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Guo X, Ji X, Liu Z, Feng Z, Zhang Z, Du S, Li X, Ma J, Sun Z. Complex impact of metals on the fate of disinfection by-products in drinking water pipelines: A systematic review. WATER RESEARCH 2024; 261:121991. [PMID: 38941679 DOI: 10.1016/j.watres.2024.121991] [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: 04/16/2024] [Revised: 06/14/2024] [Accepted: 06/21/2024] [Indexed: 06/30/2024]
Abstract
Metals in the drinking water distribution system (DWDS) play an important role on the fate of disinfection by-products (DBPs). They can increase the formation of DBPs through several mechanisms, such as enhancing the proportion of reactive halogen species (RHS), catalysing the reaction between natural organic matter (NOM) and RHS through complexation, or by increasing the conversion of NOM into DBP precursors. This review comprehensively summarizes these complex processes, focusing on the most important metals (copper, iron, manganese) in DWDS and their impact on various DBPs. It organizes the dispersed 'metals-DBPs' experimental results into an easily accessible content structure and presents their underlying common or unique mechanisms. Furthermore, the practically valuable application directions of these research findings were analysed, including the toxicity changes of DBPs in DWDS under the influence of metals and the potential enhancement of generalization in DBP model research by the introduction of metals. Overall, this review revealed that the metal environment within DWDS is a crucial factor influencing DBP levels in tap water.
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Affiliation(s)
- Xinming Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150096, China
| | - Xiaoyue Ji
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150096, China
| | - Zihan Liu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150096, China
| | - Zhuoran Feng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150096, China
| | - ZiFeng Zhang
- International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shuang Du
- Institute of NBC Defense. PLA Army, P.O.Box1048, Beijing 102205 China
| | - Xueyan Li
- Suzhou University Science & Technology, School of Environmental Science & Engineering, Suzhou 215009, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150096, China
| | - Zhiqiang Sun
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150096, China.
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2
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Li G, Chen Q, Zhou Y, Su Y, Wu B, Yu J, Yang M, Shi B. Manganese and iron oxides on pipe surface promote dissolved aluminum accumulation in drinking water distribution systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 924:171606. [PMID: 38492600 DOI: 10.1016/j.scitotenv.2024.171606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 03/18/2024]
Abstract
Aluminum-containing deposits are pervasive in drinking water distribution systems (DWDSs). However, the mechanisms driving dissolved Al transformation to pipe deposits remain elusive. This study investigated dissolved Al accumulation in DWDSs by batch experiments and long-term pipe experiments using actual finished water. PVC pipe experiments showed that dissolved Al hardly deposited on clean PVC pipe walls at alkaline pH. However, it could be substantially anchored by the pipe surface covered with Mn and Fe deposits formed from Mn(II) oxidation and Fe(III) precipitation. Batch experiments verified that the synthesized Mn and Fe oxides exhibited a strong capacity for dissolved Al uptake at pH 7.7 and 9.0 (dissolved Al was the dominant form). Biofilms on pipe walls also enhanced dissolved Al accumulation. Iron pipe experiments showed that corroded iron pipes with abundant iron corrosion products readily accumulated Al. Compared to chlorination and chloramination, non-disinfected conditions were more favorable for particulate Al deposition on iron pipe surface, probably due to Al immobilization by biofilms. In addition, continuous Al accumulation in iron pipes enhanced Fe release to pipe water. This study highlighted the important role of metal oxides in dissolved Al accumulation in DWDSs with abundant Mn and Fe solids, which provided new insights into deposit formation and control strategies.
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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
| | - Yue Zhou
- 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
| | - 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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Miao X, Liu C, Liu M, Han X, Zhu L, Bai X. The role of pipe biofilms on dissemination of viral pathogens and virulence factor genes in a full-scale drinking water supply system. JOURNAL OF HAZARDOUS MATERIALS 2022; 432:128694. [PMID: 35316639 DOI: 10.1016/j.jhazmat.2022.128694] [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: 12/11/2021] [Revised: 02/24/2022] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Water is an important medium for virus transmission and viral pathogens are increasingly appreciated as a significant water safety issue. However, the effect of pipe biofilms on viral pathogens remains unclear. This research aimed to investigate the dissemination of viruses in a full-scale drinking water supply system (DWSS) and the effect of pipe biofilms on viral pathogens in bulking water. Viral pathogens, pathogenic viral hosts, and viral virulence factors (VFs) were found to disseminate from source water to tap water. The proportion of virus and viral VFs in the biofilm was far less than that in water. The contribution of biofilms in pipe wall to viruses and viral VFs in bulking water was less than 4%, and viruses in the biofilm had no obvious effect on pathogenic viruses in water. Dominant viruses carrying VFs changed from Cyanobacteria virus to Mycobacterium virus after advanced water treatment. Mycobacterium and organics were identified as the key factors influencing composition and abundance of viral VFs, which could explain 41.1% of the variation in viral virulence in the water supply system. Host bacteria and organics may be used as the key targets to control the risk of viruses in DWSSs.
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Affiliation(s)
- Xiaocao Miao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Chenxu Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Mingkun Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Xue Han
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Lingling Zhu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Xiaohui Bai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China.
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4
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Li J, Ren A, van der Mark E, Liu G. Direct evidence of microbiological water quality changes on bacterial quantity and community caused by plumbing system. J Environ Sci (China) 2022; 116:175-183. [PMID: 35219416 DOI: 10.1016/j.jes.2021.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 04/22/2021] [Accepted: 04/25/2021] [Indexed: 06/14/2023]
Abstract
Drinking water quality deteriorates from treatment plant to customer taps, especially in the plumbing system. There is no direct evidence about what the differences are contributed by plumbing system. This study compared the water quality in the water main and at customer tap by preparing a sampling tap on the water main. The biomass was quantified by adenosine triphosphate (ATP) and the microbial community was profiled by 454 pyrosequencing. The results showed that in distribution pipes, biofilm contributed >94% of the total biomass, while loose deposits showed little contribution (< 2%) because of the low amount of loose deposits. The distribution of biological stable water had minor effects on the microbiocidal water quality regarding both quantity (ATP 1 ng/L vs. 1.7 ng/L) and community of the bacteria. Whereas the plumbing system has significant contribution to the increase of active biomass (1.7 ng/L vs. 2.9 ng/L) and the changes of bacterial community. The relative abundance of Sphingomonas spp. at tap (22%) was higher than that at water main (2%), while the relative abundance of Pseudomonas spp. in tap water (15%) was lower than that in the water from street water main (29%). Though only one location was prepared and studied, the present study showed that the protocol of making sampling tap on water main offered directly evidences about the impacts of plumbing system on tap water quality, which makes it possible to distinguish and study the processes in distribution system and plumbing system separately.
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Affiliation(s)
- Jun Li
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Anran Ren
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ed van der Mark
- Dunea Water Company, Plaza of the United Nations 11-15, Zoetermeer 2700 AT, the Netherlands
| | - Gang Liu
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China; Sanitary engineering, Department of Water management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft 2600 GA, the Netherlands.
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5
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Braga AS, Filion Y. The interplay of suspended sediment concentration, particle size and fluid velocity on the rapid deposition of suspended iron oxide particles in PVC drinking water pipes. WATER RESEARCH X 2022; 15:100143. [PMID: 35494337 PMCID: PMC9047010 DOI: 10.1016/j.wroa.2022.100143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/08/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
The inner walls of drinking water pipes are often expected to be clean and controlled surfaces to assure safe water access to the public. However, these surfaces are typically contaminated with particulate materials and biofilms that eventually degrade water quality. While water utilities place significant efforts in identifying and flushing material deposits from compromised pipes, the development of effective preventive strategies is still limited by the lack of knowledge about material accumulation processes. The aim of this paper is to examine the interplay between suspended sediment concentration, particle size and fluid velocity and the attachment of suspended iron oxide particles in PVC drinking water pipes. For that purpose, a series of short experiments were completed, whereby water amended with a known concentration of selected and stable iron oxide particles was introduced in a full-scale pipe loop laboratory over a short period of time and both turbidity and suspended sediment concentration (SSC) were measured at the inlet and outlet of the pipe loop. Results showed that a selected fraction of the injected particles with sizes above a specific threshold in the range of 4.6 to 6.8 µm had not reached the downstream section of the pipe loop, but instead remained attached to the pipe walls. In addition, exponential decay of the SSC was observed to occur along the pipes and to cause most of the sediments to accumulate in the upstream section of the pipe loop. The research improved our understanding of the physical processes of particulate material accumulation in DWDSs, and it will help water utilities forecast and monitor material accumulation and discolouration potential.
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6
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Climate Change: Water Temperature and Invertebrate Propagation in Drinking-Water Distribution Systems, Effects, and Risk Assessment. WATER 2022. [DOI: 10.3390/w14081246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This paper provides a summary of the knowledge of drinking-water temperature increases and present daily, seasonal, and yearly temperature data of drinking-water distribution systems (DWDS). The increasing water temperatures lead to challenges in DWDS management, and we must assume a promotion of invertebrates as pipe inhabitants. Macro-, meio-, and microinvertebrates were found in nearly all DWDS. Data in relation to diversity and abundance clearly point out a high probability of mass development, and invertebrate monitoring must be the focus of any DWDS management. The water temperature of DWDS is increasing due to climate change effects, and as a consequence, the growth and reproduction of invertebrates is increasing. The seasonal development of a chironomid (Paratanytarus grimmii) and longtime development of water lice (Asellus aquaticus) are given. Due to increased water temperatures, a third generation of water lice per year has been observed, which is one reason for the observed mass development. This leads to an impact on drinking-water quality and an increased health risk, as invertebrates can serve as a host or vehicle for potential harmful microbes. More research is needed especially on (i) water temperature monitoring in drinking-water distribution systems, (ii) invertebrate development, and (iii) health risks.
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7
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Occurrence of P. aeruginosa in Water Intended for Human Consumption and in Swimming Pool Water. ENVIRONMENTS 2021. [DOI: 10.3390/environments8120132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Considering the fact that water is a basic need of every living being, it is important to ensure its safety. In this work, the data on the presence of the opportunistic pathogen P. aeruginosa in drinking water (n = 4171) as well as in pool water (n = 5059) in Primorje-Gorski Kotar County in Croatia in the five-year period (2016–2020) were analysed. In addition, the national criteria were compared with those of neighboring countries and worldwide. The proportion of P. aeruginosa-positive samples was similar for drinking water (3.9%) and pool water (4.6%). The prevalence of this bacterium was most pronounced in the warmer season. P. aeruginosa-positive drinking water samples were mostly collected during building commissioning, while pool samples were from entertainment and spa/hydromassage pools. Outdoor pools showed a higher percentage of positive samples than indoor pools, as well as the pools filled with freshwater rather than seawater. The highest P. aeruginosa load was found in rehabilitation pools. Croatia, Serbia and Montenegro are countries that have included P. aeruginosa in their national regulations as an indicator of the safety of water for human consumption as well as for bottled water, while Slovenia and Bosnia and Herzegovina have limited this requirement to bottled water only. In the case of swimming pool water, this parameter is mandatory in all countries considered in this study.
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8
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Water Lice and Other Macroinvertebrates in Drinking Water Pipes: Diversity, Abundance and Health Risk. WATER 2021. [DOI: 10.3390/w13030276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Activities to ensure and maintain water quality in drinking water networks, including flushing, are presented after standardized hydrant sampling combined with a stainless-steel low pressure–high flow rate (NDHF) filter and a 100 µm mesh size was used to separate pipe inhabitants. A databank of more than 1000 hydrant samples in European lowland areas was developed and used to analyze the diversity and abundance of macroinvertebrates in drinking water networks. Load classes for water louse (Asellus aquaticus) and oligochaetes are given with three evaluation classes: normal colonization, increased colonization, and mass development. The response of Asellus aquaticus in drinking water networks to environmental conditions are presented as are their growth and reproduction, promotion of a third generation by climate change effects, food limitations, and the composition and stability of their feces. Finally, the health risks posed by dead water lice and water lice feces with bacterial regrowth and the promotion of microbe development on house filters are analyzed.
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9
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Vavourakis CD, Heijnen L, Peters MCFM, Marang L, Ketelaars HAM, Hijnen WAM. Spatial and Temporal Dynamics in Attached and Suspended Bacterial Communities in Three Drinking Water Distribution Systems with Variable Biological Stability. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14535-14546. [PMID: 33135888 DOI: 10.1021/acs.est.0c04532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Microbial presence and regrowth in drinking water distribution systems (DWDSs) is routinely monitored to assess the biological stability of drinking water without a residual disinfectant, but the conventional microbiological culture methods currently used target only a very small fraction of the complete DWDS microbiome. Here, we sequenced 16S rRNA gene amplicons to elucidate the attached and suspended prokaryotic community dynamics within three nonchlorinated DWDSs with variable regrowth conditions distributing similarly treated surface water from the same source. One rural location, with less regrowth related issues, differed most strikingly from the other two urban locations by the exclusive presence of Pseudonocardia (Actinobacteria) in the biofilm and the absence of Limnobacter (Betaproteobacteriales) in the water and loose deposits during summer. There was a dominant seasonal effect on the drinking water microbiomes at all three locations. For one urban location, it was established that the most significant changes in the microbial community composition on a spatial scale occurred shortly after freshly treated water entered the DWDS. However, summerly regrowth of Limnobacter, one of the dominant genera in the distributed drinking water, already occurred in the clean water reservoir at the treatment plant before further distribution. The highlighted bacterial lineages within these highly diverse DWDS communities might be important new indicators for undesirable regrowth conditions affecting the final drinking water quality.
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Affiliation(s)
| | - Leo Heijnen
- KWR Watercycle Research Institute, Groningenhaven 7, 3433PE Nieuwegein, The Netherlands
| | | | - Leonie Marang
- Evides Water Company, P.O. Box 4472, 3006 AL, Rotterdam, The Netherlands
| | - Henk A M Ketelaars
- Evides Water Company, P.O. Box 4472, 3006 AL, Rotterdam, The Netherlands
| | - Wim A M Hijnen
- Evides Water Company, P.O. Box 4472, 3006 AL, Rotterdam, The Netherlands
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10
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Liu G, Zhang Y, Liu X, Hammes F, Liu WT, Medema G, Wessels P, van der Meer W. 360-Degree Distribution of Biofilm Quantity and Community in an Operational Unchlorinated Drinking Water Distribution Pipe. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5619-5628. [PMID: 32259432 PMCID: PMC7203839 DOI: 10.1021/acs.est.9b06603] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In the present study, triplicate rings of 360° pipe surfaces of an operational drinking water distribution pipe were swabbed. Each ring was equally divided into 16 parts for swabbing. The collected swabs were grouped into 3 sections and compared with the biofilm samples sampled by sonication of specimens from the same pipe. The results showed that the biofilm is unevenly distributed over the 16 parts and the 3 sections of the pipe surface. Both the active biomass and the number of observed OTUs increased as the measurements proceeded from the top to the bottom of the pipe. The bacterial community was dominated in all sections by Proteobacteria. At the genus level, Nitrospira spp., Terrimonas spp., and Hyphomicrobium spp. were dominant in all sections. Gaiella spp. and Vicinamibacter spp. dominated in S-I, Blastopirellula spp. and Pirellula spp. dominated in S-II, while Holophaga spp. and Phaeodactylibacter spp. dominated in S-III. When swabbing and pipe specimen sonication were compared, the results showed that the sampling strategy significantly influences the obtained biofilm bacterial community. A consistent multisectional swabbing strategy is proposed for future biofilm sampling; it involves collecting swabs from all sections and comparing the swabs from the same position/section across locations.
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Affiliation(s)
- Gang Liu
- Key
Laboratory of Drinking Water Science and Technology, Research Centre
for Eco-Environmental Sciences, Chinese
Academy of Sciences, Beijing, 100085, P. R. China
- Oasen
Drinkwater, P.O. Box
122, 2801SB, Gouda, The Netherlands
- Sanitary
Engineering, Department of Water Management, Faculty of Civil Engineering
and Geosciences, Delft University of Technology, P.O. Box 5048, 2600GA Delft, The Netherlands
- Phone: 0086 17600879707; e-mail: ,
| | - Ya Zhang
- Department
of Civil and Environmental Engineering, University of Illinois at Urbana−Champaign, 205 North Mathews Avenue, Urbana, Illinois 61801, United States
| | - Xinlei Liu
- Catalysis
Engineering, Chemical Engineering Department, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Frederik Hammes
- Eawag,
Swiss
Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Wen-Tso Liu
- Department
of Civil and Environmental Engineering, University of Illinois at Urbana−Champaign, 205 North Mathews Avenue, Urbana, Illinois 61801, United States
| | - Gertjan Medema
- Sanitary
Engineering, Department of Water Management, Faculty of Civil Engineering
and Geosciences, Delft University of Technology, P.O. Box 5048, 2600GA Delft, The Netherlands
- KWR
Watercycle Research Institute, P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands
| | - Peter Wessels
- Oasen
Drinkwater, P.O. Box
122, 2801SB, Gouda, The Netherlands
| | - Walter van der Meer
- Oasen
Drinkwater, P.O. Box
122, 2801SB, Gouda, The Netherlands
- Science
and Technology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
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11
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Chen L, Ling F, Bakker G, Liu WT, Medema G, van der Meer W, Liu G. Assessing the transition effects in a drinking water distribution system caused by changing supply water quality: an indirect approach by characterizing suspended solids. WATER RESEARCH 2020; 168:115159. [PMID: 31614234 DOI: 10.1016/j.watres.2019.115159] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 05/16/2023]
Abstract
Worldwide, it is common that the drinking water distribution systems (DWDSs) may be subjected to changes of supply water quality due to the needs of upgrading the treatment processes or switching the source water. However, the potential impacts of quality changed supply water on the stabilized ecological niches within DWDSs and the associated water quality deterioration risks were poorly documented. In the present study, such transition effects caused by changing the supply water quality that resulted from destabilization of biofilm and loose deposits in DWDS were investigated by analyzing the physiochemical and microbiological characteristics of suspended particles before (T0), during (T3-weeks) and after upgrading the treatments (T6-months) in an unchlorinated DWDS in the Netherlands. Our results demonstrated that after 6 months' time the upgraded treatments significantly improved the water quality. Remarkably, water quality deterioration was observed at the initial stage when the quality-improved treated water distributed into the network at T3-weeks, observed as a spike of total suspended solids (TSS, 50-260%), active biomass (ATP, 95-230%) and inorganic elements (e.g. Mn, 130-250%). Furthermore, pyrosequencing results revealed sharp differences in microbial community composition and structure for the bacteria associated with suspended particles between T0 and T3-weeks, which re-stabilized after 6 months at T6-months. The successful capture of transition effects was especially confirmed by the domination of Nitrospira spp. and Polaromonas spp. in the distribution system at T3-weeks, which were detected at rather low relative abundance at treatment plant. Though the transitional effects were captured, this study shows that the introduction of softening and additional filtration did not have an effect on the water quality for the consumer which improved considerably after 6-months' period. The methodology of monitoring suspended particles with MuPFiSs and additional analysis is capable of detecting transitional effects by monitoring the dynamics of suspended particles and its physiochemical and microbiological composition.
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Affiliation(s)
- Lihua Chen
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600, GA, Delft, the Netherlands
| | - Fangqiong Ling
- Department of Energy, Environmental and Chemical Engineering, School of Engineering and Applied Science, Washington University in St. Louis, St. Louis, Missouri, 63130, USA
| | - Geo Bakker
- Vitens N.V., P.O. Box 1205, 8001, BE, Zwolle, the Netherlands
| | - Wen-Tso Liu
- Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, 205 N. Mathews Ave., Urbana, IL, 61801, USA
| | - Gertjan Medema
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; KWR Watercycle Research Institute, P.O. Box 1072, 3430, BB, Nieuwegein, the Netherlands
| | - Walter van der Meer
- Oasen Water Company, PO BOX 122, 2800, AC, Gouda, the Netherlands; Science and Technology, University of Twente, P.O. Box 217, 7500, AE, Enschede, the Netherlands
| | - Gang Liu
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600, GA, Delft, the Netherlands.
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12
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Ding S, Deng Y, Bond T, Fang C, Cao Z, Chu W. Disinfection byproduct formation during drinking water treatment and distribution: A review of unintended effects of engineering agents and materials. WATER RESEARCH 2019; 160:313-329. [PMID: 31154129 DOI: 10.1016/j.watres.2019.05.024] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 06/09/2023]
Abstract
Unintended effects of engineering agents and materials on the formation of undesirable disinfection byproducts (DBPs) during drinking water treatment and distribution were comprehensively reviewed. Specially, coagulants, biologically active filtration biofilms, activated carbons, nanomaterials, ion-exchange resins, membrane materials in drinking water treatment and piping materials, deposits and biofilms within drinking water distribution systems were discussed, which may serve as DBP precursors, transform DBPs into more toxic species, and/or catalyze the formation of DBPs. Speciation and quantity of DBPs generated rely heavily on the material characteristics, solution chemistry conditions, and operating factors. For example, quaternary ammonium polymer coagulants can increase concentrations of N-nitrosodimethylamine (NDMA) to above the California notification level (10 ng/L). Meanwhile, the application of strong base ion-exchange resins has been associated with the formation of N-nitrosamines and trichloronitromethane up to concentrations of 400 ng/L and 9.0 μg/L, respectively. Organic compounds leaching from membranes and plastic and rubber pipes can generate high NDMA (180-450 ng/L) and chloral hydrate (∼12.4 μg/L) upon downstream disinfection. Activated carbon and membranes preferentially remove organic precursors over bromide, resulting in a higher proportion of brominated DBPs. Copper corrosion products (CCPs) accelerate the decay of disinfectants and increase the formation of halogenated DBPs. Chlorination of high bromide waters containing CCPs can form bromate at concentrations exceeding regulatory limits. Owing to the aforementioned concern for the drinking water quality, the application of these materials and reagents during drinking water treatment and distribution should be based on the removal of pollutants with consideration for balancing DBP formation during disinfection scenarios. Overall, this review highlights situations in which the use of engineering agents and materials in drinking water treatment and distribution needs balance against deleterious impacts on DBP formation.
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Affiliation(s)
- Shunke Ding
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Yang Deng
- Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ, 07043, USA
| | - Tom Bond
- Department of Civil and Environmental Engineering, University of Surrey, Guildford, GU2 7XH, UK
| | - Chao Fang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Zhongqi Cao
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Wenhai Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
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13
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Islam MA, Ehiraj B, Cheng CK, Dubey BN, Khan MMR. Biofilm re-vitalization using hydrodynamic shear stress for stable power generation in microbial fuel cell. J Electroanal Chem (Lausanne) 2019. [DOI: 10.1016/j.jelechem.2019.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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14
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Liu G, Zhang Y, van der Mark E, Magic-Knezev A, Pinto A, van den Bogert B, Liu W, van der Meer W, Medema G. Assessing the origin of bacteria in tap water and distribution system in an unchlorinated drinking water system by SourceTracker using microbial community fingerprints. WATER RESEARCH 2018; 138:86-96. [PMID: 29573632 DOI: 10.1016/j.watres.2018.03.043] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 05/10/2023]
Abstract
The general consensus is that the abundance of tap water bacteria is greatly influenced by water purification and distribution. Those bacteria that are released from biofilm in the distribution system are especially considered as the major potential risk for drinking water bio-safety. For the first time, this full-scale study has captured and identified the proportional contribution of the source water, treated water, and distribution system in shaping the tap water bacterial community based on their microbial community fingerprints using the Bayesian "SourceTracker" method. The bacterial community profiles and diversity analyses illustrated that the water purification process shaped the community of planktonic and suspended particle-associated bacteria in treated water. The bacterial communities associated with suspended particles, loose deposits, and biofilm were similar to each other, while the community of tap water planktonic bacteria varied across different locations in distribution system. The microbial source tracking results showed that there was not a detectable contribution of source water to bacterial community in the tap water and distribution system. The planktonic bacteria in the treated water was the major contributor to planktonic bacteria in the tap water (17.7-54.1%). The particle-associated bacterial community in the treated water seeded the bacterial community associated with loose deposits (24.9-32.7%) and biofilm (37.8-43.8%) in the distribution system. In return, the loose deposits and biofilm showed a significant influence on tap water planktonic and particle-associated bacteria, which were location dependent and influenced by hydraulic changes. This was revealed by the increased contribution of loose deposits to tap water planktonic bacteria (from 2.5% to 38.0%) and an increased contribution of biofilm to tap water particle-associated bacteria (from 5.9% to 19.7%) caused by possible hydraulic disturbance from proximal to distal regions. Therefore, our findings indicate that the tap water bacteria could possibly be managed by selecting and operating the purification process properly and cleaning the distribution system effectively.
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Affiliation(s)
- Gang Liu
- Oasen Water Company, P.O. Box 122, 2800AC, Gouda, The Netherlands; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600GA, Delft, The Netherlands.
| | - Ya Zhang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL, 61801, United States
| | - Ed van der Mark
- Dunea Water Company, P.O. Box 756, 2700 AT, Zoetermeer, The Netherlands
| | | | - Ameet Pinto
- Department of Civil and Environmental Engineering, Northeastern University, Boston, United States
| | | | - Wentso Liu
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL, 61801, United States
| | - Walter van der Meer
- Oasen Water Company, P.O. Box 122, 2800AC, Gouda, The Netherlands; Science and Technology, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands
| | - Gertjan Medema
- Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600GA, Delft, The Netherlands; KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands
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15
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Liu G, Tao Y, Zhang Y, Lut M, Knibbe WJ, van der Wielen P, Liu W, Medema G, van der Meer W. Hotspots for selected metal elements and microbes accumulation and the corresponding water quality deterioration potential in an unchlorinated drinking water distribution system. WATER RESEARCH 2017; 124:435-445. [PMID: 28787681 DOI: 10.1016/j.watres.2017.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/02/2017] [Accepted: 08/02/2017] [Indexed: 05/26/2023]
Abstract
Biofilm formation, loose deposit accumulation and water quality deterioration in drinking water distribution systems have been widely reported. However, the accumulation and distribution of harbored elements and microbes in the different niches (loose deposits, PVC-U biofilm, and HDPE biofilm) and their corresponding potential contribution to water quality deterioration remain unknown. This precludes an in-depth understanding of water quality deterioration and the development of proactive management strategies. The present study quantitatively evaluated the distribution of elements, ATP, Aeromonas spp., and bacterial communities in distribution pipes (PVC-U, D = 110 mm, loose deposit and biofilm niches) and household connection pipes (HDPE, D = 32 mm, HDPE biofilm niches) at ten locations in an unchlorinated distribution system. The results show that loose deposits in PVC-U pipes, acting as sinks, constitute a hotspot (highest total amount per meter pipe) for elements, ATP, and target bacteria groups (e.g., Aeromonas spp., Mycobacterium spp., and Legionella spp.). When drinking water distribution system niches with harbored elements and microbes become sources in the event of disturbances, the highest quality deterioration potential (QDP) is that of HDPE biofilm; this can be attributed to its high surface-to-volume ratio. 16s rRNA analysis demonstrates that, at the genus level, the bacterial communities in the water, loose deposits, PVC-U biofilm, and HDPE biofilm were dominated, respectively, by Polaromonas spp. (2-23%), Nitrosipra spp. (1-47%), Flavobacterium spp. (1-36%), and Flavobacterium spp. (5-67%). The combined results of elemental composition and bacterial community analyses indicate that different dominant bio-chemical processes might occur within the different niches-for example, iron-arsenic oxidizing in loose deposits, bio-calumniation in PVC-U biofilm, and methane oxidizing in HDPE biofilm. The release of 20% loose deposits, 20% PVC-U biofilm and 10% HDPE biofilm will cause significant changes of water bacterial community.
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Affiliation(s)
- Gang Liu
- Oasen Water Company, P.O. Box 122, 2800AC, Gouda, The Netherlands; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600GA, Delft, The Netherlands.
| | - Yu Tao
- Department of Chemical Engineering, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
| | - Ya Zhang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL, 61801, United States
| | - Maarten Lut
- Oasen Water Company, P.O. Box 122, 2800AC, Gouda, The Netherlands
| | | | - Paul van der Wielen
- KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands; Laboratory of Microbiology, Wageningen University, P.O. Box 8033, 6700 EH, Wageningen, The Netherlands
| | - Wentso Liu
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL, 61801, United States
| | - Gertjan Medema
- Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600GA, Delft, The Netherlands; KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands
| | - Walter van der Meer
- Oasen Water Company, P.O. Box 122, 2800AC, Gouda, The Netherlands; Science and Technology, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands
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16
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Liu G, Zhang Y, Knibbe WJ, Feng C, Liu W, Medema G, van der Meer W. Potential impacts of changing supply-water quality on drinking water distribution: A review. WATER RESEARCH 2017; 116:135-148. [PMID: 28329709 DOI: 10.1016/j.watres.2017.03.031] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/17/2017] [Accepted: 03/15/2017] [Indexed: 05/12/2023]
Abstract
Driven by the development of water purification technologies and water quality regulations, the use of better source water and/or upgraded water treatment processes to improve drinking water quality have become common practices worldwide. However, even though these elements lead to improved water quality, the water quality may be impacted during its distribution through piped networks due to the processes such as pipe material release, biofilm formation and detachment, accumulation and resuspension of loose deposits. Irregular changes in supply-water quality may cause physiochemical and microbiological de-stabilization of pipe material, biofilms and loose deposits in the distribution system that have been established over decades and may harbor components that cause health or esthetical issues (brown water). Even though it is clearly relevant to customers' health (e.g., recent Flint water crisis), until now, switching of supply-water quality is done without any systematic evaluation. This article reviews the contaminants that develop in the water distribution system and their characteristics, as well as the possible transition effects during the switching of treated water quality by destabilization and the release of pipe material and contaminants into the water and the subsequent risks. At the end of this article, a framework is proposed for the evaluation of potential transition effects.
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Affiliation(s)
- Gang Liu
- Oasen Drinkwater, PO BOX 122, 2800 AC, Gouda, The Netherlands; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA, Delft, The Netherlands.
| | - Ya Zhang
- Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, 205 N. Mathews Ave., Urbana, IL, 61801, USA
| | | | - Cuijie Feng
- Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA, Delft, The Netherlands
| | - Wentso Liu
- Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, 205 N. Mathews Ave., Urbana, IL, 61801, USA
| | - Gertjan Medema
- Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA, Delft, The Netherlands; KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands
| | - Walter van der Meer
- Oasen Drinkwater, PO BOX 122, 2800 AC, Gouda, The Netherlands; Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
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17
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Zhou X, Zhang K, Zhang T, Li C, Mao X. An ignored and potential source of taste and odor (T&O) issues—biofilms in drinking water distribution system (DWDS). Appl Microbiol Biotechnol 2017; 101:3537-3550. [DOI: 10.1007/s00253-017-8223-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/26/2017] [Accepted: 03/04/2017] [Indexed: 01/10/2023]
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18
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Van Nevel S, Buysschaert B, De Roy K, De Gusseme B, Clement L, Boon N. Flow cytometry for immediate follow-up of drinking water networks after maintenance. WATER RESEARCH 2017; 111:66-73. [PMID: 28043001 DOI: 10.1016/j.watres.2016.12.040] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 12/22/2016] [Accepted: 12/24/2016] [Indexed: 05/16/2023]
Abstract
Drinking water networks need maintenance every once in a while, either planned interventions or emergency repairs. When this involves opening of the water pipes, precautionary measures need to be taken to avoid contamination of the drinking water at all time. Drinking water suppliers routinely apply plating for faecal indicator organisms as quality control in such a situation. However, this takes at least 21 h of waiting time, which can be crucial when dealing with major supply pipes. A combination of flow cytometric (FCM) bacterial cell counts with FCM fingerprinting techniques is proposed in this study as a fast and sensitive additional technique. In three full scale situations, major supply pipes with 400-1050 mm diameter were emptied for maintenance, shock-chlorinated and flushed with large amounts of clean drinking water before taking back in operation. FCM measurements of the discharged flushing water revealed fast lowering and stabilizing bacterial concentrations once flushing is initiated. Immediate comparison with clean reference drinking water used for flushing was done, and the moment when both waters had similar bacterial concentrations was considered as the endpoint of the necessary flushing works. This was usually after 2-4 h of flushing. FCM fingerprinting, based on both bacteria and FCM background, was used as additional method to verify how similar flushing and reference samples were and yielded similar results. The FCM approved samples were several hours later approved as well by the drinking water supplier after plating and incubation for total Coliforms and Enterococci. These were used as decisive control to set the pipes back in operation. FCM proved to be a more conservative test than plating, yet it yielded immediate results. Application of these FCM methods can therefore avoid long unnecessary waiting times and large drinking water losses.
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Affiliation(s)
- Sam Van Nevel
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium
| | - Benjamin Buysschaert
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium
| | - Karen De Roy
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium
| | - Bart De Gusseme
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium; Engineering TMVW (FARYS), Stropstraat 1, B-9000 Gent, Belgium
| | - Lieven Clement
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Krijgslaan 281 S9, B-9000 Gent, Belgium
| | - Nico Boon
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
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19
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Liu S, Gunawan C, Barraud N, Rice SA, Harry EJ, Amal R. Understanding, Monitoring, and Controlling Biofilm Growth in Drinking Water Distribution Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8954-8976. [PMID: 27479445 DOI: 10.1021/acs.est.6b00835] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In drinking water distribution systems (DWDS), biofilms are the predominant mode of microbial growth, with the presence of extracellular polymeric substance (EPS) protecting the biomass from environmental and shear stresses. Biofilm formation poses a significant problem to the drinking water industry as a potential source of bacterial contamination, including pathogens, and, in many cases, also affecting the taste and odor of drinking water and promoting the corrosion of pipes. This article critically reviews important research findings on biofilm growth in DWDS, examining the factors affecting their formation and characteristics as well as the various technologies to characterize and monitor and, ultimately, to control their growth. Research indicates that temperature fluctuations potentially affect not only the initial bacteria-to-surface attachment but also the growth rates of biofilms. For the latter, the effect is unique for each type of biofilm-forming bacteria; ammonia-oxidizing bacteria, for example, grow more-developed biofilms at a typical summer temperature of 22 °C compared to 12 °C in fall, and the opposite occurs for the pathogenic Vibrio cholerae. Recent investigations have found the formation of thinner yet denser biofilms under high and turbulent flow regimes of drinking water, in comparison to the more porous and loosely attached biofilms at low flow rates. Furthermore, in addition to the rather well-known tendency of significant biofilm growth on corrosion-prone metal pipes, research efforts also found leaching of growth-promoting organic compounds from the increasingly popular use of polymer-based pipes. Knowledge of the unique microbial members of drinking water biofilms and, importantly, the influence of water characteristics and operational conditions on their growth can be applied to optimize various operational parameters to minimize biofilm accumulation. More-detailed characterizations of the biofilm population size and structure are now feasible with fluorescence microscopy (epifluorescence and CLSM imaging with DNA, RNA, EPS, and protein and lipid stains) and electron microscopy imaging (ESEM). Importantly, thorough identification of microbial fingerprints in drinking water biofilms is achievable with DNA sequencing techniques (the 16S rRNA gene-based identification), which have revealed a prevalence of previously undetected bacterial members. Technologies are now moving toward in situ monitoring of biomass growth in distribution networks, including the development of optical fibers capable of differentiating biomass from chemical deposits. Taken together, management of biofilm growth in water distribution systems requires an integrated approach, starting from the treatment of water prior to entering the networks to the potential implementation of "biofilm-limiting" operational conditions and, finally, ending with the careful selection of available technologies for biofilm monitoring and control. For the latter, conventional practices, including chlorine-chloramine disinfection, flushing of DWDS, nutrient removal, and emerging technologies are discussed with their associated challenges.
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Affiliation(s)
| | - Cindy Gunawan
- ithree institute, University of Technology Sydney , Sydney, NSW 2007, Australia
| | - Nicolas Barraud
- Department of Microbiology, Genetics of Biofilms Unit, Institut Pasteur , Paris 75015, France
| | - Scott A Rice
- The Singapore Centre for Environmental Life Sciences Engineering and School of Biological Sciences, Nanyang Technological University , 639798, Singapore
| | - Elizabeth J Harry
- ithree institute, University of Technology Sydney , Sydney, NSW 2007, Australia
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20
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Comparison of Particle-Associated Bacteria from a Drinking Water Treatment Plant and Distribution Reservoirs with Different Water Sources. Sci Rep 2016; 6:20367. [PMID: 26832989 PMCID: PMC4735813 DOI: 10.1038/srep20367] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 12/31/2015] [Indexed: 11/08/2022] Open
Abstract
This study assessed the characteristics of and changes in the suspended particles and the associated bacteria in an unchlorinated drinking water distribution system and its reservoirs with different water sources. The results show that particle-associated bacteria (PAB) were present at a level of 0.8-4.5 × 10(3) cells ml(-1) with a biological activity of 0.01-0.04 ng l(-1) ATP. Different PAB communities in the waters produced from different sources were revealed by a 16S rRNA-based pyrosequencing analysis. The quantified biomass underestimation due to the multiple cells attached per particle was ≥ 85%. The distribution of the biologically stable water increased the number of cells per particle (from 48 to 90) but had minor effects on the PAB community. Significant changes were observed at the mixing reservoir. Our results show the characteristics of and changes in suspended PAB during distribution, and highlight the significance of suspended PAB in the distribution system, because suspended PAB can lead to a considerable underestimation of biomass, and because they exist as biofilm, which has a greater mobility than pipe-wall biofilm and therefore presents a greater risk, given the higher probability that it will reach the customers' taps and be ingested.
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21
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Kumpel E, Nelson KL. Intermittent Water Supply: Prevalence, Practice, and Microbial Water Quality. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:542-553. [PMID: 26670120 DOI: 10.1021/acs.est.5b03973] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Intermittent water supplies (IWS), in which water is provided through pipes for only limited durations, serve at least 300 million people around the world. However, providing water intermittently can compromise water quality in the distribution system. In IWS systems, the pipes do not supply water for periods of time, supply periods are shortened, and pipes experience regular flow restarting and draining. These unique behaviors affect distribution system water quality in ways that are different than during normal operations in continuous water supplies (CWS). A better understanding of the influence of IWS on mechanisms causing contamination can help lead to incremental steps that protect water quality and minimize health risks. This review examines the status and nature of IWS practices throughout the world, the evidence of the effect of IWS on water quality, and how the typical contexts in which IWS systems often exist-low-income countries with under-resourced utilities and inadequate sanitation infrastructure-can exacerbate mechanisms causing contamination. We then highlight knowledge gaps for further research to improve our understanding of water quality in IWS.
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Affiliation(s)
- Emily Kumpel
- Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States
- The Aquaya Institute, Nairobi, Kenya
| | - Kara L Nelson
- Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States
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22
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van der Kooij D, Martijn B, Schaap PG, Hoogenboezem W, Veenendaal HR, van der Wielen PWJJ. Improved biostability assessment of drinking water with a suite of test methods at a water supply treating eutrophic lake water. WATER RESEARCH 2015; 87:347-355. [PMID: 26451977 DOI: 10.1016/j.watres.2015.09.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 09/24/2015] [Accepted: 09/25/2015] [Indexed: 06/05/2023]
Abstract
Assessment of drinking-water biostability is generally based on measuring bacterial growth in short-term batch tests. However, microbial growth in the distribution system is affected by multiple interactions between water, biofilms and sediments. Therefore a diversity of test methods was applied to characterize the biostability of drinking water distributed without disinfectant residual at a surface-water supply. This drinking water complied with the standards for the heterotrophic plate count and coliforms, but aeromonads periodically exceeded the regulatory limit (1000 CFU 100 mL(-1)). Compounds promoting growth of the biopolymer-utilizing Flavobacterium johnsoniae strain A3 accounted for c. 21% of the easily assimilable organic carbon (AOC) concentration (17 ± 2 μg C L(-1)) determined by growth of pure cultures in the water after granular activated-carbon filtration (GACF). Growth of the indigenous bacteria measured as adenosine tri-phosphate in water samples incubated at 25 °C confirmed the low AOC in the GACF but revealed the presence of compounds promoting growth after more than one week of incubation. Furthermore, the concentration of particulate organic carbon in the GACF (83 ± 42 μg C L(-1), including 65% carbohydrates) exceeded the AOC concentration. The increased biomass accumulation rate in the continuous biofouling monitor (CBM) at the distribution system reservoir demonstrated the presence of easily biodegradable by-products related to ClO2 dosage to the GACF and in the CBM at 42 km from the treatment plant an iron-associated biomass accumulation was observed. The various methods applied thus distinguished between easily assimilable compounds, biopolymers, slowly biodegradable compounds and biomass-accumulation potential, providing an improved assessment of the biostability of the water. Regrowth of aeromonads may be related to biomass-turnover processes in the distribution system, but establishment of quantitative relationships is needed for confirmation.
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Affiliation(s)
- Dick van der Kooij
- KWR Watercycle Research Institute, Post Box 1072, 3430 BB Nieuwegein, The Netherlands.
| | - Bram Martijn
- PWN Technologies, PO Box 2046, 1990 AA Velserbroek, The Netherlands.
| | - Peter G Schaap
- Water Supply Company Noord-Holland PWN, Rijksweg 501, Velserbroek, The Netherlands.
| | - Wim Hoogenboezem
- Het Waterlaboratorium, J.W. Lucasweg 2, 2031 BE Haarlem, The Netherlands.
| | - Harm R Veenendaal
- KWR Watercycle Research Institute, Post Box 1072, 3430 BB Nieuwegein, The Netherlands
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23
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Pérez CA, Moncho-Jordá A, Hidalgo-Álvarez R, Casanova H. A comparative study on the effect of hydrodynamic interactions in the non-sequential deposition of concentrated colloidal dispersions: stochastic rotation dynamics and Brownian dynamics simulations. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1042084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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Tong H, Zhao P, Zhang H, Tian Y, Chen X, Zhao W, Li M. Identification and characterization of steady and occluded water in drinking water distribution systems. CHEMOSPHERE 2015; 119:1141-1147. [PMID: 25460754 DOI: 10.1016/j.chemosphere.2014.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/28/2014] [Accepted: 10/04/2014] [Indexed: 06/04/2023]
Abstract
Deterioration and leakage of drinking water in distribution systems have been a major issue in the water industry for years, which are associated with corrosion. This paper discovers that occluded water in the scales of the pipes has an acidic environment and high concentration of iron, manganese, chloride, sulfate and nitrate, which aggravates many pipeline leakage accidents. Six types of water samples have been analyzed under the flowing and stagnant periods. Both the water in the exterior of the tubercles and stagnant water carry suspended iron particles, which explains the occurrence of "red water" when the system hydraulic conditions change. Nitrate is more concentrated in occluded water under flowing condition in comparison with that in flowing water. However, the concentration of nitrate in occluded water under stagnant condition is found to be less than that in stagnant water. A high concentration of manganese is found to exist in steady water, occluded water and stagnant water. These findings impact secondary pollution and the corrosion of pipes and containers used in drinking water distribution systems. The unique method that taking occluded water from tiny holes which were drilled from the pipes' exteriors carefully according to the positions of corrosion scales has an important contribution to research on corrosion in distribution systems. And this paper furthers our understanding and contributes to the growing body of knowledge regarding occluded environments in corrosion scales.
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Affiliation(s)
- Huiyan Tong
- Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Peng Zhao
- Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
| | - Hongwei Zhang
- Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Yimei Tian
- Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Xi Chen
- Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Weigao Zhao
- Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Mei Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China.
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25
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Prest EI, El-Chakhtoura J, Hammes F, Saikaly PE, van Loosdrecht MCM, Vrouwenvelder JS. Combining flow cytometry and 16S rRNA gene pyrosequencing: a promising approach for drinking water monitoring and characterization. WATER RESEARCH 2014; 63:179-189. [PMID: 25000200 DOI: 10.1016/j.watres.2014.06.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 06/13/2014] [Accepted: 06/14/2014] [Indexed: 06/03/2023]
Abstract
The combination of flow cytometry (FCM) and 16S rRNA gene pyrosequencing data was investigated for the purpose of monitoring and characterizing microbial changes in drinking water distribution systems. High frequency sampling (5 min intervals for 1 h) was performed at the outlet of a treatment plant and at one location in the full-scale distribution network. In total, 52 bulk water samples were analysed with FCM, pyrosequencing and conventional methods (adenosine-triphosphate, ATP; heterotrophic plate count, HPC). FCM and pyrosequencing results individually showed that changes in the microbial community occurred in the water distribution system, which was not detected with conventional monitoring. FCM data showed an increase in the total bacterial cell concentrations (from 345 ± 15 × 10(3) to 425 ± 35 × 10(3) cells mL(-1)) and in the percentage of intact bacterial cells (from 39 ± 3.5% to 53 ± 4.4%) during water distribution. This shift was also observed in the FCM fluorescence fingerprints, which are characteristic of each water sample. A similar shift was detected in the microbial community composition as characterized with pyrosequencing, showing that FCM and genetic fingerprints are congruent. FCM and pyrosequencing data were subsequently combined for the calculation of cell concentration changes for each bacterial phylum. The results revealed an increase in cell concentrations of specific bacterial phyla (e.g., Proteobacteria), along with a decrease in other phyla (e.g., Actinobacteria), which could not be concluded from the two methods individually. The combination of FCM and pyrosequencing methods is a promising approach for future drinking water quality monitoring and for advanced studies on drinking water distribution pipeline ecology.
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Affiliation(s)
- E I Prest
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
| | - J El-Chakhtoura
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands; Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - F Hammes
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, CH-8600 Dübendorf, Switzerland
| | - P E Saikaly
- Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - M C M van Loosdrecht
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - J S Vrouwenvelder
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands; Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Wetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands
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Fabbricino M, Korshin GV. Changes of the corrosion potential of iron in stagnation and flow conditions and their relationship with metal release. WATER RESEARCH 2014; 62:136-146. [PMID: 24950460 DOI: 10.1016/j.watres.2014.05.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/25/2014] [Accepted: 05/29/2014] [Indexed: 06/03/2023]
Abstract
This study examined the behavior of corrosion potential (Ecorr) of iron exposed to drinking water during episodes of stagnation and flow. These measurements showed that during stagnation episodes, Ecorr values decrease prominently and consistently. This decrease is initially rapid but it becomes slower as the stagnation time increases. During flow episodes, the Ecorr values increase and reach a quasi-steady state. Experiments with varying concentrations of dissolved oxygen showed that the decrease of Ecorr values characteristic for stagnation is likely to be associated with the consumption of dissolved oxygen by the exposed metal. The corrosion potential of iron and its changes during stagnation were sensitive to the concentrations of sulfate and chloride ions. Measurements of iron release showed that both the absolute values of Ecorr measured prior to or after stagnation episodes were well correlated with the logarithms of concentrations of total iron. The slope of this dependence showed that the observed correlations between Ecorr values and Fe concentrations corresponded to the coupling between the oxidant consumption and changes of Fe redox status. These results demonstrate that in situ Ecorr measurements can be a sensitive method with which to ascertain effects of hydrodynamic conditions and short-term variations of water chemistry on metal release and corrosion in drinking water. This approach is valuable practically because Ecorr measurements are precise, can be carried out in situ with any desired time resolution, do not affect the state of exposed surface in any extent and can be carried out with readily available equipment.
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Affiliation(s)
- Massimiliano Fabbricino
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples, Italy.
| | - Gregory V Korshin
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195-2700, United States.
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27
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Liu G, Bakker GL, Li S, Vreeburg JHG, Verberk JQJC, Medema GJ, Liu WT, Van Dijk JC. Pyrosequencing reveals bacterial communities in unchlorinated drinking water distribution system: an integral study of bulk water, suspended solids, loose deposits, and pipe wall biofilm. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:5467-76. [PMID: 24766451 DOI: 10.1021/es5009467] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The current understanding of drinking water distribution system (DWDS) microbiology is limited to pipe wall biofilm and bulk water; the contributions of particle-associated bacteria (from suspended solids and loose deposits) have long been neglected. Analyzing the composition and correlation of bacterial communities from different phases helped us to locate where most of the bacteria are and understand the interactions among these phases. In the present study, the bacteria from four critical phases of an unchlorinated DWDS, including bulk water, pipe wall biofilm, suspended solids, and loose deposits, were quantified and identified by adenosine triphosphate analysis and pyrosequencing, respectively. The results showed that the bulk water bacteria (including the contribution of suspended solids) contributed less than 2% of the total bacteria. The bacteria associated with loose deposits and pipe wall biofilm that accumulated in the DWDS accounted for over 98% of the total bacteria, and the contributions of bacteria in loose deposits and pipe wall biofilm were comparable. Depending on the amount of loose deposits, its contribution can be 7-fold higher than the pipe wall biofilm. Pyrosequencing revealed relatively stable bacterial communities in bulk water, pipe wall biofilm, and suspended solids throughout the distribution system; however, the communities present in loose deposits were dependent on the amount of loose deposits locally. Bacteria within the phases of suspended solids, loose deposits, and pipe wall biofilm were similar in phylogenetic composition. The bulk water bacteria (dominated by Polaromonas spp.) were clearly different from the bacteria from the other three phases (dominated by Sphingomonas spp.). This study highlighted that the integral DWDS ecology should include contributions from all of the four phases, especially the bacteria harbored by loose deposits. The accumulation of loose deposits and the aging process create variable microenvironments inside loose deposits structures for bacteria to grow. Moreover, loose deposits protect the associated bacteria from disinfectants, and due to their mobility, the associated bacteria reach taps easily.
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Affiliation(s)
- G Liu
- Section Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology , P.O. Box 5048, 2600 GA Delft, The Netherlands
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28
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Kumpel E, Nelson KL. Mechanisms affecting water quality in an intermittent piped water supply. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2766-2775. [PMID: 24459990 DOI: 10.1021/es405054u] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Drinking water distribution systems throughout the world supply water intermittently, leaving pipes without pressure between supply cycles. Understanding the multiple mechanisms that affect contamination in these intermittent water supplies (IWS) can be used to develop strategies to improve water quality. To study these effects, we tested water quality in an IWS system with infrequent and short water delivery periods in Hubli-Dharwad, India. We continuously measured pressure and physicochemical parameters and periodically collected grab samples to test for total coliform and E. coli throughout supply cycles at 11 sites. When the supply was first turned on, water with elevated turbidity and high concentrations of indicator bacteria was flushed out of pipes. At low pressures (<10 psi), elevated indicator bacteria were frequently detected even when there was a chlorine residual, suggesting persistent contamination had occurred through intrusion or backflow. At pressures between 10 and 17 psi, evidence of periodic contamination suggested that transient intrusion, backflow, release of particulates, or sloughing of biofilms from pipe walls had occurred. Few total coliform and no E. coli were detected when water was delivered with a chlorine residual and at pressures >17 psi.
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Affiliation(s)
- Emily Kumpel
- Civil and Environmental Engineering, University of California , Berkeley
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29
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Lu P, Zhang X, Zhang C, Niu Z, Xie S, Chen C. Biostability in distribution systems in one city in southern China: characteristics, modeling and control strategy. J Environ Sci (China) 2014; 26:323-331. [PMID: 25076523 DOI: 10.1016/s1001-0742(13)60422-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study investigated the bacterial regrowth in drinking water distribution systems receiving finished water from an advanced drinking water treatment plant in one city in southern China. Thirteen nodes in two water supply zones with different aged pipelines were selected to monitor water temperature, dissolved oxygen (DO), chloramine residual, assimilable organic carbon (AOC), and heterotrophic plate counts (HPC). Regression and principal component analyses indicated that HPC had a strong correlation with chloramine residual. Based on Chick-Watson's Law and the Monod equation, biostability curves under different conditions were developed to achieve the goal of HPC < or = 100 CFU/mL. The biostability curves could interpret the scenario under various AOC concentrations and predict the required chloramine residual concentration under the condition of high AOC level. The simulation was also carried out to predict the scenario with a stricter HPC goal (< or = 50 CFU/mL) and determine the required chloramine residual. The biological regrowth control strategy was assessed using biostability curve analysis. The results indicated that maintaining high chloramine residual concentration was the most practical way to achieve the goal of HPC < or = 100 CFU/mL. Biostability curves could be a very useful tool for biostability control in distribution systems. This work could provide some new insights towards biostability control in real distribution systems.
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30
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Liu G, Verberk JQJC, Van Dijk JC. Bacteriology of drinking water distribution systems: an integral and multidimensional review. Appl Microbiol Biotechnol 2013; 97:9265-76. [DOI: 10.1007/s00253-013-5217-y] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/25/2013] [Accepted: 08/26/2013] [Indexed: 11/27/2022]
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Kumpel E, Nelson KL. Comparing microbial water quality in an intermittent and continuous piped water supply. WATER RESEARCH 2013; 47:5176-88. [PMID: 23866140 DOI: 10.1016/j.watres.2013.05.058] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/30/2013] [Accepted: 05/31/2013] [Indexed: 05/20/2023]
Abstract
Supplying piped water intermittently is a common practice throughout the world that increases the risk of microbial contamination through multiple mechanisms. Converting an intermittent supply to a continuous supply has the potential to improve the quality of water delivered to consumers. To understand the effects of this upgrade on water quality, we tested samples from reservoirs, consumer taps, and drinking water provided by households (e.g. from storage containers) from an intermittent and continuous supply in Hubli-Dharwad, India, over one year. Water samples were tested for total coliform, Escherichia coli, turbidity, free chlorine, and combined chlorine. While water quality was similar at service reservoirs supplying the continuous and intermittent sections of the network, indicator bacteria were detected more frequently and at higher concentrations in samples from taps supplied intermittently compared to those supplied continuously (p < 0.01). Detection of E. coli was rare in continuous supply, with 0.7% of tap samples positive compared to 31.7% of intermittent water supply tap samples positive for E. coli. In samples from both continuously and intermittently supplied taps, higher concentrations of total coliform were measured after rainfall events. While source water quality declined slightly during the rainy season, only tap water from intermittent supply had significantly more indicator bacteria throughout the rainy season compared to the dry season. Drinking water samples provided by households in both continuous and intermittent supplies had higher concentrations of indicator bacteria than samples collected directly from taps. Most households with continuous supply continued to store water for drinking, resulting in re-contamination, which may reduce the benefits to water quality of converting to continuous supply.
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Affiliation(s)
- Emily Kumpel
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720-1710, USA
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32
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Chen L, Jia RB, Li L. Bacterial community of iron tubercles from a drinking water distribution system and its occurrence in stagnant tap water. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2013; 15:1332-1340. [PMID: 23702591 DOI: 10.1039/c3em00171g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Bacteria in drinking water distribution systems can cause deterioration of the water quality, and the microbial quality of tap water is closely related to consumer health. In the present study, the potential effects of bacteria attached to cast iron pipes on tap water in a distribution system were investigated. Comparison of the bacterial community composition of pipe tubercles with that of stagnant tap water samples based on a denaturing gradient gel electrophoresis analysis of the 16S rRNA gene revealed that the communities were related. Specifically, the main bacterial members were identical to each other. The bacterial community was found to be dominated by Firmicutes, Actinobacteria, and Proteobacteria, which included Rhizobium, Pseudomonas, Lactococcus, Brevundimonas, Rheinheimera, Arthrobacter, Bacillus, and Herbaspirillum. Heterotrophic bacteria proliferation was observed during the period of stagnation, followed by a decrease of assimilable organic carbon and a slight increase of microbially available phosphorus. These findings indicated that the regrowth of bacteria might be boosted by the release of nutrients such as phosphorus from the pipe walls, as well as the decline of residual chlorine during stagnation. Inorganic contaminants at low levels, including Al, Mn, Zn, Pb, Cr, Cu, and Ni, were detected in tubercles and were concentrated in particulates from tap water following the release of iron during stagnation.
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Affiliation(s)
- Lu Chen
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, China
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33
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Liu G, Lut MC, Verberk JQJC, Van Dijk JC. A comparison of additional treatment processes to limit particle accumulation and microbial growth during drinking water distribution. WATER RESEARCH 2013; 47:2719-2728. [PMID: 23510692 DOI: 10.1016/j.watres.2013.02.035] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 01/24/2013] [Accepted: 02/10/2013] [Indexed: 06/01/2023]
Abstract
Water quality changes, particle accumulation and microbial growth occurring in pilot-scale water distribution systems fed with normally treated and additional treated groundwater were monitored over a period of almost one year. The treatment processes were ranked in the following order: nanofiltration (NF) > (better than) ultrafiltration (UF) > ion exchange (IEX) for limiting particle accumulation. A different order was found for limiting overall microbial growth: NF > IEX > UF. There were strong correlations between particle load and particle accumulation, and between nutrient load and microbial growth. It was concluded that particle accumulation can be controlled by reducing the particle load in water treatment plants; and the microbial growth can be better controlled by limiting organic nutrients rather than removing biomass in water treatment plants. The major focus of this study was on microbial growth. The results demonstrated that growth occurred in all types of treated water, including the phases of bulk water, biofilm and loose deposits. Considering the growth in different phases, similar growth in bulk water was observed for all treatments; NF strongly reduced growth both in loose deposits and in biofilm; UF promoted growth in biofilm, while strongly limiting growth in loose deposits. IEX had good efficiency in between UF and NF, limiting both growths in loose deposits and in biofilm. Significant growth was found in loose deposits, suggesting that loose deposit biomass should be taken into account for growth evaluation and/or prediction. Strong correlations were found between microbial growth and pressure drop in a membrane fouling simulator which proved that a membrane fouling simulator can be a fast growth predictor (within a week). Different results obtained by adenosine triphosphate and flow cytometry cell counts revealed that ATP can accurately describe both suspended and particle-associated biomass, and flow cytometry files of TCC measurements needs to be further processed for particle loaded samples and/or a pretreatment protocol should be developed.
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Affiliation(s)
- G Liu
- Section Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The Netherlands.
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34
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Khadse GK, Kalita MD, Labhsetwar PK. Change in drinking water quality from source to point-of-use and storage: a case study from Guwahati, India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2012; 184:5343-5361. [PMID: 22037861 DOI: 10.1007/s10661-011-2344-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 08/30/2011] [Indexed: 05/31/2023]
Abstract
To ascertain the quality of drinking water being supplied and maintained at Guwahati, the study was conducted on the status of water supply in city through surveillance of drinking water quality for consecutive 7 days at various treatment stages, distribution network and consumer ends. The performance of five water treatment plants (WTPs), viz. Panbazar WTP, Satpukhuri WTP, Kamakhya WTP, PHED WTP and Hegrabari WTP were assessed for summer, piost-post-monsoon and winter seasons. No significant change in raw water quality was observed on day-to-day basis. Residual chlorine was found in the range of nil to 0.2 mg/L in the treated water. During post-monsoon, winter, and summer seasons the thermotolerent TC and FC counts ranged between Nil to 168 CFU/100 ml and Nil to 84 CFU/100 ml; Nil to 3356 CFU/100 ml and Nil to 152 CFU/100 ml; and Nil to 960 CFU/100 ml and Nil to 108 CFU/100 ml respectively. There was variation in bacterial counts among the different service reservoirs and consumer ends, which may be attributed to the general management practices for maintenance of service reservoirs and the possibility of enroute contamination. Evaluation of the raw water quality indicate that the water is suitable for drinking after conventional treatment followed by disinfection. The finished water quality meets the level of standards described as per Bureau of Indian Standard specifications (BIS:10500 1991) for potability in terms of its physico-chemical characteristics.
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Affiliation(s)
- Gajanan Kisan Khadse
- National Environmental Engineering Research Institute, Nehru Marg, Nagpur, India.
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35
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Proulx F, Rodriguez MJ, Sérodes JB, Bouchard C. Spatio-temporal variability of tastes and odors of drinking water within a distribution system. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2012; 105:12-20. [PMID: 22513044 DOI: 10.1016/j.jenvman.2012.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 02/08/2012] [Accepted: 03/02/2012] [Indexed: 05/31/2023]
Abstract
The threshold of human perception in the detection of tastes and odors (T&O) relating to compounds in drinking water is variable. For example, chlorine can be detected at the ppm level and geosmin can be perceived at the ppt level. In this paper, sensory tests (using a human panel), physicochemical analyses (total and free residual chlorine, temperature, metals, geosmin, and 2-methylisoborneol (2MIB)) and microbiological analyses (algae, Actinomycetes and heterotrophic plate count) were performed for water samples collected during a seventeen-month period at ten different locations of a municipal distribution network of Quebec City (Canada). The results showed that different flavors(1) assessed by a panel and aggregated into global flavor intensity (GFI) vary considerably spatially and seasonally. Multiple regression analysis showed that the factors best explaining the variability of GFI are (in order) the season, the location, the concentration of total residual chlorine and the presence of cyanobacteria. Results also demonstrate that chlorine has a masking effect on other T&O.
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Affiliation(s)
- Francois Proulx
- Environmental Department, Municipality of Quebec, Quebec City, QC, Canada.
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36
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Pérez CA, Moncho-Jordá A, Hidalgo-Álvarez R, Casanova H. Brownian dynamics simulation of monolayer formation by deposition of colloidal particles: a kinetic study at high bulk particle concentration. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2012; 35:69. [PMID: 22864541 DOI: 10.1140/epje/i2012-12069-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/30/2012] [Accepted: 07/10/2012] [Indexed: 06/01/2023]
Abstract
Brownian dynamics simulations (BDS) of sedimentation and irreversible adsorption of colloidal particles on a planar surface were carried out at bulk particle volume fractions (φ) in the range 0.05 to 0.25. The sedimentation and adsorption of colloidal particles were simulated as a non-sequential process that allows simultaneous settling and adsorption of particles. A kinetic model for the formation of particle monolayers based on the available surface fraction (θ(A)) is proposed to predict simulation results. The simulations show a value of 0.625 for the maximum fractional surface coverage (θ(∞)) and a monolayer structure insensitive to φ. However, the kinetic order of the monolayer formation process has a strong dependence with φ, changing from a value close to a unit, at low φ, to a value around two at high φ. This change in the kinetic reaction order is associated to differences of particle adsorption mechanism on the surface. At low φ values, the monolayer formation is achieved by independent adsorption of single particles and the reaction order is close to 1. At high φ values, the simultaneous adsorption of two particles on the surface leads to an increase of the reaction order to values close to 2.
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Affiliation(s)
- C A Pérez
- Colloids Group, Institute of Chemistry, University of Antioquia, Medellin, Colombia
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37
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Khadse GK, Kalita M, Pimpalkar SN, Labhsetwar PK. Drinking water quality monitoring and surveillance for safe water supply in Gangtok, India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2011; 178:401-414. [PMID: 20859681 DOI: 10.1007/s10661-010-1699-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 08/25/2010] [Indexed: 05/29/2023]
Abstract
To ascertain the quality of drinking water being supplied, water quality monitoring and surveillance was conducted in Gangtok city at various treatment stages, service reservoirs, distribution network, public standposts, and households. No significant change in raw water quality was observed on day-to-day basis. Residual chlorine was found in the range of nil to 0.2 mg/l in the sump water/finished water. Throughout the year (i.e., during summer, winter, and monsoon seasons), the total coliform and fecal coliform counts were ranged from nil to 7 CFU/100 ml and nil to 3 CFU/100 ml, respectively, in sump water of Selep and VIP complex water treatment plant; however, at consumer end, those were observed as nil to 210 CFU/100 ml and nil to 90 CFU/100 ml, respectively. These variations in bacterial counts among the different service reservoirs and consumer ends may be attributed to the general management practices for maintenance of service reservoirs and the possibility of enroute contamination. Evaluation of the raw water quality indicates that the water is suitable for drinking after conventional treatment followed by disinfection. The finished water quality meets the level of standards described as per Bureau of Indian Standard specifications (BIS:10500 1991) for potability in terms of its physicochemical characteristics.
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Affiliation(s)
- Gajanan K Khadse
- National Environmental Engineering, Research Institute, Nehru Marg, Nagpur 440020, India.
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38
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Culture-independent techniques applied to food industry water surveillance — A case study. Int J Food Microbiol 2010; 141 Suppl 1:S147-55. [DOI: 10.1016/j.ijfoodmicro.2010.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 01/22/2010] [Accepted: 03/07/2010] [Indexed: 11/24/2022]
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39
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Poitelon JB, Joyeux M, Welté B, Duguet JP, Prestel E, DuBow MS. Variations of bacterial 16S rDNA phylotypes prior to and after chlorination for drinking water production from two surface water treatment plants. J Ind Microbiol Biotechnol 2009; 37:117-28. [DOI: 10.1007/s10295-009-0653-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 10/20/2009] [Indexed: 01/07/2023]
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40
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Hashmi I, Farooq S, Qaiser S. Chlorination and water quality monitoring within a public drinking water supply in Rawalpindi Cantt (Westridge and Tench) area, Pakistan. ENVIRONMENTAL MONITORING AND ASSESSMENT 2009; 158:393-403. [PMID: 18972214 DOI: 10.1007/s10661-008-0592-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 09/29/2008] [Indexed: 05/27/2023]
Abstract
Concern over the presence of fecal coliform in public drinking water supplies has been expressed in recent years in Pakistan since it has been regarded as pathogenic organism of prime importance in gastroenteritis. Two major drinking water distribution systems in the Cantt area of Rawalpindi district covering the Westridge and Tench areas was monitored over a 2-month period to determine the prevalence of fecal coliform and chlorine residual. The collected samples were examined for total chlorine, free chlorine residual, chloramines, total coliforms, fecal coliforms, and turbidity. The drinking water quality monitoring in the distribution network was performed by collecting samples from water source, overhead reservoir, and residential taps. In the Westridge area, total chlorine varied from the lowest value of 0.27 mg/L at Station # W-5 to the highest value of 0.42 mg/L at Station # W-2, total coliforms varied from 1.1 to 3.6 most probable number (MPN)/100 mL with presence of Escherichia coli in all samples, total dissolved solids (TDS) ranged from 199.5 to 205 mg/L, conductivity fluctuated between 399 and 411 microS/cm, and turbidity varied from 0.43 to 0.73 NTU. In the Tench area, the value of total chlorine ranged from 0.14 mg/L at Station # T-7 to 0.55 mg/L at Station # T-1. Total coliform varied from 3.6 to 5.1 MPN/100 mL and fecal coliform were detected at all the stations except at Station # T-1. TDS ranged from 201.4 to 257 mg/L, conductivity varied from 343 to 513 microS/cm, and turbidity ranged between 0.66 and 1.55 NTU. It is recommended to the respective agencies to ensure that the chlorine residual is available at consumer end.
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Affiliation(s)
- Imran Hashmi
- Institute of Environmental Sciences and Engineering, National University of Sciences and Technology, Tamiz-Ud-Din Road, Rawalpindi, Pakistan.
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41
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Poitelon JB, Joyeux M, Welté B, Duguet JP, Prestel E, Lespinet O, DuBow MS. Assessment of phylogenetic diversity of bacterial microflora in drinking water using serial analysis of ribosomal sequence tags. WATER RESEARCH 2009; 43:4197-4206. [PMID: 19665751 DOI: 10.1016/j.watres.2009.07.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 05/15/2009] [Accepted: 07/02/2009] [Indexed: 05/28/2023]
Abstract
We examined chlorinated drinking water samples from three different surface water treatment plants for bacterial 16S rDNA diversity using the serial analysis of V6 ribosomal sequence tag (SARST-V6) method. A considerable degree of diversity was observed in each sample, with an estimated richness ranging from 173 to 333 phylotypes. The community structure shows that there are differences in bacterial evenness between sampled sites. The taxonomic composition of the microbial communities was found to be dominated by members of the Proteobacteria (57.2-77.4%), broadly distributed among the classes Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Additionally, a large proportion of sequences (6.3-36.5%) were found to be distantly related to database sequences of unknown phylogenetic affiliation. Given the apparent significance of this bacterial group in drinking water, a 16S rDNA analysis was performed and confirmed their presence and phylogeny. Notwithstanding the potential under-representation of certain bacterial phyla using the SARST-V6 primer pairs, as revealed by a refined computer algorithm, our results suggest that 16S rDNA corresponding to a variety of eubacterial groups can be detected in finished drinking water, suggesting that this water may contain a higher level of bacterial diversity than previously observed.
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Mustonen SM, Tissari S, Huikko L, Kolehmainen M, Lehtola MJ, Hirvonen A. Evaluating online data of water quality changes in a pilot drinking water distribution system with multivariate data exploration methods. WATER RESEARCH 2008; 42:2421-2430. [PMID: 18295299 DOI: 10.1016/j.watres.2008.01.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 11/25/2007] [Accepted: 01/17/2008] [Indexed: 05/25/2023]
Abstract
The distribution of drinking water generates soft deposits and biofilms in the pipelines of distribution systems. Disturbances in water distribution can detach these deposits and biofilms and thus deteriorate the water quality. We studied the effects of simulated pressure shocks on the water quality with online analysers. The study was conducted with copper and composite plastic pipelines in a pilot distribution system. The online data gathered during the study was evaluated with Self-Organising Map (SOM) and Sammon's mapping, which are useful methods in exploring large amounts of multivariate data. The objective was to test the usefulness of these methods in pinpointing the abnormal water quality changes in the online data. The pressure shocks increased temporarily the number of particles, turbidity and electrical conductivity. SOM and Sammon's mapping were able to separate these situations from the normal data and thus make those visible. Therefore these methods make it possible to detect abrupt changes in water quality and thus to react rapidly to any disturbances in the system. These methods are useful in developing alert systems and predictive applications connected to online monitoring.
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Affiliation(s)
- Satu M Mustonen
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, FI-70211 Kuopio, Finland
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Lehtola MJ, Miettinen IT, Hirvonen A, Vartiainen T, Martikainen PJ. Estimates of microbial quality and concentration of copper in distributed drinking water are highly dependent on sampling strategy. Int J Hyg Environ Health 2007; 210:725-732. [PMID: 17223387 DOI: 10.1016/j.ijheh.2006.11.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Revised: 11/09/2006] [Accepted: 11/17/2006] [Indexed: 11/16/2022]
Abstract
The numbers of bacteria generally increase in distributed water. Often household pipelines or water fittings (e.g., taps) represent the most critical location for microbial growth in water distribution systems. According to the European Union drinking water directive, there should not be abnormal changes in the colony counts in water. We used a pilot distribution system to study the effects of water stagnation on drinking water microbial quality, concentration of copper and formation of biofilms with two commonly used pipeline materials in households; copper and plastic (polyethylene). Water stagnation for more than 4h significantly increased both the copper concentration and the number of bacteria in water. Heterotrophic plate counts were six times higher in PE pipes and ten times higher in copper pipes after 16 h of stagnation than after only 40 min stagnation. The increase in the heterotrophic plate counts was linear with time in both copper and plastic pipelines. In the distribution system, bacteria originated mainly from biofilms, because in laboratory tests with water, there was only minor growth of bacteria after 16 h stagnation. Our study indicates that water stagnation in the distribution system clearly affects microbial numbers and the concentration of copper in water, and should be considered when planning the sampling strategy for drinking water quality control in distribution systems.
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Affiliation(s)
- Markku J Lehtola
- Laboratory of Environmental Microbiology, National Public Health Institute, Department of Environmental Health, P.O. Box 95, FI-70701, Kuopio, Finland.
| | - Ilkka T Miettinen
- Laboratory of Environmental Microbiology, National Public Health Institute, Department of Environmental Health, P.O. Box 95, FI-70701, Kuopio, Finland
| | - Arja Hirvonen
- Department of Environmental Sciences, University of Kuopio, Kuopio, Finland
| | - Terttu Vartiainen
- Laboratory of Chemistry, National Public Health Institute, Department of Environmental Health, Kuopio, Finland; Department of Environmental Sciences, University of Kuopio, Kuopio, Finland
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Besner MC, Gauthier V, Trépanier M, Martel K, Prévost M. Assessing the effect of distribution system O&M on water quality. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/j.1551-8833.2007.tb08082.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Lehtola MJ, Laxander M, Miettinen IT, Hirvonen A, Vartiainen T, Martikainen PJ. The effects of changing water flow velocity on the formation of biofilms and water quality in pilot distribution system consisting of copper or polyethylene pipes. WATER RESEARCH 2006; 40:2151-60. [PMID: 16725175 DOI: 10.1016/j.watres.2006.04.010] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Revised: 04/13/2006] [Accepted: 04/13/2006] [Indexed: 05/09/2023]
Abstract
We studied the effects of flow velocity on the formation of biofilms and the concentration of bacteria in water in copper and plastic (polyethylene, PE) pipes. The formation of biofilms increased with the flow velocity of water. The increase in microbial numbers and contents of ATP was clearer in the PE pipes than in the copper pipes. This was also seen as increased consumption of microbial nutrients in the pipeline system. This indicates that the mass transfer of nutrients is in major role in the growth of biofilms. However, the increased biomass of biofilms did not affect microbial numbers in the water. Rapid changes in water flow rate resuspended biofilms and sediments which increased the concentrations of bacteria and copper in water. The disturbance caused by the changing water flow was also seen as an increase in the particle counts and water turbidity recorded with online instrumentation.
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Affiliation(s)
- Markku J Lehtola
- Laboratory of Environmental Microbiology, National Public Health Institute, Department of Environmental Health, P.O. Box 95, FI-70701 Kuopio, Finland.
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Berry D, Xi C, Raskin L. Microbial ecology of drinking water distribution systems. Curr Opin Biotechnol 2006; 17:297-302. [PMID: 16701992 DOI: 10.1016/j.copbio.2006.05.007] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 04/25/2006] [Accepted: 05/05/2006] [Indexed: 11/16/2022]
Abstract
The supply of clean drinking water is a major, and relatively recent, public health milestone. Control of microbial growth in drinking water distribution systems, often achieved through the addition of disinfectants, is essential to limiting waterborne illness, particularly in immunocompromised subpopulations. Recent inquiries into the microbial ecology of distribution systems have found that pathogen resistance to chlorination is affected by microbial community diversity and interspecies relationships. Research indicates that multispecies biofilms are generally more resistant to disinfection than single-species biofilms. Other recent findings are the increased survival of the bacterial pathogen Legionella pneumophila when present inside its protozoan host Hartmannella vermiformis and the depletion of chloramine disinfectant residuals by nitrifying bacteria, leading to increased overall microbial growth. Interactions such as these are unaccounted for in current disinfection models. An understanding of the microbial ecology of distribution systems is necessary to design innovative and effective control strategies that will ensure safe and high-quality drinking water.
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Affiliation(s)
- David Berry
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, 48109-2125, USA
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Vaerewijck MJM, Huys G, Palomino JC, Swings J, Portaels F. Mycobacteria in drinking water distribution systems: ecology and significance for human health. FEMS Microbiol Rev 2005; 29:911-34. [PMID: 16219512 DOI: 10.1016/j.femsre.2005.02.001] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2004] [Revised: 11/29/2004] [Accepted: 02/05/2005] [Indexed: 01/04/2023] Open
Abstract
In contrast to the notorious pathogens Mycobacterium tuberculosis and M. leprae, the majority of the mycobacterial species described to date are generally not considered as obligate human pathogens. The natural reservoirs of these non-primary pathogenic mycobacteria include aquatic and terrestrial environments. Under certain circumstances, e.g., skin lesions, pulmonary or immune dysfunctions and chronic diseases, these environmental mycobacteria (EM) may cause disease. EM such as M. avium, M. kansasii, and M. xenopi have frequently been isolated from drinking water and hospital water distribution systems. Biofilm formation, amoeba-associated lifestyle, and resistance to chlorine have been recognized as important factors that contribute to the survival, colonization and persistence of EM in water distribution systems. Although the presence of EM in tap water has been linked to nosocomial infections and pseudo-infections, it remains unclear if these EM provide a health risk for immunocompromised people, in particular AIDS patients. In this regard, control strategies based on maintenance of an effective disinfectant residual and low concentration of nutrients have been proposed to keep EM numbers to a minimum in water distribution systems.
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Affiliation(s)
- Mario J M Vaerewijck
- Laboratory of Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
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Abstract
The molecular aetiology of familial susceptibility to disseminated mycobacterial disease, usually involving weakly pathogenic strains of mycobacteria, has now been elucidated in more than 30 families. Mutations have been identified in five genes in the interleukin-12-dependent interferon-gamma pathway, highlighting the importance of this pathway in human mycobacterial immunity. Knowledge derived from the study of these rare patients contributes to our understanding of the immune response to common mycobacterial pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae, which remain major public health problems globally. This knowledge can be applied to the rational development of novel therapies and vaccines for these important mycobacterial diseases.
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Affiliation(s)
- Melanie Newport
- Cambridge Institute for Medical Research, Addenbrookes Hospital, Hills Road, Cambridge, CB2 2XY, UK.
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