the biofilms, and the abundances of these possible pathogens were highest in the middle of the pipe wall among three areas. The detachment of the biofilms is the main reason for the deterioration of the water quality in DWDSs. The results of this study suggest that the biofilms in the middle of the pipe wall have highly potential risk for drinking water safety, which provides new ideas for the study of the microbial ecology in DWDS.
authors.affiliation: College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Jingqing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Hongxing
authors.initials: H
authors.lastname: Ren
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Xianbei
authors.initials: X
authors.lastname: Ye
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Lou
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, 310053, China.
authors.forename: Dongqing
authors.initials: D
authors.lastname: Cheng
authors.affiliation: Shaoxing Water Environmental Science Institute Co. Ltd, Shaoxing, 312000, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: He
authors.affiliation: Shaoxing Water Environmental Science Institute Co. Ltd, Shaoxing, 312000, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Shaoxing Water Environmental Science Institute Co. Ltd, Shaoxing, 312000, China.
authors.forename: Shangde
authors.initials: S
authors.lastname: Qiu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Liusong
authors.initials: L
authors.lastname: Fu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China. blhu@zju.edu.cn.
authors.forename: Baolan
authors.initials: B
authors.lastname: Hu
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D058491:Bacterial Load; D018441:Biofilms / Q000254:growth & development*; D058448:Biota; D002681:China; D002713:Chlorine; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004203:Disinfection; D060766:Drinking Water / Q000737:chemistry; D004783:Environmental Microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D060766:Drinking Water; D012336:RNA, Ribosomal, 16S; D002713:Chlorine
keywords: Bacterial community; Biofilms; Drinking water distribution system; Possible pathogens; Radial-spatial distribution