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Zhang Y, Li X, Ren A, Yao M, Chen C, Zhang H, van der Meer W, Liu G. Impacts of water treatments on bacterial communities of biofilm and loose deposits in drinking water distribution systems. ENVIRONMENT INTERNATIONAL 2024; 190:108893. [PMID: 39079336 DOI: 10.1016/j.envint.2024.108893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/05/2024] [Accepted: 07/15/2024] [Indexed: 08/28/2024]
Abstract
Treated drinking water is delivered to customers through drinking water distribution systems (DWDSs). Although studies have focused on exploring the microbial ecology of DWDSs, knowledge about the effects of different water treatments on the bacterial community of biofilm and loose deposits in DWDS is limited. This study assessed the effects of additional treatments on the bacterial communities developed in 10 months' old pilot DWDSs. The results showed a similar bacterial community in the pipe-wall biofilm, which was dominated by Novosphingobium spp. (20-82 %) and Sphingomonas spp. (11-53 %), regardless of the treatment applied. The bacterial communities that were retained in the distribution systems (including pipe-wall biofilm and loose deposits) were similar to the particle-associated bacteria (PAB) in the corresponding supply water. The additional treatments showed clear effects of the removal and/or introduction of particles. The genera Aeromonas spp., Clostridium spp., Legionella spp., and Pseudomonas spp., which contain opportunistic pathogenic species, were only detected among the PAB in ion exchange system. Our study demonstrated that the biofilm community is consistent across treatments, and the contribution from bacteria in loose deposits is important but can be controlled by removing particles. These findings offer more insight into the origin and development of microbial ecology in DWDSs and suggest paths for further research on the possibility of managing the microbial ecology in distribution systems.
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Affiliation(s)
- Yue Zhang
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing, China; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands
| | - Xiaoming Li
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing, China
| | - Anran Ren
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing, China; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands
| | - Mingchen Yao
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing, China; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands
| | - Chen Chen
- Beijing Waterworks Group Co., Ltd., Beijing, China
| | - Haichen Zhang
- Utrecht University, Heidelberglaan 8, 3584 CS Utrecht, the Netherlands
| | - Walter van der Meer
- Science and Technology, University of Twente, P.O. Box 217, 7500AE Enschede, the Netherlands
| | - Gang Liu
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing, China; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands.
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2
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Wang F, Pan J, Hu Y, Zhou J, Wang H, Huang X, Chu W, van der Hoek JP. Effects of biological activated carbon filter running time on disinfection by-product precursor removal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155936. [PMID: 35580672 DOI: 10.1016/j.scitotenv.2022.155936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/25/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Biological activated carbon (BAC) filtration is usually considered to be able to decrease formation potentials (FPs) of disinfection by-products (DBPs) in drinking water treatment plant (DWTP). However, BAC filters with long running time may release microbial metabolites to effluents and therefore increase FPs of nitrogenous DBPs with high toxicity. To verify this hypothesis, this study continuously tracked BAC filters in a DWTP for one year, and assessed effects of old (running time 8-9 years) and new (running time 0-13 months) BAC filters on FPs of 15 regulated and unregulated DBPs. Results revealed that dissolved organic carbon (DOC) removal was slightly higher in the new BAC than the old one. All fluorescent components of dissolved organic matter evidently declined after new BAC filtration, but fulvic acid-like and soluble microbial product-like substances increased after old BAC filtration, which could be caused by microbial leakage. Correspondingly, new BAC filter generally removed more DBP FPs than the old one. 46.5% HAA7 FPs from chlorination and 44.3% THM4 FPs from chloramination were removed by new BAC filter. However, some DBP FPs, especially HAN FPs, were poorly removed or even increased by the old BAC filter. Proteobacteria could be a main contributor for DBP precursor removal in BAC filters. Herminiimonas, most abundant genera in new BAC filter, may explain its better DOC and UV254 removal performance and lower DBP FPs, while Bradyrhizobium, most abundant genera in old BAC filter, might produce more extracellular polymeric substances and therefore increased N-DBP FPs in old BAC effluent. This study provided insight into variations of DBP FPs and microbial communities in the new and old BAC filters, and will be helpful for the optimization of DWTP design and operation for public health.
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Affiliation(s)
- Feifei Wang
- School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, PR China
| | - Jiazheng Pan
- School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, PR China.
| | - Yulin Hu
- School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, PR China
| | - Jie Zhou
- School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, PR China
| | - Haoqian Wang
- School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, PR China
| | - Xin Huang
- School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, PR China
| | - Wenhai Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, PR China.
| | - Jan Peter van der Hoek
- Department of Water Management, Delft University of Technology, 2628 CN Delft, the Netherlands; Research & Innovation Program, Waternet, 1096 AC Amsterdam, the Netherlands
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3
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Rahmatika I, Kurisu F, Furumai H, Kasuga I. Dynamics of the Microbial Community and Opportunistic Pathogens after Water Stagnation in the Premise Plumbing of a Building. Microbes Environ 2022; 37. [PMID: 35321996 PMCID: PMC8958293 DOI: 10.1264/jsme2.me21065] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In premise plumbing, microbial water quality may deteriorate under certain conditions, such as stagnation. Stagnation results in a loss of disinfectant residual, which may lead to the regrowth of microorganisms, including opportunistic pathogens. In the present study, microbial regrowth was investigated at eight faucets in a building over four seasons in one year. Water samples were obtained before and after 24 h of stagnation. In the first 100 mL after stagnation, total cell counts measured by flow cytometry increased 14- to 220-fold with a simultaneous decrease in free chlorine from 0.17–0.36 mg L–1 to <0.02 mg L–1. After stagnation, total cell counts were not significantly different among seasons; however, the composition of the microbial community varied seasonally. The relative abundance of Pseudomonas spp. was dominant in winter, whereas Sphingomonas spp. were dominant in most faucets after stagnation in other seasons. Opportunistic pathogens, such as Legionella pneumophila, Mycobacterium avium, Pseudomonas aeruginosa, and Acanthamoeba spp., were below the quantification limit for real-time quantitative PCR in all samples. However, sequences related to other opportunistic pathogens, including L. feeleii, L. maceachernii, L. micdadei, M. paragordonae, M. gordonae, and M. haemophilum, were detected. These results indicate that health risks may increase after stagnation due to the regrowth of opportunistic pathogens.
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Affiliation(s)
- Iftita Rahmatika
- Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo
| | - Futoshi Kurisu
- Research Center for Water Environment Technology, Graduate School of Engineering, The University of Tokyo
| | - Hiroaki Furumai
- Research Center for Water Environment Technology, Graduate School of Engineering, The University of Tokyo
| | - Ikuro Kasuga
- Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo
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4
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Zhang C, Struewing I, Mistry JH, Wahman DG, Pressman J, Lu J. Legionella and other opportunistic pathogens in full-scale chloraminated municipal drinking water distribution systems. WATER RESEARCH 2021; 205:117571. [PMID: 34628111 PMCID: PMC8629321 DOI: 10.1016/j.watres.2021.117571] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 08/02/2021] [Accepted: 08/13/2021] [Indexed: 05/06/2023]
Abstract
Water-based opportunistic pathogens (OPs) are a leading cause of drinking-water-related disease outbreaks, especially in developed countries such as the United States (US). Physicochemical water quality parameters, especially disinfectant residuals, control the (re)growth, presence, colonization, and concentrations of OPs in drinking water distribution systems (DWDSs), while the relationship between OPs and those parameters remain unclear. This study aimed to quantify how physicochemical parameters, mainly monochloramine residual concentration, hydraulic residence time (HRT), and seasonality, affected the occurrence and concentrations of four common OPs (Legionella, Mycobacterium, Pseudomonas, and Vermamoeba vermiformis) in four full-scale DWDSs in the US. Legionella as a dominant OP occurred in 93.8% of the 64 sampling events and had a mean density of 4.27 × 105 genome copies per liter. Legionella positively correlated with Mycobacterium, Pseudomonas, and total bacteria. Multiple regression with data from the four DWDSs showed that Legionella had significant correlations with total chlorine residual level, free ammonia concentration, and trihalomethane concentration. Therefore, Legionella is a promising indicator of water-based OPs, reflecting microbial water quality in chloraminated DWDSs. The OP concentrations had strong seasonal variations and peaked in winter and/or spring possibly because of reduced water usage (i.e., increased water stagnation or HRT) during cold seasons. The OP concentrations generally increased with HRT presumably because of disinfectant residual decay, indicating the importance of well-maintaining disinfectant residuals in DWDSs for OP control. The concentrations of Mycobacterium, Pseudomonas, and V. vermiformis were significantly associated with total chlorine residual concentration, free ammonia concentration, and pH and trihalomethane concentration, respectively. Overall, this study demonstrates how the significant spatiotemporal variations of OP concentrations in chloraminated DWDSs correlated with critical physicochemical water quality parameters such as disinfectant residual levels. This work also indicates that Legionella is a promising indicator of OPs and microbial water quality in chloraminated DWDSs.
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Affiliation(s)
- Chiqian Zhang
- Pegasus Technical Services, Inc., Cincinnati, Ohio, USA
| | - Ian Struewing
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Jatin H Mistry
- United States Environmental Protection Agency, Region 6, Dallas, Texas, USA
| | - David G Wahman
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Jonathan Pressman
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA.
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5
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Wang Z, Li L, Ariss RW, Coburn KM, Behbahani M, Xue Z, Seo Y. The role of biofilms on the formation and decay of disinfection by-products in chlor(am)inated water distribution systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 753:141606. [PMID: 32890868 DOI: 10.1016/j.scitotenv.2020.141606] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/07/2020] [Accepted: 08/08/2020] [Indexed: 06/11/2023]
Abstract
This study investigated the role of biofilms on the formation and decay of disinfection by-products (DBPs) in chlorine (Cl2) or monochloramine (NH2Cl) disinfected reactors under the conditions related to drinking water distribution systems (DWDSs). Biofilm analysis results revealed that at 0.5 mg/L of disinfectant residual, both Cl2 and NH2Cl were not effective to remove biofilms. As the disinfectant residual increased, biofilms could be eradicated by Cl2, while remaining biofilms were still present even under the highest allowable NH2Cl dose (4 mg/L) for 25 days. Low DBP formation was observed under the recommended minimum Cl2 residual (0.5 mg/L), which could be attributed to limited Cl2 reactions with biofilms, as well as a combination of the volatilization and biodegradation of DBPs. However, when Cl2 residuals reached 2 mg/L, DBP concentrations in bulk water increased sharply beyond the DBP formation of the feed solution, with trihalomethanes and haloacetic acids being the most prevalent DBP species. The sharp increase was temporary for 15 days because of the removal of biofilms. For unregulated DBPs, high levels of haloacetonitriles were observed as attached biofilms reacted with the increased Cl2 dose and provided an additional organic nitrogen source for nitrogenous DBP formation. When maximum Cl2 residual (4 mg/L) was applied, no further increase of DBPs was observed because of biofilm eradication. For NH2Cl disinfection, the DBP levels were much lower than those of Cl2 disinfection, with small differences in DBP formation for different NH2Cl residuals. Overall, this study provides insights into optimizing disinfection protocols for water utilities by balancing the benefits of disinfection application for biofilm control with minimized toxic DBP formation in DWDSs.
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Affiliation(s)
- Zhikang Wang
- College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, Guizhou Province 550025, PR China; Department of Chemical Engineering, University of Toledo, 3048 Nitschke Hall, 2801 W. Bancroft St., Toledo, OH 43606-3390, USA
| | - Lei Li
- Department of Civil and Environmental Engineering, University of Toledo, 3006 Nitschke Hall, 2801 W. Bancroft St., Toledo, OH 43606-3390, USA
| | - Robert W Ariss
- College of Medicine and Life Sciences, University of Toledo, 3000 Arlington Ave, Toledo, OH 43614-2595, USA
| | - Kimberly M Coburn
- Department of Civil and Environmental Engineering, University of Toledo, 3006 Nitschke Hall, 2801 W. Bancroft St., Toledo, OH 43606-3390, USA
| | - Mohsen Behbahani
- Department of Civil and Environmental Engineering, University of Toledo, 3006 Nitschke Hall, 2801 W. Bancroft St., Toledo, OH 43606-3390, USA
| | - Zheng Xue
- Department of Civil and Environmental Engineering, University of Toledo, 3006 Nitschke Hall, 2801 W. Bancroft St., Toledo, OH 43606-3390, USA
| | - Youngwoo Seo
- Department of Chemical Engineering, University of Toledo, 3048 Nitschke Hall, 2801 W. Bancroft St., Toledo, OH 43606-3390, USA; Department of Civil and Environmental Engineering, University of Toledo, 3006 Nitschke Hall, 2801 W. Bancroft St., Toledo, OH 43606-3390, USA.
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6
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Li N, Li X, Shi ZY, Fan XY, Zhou ZW. Response of high-, mid- and low-abundant taxa and potential pathogens to eight disinfection methods and their interactions in domestic hot water system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 749:141440. [PMID: 32829270 DOI: 10.1016/j.scitotenv.2020.141440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
Eight disinfection methods were applied to control biofilm contamination in domestic hot water system. The inactivation efficiency, responses of high- (≥1%), mid- (0.1% ~ 1%) and low-abundant taxa (≤0.1%) to disinfection, and interactions within and across three sub-communities were investigated. Ultraviolet was the most effective disinfection method for total bacteria and Escherichia coli, and chlorine dioxide had the highest inactivation efficiency on heterotrophic bacteria, while silver ions exhibited poor performance on all of them. At the phylum level, the responses of microorganisms to eight disinfection methods were different, but Proteobacteria and Firmicutes dominated in most samples. Eight disinfection methods had a greater impact on the proportion of high- and mid-abundant taxa than that of low-abundant taxa, and led to dissimilar transformations of genera among high-, mid- and low-abundant taxa in each sample. High-, mid- and low-abundant taxa of different samples showed similar structures and were roughly clustered into three Groups. Moreover, high-abundant taxa had more complex internal interactions than mid- and low-abundant taxa, and mainly presented co-occurrence patterns. The associations between high- and low-abundant taxa were close, and some low-abundant genera were identified as hub bacteria, such as Paracoccus, Thioalkalispira and Flavitalea. Furthermore, a total of 23 potential pathogens were detected in this study, and they mainly showed positive interactions, with Mycobacteria and Streptococcus as keystone genera. These results highlight the dissimilar responses of high-, mid- and low-abundant taxa to disinfection, and the critical role of some low-abundant genera in the microbial network, as well as the co-occurrence patterns among potential pathogens.
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Affiliation(s)
- Na Li
- College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, PR China
| | - Xing Li
- College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, PR China
| | - Zhi-Yuan Shi
- Shanghai Investigation, Design & Research Institute Co., Ltd, Shanghai 200335, PR China
| | - Xiao-Yan Fan
- College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, PR China.
| | - Zhi-Wei Zhou
- College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, PR China
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7
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Paduano S, Marchesi I, Casali ME, Valeriani F, Frezza G, Vecchi E, Sircana L, Romano Spica V, Borella P, Bargellini A. Characterisation of Microbial Community Associated with Different Disinfection Treatments in Hospital hot Water Networks. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E2158. [PMID: 32213901 PMCID: PMC7143765 DOI: 10.3390/ijerph17062158] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/20/2020] [Accepted: 03/22/2020] [Indexed: 12/16/2022]
Abstract
Many disinfection treatments can be adopted for controlling opportunistic pathogens in hospital water networks in order to reduce infection risk for immunocompromised patients. Each method has limits and strengths and it could determine modifications on bacterial community. The aim of our investigation was to study under real-life conditions the microbial community associated with different chemical (monochloramine, hydrogen peroxide, chlorine dioxide) and non-chemical (hyperthermia) treatments, continuously applied since many years in four hot water networks of the same hospital. Municipal cold water, untreated secondary, and treated hot water were analysed for microbiome characterization by 16S amplicon sequencing. Cold waters had a common microbial profile at genera level. The hot water bacterial profiles differed according to treatment. Our results confirm the effectiveness of disinfection strategies in our hospital for controlling potential pathogens such as Legionella, as the investigated genera containing opportunistic pathogens were absent or had relative abundances ≤1%, except for non-tuberculous mycobacteria, Sphingomonas, Ochrobactrum and Brevundimonas. Monitoring the microbial complexity of healthcare water networks through 16S amplicon sequencing is an innovative and effective approach useful for Public Health purpose in order to verify possible modifications of microbiota associated with disinfection treatments.
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Affiliation(s)
- Stefania Paduano
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
| | - Isabella Marchesi
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
| | - Maria Elisabetta Casali
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
- University Hospital Policlinico of Modena, 41124 Modena, Italy; (E.V.); (L.S.)
| | - Federica Valeriani
- Department of Movement, Human and Health Sciences, Public Health Unit, University of Rome ‘Foro Italico’, 00135 Rome, Italy; (F.V.); (V.R.S.)
| | - Giuseppina Frezza
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
| | - Elena Vecchi
- University Hospital Policlinico of Modena, 41124 Modena, Italy; (E.V.); (L.S.)
| | - Luca Sircana
- University Hospital Policlinico of Modena, 41124 Modena, Italy; (E.V.); (L.S.)
| | - Vincenzo Romano Spica
- Department of Movement, Human and Health Sciences, Public Health Unit, University of Rome ‘Foro Italico’, 00135 Rome, Italy; (F.V.); (V.R.S.)
| | - Paola Borella
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
| | - Annalisa Bargellini
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
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8
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Song P, Zhou B, Feng G, Brooks JP, Zhou H, Zhao Z, Liu Y, Li Y. The influence of chlorination timing and concentration on microbial communities in labyrinth channels: implications for biofilm removal. BIOFOULING 2019; 35:401-415. [PMID: 31142151 DOI: 10.1080/08927014.2019.1600191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/18/2019] [Accepted: 03/22/2019] [Indexed: 06/09/2023]
Abstract
Chlorination is an effective method to control biofilm formation in enclosed pipelines. To date, very little is known about how to control biofilms at the mesoscale in complex pipelines through chlorination. In this study, the dynamic of microbial communities was examined under different residual chlorine concentrations on the biofilms attached to labyrinth channels for drip irrigation using reclaimed water. The results indicated that the microbial phospholipid fatty acids, extracellular polymeric substances, microbial dynamics, and the ace and Shannon microbial diversity indices showed a gradual decrease after chlorination. However, chlorination increased microbial activity by 0.5-19.2%. The increase in the relative abundances of chloride-resistant bacteria (Acinetobacter and Thermomonas) could lead to a potential risk of chlorine resistance. Thus, keeping a low chlorine concentration (0.83 mg l-1 for 3 h) is effective for controlling biofilm formation in the labyrinth channels.
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Affiliation(s)
- Peng Song
- a College of Water Resources and Civil Engineering , China Agricultural University , Beijing , PR China
- b Genetics and Sustainable Agricultural Research Unit , United States Department of Agriculture , Starkville , MS , USA
| | - Bo Zhou
- a College of Water Resources and Civil Engineering , China Agricultural University , Beijing , PR China
- c College of Agricultural and Life Sciences , University of Wisconsin-Madison , Madison , WI , USA
| | - Gary Feng
- b Genetics and Sustainable Agricultural Research Unit , United States Department of Agriculture , Starkville , MS , USA
| | - John P Brooks
- b Genetics and Sustainable Agricultural Research Unit , United States Department of Agriculture , Starkville , MS , USA
| | - Hongxu Zhou
- a College of Water Resources and Civil Engineering , China Agricultural University , Beijing , PR China
| | - Zhirui Zhao
- d Research Center for Eco-environmental Sciences , Chinese Academy of Sciences , Beijing , PR China
| | - Yaoze Liu
- e Department of Environmental and Sustainable Engineering , University at Albany , Albany , NY , USA
| | - Yunkai Li
- a College of Water Resources and Civil Engineering , China Agricultural University , Beijing , PR China
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9
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Liu L, Xing X, Hu C, Wang H, Lyu L. Effect of sequential UV/free chlorine disinfection on opportunistic pathogens and microbial community structure in simulated drinking water distribution systems. CHEMOSPHERE 2019; 219:971-980. [PMID: 30682762 DOI: 10.1016/j.chemosphere.2018.12.067] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/04/2018] [Accepted: 12/08/2018] [Indexed: 06/09/2023]
Abstract
Drinking water distribution systems (DWDS) may be a "Trojan Horse" for some waterborne diseases caused by opportunistic pathogens (OPs). In this study, two simulated DWDS inoculated with groundwater were treated with chlorine (Cl2) and ultraviolet/chlorine (UV/Cl2) respectively to compare their effects on the OPs distributed in four different phases (bulk water, biofilms, corrosion products, and loose deposits) of DWDS. 16S rRNA genes sequencing and qPCR were used to profile microbial community and quantify target genes of OPs, respectively. Results showed that UV/Cl2 was more effective than single Cl2 to control the regrowth of OPs in the water with the same residual chlorine concentration. However, the OPs inhabiting the biofilms, corrosion products, and loose deposits seemed to be tolerant to UV/Cl2 and Cl2, demonstrating that OPs residing in these phases were resistant to the disinfection processes. Some significant microbial correlations between OPs and Acanthamoeba were found by Spearman correlative analysis (p < 0.05), demonstrating that the ecological interactions may exist in the DWDS. 16S rRNA genes sequencing of water samples revealed a significant different microbial community structure between UV/Cl2 and Cl2. This study may give some implications for controlling the OPs in the DWDS disinfected with UV/Cl2.
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Affiliation(s)
- Lizhong Liu
- Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang City, Jiangxi 330013, China; School of Water Resource and Environmental Engineering, East China University of Technology, Nanchang City, Jiangxi 330013, China
| | - Xueci Xing
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Institute of Environmental Research at Greater Bay, Guangzhou University, Guangzhou 510006, China.
| | - Chun Hu
- Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Institute of Environmental Research at Greater Bay, Guangzhou University, Guangzhou 510006, China
| | - Haibo Wang
- Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Lai Lyu
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Institute of Environmental Research at Greater Bay, Guangzhou University, Guangzhou 510006, China
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10
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Bertelli C, Courtois S, Rosikiewicz M, Piriou P, Aeby S, Robert S, Loret JF, Greub G. Reduced Chlorine in Drinking Water Distribution Systems Impacts Bacterial Biodiversity in Biofilms. Front Microbiol 2018; 9:2520. [PMID: 30405577 PMCID: PMC6205969 DOI: 10.3389/fmicb.2018.02520] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/03/2018] [Indexed: 12/14/2022] Open
Abstract
In drinking water distribution systems (DWDS), a disinfectant residual is usually applied to limit bacterial regrowth. However, delivering water with no or reduced chlorine residual could potentially decrease the selection for antimicrobial resistant microorganisms, favor bacterial regrowth and result in changes in bacterial populations. To evaluate the feasibility of water reduction in local DWDS while ensuring water safety, water quality was measured over 2 months in two different networks, each of them harboring sub-areas with normal and reduced chlorine. Water quality remained good in chlorine reduced samples, with limited development of total flora and absence of coliforms. Furthermore, 16S rRNA amplicon-based metagenomics was used to investigate the diversity and the composition of microbial communities in the sub-networks. Taxonomic classification of sequence reads showed a reduced bacterial diversity in sampling points with higher chlorine residuals. Chlorine disinfection created more homogeneous bacterial population, dominated by Pseudomonas, a genus that contains some major opportunistic pathogens such as P. aeruginosa. In the absence of chlorine, a larger and unknown biodiversity was unveiled, also highlighted by a decreased rate of taxonomic classification to the genus and species level. Overall, this experiment in a functional DWDS will facilitate the move toward potable water delivery systems without residual disinfectants and will improve water taste for consumers.
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Affiliation(s)
- Claire Bertelli
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | | | - Marta Rosikiewicz
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | | | - Sébastien Aeby
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | | | | | - Gilbert Greub
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
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Oh HS, Constancias F, Ramasamy C, Tang PYP, Yee MO, Fane AG, McDougald D, Rice SA. Biofouling control in reverse osmosis by nitric oxide treatment and its impact on the bacterial community. J Memb Sci 2018. [DOI: 10.1016/j.memsci.2018.01.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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12
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Maharjan P, Dey S, Huff G, Zhang W, Phillips GK, Watkins S. Effect of chlorine treatment on inhibition of E. coli serogroup O2 incorporation into 7-day-old biofilm on polyvinylchloride surface. Poult Sci 2017; 96:2862-2870. [PMID: 28419339 DOI: 10.3382/ps/pex088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 03/21/2017] [Indexed: 12/30/2022] Open
Abstract
Poultry waterlines are constructed using polyvinylchloride (PVC) material on which bacterial biofilm can easily form. Biofilm can harbor pathogens including avian pathogenic E. coli (APEC) strains. An in vitro evaluation was performed to determine if E. coli sero group O2 (avian pathogenic) could attach on a PVC surface that had pre-formed biofilm and if this phenomenon could be affected when water was treated with chlorine. Initially, biofilm growth was induced in PVC test coupons (15.16 cm2) for a 7-day period mimicking the waterline scenario in the first wk of poultry brooding; and then this biofilm was challenged with E. coli O2 seeded water in presence/absence of chlorine treatment. After rinsing, test coupons were sampled for bacterial (APC) and E. coli O2 enumeration at various occasions post seeding the pathogen and chlorine treatment. Day 7 APC recovered from coupons was 4.35 log10 cfu/cm2 in trial 1 and 3.66 log10 cfu/cm2 in trial 2. E. coli O2 was not recovered from chlorine treated test coupons (P < 0.05), whereas it was retrieved from untreated coupons (untreated contained > 3 log10 cfu/cm2 in trial 1 and > 2 log10 cfu/cm2 in trial 2). This study suggests that E. coli O2 can incorporate into pre-formed biofilm on a PVC surface within 24 h if water sanitation is not present, and the attachment time of the pathogen can prolong in the absence of already formed biofilm.
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Affiliation(s)
- P Maharjan
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville 72701
| | - S Dey
- Program in Cell and Molecular Biology, University of Arkansas, Fayetteville 72701.,Department of Biological Sciences, University of Arkansas, Fayetteville 72701
| | - G Huff
- USDA-ARS Poultry Production and Product Safety Research, University of Arkansas, Fayetteville 72701
| | - W Zhang
- Department of Civil Engineering, University of Arkansas, Fayetteville, 72701
| | - G K Phillips
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville 72701
| | - S Watkins
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville 72701
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Maharjan P, Huff G, Zhang W, Watkins S. Biofilm growth on polyvinylchloride surface incubated in suboptimal microbial warm water and effect of sanitizers on biofilm removal post biofilm formation. Poult Sci 2017; 96:83-87. [PMID: 27597778 DOI: 10.3382/ps/pew284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/08/2016] [Accepted: 07/06/2016] [Indexed: 11/20/2022] Open
Abstract
An in vitro experiment was conducted to understand the nature of biofilm growth on polyvinyl chloride (PVC) surface when exposed to suboptimal-quality microbial water (>4 log10 cfu/mL) obtained from a poultry drinking water source mimicking water in waterlines during the first week of poultry brooding condition. PVC sections (internal surface area of 15.16 cm2) were utilized in the study to grow biofilm. After a 7-d test period, test coupons with 7-day-old biofilm were transferred into autoclaved municipal water and then treated with either chlorine-based or hydrogen peroxide-based sanitizer at bird drinking water rate, to see the impact on removal of biofilm formed on test coupons. Two trials (T1 and T2) were conducted. Test coupons used in T1 and T2 had the bacterial growth of 3.67 (SEM 0.04) and 3.97 (SEM 0.11) log10 cfu/cm2 on d 7. After sanitizer application, chlorine-based sanitizer removed bacteria in biofilm completely (0 cfu/cm2) within 24 h post treatment whereas hydrogen peroxide-based sanitizer reduced the counts to 1.68 log10 cfu/cm2 (P < 0.05) by 48 h post sanitizer application. Control remained the same (P > 0.05). Results indicated that biofilm formation can occur quickly under suboptimal water condition on PVC surface, and sanitizer application helped mitigate already formed biofilm, yet chlorine proved to be more effective than hydrogen peroxide.
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Affiliation(s)
- Pramir Maharjan
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Geraldine Huff
- USDA-ARS Poultry Production and Product Safety Research, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Wen Zhang
- Department of Civil Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Susan Watkins
- Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, 72701, USA
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Mathieu L, Francius G, El Zein R, Angel E, Block JC. Bacterial repopulation of drinking water pipe walls after chlorination. BIOFOULING 2016; 32:925-934. [PMID: 27483985 DOI: 10.1080/08927014.2016.1212989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 07/05/2016] [Indexed: 06/06/2023]
Abstract
The short-term kinetics of bacterial repopulation were evaluated after chlorination of high-density polyethylene (HDPE) colonized with drinking water biofilms and compared with bare HDPE surfaces. The effect of chlorination was partial as a residual biofilm persisted and was time-limited as repopulation occurred immediately after water resupply. The total number of bacteria reached the same levels on both the bare and chlorinated biofilm-fouled HDPE after a seven-day exposure to drinking water. Due to the presence of a residual biofilm, the hydrophobicity of chlorinated biofilm-fouled surface exhibited much lower adhesion forces (2.1 nN) compared to bare surfaces (8.9 nN). This could explain the rapid repopulation after chlorination, with a twofold faster bacterial accumulation rate on the bare HDPE surface. γ-Proteobacteria dominated the early stages of repopulation of both surfaces and a shift in the dominance occurred over the colonization time. Such observations define a timescale for cleaning frequency in industrial environments and guidelines for a rinsing procedure using drinking water.
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Affiliation(s)
- Laurence Mathieu
- a EPHE , PSL Research University, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME , UMR 7564 , Nancy , France
| | - Grégory Francius
- b CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME , UMR 7564 , Nancy , France
| | - Racha El Zein
- b CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME , UMR 7564 , Nancy , France
| | - Edith Angel
- a EPHE , PSL Research University, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME , UMR 7564 , Nancy , France
| | - Jean-Claude Block
- b CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME , UMR 7564 , Nancy , France
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15
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Revetta R, Gomez-Alvarez V, Gerke T, Santo Domingo J, Ashbolt N. Changes in bacterial composition of biofilm in a metropolitan drinking water distribution system. J Appl Microbiol 2016; 121:294-305. [DOI: 10.1111/jam.13150] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 03/15/2016] [Accepted: 03/28/2016] [Indexed: 01/18/2023]
Affiliation(s)
- R.P. Revetta
- United States Environmental Protection Agency; Cincinnati OH USA
| | - V. Gomez-Alvarez
- United States Environmental Protection Agency; Cincinnati OH USA
| | - T.L. Gerke
- ORISE; United States Environmental Protection Agency; Cincinnati OH USA
| | | | - N.J. Ashbolt
- United States Environmental Protection Agency; Cincinnati OH USA
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16
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Bautista-de Los Santos QM, Schroeder JL, Blakemore O, Moses J, Haffey M, Sloan W, Pinto AJ. The impact of sampling, PCR, and sequencing replication on discerning changes in drinking water bacterial community over diurnal time-scales. WATER RESEARCH 2016; 90:216-224. [PMID: 26734781 DOI: 10.1016/j.watres.2015.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/12/2015] [Accepted: 12/05/2015] [Indexed: 05/10/2023]
Abstract
High-throughput and deep DNA sequencing, particularly amplicon sequencing, is being increasingly utilized to reveal spatial and temporal dynamics of bacterial communities in drinking water systems. Whilst the sampling and methodological biases associated with PCR and sequencing have been studied in other environments, they have not been quantified for drinking water. These biases are likely to have the greatest effect on the ability to characterize subtle spatio-temporal patterns influenced by process/environmental conditions. In such cases, intra-sample variability may swamp any underlying small, systematic variation. To evaluate this, we undertook a study with replication at multiple levels including sampling sites, sample collection, PCR amplification, and high throughput sequencing of 16S rRNA amplicons. The variability inherent to the PCR amplification and sequencing steps is significant enough to mask differences between bacterial communities from replicate samples. This was largely driven by greater variability in detection of rare bacteria (relative abundance <0.01%) across PCR/sequencing replicates as compared to replicate samples. Despite this, we captured significant changes in bacterial community over diurnal time-scales and find that the extent and pattern of diurnal changes is specific to each sampling location. Further, we find diurnal changes in bacterial community arise due to differences in the presence/absence of the low abundance bacteria and changes in the relative abundance of dominant bacteria. Finally, we show that bacterial community composition is significantly different across sampling sites for time-periods during which there are typically rapid changes in water use. This suggests hydraulic changes (driven by changes in water demand) contribute to shaping the bacterial community in bulk drinking water over diurnal time-scales.
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Affiliation(s)
| | - Joanna L Schroeder
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, UK
| | - Oliver Blakemore
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, UK; United Utilities, Liverpool, UK
| | | | | | - William Sloan
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, UK
| | - Ameet J Pinto
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, UK.
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17
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Falkinham JO, Hilborn ED, Arduino MJ, Pruden A, Edwards MA. Epidemiology and Ecology of Opportunistic Premise Plumbing Pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:749-58. [PMID: 25793551 PMCID: PMC4529011 DOI: 10.1289/ehp.1408692] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 03/17/2015] [Indexed: 05/11/2023]
Abstract
BACKGROUND Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa are opportunistic premise plumbing pathogens (OPPPs) that persist and grow in household plumbing, habitats they share with humans. Infections caused by these OPPPs involve individuals with preexisting risk factors and frequently require hospitalization. OBJECTIVES The objectives of this report are to alert professionals of the impact of OPPPs, the fact that 30% of the population may be exposed to OPPPs, and the need to develop means to reduce OPPP exposure. We herein present a review of the epidemiology and ecology of these three bacterial OPPPs, specifically to identify common and unique features. METHODS A Water Research Foundation-sponsored workshop gathered experts from across the United States to review the characteristics of OPPPs, identify problems, and develop a list of research priorities to address critical knowledge gaps with respect to increasing OPPP-associated disease. DISCUSSION OPPPs share the common characteristics of disinfectant resistance and growth in biofilms in water distribution systems or premise plumbing. Thus, they share a number of habitats with humans (e.g., showers) that can lead to exposure and infection. The frequency of OPPP-infected individuals is rising and will likely continue to rise as the number of at-risk individuals is increasing. Improved reporting of OPPP disease and increased understanding of the genetic, physiologic, and structural characteristics governing the persistence and growth of OPPPs in drinking water distribution systems and premise plumbing is needed. CONCLUSIONS Because broadly effective community-level engineering interventions for the control of OPPPs have yet to be identified, and because the number of at-risk individuals will continue to rise, it is likely that OPPP-related infections will continue to increase. However, it is possible that individuals can take measures (e.g., raise hot water heater temperatures and filter water) to reduce home exposures.
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Affiliation(s)
- Joseph O Falkinham
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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18
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Wang H, Masters S, Falkinham JO, Edwards MA, Pruden A. Distribution System Water Quality Affects Responses of Opportunistic Pathogen Gene Markers in Household Water Heaters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:8416-24. [PMID: 26121595 DOI: 10.1021/acs.est.5b01538] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Illustrative distribution system operation and management practices shaped the occurrence and persistence of Legionella spp., nontuberculous mycobacteria (NTM), Pseudomonas aeruginosa, and two amoebae host (Acanthamoeba spp., Vermamoeba vermiformis) gene markers in the effluent of standardized simulated household water heaters (SWHs). The interplay between disinfectant type (chlorine or chloramine), water age (2.3-5.7 days) and materials (polyvinyl chloride (PVC), cement or iron) in upstream simulated distribution systems (SDSs) profoundly influenced levels of pathogen gene markers in corresponding SWH bulk waters. For example, Legionella spp. were 3-4 log higher in SWHs receiving water from chloraminated vs chlorinated SDSs, because of disinfectant decay from nitrification. By contrast, SWHs fed with chlorinated PVC SDS water not only harbored the lowest levels of all pathogen markers, but effluent from the chlorinated SWHs were even lower than influent levels in several instances (e.g., 2 log less Legionella spp. and NTM for PVC and 3-5 log less P. aeruginosa for cement). However, pathogen gene marker influent levels correlated positively to effluent levels in the SWHs (P < 0.05). Likewise, microbial community structures were similar between SWHs and the corresponding SDS feed waters. This study highlights the importance and challenges of distribution system management/operation to help control opportunistic pathogens.
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Affiliation(s)
- Hong Wang
- †State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Sheldon Masters
- ‡Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Joseph O Falkinham
- §Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Marc A Edwards
- ‡Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Amy Pruden
- ‡Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
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19
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Baron JL, Harris JK, Holinger EP, Duda S, Stevens MJ, Robertson CE, Ross KA, Pace NR, Stout JE. Effect of monochloramine treatment on the microbial ecology of Legionella and associated bacterial populations in a hospital hot water system. Syst Appl Microbiol 2015; 38:198-205. [PMID: 25840824 DOI: 10.1016/j.syapm.2015.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 12/22/2022]
Abstract
Opportunistic pathogens, including Legionella spp. and non-tuberculous mycobacteria, can thrive in building hot water systems despite municipal and traditional on-site chlorine disinfection. Monochloramine is a relatively new approach to on-site disinfection, but the microbiological impact of on-site chloramine use has not been well studied. We hypothesized that comparison of the microbial ecology associated with monochloramine treatment versus no on-site treatment would yield highly dissimilar bacterial communities. Hot water samples were collected monthly from 7 locations for three months from two buildings in a Pennsylvania hospital complex supplied with common municipal water: (1) a hospital administrative building (no on-site treatment) and (2) an adjacent acute-care hospital treated on-site with monochloramine to control Legionella spp. Water samples were subjected to DNA extraction, rRNA PCR, and 454 pyrosequencing. Stark differences in the microbiome of the chloraminated water and the control were observed. Bacteria in the treated samples were primarily Sphingomonadales and Limnohabitans, whereas Flexibacter and Planctomycetaceae predominated in untreated control samples. Serendipitously, one sampling month coincided with dysfunction of the on-site disinfection system that resulted in a Legionella bloom detected by sequencing and culture. This study also demonstrates the potential utility of high-throughput DNA sequencing to monitor microbial ecology in water systems.
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Affiliation(s)
- Julianne L Baron
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15261, USA; Special Pathogens Laboratory, Pittsburgh, PA 15219, USA
| | - J Kirk Harris
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Eric P Holinger
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Scott Duda
- Special Pathogens Laboratory, Pittsburgh, PA 15219, USA
| | - Mark J Stevens
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Charles E Robertson
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Kimberly A Ross
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Norman R Pace
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Janet E Stout
- Special Pathogens Laboratory, Pittsburgh, PA 15219, USA; Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, PA 15261, USA.
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20
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Gomez-Alvarez V, Humrighouse BW, Revetta RP, Santo Domingo JW. Bacterial composition in a metropolitan drinking water distribution system utilizing different source waters. JOURNAL OF WATER AND HEALTH 2015; 13:140-151. [PMID: 25719474 DOI: 10.2166/wh.2014.057] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigated the bacterial composition of water samples from two service areas within a drinking water distribution system (DWDS), each associated with a different primary source of water (groundwater, GW; surface water, SW) and different treatment process. Community analysis based on 16S rRNA gene clone libraries indicated that Actinobacteria (Mycobacterium spp.) and α-Proteobacteria represented nearly 43 and 38% of the total sequences, respectively. Sequences closely related to Legionella, Pseudomonas, and Vibrio spp. were also identified. In spite of the high number of sequences (71%) shared in both areas, multivariable analysis revealed significant differences between the GW and SW areas. While the dominant phylotypes where not significantly contributing in the ordination of samples, the populations associated with the core of phylotypes (1-10% in each sample) significantly contributed to the differences between both service areas. Diversity indices indicate that the microbial community inhabiting the SW area is more diverse and contains more distantly related species coexisting with local assemblages as compared with the GW area. The bacterial community structure of SW and GW service areas were dissimilar, suggesting that their respective source water and/or water quality parameters shaped by the treatment processes may contribute to the differences in community structure observed.
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Affiliation(s)
| | - Ben W Humrighouse
- Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio, USA and US Centers for Disease Control and Prevention, 1600 Clifton Road, Mail Stop D11, Atlanta, GA 30333, USA
| | - Randy P Revetta
- United States Environmental Protection Agency, Cincinnati, Ohio, USA E-mail:
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21
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Wang H, Proctor CR, Edwards MA, Pryor M, Santo Domingo JW, Ryu H, Camper AK, Olson A, Pruden A. Microbial community response to chlorine conversion in a chloraminated drinking water distribution system. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:10624-10633. [PMID: 25118569 DOI: 10.1021/es502646d] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Temporary conversion to chlorine (i.e., "chlorine burn") is a common approach to controlling nitrification in chloraminated drinking water distribution systems, yet its effectiveness and mode(s) of action are not fully understood. This study characterized occurrence of nitrifying populations before, during and after a chlorine burn at 46 sites in a chloraminated distribution system with varying pipe materials and levels of observed nitrification. Quantitative polymerase chain reaction analysis of gene markers present in nitrifying populations indicated higher frequency of detection of ammonia oxidizing bacteria (AOB) (72% of samples) relative to ammonia oxidizing archaea (AOA) (28% of samples). Nitrospira nitrite oxidizing bacteria (NOB) were detected at 45% of samples, while presence of Nitrobacter NOB could not be confirmed at any of the samples. During the chlorine burn, the numbers of AOA, AOB, and Nitrospira greatly reduced (i.e., 0.8-2.4 log). However, rapid and continued regrowth of AOB and Nitrospira were observed along with nitrite production in the bulk water within four months after the chlorine burn, and nitrification outbreaks appeared to worsen 6-12 months later, even after adopting a twice annual burn program. Although high throughput sequencing of 16S rRNA genes revealed a distinct community shift and higher diversity index during the chlorine burn, it steadily returned towards a condition more similar to pre-burn than burn stage. Significant factors associated with nitrifier and microbial community composition included water age and sampling location type, but not pipe material. Overall, these results indicate that there is limited long-term effect of chlorine burns on nitrifying populations and the broader microbial community.
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Affiliation(s)
- Hong Wang
- Via Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
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22
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Spatial-temporal survey and occupancy-abundance modeling to predict bacterial community dynamics in the drinking water microbiome. mBio 2014; 5:e01135-14. [PMID: 24865557 PMCID: PMC4045074 DOI: 10.1128/mbio.01135-14] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Bacterial communities migrate continuously from the drinking water treatment plant through the drinking water distribution system and into our built environment. Understanding bacterial dynamics in the distribution system is critical to ensuring that safe drinking water is being supplied to customers. We present a 15-month survey of bacterial community dynamics in the drinking water system of Ann Arbor, MI. By sampling the water leaving the treatment plant and at nine points in the distribution system, we show that the bacterial community spatial dynamics of distance decay and dispersivity conform to the layout of the drinking water distribution system. However, the patterns in spatial dynamics were weaker than those for the temporal trends, which exhibited seasonal cycling correlating with temperature and source water use patterns and also demonstrated reproducibility on an annual time scale. The temporal trends were driven by two seasonal bacterial clusters consisting of multiple taxa with different networks of association within the larger drinking water bacterial community. Finally, we show that the Ann Arbor data set robustly conforms to previously described interspecific occupancy abundance models that link the relative abundance of a taxon to the frequency of its detection. Relying on these insights, we propose a predictive framework for microbial management in drinking water systems. Further, we recommend that long-term microbial observatories that collect high-resolution, spatially distributed, multiyear time series of community composition and environmental variables be established to enable the development and testing of the predictive framework. IMPORTANCE Safe and regulation-compliant drinking water may contain up to millions of microorganisms per liter, representing phylogenetically diverse groups of bacteria, archaea, and eukarya that affect public health, water infrastructure, and the aesthetic quality of water. The ability to predict the dynamics of the drinking water microbiome will ensure that microbial contamination risks can be better managed. Through a spatial-temporal survey of drinking water bacterial communities, we present novel insights into their spatial and temporal community dynamics and recommend steps to link these insights in a predictive framework for microbial management of drinking water systems. Such a predictive framework will not only help to eliminate microbial risks but also help to modify existing water quality monitoring efforts and make them more resource efficient. Further, a predictive framework for microbial management will be critical if we are to fully anticipate the risks and benefits of the beneficial manipulation of the drinking water microbiome.
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23
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Liu G, Bakker GL, Li S, Vreeburg JHG, Verberk JQJC, Medema GJ, Liu WT, Van Dijk JC. Pyrosequencing reveals bacterial communities in unchlorinated drinking water distribution system: an integral study of bulk water, suspended solids, loose deposits, and pipe wall biofilm. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:5467-76. [PMID: 24766451 DOI: 10.1021/es5009467] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The current understanding of drinking water distribution system (DWDS) microbiology is limited to pipe wall biofilm and bulk water; the contributions of particle-associated bacteria (from suspended solids and loose deposits) have long been neglected. Analyzing the composition and correlation of bacterial communities from different phases helped us to locate where most of the bacteria are and understand the interactions among these phases. In the present study, the bacteria from four critical phases of an unchlorinated DWDS, including bulk water, pipe wall biofilm, suspended solids, and loose deposits, were quantified and identified by adenosine triphosphate analysis and pyrosequencing, respectively. The results showed that the bulk water bacteria (including the contribution of suspended solids) contributed less than 2% of the total bacteria. The bacteria associated with loose deposits and pipe wall biofilm that accumulated in the DWDS accounted for over 98% of the total bacteria, and the contributions of bacteria in loose deposits and pipe wall biofilm were comparable. Depending on the amount of loose deposits, its contribution can be 7-fold higher than the pipe wall biofilm. Pyrosequencing revealed relatively stable bacterial communities in bulk water, pipe wall biofilm, and suspended solids throughout the distribution system; however, the communities present in loose deposits were dependent on the amount of loose deposits locally. Bacteria within the phases of suspended solids, loose deposits, and pipe wall biofilm were similar in phylogenetic composition. The bulk water bacteria (dominated by Polaromonas spp.) were clearly different from the bacteria from the other three phases (dominated by Sphingomonas spp.). This study highlighted that the integral DWDS ecology should include contributions from all of the four phases, especially the bacteria harbored by loose deposits. The accumulation of loose deposits and the aging process create variable microenvironments inside loose deposits structures for bacteria to grow. Moreover, loose deposits protect the associated bacteria from disinfectants, and due to their mobility, the associated bacteria reach taps easily.
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Affiliation(s)
- G Liu
- Section Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology , P.O. Box 5048, 2600 GA Delft, The Netherlands
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Wang H, Masters S, Edwards MA, Falkinham JO, Pruden A. Effect of disinfectant, water age, and pipe materials on bacterial and eukaryotic community structure in drinking water biofilm. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:1426-35. [PMID: 24401122 DOI: 10.1021/es402636u] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Availability of safe, pathogen-free drinking water is vital to public health; however, it is impossible to deliver sterile drinking water to consumers. Recent microbiome research is bringing new understanding to the true extent and diversity of microbes that inhabit water distribution systems. The purpose of this study was to determine how water chemistry in main distribution lines shape the microbiome in drinking water biofilms and to explore potential associations between opportunistic pathogens and indigenous drinking water microbes. Effects of disinfectant (chloramines, chlorine), water age (2.3 days, 5.7 days), and pipe material (cement, iron, PVC) were compared in parallel triplicate simulated water distribution systems. Pyrosequencing was employed to characterize bacteria and terminal restriction fragment polymorphism was used to profile both bacteria and eukaryotes inhabiting pipe biofilms. Disinfectant and water age were both observed to be strong factors in shaping bacterial and eukaryotic community structures. Pipe material only influenced the bacterial community structure (ANOSIM test, P < 0.05). Interactive effects of disinfectant, pipe material, and water age on both bacteria and eukaryotes were noted. Disinfectant concentration had the strongest effect on bacteria, while dissolved oxygen appeared to be a major driver for eukaryotes (BEST test). Several correlations of similarity metrics among populations of bacteria, eukaryotes, and opportunistic pathogens, as well as one significant association between mycobacterial and proteobacterial operational taxonomic units, provides insight into means by which manipulating the microbiome may lead to new avenues for limiting the growth of opportunistic pathogens (e.g., Legionella) or other nuisance organisms (e.g., nitrifiers).
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Affiliation(s)
- Hong Wang
- Via Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
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Neumonía por Legionella pneumophila asociada al uso de un humidificador doméstico en una niña inmunocompetente. Med Clin (Barc) 2014; 142:70-2. [DOI: 10.1016/j.medcli.2013.02.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 02/14/2013] [Accepted: 02/14/2013] [Indexed: 11/20/2022]
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Milferstedt K, Santa-Catalina G, Godon JJ, Escudié R, Bernet N. Disturbance frequency determines morphology and community development in multi-species biofilm at the landscape scale. PLoS One 2013; 8:e80692. [PMID: 24303024 PMCID: PMC3841191 DOI: 10.1371/journal.pone.0080692] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 10/14/2013] [Indexed: 11/19/2022] Open
Abstract
Many natural and engineered biofilm systems periodically face disturbances. Here we present how the recovery time of a biofilm between disturbances (expressed as disturbance frequency) shapes the development of morphology and community structure in a multi-species biofilm at the landscape scale. It was hypothesized that a high disturbance frequency favors the development of a stable adapted biofilm system while a low disturbance frequency promotes a dynamic biofilm response. Biofilms were grown in laboratory-scale reactors over a period of 55-70 days and exposed to the biocide monochloramine at two frequencies: daily or weekly pulse injections. One untreated reactor served as control. Biofilm morphology and community structure were followed on comparably large biofilm areas at the landscape scale using automated image analysis (spatial gray level dependence matrices) and community fingerprinting (single-strand conformation polymorphisms). We demonstrated that a weekly disturbed biofilm developed a resilient morphology and community structure. Immediately after the disturbance, the biofilm simplified but recovered its initial complex morphology and community structure between two biocide pulses. In the daily treated reactor, one organism largely dominated a morphologically simple and stable biofilm. Disturbances primarily affected the abundance distribution of already present bacterial taxa but did not promote growth of previously undetected organisms. Our work indicates that disturbances can be used as lever to engineer biofilms by maintaining a biofilm between two developmental states.
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Affiliation(s)
- Kim Milferstedt
- INRA UR0050, Laboratoire de Biotechnologie de l'Environnement, Narbonne, France
- * E-mail:
| | | | - Jean-Jacques Godon
- INRA UR0050, Laboratoire de Biotechnologie de l'Environnement, Narbonne, France
| | - Renaud Escudié
- INRA UR0050, Laboratoire de Biotechnologie de l'Environnement, Narbonne, France
| | - Nicolas Bernet
- INRA UR0050, Laboratoire de Biotechnologie de l'Environnement, Narbonne, France
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Wang H, Pryor MA, Edwards MA, Falkinham JO, Pruden A. Effect of GAC pre-treatment and disinfectant on microbial community structure and opportunistic pathogen occurrence. WATER RESEARCH 2013; 47:5760-72. [PMID: 23906775 DOI: 10.1016/j.watres.2013.06.052] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 06/21/2013] [Accepted: 06/27/2013] [Indexed: 05/10/2023]
Abstract
Opportunistic pathogens in potable water systems are an emerging health concern; however, the factors influencing their proliferation are poorly understood. Here we investigated the effects of prior granular activated carbon (GAC) biofiltration [GAC-filtered water, unfiltered water, and a blend (30% GAC filtered and 70% unfiltered water)] and disinfectant type (chlorine, chloramine) on opportunistic pathogen occurrence using five annular reactors (ARs) to simulate water distribution systems, particularly premise plumbing. GAC pre-treatment effectively reduced total organic carbon (TOC), resulting in three levels of influent TOC investigated. Quantitative polymerase chain reaction (q-PCR) provided molecular evidence of natural colonization of Legionella spp., Mycobacterium spp., Acanthamoeba spp., Hartmannella vermiformis and Mycobacterium avium on AR coupons. Cultivable mycobacteria and amoeba, including pathogenic species, were also found in bulk water and biofilm samples. While q-PCR tends to overestimate live cells, it provided a quantitative comparison of target organisms colonizing the AR biofilms in terms of gene copy numbers. In most cases, total bacteria and opportunistic pathogens were higher in the three undisinfected ARs, but the levels were not proportional to the level of GAC pre-treatment/TOC. Chlorine was more effective for controlling mycobacteria and Acanthamoeba, whereas chloramine was more effective for controlling Legionella. Both chlorine and chloramine effectively inhibited M. avium and H. vermiformis colonization. Pyrosequencing of 16S rRNA genes in coupon biofilms revealed a significant effect of GAC pre-treatment and disinfectant type on the microbial community structure. Overall, this study provides insights into the potential of different disinfectants and GAC biofilters at the treatment plant and in buildings to control downstream opportunistic pathogens and broader drinking water microbial communities.
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Affiliation(s)
- Hong Wang
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA
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Liu G, Verberk JQJC, Van Dijk JC. Bacteriology of drinking water distribution systems: an integral and multidimensional review. Appl Microbiol Biotechnol 2013; 97:9265-76. [DOI: 10.1007/s00253-013-5217-y] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/25/2013] [Accepted: 08/26/2013] [Indexed: 11/27/2022]
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Jungfer C, Friedrich F, Varela Villarreal J, Brändle K, Gross HJ, Obst U, Schwartz T. Drinking water biofilms on copper and stainless steel exhibit specific molecular responses towards different disinfection regimes at waterworks. BIOFOULING 2013; 29:891-907. [PMID: 23875760 DOI: 10.1080/08927014.2013.813936] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Biofilms growing on copper and stainless steel substrata in natural drinking water were investigated. A modular pilot-scale distribution facility was installed at four waterworks using different raw waters and disinfection regimes. Three-month-old biofilms were analysed using molecular biology and microscopy methods. High total cell numbers, low counts of actively respiring cells and low numbers of cultivable bacteria indicated the high abundance of viable but not cultivable bacteria in the biofilms. The expression of the recA SOS responsive gene was detected and underlined the presence of transcriptionally active bacteria within the biofilms. This effect was most evident after UV disinfection, UV oxidation and UV disinfection with increased turbidity at waterworks compared to chemically treated and non-disinfected systems. Furthermore, live/dead staining techniques and environmental scanning electron microscopy imaging revealed the presence of living and intact bacteria in biofilms on copper substrata. Cluster analyses of DGGE profiles demonstrated differences in the composition of biofilms on copper and steel materials.
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Affiliation(s)
- Christina Jungfer
- Microbiology at Natural and Technical Interfaces Department, Karlsruhe Institute of Technology, Campus North, Institute of Functional Interfaces, Eggenstein-Leopoldshafen, Germany
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Revetta RP, Gomez-Alvarez V, Gerke TL, Curioso C, Santo Domingo JW, Ashbolt NJ. Establishment and early succession of bacterial communities in monochloramine-treated drinking water biofilms. FEMS Microbiol Ecol 2013; 86:404-14. [PMID: 23789638 DOI: 10.1111/1574-6941.12170] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 06/13/2013] [Accepted: 06/14/2013] [Indexed: 11/27/2022] Open
Abstract
Monochloramine is an increasingly used drinking water disinfectant and has been shown to increase nitrifying bacteria and mycobacteria in drinking waters. The potential successions and development of these bacteria were examined by 16S rRNA gene clone libraries generated from various biofilms within a water distribution system simulator. Biofilms were obtained from in-line and off-line devices using borosilicate glass beads, along with polycarbonate coupons from annular reactors incubated for up to 8 months in monochloramine-treated drinking water. No significant difference in community structures was observed between biofilm devices and coupon material; however, all biofilm communities that developed on different devices underwent similar successions over time. Early stages of biofilm formation were dominated by Serratia (29%), Cloacibacterium (23%), Diaphorobacter (16%), and Pseudomonas (7%), while Mycobacterium-like phylotypes were the most predominant populations (> 27%) in subsequent months. The development of members of the nontuberculous mycobacteria (NTM) after 3 months may impact individuals with predisposing conditions, while nitrifiers (related to Nitrospira moscoviensis and Nitrosospira multiformis) could impact water quality. Overall, 90% of the diversity in all the clone library samples was associated with the phyla Proteobacteria, Actinobacteria, and Bacteroidetes. These results provide an ecological insight into biofilm bacterial successions in monochloramine-treated drinking water.
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Affiliation(s)
- Randy P Revetta
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA
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Ling F, Liu WT. Impact of chloramination on the development of laboratory-grown biofilms fed with filter-pretreated groundwater. Microbes Environ 2012; 28:50-7. [PMID: 23124766 PMCID: PMC4070696 DOI: 10.1264/jsme2.me12095] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/23/2012] [Indexed: 11/30/2022] Open
Abstract
This study evaluated the continuous impact of monochloramine disinfection on laboratory-grown biofilms through the characterization of biofilm architecture and microbial community structure. Biofilm development and disinfection were achieved using CDC (Centers for Disease Control and Prevention) biofilm reactor systems with polyvinyl chloride (PVC) coupons as the substratum and sand filter-pretreated groundwater as the source of microbial seeding and growth nutrient. After 2 weeks of growth, the biofilms were subjected to chloramination for 8 more weeks at concentrations of 7.5±1.4 to 9.1±0.4 mg Cl2 L(-1). Control reactors received no disinfection during the development of biofilms. Confocal laser scanning microscopy and image analysis indicated that chloramination could lead to 81.4-83.5% and 86.3-95.6% reduction in biofilm biomass and thickness, respectively, but could not eliminate biofilm growth. 16S rRNA gene terminal restriction fragment length polymorphism analysis indicated that microbial community structures between chloraminated and non-chloraminated biofilms exhibited different successional trends. 16S rRNA gene pyrosequencing analysis further revealed that chloramination could select members of Actinobacteria and Acidobacteria as the dominant populations, whereas natural development leads to the selection of members of Nitrospira and Bacteroidetes as dominant biofilm populations. Overall, chloramination treatment could alter the growth of multi-species biofilms on the PVC surface, shape the biofilm architecture, and select a certain microbial community that can survive or proliferate under chloramination.
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Affiliation(s)
- Fangqiong Ling
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 N. Mathews Ave., Urbana, Illinois 61801–2352, USA
| | - Wen-Tso Liu
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 N. Mathews Ave., Urbana, Illinois 61801–2352, USA
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Chuang YH, Wang GS, Tung HH. Chlorine residuals and haloacetic acid reduction in rapid sand filtration. CHEMOSPHERE 2011; 85:1146-1153. [PMID: 21974919 DOI: 10.1016/j.chemosphere.2011.08.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 08/15/2011] [Accepted: 08/18/2011] [Indexed: 05/31/2023]
Abstract
It is quite rare to find biodegradation in rapid sand filtration for drinking water treatment. This might be due to frequent backwashes and low substrate levels. High chlorine concentrations may inhibit biofilm development, especially for plants with pre-chlorination. However, in tropical or subtropical regions, bioactivity on the sand surface may be quite significant due to high biofilm development--a result of year-round high temperature. The objective of this study is to explore the correlation between biodegradation and chlorine concentration in rapid sand filters, especially for the water treatment plants that practise pre-chlorination. In this study, haloacetic acid (HAA) biodegradation was found in conventional rapid sand filters practising pre-chlorination. Laboratory column studies and field investigations were conducted to explore the association between the biodegradation of HAAs and chlorine concentrations. The results showed that chlorine residual was an important factor that alters bioactivity development. A model based on filter influent and effluent chlorine was developed for determining threshold chlorine for biodegradation. From the model, a temperature independent chlorine concentration threshold (Cl(threshold)) for biodegradation was estimated at 0.46-0.5mgL(-1). The results imply that conventional filters with adequate control could be conducive to bioactivity, resulting in lower HAA concentrations. Optimizing biodegradable disinfection by-product removal in conventional rapid sand filter could be achieved with minor variation and a lower-than-Cl(threshold) influent chlorine concentration. Bacteria isolation was also carried out, successfully identifying several HAA degraders. These degraders are very commonly seen in drinking water systems and can be speculated as the main contributor of HAA loss.
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Affiliation(s)
- Yi-Hsueh Chuang
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, Taiwan
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Coenye T, Nelis HJ. In vitro and in vivo model systems to study microbial biofilm formation. J Microbiol Methods 2010; 83:89-105. [DOI: 10.1016/j.mimet.2010.08.018] [Citation(s) in RCA: 251] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 08/19/2010] [Accepted: 08/23/2010] [Indexed: 12/23/2022]
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Roeder RS, Lenz J, Tarne P, Gebel J, Exner M, Szewzyk U. Long-term effects of disinfectants on the community composition of drinking water biofilms. Int J Hyg Environ Health 2010; 213:183-9. [DOI: 10.1016/j.ijheh.2010.04.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 04/20/2010] [Accepted: 04/23/2010] [Indexed: 12/01/2022]
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Altman S, McGrath L, Souza C, Murton J, Camper A. Integration and decontamination ofBacillus cereusinPseudomonas fluorescensbiofilms. J Appl Microbiol 2009; 107:287-99. [DOI: 10.1111/j.1365-2672.2009.04206.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Variability of Burkholderia pseudomallei strain sensitivities to chlorine disinfection. Appl Environ Microbiol 2009; 75:5405-9. [PMID: 19542324 DOI: 10.1128/aem.00062-09] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei is a select agent and the causative agent of melioidosis. Variations in previously reported chlorine and monochloramine concentration time (Ct) values for disinfection of this organism make decisions regarding the appropriate levels of chlorine in water treatment systems difficult. This study identified the variation in Ct values for 2-, 3-, and 4-log(10) reductions of eight environmental and clinical isolates of B. pseudomallei in phosphate-buffered water. The greatest calculated Ct values for a 4-log(10) inactivation were 7.8 mg.min/liter for free available chlorine (FAC) at pH 8 and 5 degrees C and 550 mg.min/liter for monochloramine at pH 8 and 5 degrees C. Ionic strength of test solutions, culture hold times in water, and cell washing were ruled out as sources of the differences in prior observations. Tolerance to FAC was correlated with the relative amount of extracellular material produced by each isolate. Solid-phase cytometry analysis using an esterase-cleaved fluorochrome assay detected a 2-log(10)-higher level of organisms based upon metabolic activity than did culture, which in some cases increased Ct values by fivefold. Despite strain-to-strain variations in Ct values of 17-fold for FAC and 2.5-fold for monochloramine, standard FAC disinfection practices utilized in the United States should disinfect planktonic populations of these B. pseudomallei strains by 4 orders of magnitude in less than 10 min at the tested temperatures and pH levels.
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Lau HY, Ashbolt NJ. The role of biofilms and protozoa in Legionella pathogenesis: implications for drinking water. J Appl Microbiol 2009; 107:368-78. [PMID: 19302312 DOI: 10.1111/j.1365-2672.2009.04208.x] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Current models to study Legionella pathogenesis include the use of primary macrophages and monocyte cell lines, various free-living protozoan species and murine models of pneumonia. However, there are very few studies of Legionella spp. pathogenesis aimed at associating the role of biofilm colonization and parasitization of biofilm microbiota and release of virulent bacterial cell/vacuoles in drinking water distribution systems. Moreover, the implications of these environmental niches for drinking water exposure to pathogenic legionellae are poorly understood. This review summarizes the known mechanisms of Legionella spp. proliferation within Acanthamoeba and mammalian cells and advocates the use of the amoeba model to study Legionella pathogenicity because of their close association with Legionella spp. in the aquatic environment. The putative role of biofilms and amoebae in the proliferation, development and dissemination of potentially pathogenic Legionella spp. is also discussed. Elucidating the mechanisms of Legionella pathogenicity development in our drinking water systems will aid in elimination strategies and procedural designs for drinking water systems and in controlling exposure to Legionella spp. and similar pathogens.
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Affiliation(s)
- H Y Lau
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA.
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Jurgens D, Sattar S, Mah T. Chloraminated drinking water does not generate bacterial resistance to antibiotics in Pseudomonas aeruginosa biofilms. Lett Appl Microbiol 2008; 46:562-7. [DOI: 10.1111/j.1472-765x.2008.02354.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Parrilla Valero F, Chacón Villanueva S, Pérez Lleonart A. [Study of refrigeration towers associated with community outbreaks of legionellosis]. GACETA SANITARIA 2007; 21:357-60. [PMID: 17663883 DOI: 10.1157/13108513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To evaluate the factors of risk of the risk cooling towers associated to a community outbreak of legionellosis according to its characteristics of maintenance and the quality of the water with the purpose of improving the systems of prevention of this one disease. METHOD To compare the piece of information gathered between the 4 types of cooling towers: control 1, control 2, probable and confirmed. A total of 184 cooling towers have been studied associated to 17 community outbreak of legionellosis of the province of Barcelona (Spain) during the year 2004, of which 112 are control 1, 54 control 2, 8 probable and 10 confirmed. RESULTS The confirmed towers are characterized by: high levels of conductivity, total aerobes, calcic hardness, total solids in dissolution, temperature and turbidity; low levels of chlorine (< 2 ppm); of use hypochlorite as disinfectant in a 10%; greater degree of breach of the revision program and cleaning of the internal elements of the tower (tray, stuffed and separating of drops); degree of performance of the periodic disinfections and the cleaning of deposits of the 100%. A 47% of the investigated towers do not use the previous treatments of the water in spite of diminishing the parametric values of the quantitatives variables. CONCLUSIONS Measures of prevention of the legionellosis would be due to guarantee: a good quality of the water and the pursuit of its quantitatives variables; chlorine levels superior to 2 ppm; the evaluation of the individual risk for each installation; the performance of the 100% of the program of revision of the internal elements of the towers.
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