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Waegenaar F, García-Timermans C, Van Landuyt J, De Gusseme B, Boon N. Impact of operational conditions on drinking water biofilm dynamics and coliform invasion potential. Appl Environ Microbiol 2024; 90:e0004224. [PMID: 38647288 PMCID: PMC11107155 DOI: 10.1128/aem.00042-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 03/27/2024] [Indexed: 04/25/2024] Open
Abstract
Biofilms within drinking water distribution systems serve as a habitat for drinking water microorganisms. However, biofilms can negatively impact drinking water quality by causing water discoloration and deterioration and can be a reservoir for unwanted microorganisms. In this study, we investigated whether indicator organisms for drinking water quality, such as coliforms, can settle in mature drinking water biofilms. Therefore, a biofilm monitor consisting of glass rings was used to grow and sample drinking water biofilms. Two mature drinking water biofilms were characterized by flow cytometry, ATP measurements, confocal laser scanning microscopy, and 16S rRNA sequencing. Biofilms developed under treated chlorinated surface water supply exhibited lower cell densities in comparison with biofilms resulting from treated groundwater. Overall, the phenotypic as well as the genotypic characteristics were significantly different between both biofilms. In addition, the response of the biofilm microbiome and possible biofilm detachment after minor water quality changes were investigated. Limited changes in pH and free chlorine addition, to simulate operational changes that are relevant for practice, were evaluated. It was shown that both biofilms remained resilient. Finally, mature biofilms were prone to invasion of the coliform, Serratia fonticola. After spiking low concentrations (i.e., ±100 cells/100 mL) of the coliform to the corresponding bulk water samples, the coliforms were able to attach and get established within the mature biofilms. These outcomes emphasize the need for continued research on biofilm detachment and its implications for water contamination in distribution networks. IMPORTANCE The revelation that even low concentrations of coliforms can infiltrate into mature drinking water biofilms highlights a potential public health concern. Nowadays, the measurement of coliform bacteria is used as an indicator for fecal contamination and to control the effectiveness of disinfection processes and the cleanliness and integrity of distribution systems. In Flanders (Belgium), 533 out of 18,840 measurements exceeded the established norm for the coliform indicator parameter in 2021; however, the source of microbial contamination is mostly unknown. Here, we showed that mature biofilms, are susceptible to invasion of Serratia fonticola. These findings emphasize the importance of understanding and managing biofilms in drinking water distribution systems, not only for their potential to influence water quality, but also for their role in harboring and potentially disseminating pathogens. Further research into biofilm detachment, long-term responses to operational changes, and pathogen persistence within biofilms is crucial to inform strategies for safeguarding drinking water quality.
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Affiliation(s)
- Fien Waegenaar
- Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University, Ghent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Ghent, Belgium
| | - Cristina García-Timermans
- Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University, Ghent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Ghent, Belgium
| | - Josefien Van Landuyt
- Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University, Ghent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Ghent, Belgium
| | - Bart De Gusseme
- Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University, Ghent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Ghent, Belgium
- Farys, Department R&D – Innovation Water, Ghent, Belgium
| | - Nico Boon
- Department of Biotechnology, Center for Microbial Ecology and Technology (CMET), Ghent University, Ghent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Ghent, Belgium
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2
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Li G, Chen Q, Wang H, Su Y, Wu B, Yu J, Yang M, Shi B. Corroded iron pipe inhibits microbial-mediated Mn(II) oxidation and MnO x accumulation compared to PVC pipe. WATER RESEARCH 2024; 251:121142. [PMID: 38246084 DOI: 10.1016/j.watres.2024.121142] [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: 09/24/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 01/23/2024]
Abstract
MnOx deposits in distribution pipes can cause severe discoloration problems in drinking water. However, the impact of pipe materials on Mn(II) oxidation and MnOx accumulation remains unclear. This study investigated microbial-mediated Mn(II) oxidation and deposit formation through 300-day pipe loop experiments with corroded galvanized steel pipes (DN100) and new polyvinyl chloride (PVC) pipes (DN100). The results showed that influent Mn(II) was entirely oxidized within 48 h in the PVC pipes with biofilms in the absence of chlorine, while most influent Mn(II) remained unoxidized in the iron pipes. Dissolved oxygen (DO) monitoring showed that the DO in the PVC pipes was consistently higher than 8.0 mg/L, but that in the iron pipes dropped to 6.5 mg/L. Microbial analysis revealed that the abundance of potential Mn(II)-oxidizing bacteria in the low-DO iron pipes was less than that in the PVC pipes. Analysis of the Mn(II) concentration dynamics in different pipes revealed that the early Mn(II) disappearance in the iron pipes was contributed mainly to Mn(II) adsorption by iron corrosion products rather than microbial Mn(II) oxidation. When aeration was performed to increase the DO concentration to 8.0 mg/L in the iron pipes, complete Mn(II) oxidation occurred. This study provides insights into Mn(II) transformation in different pipes and highlights the critical role of DO in microbial Mn(II) oxidation in drinking water pipes.
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Affiliation(s)
- Guiwei Li
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Qi Chen
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Institute of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450045, China
| | - Haibo Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yuliang Su
- Zhuhai Water Environment Holdings Group Ltd., Zhuhai, Guangdong 519000, China
| | - Bin Wu
- Zhuhai Water Environment Holdings Group Ltd., Zhuhai, Guangdong 519000, China
| | - Jianwei Yu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Yang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baoyou Shi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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3
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Li M, Zhang D, Zhang R, Wang F, Song Y, Chen F, Yang J, Li C. Recent advances in the unlined cast iron pipe scale characteristics, cleaning techniques and harmless disposal methods: An overview. CHEMOSPHERE 2023; 340:139849. [PMID: 37595692 DOI: 10.1016/j.chemosphere.2023.139849] [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: 06/13/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/20/2023]
Abstract
Drinking water discoloration and its potential health risks (e.g., heavy metals, pathogens, carcinogenic organics) have aroused wide public concerns around the world, and the characteristics and corresponding cleaning techniques of pipe scales are one of the most important research fields closely related to people's lives and health. This Overview Article summarizes the latest research achievements about the new insights into the unlined cast iron pipe corrosion scale characteristics as well as the advanced cleaning techniques applied in drinking water distribution systems. The typical pollutants such as heavy metal ions, pathogens and disinfection by-products (DBPs) in pipe scales and the main cleaning techniques including unidirectional flushing (UDF), air scouring, ice pigging and guided ultrasonic waves (GUW) are categorized and elaborated. In the final part, the current challenges and future opportunities are also further discussed from the viewpoint of evolution process of pipe scales as well as the widespread application of advanced cleaning techniques. Moreover, the possible technical route for the innocent treatment and resource utilization of pipe scale waste is also proposed. It is anticipated that this review will attract more attention toward the in-depth study of pipe scales and their cleaning techniques to enjoy cleaner and healthier drinking water for people.
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Affiliation(s)
- Ming Li
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China
| | - Dong Zhang
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China
| | - Ru Zhang
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China
| | - Fang Wang
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China.
| | - Yang Song
- Resources and Environment Innovation Institute, Shandong Jianzhu University, Jinan, 250101, China.
| | - Feiyong Chen
- Resources and Environment Innovation Institute, Shandong Jianzhu University, Jinan, 250101, China
| | - Juan Yang
- Nanjing Chibo Environmental Technology (China) Co., Ltd., Nanjing, 210044, Jiangsu Province, China
| | - Changming Li
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China.
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4
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Niu J, Chen D, Shang C, Xiao L, Wang Y, Zeng W, Zheng X, Chen Z, Du X, Chen X. Niche Differentiation of Biofilm Microorganisms in a Full-scale Municipal Drinking Water Distribution System in China and Their Implication for Biofilm Control. MICROBIAL ECOLOGY 2023; 86:2770-2780. [PMID: 37542538 DOI: 10.1007/s00248-023-02274-y] [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: 04/28/2023] [Accepted: 07/21/2023] [Indexed: 08/07/2023]
Abstract
Biofilms on the inner surface of a drinking water distribution system (DWDS) affect water quality and stability. Understanding the niche differentiation of biofilm microbial communities is necessary for the efficient control of DWDS biofilms. However, biofilm studies are difficult to conduct in the actual DWDS because of inaccessibility to the pipes buried underground. Taking the opportunity of infrastructure construction and relevant pipeline replacement in China, biofilms in a DWDS (a water main and its branch pipes) were collected in situ, followed by analysis on the abundances and community structures of bacterial and archaeal using quantitative PCR and high-throughput sequencing, respectively. Results showed that archaea were detected only in the biofilms of the water main, with a range of 9.4×103~1.1×105 copies/cm2. By contrast, bacteria were detected in the biofilms of branch pipes and the distal part of the water main, with a range of 8.8×103~9.6×106 copies/cm2. Among the biofilm samples, the archaeal community in the central part of the water main showed the highest richness and diversity. Nitrosopumilus was found to be predominant (86.22%) in the biofilms of the proximal part of the water main. However, Methanobrevibacter (87.15%) predominated in the distal part of the water main. The bacterial community of the water main and branch pipes was primarily composed of Firmicutes and Proteobacteria at the phylum level, respectively. Regardless of archaea or bacteria, only few operational taxonomic units (OTUs) (<0.5% of total OTUs) were shared by all the biofilms, indicating the niche differentiation of biofilm microorganisms. Moreover, the high Mn content in the biofilms of the distal sampling location (D3) in the water main was linked to the predominance of Bacillus. Functional gene prediction revealed that the proportion of infectious disease-related genes was 0.44-0.67% in the tested biofilms. Furthermore, functional genes related to the resistance of the bacterial community to disinfections and antibiotics were detected in all the samples, that is, glutathione metabolism-relating genes (0.14-0.65%) and beta-lactam resistance gene (0.01-0.05%). The results of this study indicate the ubiquity of archaea and bacteria in the biofilms of water main and branch pipes, respectively, and pipe diameters could be a major influencing factor on bacterial community structure. In the water main, the key finding was the predominant existence of archaea, particularly Nitrosopumilus and methanogen. Hence, their routine monitoring and probable influences on water quality in pipelines with large diameter should be given more attention. Besides, since Mn-related Bacillus and suspected pathogenic Enterococcus were detected in the biofilm, supplementation of disinfectant may be a feasible strategy for inhibiting their growth and ensuring water quality. In addition, the monitoring on their abundance variation could help to determine the frequency and methods of pipeline maintenance.
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Affiliation(s)
- Jia Niu
- Center of Safe and Energy-saving Engineering Technology for Urban Water Supply and Drainage System, School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, Fujian, 350118, People's Republic of China
| | - Daogan Chen
- Center of Safe and Energy-saving Engineering Technology for Urban Water Supply and Drainage System, School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, Fujian, 350118, People's Republic of China
| | - Chenghao Shang
- Center of Safe and Energy-saving Engineering Technology for Urban Water Supply and Drainage System, School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, Fujian, 350118, People's Republic of China
| | - Liang Xiao
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou, 350108, People's Republic of China
| | - Yue Wang
- Fuzhou Water Supply Company, Fuzhou, Fujian, 350001, People's Republic of China
| | - Wuqiang Zeng
- Center of Safe and Energy-saving Engineering Technology for Urban Water Supply and Drainage System, School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, Fujian, 350118, People's Republic of China
| | - Xianliang Zheng
- Center of Safe and Energy-saving Engineering Technology for Urban Water Supply and Drainage System, School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, Fujian, 350118, People's Republic of China
| | - Ziyi Chen
- Center of Safe and Energy-saving Engineering Technology for Urban Water Supply and Drainage System, School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, Fujian, 350118, People's Republic of China
| | - Xupu Du
- Center of Safe and Energy-saving Engineering Technology for Urban Water Supply and Drainage System, School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, Fujian, 350118, People's Republic of China
| | - Xiaochen Chen
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou, 350108, People's Republic of China.
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5
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Boxall J, Blokker M, Schaap P, Speight V, Husband S. Managing discolouration in drinking water distribution systems by integrating understanding of material behaviour. WATER RESEARCH 2023; 243:120416. [PMID: 37516082 DOI: 10.1016/j.watres.2023.120416] [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: 04/24/2023] [Revised: 06/30/2023] [Accepted: 07/24/2023] [Indexed: 07/31/2023]
Abstract
Discoloured drinking water, caused by elevated concentrations of organic and inorganic particles, is unacceptable. It occurs due to accumulation and subsequent mobilisation of material from within drinking water distribution infrastructure. Discolouration is currently partially explained by either the theories of cohesive layers or gravitational sedimentation. It is proposed and shown here how the processes behind these two theories both occur and how to integrate them to better explain observed behaviour and inform operational interventions to reduce discolouration. Deficiencies in understanding regarding the process and factors that influence material accumulation are highlighted. Future research addressing these deficiencies will enable determination of long term sustainable management strategies balancing capital investment and operational maintenance to safeguard distribution of high quality drinking water.
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Affiliation(s)
- Joby Boxall
- Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, UK.
| | - Mirjam Blokker
- KWR Water Research Institute, the Netherlands Delft University of Technology, the Netherlands
| | | | - Vanessa Speight
- Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, UK
| | - Stewart Husband
- Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, UK
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6
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van der Wielen PWJJ, Brouwer-Hanzens A, Italiaander R, Hijnen WAM. Initiating guidance values for novel biological stability parameters in drinking water to control regrowth in the distribution system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 871:161930. [PMID: 36740059 DOI: 10.1016/j.scitotenv.2023.161930] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/18/2023] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
Nine novel biological stability parameters for drinking water have been developed recently. Here, we report data for these nine parameters in treated water from 34 treatment plants in the Netherlands to deduce guidance values for these parameters. Most parameters did not show a strong correlation with another biological stability parameter in the same sample, demonstrating that most parameters hold different information on the biological stability of drinking water. Furthermore, the novel biological stability parameters in treated water varied considerably between plants and five parameters in treated water were significantly lower for drinking water produced from groundwater than surface water. The maximum biomass concentration (MBC7), cumulative biomass potential (CBP14) from the biomass production potential test (BPP-W) and the total organic carbon concentration in treated water from groundwater were predictive parameters for HPC22 and Aeromonas regrowth in the distribution system. Guidance values of 8.6 ng ATP L-1, 110 d·ng ATP L-1 and 4.1 mg C L-1 were deduced for these parameters, under which the HPC22 and Aeromonas numbers remain at regulatory level. The maximum biomass growth (MBG7) from the BPP-W test, the particulate and/or high molecular organic carbon and the iron accumulation rate in treated water from surface water were predictive parameters for HPC22 and Aeromonas regrowth in the distribution system. Deduced guidance values for these biological stability parameters were 4.5 ng ATP L-1, 47 μg C L-1 and 0.34 mg Fe m-2 day-1, respectively. We conclude from our study that a multiple parameter assessment is required to reliable describe the biological stability of drinking water, that the biological stability of drinking water produced from groundwater is described with other parameters than the biological stability of drinking water produced from surface water, and that guidance values for predictive biological stability parameters were inferred under which HPC22 and Aeromonas regrowth is under control.
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Affiliation(s)
- Paul W J J van der Wielen
- KWR Water Research Institute, Groningenhaven 7, 3433PE Nieuwegein, the Netherlands; Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708WE Wageningen, the Netherlands.
| | - Anke Brouwer-Hanzens
- KWR Water Research Institute, Groningenhaven 7, 3433PE Nieuwegein, the Netherlands
| | - Ronald Italiaander
- KWR Water Research Institute, Groningenhaven 7, 3433PE Nieuwegein, the Netherlands
| | - Wim A M Hijnen
- Evides Water Company, PO Box 4472, 3006AL Rotterdam, the Netherlands
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7
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Schurer R, de Ridder DJ, Schippers JC, Hijnen WAM, Vredenbregt L, van der Wal A. Advanced drinking water production by 1 kDa hollow fiber nanofiltration - Biological activated carbon filtration (HFNF - BACF) enhances biological stability and reduces micropollutant levels compared with conventional surface water treatment. CHEMOSPHERE 2023; 321:138049. [PMID: 36746252 DOI: 10.1016/j.chemosphere.2023.138049] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/13/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
This study comprehensively investigates the quality of drinking water produced by novel advanced treatment encompassing 1 kDa hollow fiber nanofiltration (HFNF) - Biological Activated Carbon Filtration (BACF) from (reservoir) surface water, and compares this with drinking water after conventional 'CSF' pretreatment (coagulation - flocculation - sedimentation - media filtration - UV-disinfection) - BACF. The objective of HFNF - BACF treatment is to enhance the drinking water's quality in increased biological stability, reduced concentrations of organic micropollutants (OMP), and improvement in other chemical-physical parameters, whilst maintaining sufficient hardness to avoid subsequent remineralization. For this study a large suite of quality parameters was extensively monitored in pilot plants during nearly two years, enabling the incorporation of seasonal effects. HFNF - BACF treatment accomplished a similarly high level of biological stability as regrowth-free drinking waters (total organic carbon (DOC) 0.6 mg/L, assimilable organic carbon (AOC) 4 μg/L Ac-C and <1 μg/L biopolymer-C, total microbial growth potential (MGP) as BPC14 50 ng d/L and as BGP 170 × 103 cells/mL), unlike the conventional treatment (1.9 mg/L, 10 μg/L, 9 μg/L, 130 ng d/L and 170 × 103 cells/mL, respectively) where regrowth occurred in its distribution network. Average OMP removal, including perfluoro-alkyl substances (PFAS), by HFNF - BACF (54%) was higher than conventional treatment (37%). This improvement was mainly attributable to rejection in the HFNF membrane step, indicating that the DOC concentration after HFNF pretreatment was not yet sufficiently low to eliminate competitive adsorption and/or preloading in the BACF (confirmed by laboratory experiments). The advanced treatment also performed better in turbidity, particulates and most trace metals. Importantly, hardness retention by HFNF was only moderate, rendering remineralization unnecessary. Overall, this study demonstrates the superior performance in water quality of advanced HFNF - BACF treatment compared to conventional treatment.
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Affiliation(s)
- R Schurer
- Evides Water Company, PO Box 4472, 3006 AL, Rotterdam, the Netherlands; Department of Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708 WG, Wageningen, the Netherlands; IHE Delft Institute for Water Education, Environmental Engineering and Water Technology Department, Westvest 7, 2611 AX, Delft, the Netherlands.
| | - D J de Ridder
- Evides Water Company, PO Box 4472, 3006 AL, Rotterdam, the Netherlands
| | - J C Schippers
- IHE Delft Institute for Water Education, Environmental Engineering and Water Technology Department, Westvest 7, 2611 AX, Delft, the Netherlands
| | - W A M Hijnen
- Evides Water Company, PO Box 4472, 3006 AL, Rotterdam, the Netherlands
| | - L Vredenbregt
- Pentair X-Flow, PO Box 741, 7500 AS, Enschede, the Netherlands
| | - A van der Wal
- Evides Water Company, PO Box 4472, 3006 AL, Rotterdam, the Netherlands; Department of Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708 WG, Wageningen, the Netherlands
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8
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Schurer R, Hijnen WAM, van der Wal A. The significance of the biomass subfraction of high-MW organic carbon for the microbial growth and maintenance potential of disinfectant-free drinking water produced from surface water. WATER RESEARCH 2022; 209:117898. [PMID: 34896810 DOI: 10.1016/j.watres.2021.117898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/15/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
Drinking water must be sufficiently biostable to avoid excessive microbial and invertebrate growth in disinfectant-free distribution systems. The production of biologically stable drinking water is challenging for conventional surface water treatment plants using reservoirs as feed water due to the presence of slowly biodegradable particulate and high-molecular weight biopolymeric organic carbon (high-MW OC) which increases the Microbial Growth Potential (MGP) in the feed water and produced drinking water. The study presented here provides new insights in the relationship between high-MW OC and MGP for a full-scale surface water treatment plant. Controlled-conditions addition series experiments showed that MGP increases linearly with the high-MW OC concentration with a seasonally variable ratio. Laboratory filtration indicated that MGP is mainly attributable to the high-MW OC subfraction of > 0.12 µm particle size coinciding with microbial biomass. Intensive field monitoring revealed clear seasonal patterns in the plant's feed water and treated water levels of high-MW OC, biomass and MGP. These parameters reach maximum levels in the periods of high water temperature with the notable exception of the treated water's high-MW OC concentration which exhibits an opposite seasonal pattern (reflecting seasonally variable removal in the treatment). Moreover, the field monitoring showed that MGP correlates well with the concentrations of biodegradable biopolymeric OC and with microbial biomass measured as ATP (adenosine triphosphate) and cell counts, but not with the total high-MW OC concentration in the treated water. Theoretical estimations showed that the OC quantities present in and consumed by the microbial biomass are in the same order of magnitude as slowly biodegradable biopolymers. From these results it is concluded that specifically the microbial biomass-associated and biodegradable biopolymeric OC subfraction of the totally present high-MW OC is important for MGP. Finally, the MGP-assay results and theoretical calculations showed for the high-MW OC matrix that the microbial biomass' OC consumption for maintenance is significant vis-á-vis that for growth, and that stable and high levels of biomass are sustained in the treated water which may adversely affect biological stability in the distribution network.
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Affiliation(s)
- R Schurer
- Evides Water Company, PO Box 4472, 3006 AL Rotterdam, the Netherlands; Department of Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands; IHE Delft Institute for Water Education, Environmental Engineering and Water Technology Department, Westvest 7, 2611 AX Delft, the Netherlands.
| | - W A M Hijnen
- Evides Water Company, PO Box 4472, 3006 AL Rotterdam, the Netherlands; KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, the Netherlands
| | - A van der Wal
- Evides Water Company, PO Box 4472, 3006 AL Rotterdam, the Netherlands; Department of Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
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9
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Pick FC, Fish KE, Husband S, Boxall JB. Non-invasive Biofouling Monitoring to Assess Drinking Water Distribution System Performance. Front Microbiol 2021; 12:730344. [PMID: 34777279 PMCID: PMC8581547 DOI: 10.3389/fmicb.2021.730344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
Biofilms are endemic in drinking water distribution systems (DWDS), forming on all water and infrastructure interfaces. They can pose risks to water quality and hence consumers. Our understanding of these biofilms is limited, in a large part due to difficulties in sampling them without unacceptable disruption. A novel, non-destructive and non-disruptive biofilm monitoring device (BMD), which includes use of flow cytometry analysis, was developed to assess biofouling rates. Laboratory based experiments established optimal configurations and verified reliable cell enumeration. Deployment at three operational field sites validated assessment of different biofouling rates. These differences in fouling rates were not obvious from bulk water sampling and analysis, but did have a strong correlation with long-term performance data of the associated networks. The device offers the potential to assess DWDS performance in a few months, compared to the number of years required to infer findings from historical customer contact data. Such information is vital to improve the management of our vast, complex and uncertain drinking water supply systems; for example rapidly quantifying the benefits of improvements in water treatment works or changes to maintenance of the network.
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Affiliation(s)
- Frances C Pick
- Department of Civil and Structural Engineering, Sheffield Water Centre, The University of Sheffield, Sheffield, United Kingdom
| | - Katherine E Fish
- Department of Civil and Structural Engineering, Sheffield Water Centre, The University of Sheffield, Sheffield, United Kingdom
| | - Stewart Husband
- Department of Civil and Structural Engineering, Sheffield Water Centre, The University of Sheffield, Sheffield, United Kingdom
| | - Joby B Boxall
- Department of Civil and Structural Engineering, Sheffield Water Centre, The University of Sheffield, Sheffield, United Kingdom
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10
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Zhang Y, Zhang Y, Liu L, Zhou L, Zhao Z. Impacts of antibiotics on biofilm bacterial community and disinfection performance on simulated drinking water supply pipe wall. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 288:117736. [PMID: 34256291 DOI: 10.1016/j.envpol.2021.117736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/30/2021] [Accepted: 07/04/2021] [Indexed: 06/13/2023]
Abstract
Overuse of antibiotics is accelerating the spread of resistance risk in the environment. In drinking water supply systems, the effect of antibiotics on the resistance of biofilm is unclear, and there have been few studies in disinfectant-containing systems. Here, we designed a series of drinking water supply reactors to investigate the effects of antibiotics on biofilm and bacteria in the water. At low concentrations, antibiotics could promote the growth of bacteria in biofilm; among the tested antibiotics (tetracycline, sulfadiazine and chloramphenicol), tetracycline had the strongest ability to promote this. And the antibiotic resistant bacteria (ARB) could inhibit the growth of bacteria in drinking water. Results have shown that antibiotics enhanced the bacterial chlorine resistance in the effluent, but reduced that in the biofilm. Furthermore, metagenomic analysis showed that antibiotics reduced the richness of biofilm communities. The dominant phyla in the biofilm were Proteobacteria, Planctomycetes, and Firmicutes. In tetracycline-treated biofilm, the dominant phylum was Planctomycetes. In sulfadiazine- and chloramphenicol-treated groups, bacteria with complex cell structures preferentially accumulated. The dominant class in biofilm in the ARB-added group was Gammaproteobacteria. The abundance of antibiotic resistant genes (ARGs) was correlated with biofilm community structure. This study shows that antibiotics make the biofilm community structure of drinking water more resistant to chlorine. ARGs may be selective for certain bacteria in the process, and there may ultimately be enhanced chlorine and antibiotic resistance of effluent bacteria in drinking water.
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Affiliation(s)
- Yongji Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Yingyu Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Lina Liu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Lingling Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
| | - Zhiling Zhao
- College of Civil Engineering, Huaqiao University, Jimei District, Xiamen, 361021, China
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11
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Kurajica L, Ujević Bošnjak M, Kinsela AS, Štiglić J, Waite TD, Capak K, Pavlić Z. Effects of changing supply water quality on drinking water distribution networks: Changes in NOM optical properties, disinfection byproduct formation, and Mn deposition and release. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:144159. [PMID: 33360458 DOI: 10.1016/j.scitotenv.2020.144159] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/26/2020] [Accepted: 11/26/2020] [Indexed: 06/12/2023]
Abstract
Field studies were conducted in a Croatian city supplied by two distinct groundwater sources (referred to as A and B) to investigate both the effects of changing water source on the water quality in the drinking water supply system, as well as to further understand discoloration events that occurred in city locations that switched water from source A to B. The water treatment processes at site A were found to alter organic matter (OM) characteristics, removing humic substances while enhancing protein-derived (tryptophan) content. Although the humic-like component predominated in raw waters, microbially/protein-derived components were found to increase throughout the distribution networks of both systems. Disinfection byproducts (DBPs) such as total trihalomethane (TTHM) and total haloacetic acid (THAA) were prevalent in water distribution system (WDS)-A, which correlated with elevated OM content as well as re-chlorination with hypochlorite (NaOCl). Our field study revealed that THMs were more readily formed than HAAs during ClO2 treatment. Unsurprisingly, chlorite concentrations were generally higher than chlorate concentrations during ClO2 treatment, whereas (secondary) NaOCl disinfection contributed to higher chlorate production. Principal component analysis indicated that variable pH values and humic-like OM could affect Mn, As and Al concentrations at the consumer's tap. Our results suggested that although Mn concentrations complied with regulations at WDS-B and were below 50 μg/L after disinfection, Mn was oxidized and formed particulate Mn oxides capable of causing discoloration events depending on prevailing network physico-chemical and hydraulic conditions. Aluminium also appears to be released during hydraulic disturbances from extensive deposits within the network. Thermodynamic calculations showed that Mn-oxidation was strongly dependent upon the ORP, and to lesser extent the pH value. Collectively, our results confirm that ensuring the provision of safe drinking waters to consumers requires an understanding of water quality across entire distribution networks in addition to any routine post-treatment monitoring.
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Affiliation(s)
- L Kurajica
- Croatian Institute of Public Health, Rockefeller street 7, 10000 Zagreb, Croatia
| | - M Ujević Bošnjak
- Croatian Institute of Public Health, Rockefeller street 7, 10000 Zagreb, Croatia.
| | - A S Kinsela
- Water Research Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - J Štiglić
- Croatian Institute of Public Health, Rockefeller street 7, 10000 Zagreb, Croatia
| | - T D Waite
- Water Research Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - K Capak
- Croatian Institute of Public Health, Rockefeller street 7, 10000 Zagreb, Croatia
| | - Z Pavlić
- Slavonski Brod Water Supply Company, Nikole Zrinskog 25, 35000 Slavonski Brod, Croatia
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12
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Chen R, Zhuang Y, Yu Y, Shi B. Enhanced perfluorooctanoic acid (PFOA) accumulation by combination with in-situ formed Mn oxides under drinking water conditions. WATER RESEARCH 2021; 190:116660. [PMID: 33279743 DOI: 10.1016/j.watres.2020.116660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
Particulate manganese oxide (MnOx) deposition in drinking water distribution systems (DWDS) gives rise to the risk of water discoloration at the consumers' tap; however, its role in the fate and transport of trace organic pollutants in DWDS is not clear. Perfluorooctanoic acid (PFOA), a persistent organic pollutant frequently detected in natural water, was selected to investigate the potential effect of MnOx on its transportation behavior under DWDS conditions through laboratory batch experiments. The results show that PFOA can be greatly combined with MnOx formed in-situ through a Mn(II) oxidation process by free chlorine. However, the accumulation of PFOA by preformed MnOx was negligible. It was found that 1 mg/L Mn captured over 50% of PFOA with an initial concentration of 50 ng/L during oxidation. The water compositions of actual water could contribute to the effect of PFOA accumulation to a certain extent. Characterization of the solid products revealed that PFOA is homogenously embedded into MnOx. The combination of PFOA with MnOx occurs through a bridging effect of Mn(II) between the surface hydroxyls of MnOx and the -COOH group of PFOA. The resulting MnOx-PFOA particles were more inclined to agglomerate, enabling possibly easy deposition onto the pipe wall than ordinary MnOx particles. This study provides insights into the co-occurrence of metal deposits with PFOA and the potential risks posed by PFOA accumulation to consumers through the water distribution process.
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Affiliation(s)
- Ruya Chen
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Zhuang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Ying Yu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baoyou Shi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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13
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Pei Y, McLeod JF, Payne SJ, She Z. A Comparative Study of Electroanalytical Methods for Detecting Manganese in Drinking Water Distribution Systems. Electrocatalysis (N Y) 2021. [DOI: 10.1007/s12678-020-00639-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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14
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Zhang S, Tian Y, Guo Y, Shan J, Liu R. Manganese release from corrosion products of cast iron pipes in drinking water distribution systems: Effect of water temperature, pH, alkalinity, SO 42- concentration and disinfectants. CHEMOSPHERE 2021; 262:127904. [PMID: 32799153 DOI: 10.1016/j.chemosphere.2020.127904] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/31/2020] [Accepted: 08/01/2020] [Indexed: 06/11/2023]
Abstract
Manganese accumulated in corrosion scales on drinking water distribution systems (DWDSs) can be released into bulk water, causing discolouration and thereby leading to customer concerns about drinking water quality. A static release experiment was conducted on iron pipe scales under three different temperatures, pH values, alkalinity values, sulfate (SO42-) concentrations, and disinfectants to study the separate effect of these factors on Mn release from pipe scales under stagnant conditions. Results showed that more Mn was released from corrosion scales under the conditions of lower pH, lower alkalinity, higher temperature, and higher SO42- concentrations. Three commonly used disinfectants, sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and monochloramine (NH2Cl) were found to inhibit the release of Mn from iron corrosion scales, with the ranked order of inhibitory effect of ClO2≈NaClO > NH2Cl under the same CT (product of disinfectant concentration and contact time) value. The orthogonal experimental results indicated that SO42- and alkalinity had extremely significant effects on the release of Mn from pipe scales, while pH and disinfectant type had a significant impact on the release of Mn from pipe scales. Thus, the SO42- concentration and alkalinity of the bulk water should be determined to avoid excessive release of Mn into drinking water. However, further investigation of the effect of disinfectants on Mn release in DWDSs is necessary. This research helps establish a systematic understanding of the influential factors in Mn release from pipe scales into bulk water, as well as their significant relationships.
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Affiliation(s)
- Shengnan Zhang
- School of Environmental Science and Engineering, Tianjin University, 135 Yaguan Road, Jinnan District, Tianjin, 300350, China; Renai College, Tianjin University, Jinghai District, Tianjin, 301636, China
| | - Yimei Tian
- School of Environmental Science and Engineering, Tianjin University, 135 Yaguan Road, Jinnan District, Tianjin, 300350, China.
| | - Yajing Guo
- School of Environmental Science and Engineering, Tianjin University, 135 Yaguan Road, Jinnan District, Tianjin, 300350, China; Beifang Investigation, Design & Research Co. LTD, Hexi District, Tianjin, 300222, China
| | - Jinlin Shan
- School of Environmental Science and Engineering, Tianjin University, 135 Yaguan Road, Jinnan District, Tianjin, 300350, China
| | - Ran Liu
- School of Environmental Science and Engineering, Tianjin University, 135 Yaguan Road, Jinnan District, Tianjin, 300350, China
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15
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Zhou X, Kosaka K, Nakanishi T, Welfringer T, Itoh S. Manganese accumulation on pipe surface in chlorinated drinking water distribution system: Contributions of physical and chemical pathways. WATER RESEARCH 2020; 184:116201. [PMID: 32726736 DOI: 10.1016/j.watres.2020.116201] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
The accumulation of manganese in drinking water distribution systems often causes problems of "black water" in customers' taps. In this study, Mn accumulation onto a pipe surface under chlorinated conditions was investigated by focusing on the different states of Mn in the water. Lab-scale experiments suggested that the accumulation process included both the attachment of particulate Mn onto the surface (i.e., physical pathway) and the autocatalytic oxidation of Mn ions on the surface (i.e., chemical pathway). Based on the experimental results, a numerical model of Mn accumulation on the pipe surface via the two pathways was established. According to the model predictions, the physical pathway contributed less than the chemical pathway over time since the latter accelerated as Mn accumulation increased. The chemical pathway contributed 94% when the concentration of total Mn was 10 µg/L throughout the experiment, but only 67% when the concentration was 100 µg/L. Thus, the chemical pathway was more important for low concentrations of total Mn. In addition, the type of pipe materials used only influenced the physical pathway, while the presence of bromide directly enhanced the chemical pathway. In conclusion, limiting the chemical pathway was suggested as an effective strategy for reducing Mn accumulation during long-term operation, which is achieved by controlling the state of Mn in finished water.
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Affiliation(s)
- Xinyi Zhou
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan
| | - Koji Kosaka
- Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako, Saitama 351-0197, Japan
| | - Tomohiro Nakanishi
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan.
| | - Théo Welfringer
- Graduate School of Environmental Engineering and Water Resource Management, National School for Water and Environmental Engineering, 1 quai Koch, 67000 Strasbourg, France
| | - Sadahiko Itoh
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan
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16
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Chen J, Shi Y, Cheng D, Jin Y, Hutchins W, Liu J. Survey of pathogenic bacteria of biofilms in a metropolitan drinking water distribution system. FEMS Microbiol Lett 2020; 366:5614495. [PMID: 31697369 DOI: 10.1093/femsle/fnz225] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 11/06/2019] [Indexed: 11/12/2022] Open
Abstract
Bacteria, especially pathogenic bacteria, were detected in order to estimate the safety of drinking water distribution systems (DWDSs). Sixteen biofilms and 12 water samples (six retained and six flowing) were collected from a city DWDS in eastern China. Biofilms were observed using scanning electron microscopy. Cultivable bacteria of biofilms were counted by heterotrophic plate counts, ranging from 3.61 × 101 to 1.67 × 106 CFU·cm-2. Coliforms, Salmonella, Shigella, Vibrio and Legionella were separated by Eosin-Methylene Blue (EMB) agar, Salmonella chromogenic medium, Shigella chromogenic medium, Thiosulfate Citrate Bile Salts Sucrose (TCBS) agar and Buffered Charcoal Yeast Extract (BCYE) agar and 13/16, 8/16, 7/16, 6/16, 0/16 biofilm samples were found to be positive, respectively. Retained and flowing water samples were collected to estimate the influence of hydrodynamic conditions on biofilm detachment. All six retained water samples were positive for bacteria, the count ranged from 1.2 × 103 to 2.8 × 104 CFU·mL-1 and 2/6, 3/6, 2/6, 0/6, 0/6 samples were positive for coliforms, Salmonella, Shigella, Legionella and Vibrio, respectively. While only three of six flowing water samples were bacteria positive, the counts ranged from 102 to 103 CFU·mL-1, 2/6 were coliform positive and no pathogens were detected under testing. The results show that there are pathogens in DWDS biofilms, which can cause health-related problems if detached from their surfaces.
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Affiliation(s)
- Jiang Chen
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Ya Shi
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Dongqing Cheng
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Yan Jin
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - William Hutchins
- Department of Biological Sciences, University of Wisconsin-Milwaukee 53211, U.S.A
| | - Jingqing Liu
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, Zhejiang, 310058, China
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17
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Li G, Ma X, Chen R, Yu Y, Tao H, Shi B. Field studies of manganese deposition and release in drinking water distribution systems: Insight into deposit control. WATER RESEARCH 2019; 163:114897. [PMID: 31362214 DOI: 10.1016/j.watres.2019.114897] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 07/04/2019] [Accepted: 07/21/2019] [Indexed: 06/10/2023]
Abstract
Drinking water discoloration is one of the most common customer complaints. The accumulation of residual manganese (Mn) in drinking water distribution systems (DWDS) accounts for part of the discolored water that reaches household taps. Field studies were conducted at seven full-scale DWDS to investigate the deposition and release behaviors of Mn in different forms and at different concentrations in finished water. The results show that particulate Mn tended to accumulate in DWDS even at concentrations as low as 10 μg/L. The oxidation of soluble Mn(II) ions in DWDS was highly affected by water chemistries as well as water age; 10 μg/L of soluble Mn could still transform into particulate Mn under suitable conditions. When total Mn concentration in finished water was below 5 μg/L, erosion of Mn deposits occurred in DWDS with a Mn deposit inventory. Soluble Mn release was observed when chlorine or chlorine dioxide concentration was lower than 0.1 mg/L, and the release was speculated to be a result of microbial reductive dissolution of Mn oxides. Ensuring the total Mn concentration is below 10 μg/L and decreasing the particulate Mn concentration to 5 μg/L in finished water are both recommended to minimize Mn accumulation risk in DWDS. Enhanced oxidation and filtration for Mn removal during water treatment processes are proposed.
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Affiliation(s)
- Guiwei Li
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xu Ma
- School of Environment & Natural Resource, Renmin University of China, Beijing, 100872, China
| | - Ruya Chen
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying Yu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hui Tao
- College of Environmental Science and Engineering. Hohai University, Nanjing, 210098, China
| | - Baoyou Shi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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18
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Spatiotemporal Water Quality Variations in Smaller Water Supply Systems: Using Modified CCME WQI from Groundwater Source to Distribution Networks. WATER 2019. [DOI: 10.3390/w11091884] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Original Canadian Council of Minster of the Environment Water Quality Index (CCME WQI) is being used for assessing the water quality of surface water sources and distribution systems on a case by case basis. Its full potential as a management tool for complete water supply systems (WSSs) has yet to be recognized at the global level. A framework is developed using the modified CCME WQI to assess spatiotemporal water quality from groundwater source to treatment and distribution networks in smaller systems. The modified index resolves a limitation of the original index by also evaluating the microbiological water quality parameters which have to be completely absent for meeting desired drinking water quality standards. The framework divides the distribution network in different zones, which are further segregated into districts, to improve the decision-making process. Temporal assessment identifies the seasons with higher probabilities of failures, while the spatial assessment provides an insight on the performance (i.e., Excellent to Poor) of each district in a distribution network. In addition to failure probability, risk mapping gives appropriate attention to the number of consumers in different districts. Application of the framework on two smaller WSSs (population less than 50,000) in Qassim region revealed that the remotely located districts from the treatment facility underperform in comparison to the closely situated districts. Managers can effectively apply the proposed framework to identify the locations and periods of water quality failures in each component (i.e., source, treatment, and distribution) of a smaller WSS for effective utilization of their resources in Saudi Arabia and elsewhere with similar conditions.
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19
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Lakshman Kumar A, Eashwar M, Sreedhar G, Vengatesan S, Prabu V, Shanmugam VM. Portraying manganese biofilms via a merger of EPR spectroscopy and cathodic polarization. BIOFOULING 2019; 35:768-784. [PMID: 31530181 DOI: 10.1080/08927014.2019.1658747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 08/01/2019] [Accepted: 08/16/2019] [Indexed: 06/10/2023]
Abstract
Microbial biofilms on stainless steel surfaces exposed to water from a freshwater pond were dominated by manganese-oxidizing bacteria, as initially diagnosed by microscopy and elemental analysis. The application of electron paramagnetic resonance (EPR) spectroscopy revealed conspicuous sextet (six-line) patterns that intensified with immersion time, implying the gradual accumulation of Mn(II) in the biofilms. Correspondingly, cathodic polarization designated the manganese oxide (MnOx) reduction peak in the form of a distinctive 'nose', which grew increasingly more negative with biofilm growth. The progressive expansion of cathodic current densities and the concurrent area-under-the-curve also allowed the quantification of microbially mediated MnOx deposition. Furthermore, the merger of EPR and cathodic polarization techniques yielded key insights, in tandem with Mn speciation data, into the pathways of microbial manganese transformations in biofilms, besides providing meaningful interpretations of prevailing literature. Accordingly, the natural freshwater biofilm was inferred as one supporting a complete manganese cycle encompassing multiple redox states.
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Affiliation(s)
- A Lakshman Kumar
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
- Biofilms and Biogeochemistry Group, Corrosion and Materials Protection Division, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - M Eashwar
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
- Biofilms and Biogeochemistry Group, Corrosion and Materials Protection Division, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - G Sreedhar
- Electro-Pyrometallurgy Division, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - S Vengatesan
- Electro-Inorganic Chemicals Division, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - V Prabu
- Central Instrumentation Facility, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - V M Shanmugam
- Central Instrumentation Facility, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
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20
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Comparison of biofilm cell quantification methods for drinking water distribution systems. J Microbiol Methods 2017; 144:8-21. [PMID: 29111400 DOI: 10.1016/j.mimet.2017.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/21/2017] [Accepted: 10/25/2017] [Indexed: 01/24/2023]
Abstract
Drinking water quality typically degrades after treatment during conveyance through the distribution system. Potential causes include biofilm growth in distribution pipes which may result in pathogen retention, inhibited disinfectant diffusion, and proliferation of bad tastes and odors. However, there is no standard method for direct measurement of biofilms or quantification of biofilm cells in drinking water distribution systems. Three methods are compared here for quantification of biofilm cells grown in pipe loops samplers: biofilm heterotrophic plate count (HPC), biofilm biovolume by confocal laser scanning microscopy (CLSM) and biofilm total cell count by flow cytometry (FCM) paired with Syto 9. Both biofilm biovolume by CLSM and biofilm total cell count by FCM were evaluated for quantification of the whole biofilms (including non-viable cells and viable but not culturable cells). Signal-to-background ratios and overall performance of biofilm biovolume by CLSM and biofilm total cell count by FCM were found to vary with the pipe material. Biofilm total cell count by FCM had a low signal-to-background ratio on all materials, indicating that further development is recommended before application in drinking water environments. Biofilm biovolume by CLSM showed the highest signal-to-background ratio for cement and cast iron, which suggests promise for wider application in full-scale systems. Biofilm biovolume by CLSM and Syto 9 staining allowed in-situ biofilm cell quantification thus elimination variable associated with cell detachment for quantification but had limitations associated with non-specific staining of cement and, to a lesser degree, auto-fluorescence of both cement and polyvinyl chloride materials. Due to variability in results obtained from each method, multiple methods are recommended to assess biofilm growth in drinking water distribution systems. Of the methods investigated here, HPC and CLSM and recommended for further development towards application in full-scale systems. HPC is a sample and widely applied method that quantifies viable culturable cells. CLSM analysis allows the elimination of experimental variables associated with cell detachment and affords the opportunity to evaluate biofilm components such as extracellular polymeric substances through the addition of specific probes. These two methods can be applied together to assess biofilms known to degrade treated water quality during conveyance in full-scale drinking water treatment systems. The significance of improved biofilm assessment methods for drinking water distribution systems lies in advancing understanding of biofilm growth and control mechanisms that may lead to improved water quality during conveyance and at the tap for greater public health protection.
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21
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Fish K, Osborn AM, Boxall JB. Biofilm structures (EPS and bacterial communities) in drinking water distribution systems are conditioned by hydraulics and influence discolouration. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 593-594:571-580. [PMID: 28360007 DOI: 10.1016/j.scitotenv.2017.03.176] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/13/2017] [Accepted: 03/19/2017] [Indexed: 06/07/2023]
Abstract
High-quality drinking water from treatment works is degraded during transport to customer taps through the Drinking Water Distribution System (DWDS). Interactions occurring at the pipe wall-water interface are central to this degradation and are often dominated by complex microbial biofilms that are not well understood. This study uses novel application of confocal microscopy techniques to quantify the composition of extracellular polymeric substances (EPS) and cells of DWDS biofilms together with concurrent evaluation of the bacterial community. An internationally unique, full-scale, experimental DWDS facility was used to investigate the impact of three different hydraulic patterns upon biofilms and subsequently assess their response to increases in shear stress, linking biofilms to water quality impacts such as discolouration. Greater flow variation during growth was associated with increased cell quantity but was inversely related to EPS-to-cell volume ratios and bacterial diversity. Discolouration was caused and EPS was mobilised during flushing of all conditions. Ultimately, biofilms developed under low-varied flow conditions had lowest amounts of biomass, the greatest EPS volumes per cell and the lowest discolouration response. This research shows that the interactions between hydraulics and biofilm physical and community structures are complex but critical to managing biofilms within ageing DWDS infrastructure to limit water quality degradation and protect public health.
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Affiliation(s)
- K Fish
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield S1 3JD, UK; NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, Western Bank, Sheffield S10 2TN, UK.
| | - A M Osborn
- Biosciences and Food Technology Discipline, School of Science, RMIT University, PO Box 71, Bundoora, Melbourne VIC3083, Australia
| | - J B Boxall
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield S1 3JD, UK
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22
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Sun H, Shi B, Yang F, Wang D. Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system. WATER RESEARCH 2017; 114:69-77. [PMID: 28226251 DOI: 10.1016/j.watres.2017.02.021] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/08/2017] [Accepted: 02/10/2017] [Indexed: 06/06/2023]
Abstract
Trace heavy metals accumulated in iron corrosion scales within a drinking water distribution system (DWDS) could potentially be released to bulk water and consequently deteriorate the tap water quality. The objective of this study was to identify and evaluate the release of trace heavy metals in DWDS under changing source water conditions. Experimental pipe loops with different iron corrosion scales were set up to simulate the actual DWDS. The effects of sulfate levels on heavy metal release were systemically investigated. Heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW). There were strong positive correlations (R2 > 0.8) between the releases of Fe and Mn, Fe and Ni, Fe and Cu, and Fe and Pb. When switching to higher sulfate water, iron corrosion scales in all pipe loops tended to be more stable (especially in pipes transporting GW), with a larger proportion of stable constituents (mainly Fe3O4) and fewer unstable compounds (β-FeOOH, γ-FeOOH, FeCO3 and amorphous iron oxides). The main functional iron reducing bacteria (IRB) communities were favorable for the formation of Fe3O4. The transformation of corrosion scales and the growth of sulfate reducing bacteria (SRB) accounted for the gradually reduced heavy metal release with time. The higher metal release in pipes transporting GW could be due to increased Fe6(OH)12CO3 content under higher sulfate concentrations.
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Affiliation(s)
- Huifang Sun
- Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030006, China
| | - Baoyou Shi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Fan Yang
- College of Engineering and Technology, Tianjin Agricultural University, Tianjin 300384, China
| | - Dongsheng Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Effectiveness of Devices to Monitor Biofouling and Metals Deposition on Plumbing Materials Exposed to a Full-Scale Drinking Water Distribution System. PLoS One 2017; 12:e0169140. [PMID: 28060947 PMCID: PMC5218461 DOI: 10.1371/journal.pone.0169140] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 12/12/2016] [Indexed: 11/19/2022] Open
Abstract
A Modified Robbins Device (MRD) was installed in a full-scale water distribution system to investigate biofouling and metal depositions on concrete, high-density polyethylene (HDPE) and stainless steel surfaces. Bulk water monitoring and a KIWA monitor (with glass media) were used to offline monitor biofilm development on pipe wall surfaces. Results indicated that adenosine triphosphate (ATP) and metal concentrations on coupons increased with time. However, bacterial diversities decreased. There was a positive correlation between increase of ATP and metal deposition on pipe surfaces of stainless steel and HDPE and no correlation was observed on concrete and glass surfaces. The shared bacterial diversity between bulk water and MRD was less than 20% and the diversity shared between the MRD and KIWA monitor was only 10%. The bacterial diversity on biofilm of plumbing material of MRD however, did not show a significant difference suggesting a lack of influence from plumbing material during early stage of biofilm development.
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Gonzalez D, Tjandraatmadja G, Barry K, Vanderzalm J, Kaksonen AH, Dillon P, Puzon GJ, Sidhu J, Wylie J, Goodman N, Low J. Biofouling potential and material reactivity in a simulated water distribution network supplied with stormwater recycled via managed aquifer recharge. WATER RESEARCH 2016; 105:110-118. [PMID: 27607597 DOI: 10.1016/j.watres.2016.08.066] [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: 04/10/2016] [Revised: 07/29/2016] [Accepted: 08/30/2016] [Indexed: 06/06/2023]
Abstract
The injection of stormwater into aquifers for storage and recovery during high water demand periods is a promising technology for augmenting conventional water reserves. Limited information exists regarding the potential impact of aquifer treated stormwater in distribution system infrastructure. This study describes a one year pilot distribution pipe network trial to determine the biofouling potential for cement, copper and polyvinyl chloride pipe materials exposed to stormwater stored in a limestone aquifer compared to an identical drinking water rig. Median alkalinity (123 mg/L) and colour (12 HU) in stormwater was significantly higher than in drinking water (82 mg/L and 1 HU) and pipe discolouration was more evident for stormwater samples. X-ray Diffraction and Fluorescence analyses confirmed this was driven by the presence of iron rich amorphous compounds in more thickly deposited sediments also consistent with significantly higher median levels of iron (∼0.56 mg/L) in stormwater compared to drinking water (∼0.17 mg/L). Water type did not influence biofilm development as determined by microbial density but faecal indicators were significantly higher for polyvinyl chloride and cement exposed to stormwater. Treatment to remove iron through aeration and filtration would reduce the potential for sediment accumulation. Operational and verification monitoring parameters to manage scaling, corrosion, colour, turbidity and microbial growth in recycled stormwater distribution networks are discussed.
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Affiliation(s)
- Dennis Gonzalez
- CSIRO Land and Water, Private Bag 2, Glen Osmond, SA, 5064, Australia.
| | - Grace Tjandraatmadja
- CSIRO Land and Water, CSIRO, Private Bag 10, Clayton South, Vic, 3169, Australia
| | - Karen Barry
- CSIRO Land and Water, Private Bag 2, Glen Osmond, SA, 5064, Australia
| | - Joanne Vanderzalm
- CSIRO Land and Water, Private Bag 2, Glen Osmond, SA, 5064, Australia
| | - Anna H Kaksonen
- CSIRO Land and Water, CSIRO, Private Bag 5, Wembley, WA, 6913, Australia
| | - Peter Dillon
- CSIRO Land and Water, Private Bag 2, Glen Osmond, SA, 5064, Australia
| | - Geoff J Puzon
- CSIRO Land and Water, CSIRO, Private Bag 5, Wembley, WA, 6913, Australia
| | - Jatinder Sidhu
- CSIRO Land and Water, CSIRO, GPO Box 2583, Brisbane, Qld, 4001, Australia
| | - Jason Wylie
- CSIRO Land and Water, CSIRO, Private Bag 5, Wembley, WA, 6913, Australia
| | - Nigel Goodman
- CSIRO Land and Water, CSIRO, Private Bag 10, Clayton South, Vic, 3169, Australia
| | - Jason Low
- CSIRO Land and Water, CSIRO, Private Bag 10, Clayton South, Vic, 3169, Australia
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Naz I, Hodgson D, Smith A, Marchesi J, Ahmed S, Avignone-Rossa C, Saroj DP. Effect of the chemical composition of filter media on the microbial community in wastewater biofilms at different temperatures. RSC Adv 2016; 6:104345-104353. [PMID: 28018581 PMCID: PMC5154295 DOI: 10.1039/c6ra21040f] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 10/24/2016] [Indexed: 01/22/2023] Open
Abstract
This study investigates the microbial community composition in the biofilms grown on two different support media in fixed biofilm reactors for aerobic wastewater treatment, using next generation sequencing (NGS) technology. The chemical composition of the new type of support medium (TDR) was found to be quite different from the conventionally used support medium (stone). The analysis of 16S rRNA gene fragments recovered from the laboratory scale biofilm system show that biofilm support media and temperature conditions influence bacterial community structure and composition. Greater bacterial diversity was observed under each condition, primarily due to the large number of sequences available and sustenance of rare species. There were 6 phyla found, with the highest relative abundance shown by the phylum Proteobacteria (52.71%) followed by Bacteroidetes (33.33%), Actinobacteria (4.65%), Firmicutes, Verrucomicrobia (3.1%) and Chloroflex (>1%). The dataset showed 17 genera of bacterial populations to be commonly shared under all conditions, suggesting the presence of a core microbial community in the biofilms for wastewater treatment. However, some genera in the biofilms on TDR were observed in high proportions, which may be attributed to its chemical composition, explaining the improved level of wastewater treatment. The findings show that the structure of microbial communities in biofilm systems for wastewater treatment is affected by the properties of support matrix.
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Affiliation(s)
- Iffat Naz
- Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK. ; Department of Biology, Qassim University, Buraidah 51452, Kingdom of Saudi Arabia; Environmental Microbiology Laboratory, Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan; Department of Microbial Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Douglas Hodgson
- Department of Microbial Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Ann Smith
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3XQ, UK
| | - Julian Marchesi
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3XQ, UK; Centre for Digestive and Gut Health, Imperial College London, London W2 1NY, UK
| | - Safia Ahmed
- Environmental Microbiology Laboratory, Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | | | - Devendra P Saroj
- Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK.
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Douterelo I, Husband S, Loza V, Boxall J. Dynamics of Biofilm Regrowth in Drinking Water Distribution Systems. Appl Environ Microbiol 2016; 82:4155-4168. [PMID: 27208119 PMCID: PMC4959196 DOI: 10.1128/aem.00109-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/27/2016] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED The majority of biomass within water distribution systems is in the form of attached biofilm. This is known to be central to drinking water quality degradation following treatment, yet little understanding of the dynamics of these highly heterogeneous communities exists. This paper presents original information on such dynamics, with findings demonstrating patterns of material accumulation, seasonality, and influential factors. Rigorous flushing operations repeated over a 1-year period on an operational chlorinated system in the United Kingdom are presented here. Intensive monitoring and sampling were undertaken, including time-series turbidity and detailed microbial analysis using 16S rRNA Illumina MiSeq sequencing. The results show that bacterial dynamics were influenced by differences in the supplied water and by the material remaining attached to the pipe wall following flushing. Turbidity, metals, and phosphate were the main factors correlated with the distribution of bacteria in the samples. Coupled with the lack of inhibition of biofilm development due to residual chlorine, this suggests that limiting inorganic nutrients, rather than organic carbon, might be a viable component in treatment strategies to manage biofilms. The research also showed that repeat flushing exerted beneficial selective pressure, giving another reason for flushing being a viable advantageous biofilm management option. This work advances our understanding of microbiological processes in drinking water distribution systems and helps inform strategies to optimize asset performance. IMPORTANCE This research provides novel information regarding the dynamics of biofilm formation in real drinking water distribution systems made of different materials. This new knowledge on microbiological process in water supply systems can be used to optimize the performance of the distribution network and to guarantee safe and good-quality drinking water to consumers.
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Affiliation(s)
- I Douterelo
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
| | - S Husband
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
| | - V Loza
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
| | - J Boxall
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
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27
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Ammar TA, Abid KY, El-Bindary AA, El-Sonbati AZ. Comparison of commercial analytical techniques for measuring chlorine dioxide in urban desalinated drinking water. JOURNAL OF WATER AND HEALTH 2015; 13:970-984. [PMID: 26608759 DOI: 10.2166/wh.2015.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Most drinking water industries are closely examining options to maintain a certain level of disinfectant residual through the entire distribution system. Chlorine dioxide is one of the promising disinfectants that is usually used as a secondary disinfectant, whereas the selection of the proper monitoring analytical technique to ensure disinfection and regulatory compliance has been debated within the industry. This research endeavored to objectively compare the performance of commercially available analytical techniques used for chlorine dioxide measurements (namely, chronoamperometry, DPD (N,N-diethyl-p-phenylenediamine), Lissamine Green B (LGB WET) and amperometric titration), to determine the superior technique. The commonly available commercial analytical techniques were evaluated over a wide range of chlorine dioxide concentrations. In reference to pre-defined criteria, the superior analytical technique was determined. To discern the effectiveness of such superior technique, various factors, such as sample temperature, high ionic strength, and other interferences that might influence the performance were examined. Among the four techniques, chronoamperometry technique indicates a significant level of accuracy and precision. Furthermore, the various influencing factors studied did not diminish the technique's performance where it was fairly adequate in all matrices. This study is a step towards proper disinfection monitoring and it confidently assists engineers with chlorine dioxide disinfection system planning and management.
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Affiliation(s)
- T A Ammar
- Qatar General Electricity and Water Corporation (KAHRAMAA), PO Box 41, Doha, Qatar E-mail:
| | - K Y Abid
- Qatar General Electricity and Water Corporation (KAHRAMAA), PO Box 41, Doha, Qatar E-mail:
| | - A A El-Bindary
- Chemistry Department, Faculty of Science, Damietta University, PO Box 6, New Damietta, Egypt
| | - A Z El-Sonbati
- Chemistry Department, Faculty of Science, Damietta University, PO Box 6, New Damietta, Egypt
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28
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Lührig K, Canbäck B, Paul CJ, Johansson T, Persson KM, Rådström P. Bacterial community analysis of drinking water biofilms in southern Sweden. Microbes Environ 2015; 30:99-107. [PMID: 25739379 PMCID: PMC4356470 DOI: 10.1264/jsme2.me14123] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Next-generation sequencing of the V1-V2 and V3 variable regions of the 16S rRNA gene generated a total of 674,116 reads that described six distinct bacterial biofilm communities from both water meters and pipes. A high degree of reproducibility was demonstrated for the experimental and analytical work-flow by analyzing the communities present in parallel water meters, the rare occurrence of biological replicates within a working drinking water distribution system. The communities observed in water meters from households that did not complain about their drinking water were defined by sequences representing Proteobacteria (82-87%), with 22-40% of all sequences being classified as Sphingomonadaceae. However, a water meter biofilm community from a household with consumer reports of red water and flowing water containing elevated levels of iron and manganese had fewer sequences representing Proteobacteria (44%); only 0.6% of all sequences were classified as Sphingomonadaceae; and, in contrast to the other water meter communities, markedly more sequences represented Nitrospira and Pedomicrobium. The biofilm communities in pipes were distinct from those in water meters, and contained sequences that were identified as Mycobacterium, Nocardia, Desulfovibrio, and Sulfuricurvum. The approach employed in the present study resolved the bacterial diversity present in these biofilm communities as well as the differences that occurred in biofilms within a single distribution system, and suggests that next-generation sequencing of 16S rRNA amplicons can show changes in bacterial biofilm communities associated with different water qualities.
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Affiliation(s)
- Katharina Lührig
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden; Sydvatten AB, Hyllie Stationstorg 21, SE-215 32 Malmö, Sweden
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29
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Gomes IB, Simões M, Simões LC. An overview on the reactors to study drinking water biofilms. WATER RESEARCH 2014; 62:63-87. [PMID: 24937357 DOI: 10.1016/j.watres.2014.05.039] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 06/03/2023]
Abstract
The development of biofilms in drinking water distribution systems (DWDS) can cause pipe degradation, changes in the water organoleptic properties but the main problem is related to the public health. Biofilms are the main responsible for the microbial presence in drinking water (DW) and can be reservoirs for pathogens. Therefore, the understanding of the mechanisms underlying biofilm formation and behavior is of utmost importance in order to create effective control strategies. As the study of biofilms in real DWDS is difficult, several devices have been developed. These devices allow biofilm formation under controlled conditions of physical (flow velocity, shear stress, temperature, type of pipe material, etc), chemical (type and amount of nutrients, type of disinfectant and residuals, organic and inorganic particles, ions, etc) and biological (composition of microbial community - type of microorganism and characteristics) parameters, ensuring that the operational conditions are similar as possible to the DWDS conditions in order to achieve results that can be applied to the real scenarios. The devices used in DW biofilm studies can be divided essentially in two groups, those usually applied in situ and the bench top laboratorial reactors. The selection of a device should be obviously in accordance with the aim of the study and its advantages and limitations should be evaluated to obtain reproducible results that can be transposed into the reality of the DWDS. The aim of this review is to provide an overview on the main reactors used in DW biofilm studies, describing their characteristics and applications, taking into account their main advantages and limitations.
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Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - L C Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal; CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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30
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Douterelo I, Husband S, Boxall JB. The bacteriological composition of biomass recovered by flushing an operational drinking water distribution system. WATER RESEARCH 2014; 54:100-114. [PMID: 24565801 DOI: 10.1016/j.watres.2014.01.049] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 01/23/2014] [Accepted: 01/26/2014] [Indexed: 06/03/2023]
Abstract
This study investigates the influence of pipe characteristics on the bacteriological composition of material mobilised from a drinking water distribution system (DWDS) and the impact of biofilm removal on water quality. Hydrants in a single UK Distribution Management Area (DMA) with both polyethylene and cast iron pipe sections were subjected to incremental increases in flow to mobilise material from the pipe walls. Turbidity was monitored during these operations and water samples were collected for physico-chemical and bacteriological analysis. DNA was extracted from the material mobilised into the bulk water before and during flushing. Bacterial tag-encoded 454 pyrosequencing was then used to characterize the bacterial communities present in this material. Turbidity values were high in the samples from cast iron pipes. Iron, aluminium, manganese and phosphate concentrations were found to correlate to observed turbidity. The bacterial community composition of the material mobilised from the pipes was significantly different between plastic and cast iron pipe sections (p < 0.5). High relative abundances of Alphaproteobacteria (23.3%), Clostridia (10.3%) and Actinobacteria (10.3%) were detected in the material removed from plastic pipes. Sequences related to Alphaproteobacteria (22.8%), Bacilli (16.6%), and Gammaproteobacteria (1.4%) were predominant in the samples obtained from cast iron pipes. The highest species richness and diversity were found in the samples from material mobilised from plastic pipes. Spirochaeta spp., Methylobacterium spp. Clostridium spp. and Desulfobacterium spp., were the most represented genera in the material obtained prior to and during the flushing of the plastic pipes. In cast iron pipes a high relative abundance of bacteria able to utilise different iron and manganese compounds were found such as Lysinibacillus spp., Geobacillus spp. and Magnetobacterium spp.
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Affiliation(s)
- I Douterelo
- Pennine Water Group, Department of Civil and Structural Engineering, Sir Frederick Mappin Building, University of Sheffield, Sheffield S1 3JD, UK.
| | - S Husband
- Pennine Water Group, Department of Civil and Structural Engineering, Sir Frederick Mappin Building, University of Sheffield, Sheffield S1 3JD, UK
| | - J B Boxall
- Pennine Water Group, Department of Civil and Structural Engineering, Sir Frederick Mappin Building, University of Sheffield, Sheffield S1 3JD, UK
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Douterelo I, Sharpe R, Boxall J. Bacterial community dynamics during the early stages of biofilm formation in a chlorinated experimental drinking water distribution system: implications for drinking water discolouration. J Appl Microbiol 2014; 117:286-301. [PMID: 24712449 PMCID: PMC4282425 DOI: 10.1111/jam.12516] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/19/2014] [Accepted: 04/01/2014] [Indexed: 12/01/2022]
Abstract
Aims To characterize bacterial communities during the early stages of biofilm formation and their role in water discolouration in a fully representative, chlorinated, experimental drinking water distribution systems (DWDS). Methods and Results Biofilm development was monitored in an experimental DWDS over 28 days; subsequently the system was disturbed by raising hydraulic conditions to simulate pipe burst, cleaning or other system conditions. Biofilm cell cover was monitored by fluorescent microscopy and a fingerprinting technique used to assess changes in bacterial community. Selected samples were analysed by cloning and sequencing of the 16S rRNA gene. Fingerprinting analysis revealed significant changes in the bacterial community structure over time (P < 0·05). Cell coverage increased over time accompanied by an increase in bacterial richness and diversity. Conclusions Shifts in the bacterial community structure were observed along with an increase in cell coverage, bacterial richness and diversity. Species related to Pseudomonas spp. and Janthinobacterium spp. dominated the process of initial attachment. Based on fingerprinting results, the hydraulic regimes did not affect the bacteriological composition of biofilms, but they did influence their mechanical stability. Significance and Importance of the Study This study gives a better insight into the early stages of biofilm formation in DWDS and will contribute to the improvement of management strategies to control the formation of biofilms and the risk of discolouration.
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Affiliation(s)
- I Douterelo
- Pennine Water Group, Department of Civil and Structural Engineering, University of Sheffield, Sheffield, UK
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32
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Influence of Chemical and Biological Parameters on Iron and Manganese Accumulation in Water Distribution Networks. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.proeng.2014.02.149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Douterelo I, Sharpe RL, Boxall JB. Influence of hydraulic regimes on bacterial community structure and composition in an experimental drinking water distribution system. WATER RESEARCH 2013. [PMID: 23182667 DOI: 10.1016/j.watres.2012.09.053] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Microbial biofilms formed on the inner-pipe surfaces of drinking water distribution systems (DWDS) can alter drinking water quality, particularly if they are mechanically detached from the pipe wall to the bulk water, such as due to changes in hydraulic conditions. Results are presented here from applying 454 pyrosequencing of the 16S ribosomal RNA (rRNA) gene to investigate the influence of different hydrological regimes on bacterial community structure and to study the potential mobilisation of material from the pipe walls to the network using a full scale, temperature-controlled experimental pipeline facility accurately representative of live DWDS. Analysis of pyrosequencing and water physico-chemical data showed that habitat type (water vs. biofilm) and hydraulic conditions influenced bacterial community structure and composition in our experimental DWDS. Bacterial community composition clearly differed between biofilms and bulk water samples. Gammaproteobacteria and Betaproteobacteria were the most abundant phyla in biofilms while Alphaproteobacteria was predominant in bulk water samples. This suggests that bacteria inhabiting biofilms, predominantly species belonging to genera Pseudomonas, Zooglea and Janthinobacterium, have an enhanced ability to express extracellular polymeric substances to adhere to surfaces and to favour co-aggregation between cells than those found in the bulk water. Highest species richness and diversity were detected in 28 days old biofilms with this being accentuated at highly varied flow conditions. Flushing altered the pipe-wall bacterial community structure but did not completely remove bacteria from the pipe walls, particularly under highly varied flow conditions, suggesting that under these conditions more compact biofilms were generated. This research brings new knowledge regarding the influence of different hydraulic regimes on the composition and structure of bacterial communities within DWDS and the implication that this might have on drinking water quality.
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Affiliation(s)
- I Douterelo
- Pennine Water Group, Department of Civil and Structural Engineering, Mappin Street, University of Sheffield, Sheffield S1 3JD, UK.
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Bal Krishna KC, Sathasivan A, Chandra Sarker D. Evidence of soluble microbial products accelerating chloramine decay in nitrifying bulk water samples. WATER RESEARCH 2012; 46:3977-3988. [PMID: 22695354 DOI: 10.1016/j.watres.2012.05.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 06/01/2023]
Abstract
The discovery of a microbially derived soluble product that accelerates chloramine decay is described. Nitrifying bacteria are believed to be wholly responsible for rapid chloramine loss in drinking water systems. However, a recent investigation showed that an unidentified soluble agent significantly accelerated chloramine decay. The agent was suspected to be either natural organic matter (NOM) or soluble microbial products (SMPs). A laboratory scale reactor was fed chloraminated reverse osmosis (RO) treated water to eliminate the interference from NOM. Once nitrification had set in, experiments were conducted on the reactor and feed waters to determine the identity of the component. The study showed the presence of SMPs released by microbes in severely nitrified waters. Further experiments proved that the SMPs significantly accelerated chloramine decay, probably through catalytic reaction. Moreover, application of common protein denaturing techniques stopped the reaction implying that the compound responsible was likely to be a protein. This significant finding will pave the way for better control of chloramine in the distribution systems.
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Affiliation(s)
- K C Bal Krishna
- Department of Civil and Construction Engineering, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
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