scholarly journals Unchartered waters: the unintended impacts of residual chlorine on water quality and biofilms

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Katherine E. Fish ◽  
Nik Reeves-McLaren ◽  
Stewart Husband ◽  
Joby Boxall
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Internal Surface ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Water Safety ◽  
Internal Surface Area ◽  
Drinking Water Distribution Systems

Abstract Disinfection residuals in drinking water protect water quality and public heath by limiting planktonic microbial regrowth during distribution. However, we do not consider the consequences and selective pressures of such residuals on the ubiquitous biofilms that persist on the vast internal surface area of drinking water distribution systems. Using a full scale experimental facility, integrated analyses were applied to determine the physical, chemical and biological impacts of different free chlorine regimes on biofilm characteristics (composition, structure and microbiome) and water quality. Unexpectedly, higher free chlorine concentrations resulted in greater water quality degredation, observable as elevated inorganic loading and greater discolouration (a major cause of water quality complaints and a mask for other failures). High-chlorine concentrations also reduced biofilm cell concentrations but selected for a distinct biofilm bacterial community and inorganic composition, presenting unique risks. The results challenge the assumption that a measurable free chlorine residual necessarily assures drinking water safety.

scholarly journals Spatial diversity of chlorine residual in a drinking water distribution system: application of an integrated fuzzy logic technique

2014 ◽  
Vol 17 (2) ◽  
pp. 293-306 ◽  
Author(s):  
Donatella Termini ◽  
Gaspare Viviani
Keyword(s):  
Water Quality ◽  
Fuzzy Logic ◽  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Residual Chlorine ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
Fuzzy Logic Technique

A reduction in the concentration of chlorine, which is used as a chemical disinfectant for water in drinking water distribution systems, can be considered to be an index of the progressive deterioration of water quality. In this work, attention is given to the spatial distribution of the residual chlorine in drinking water distribution systems. The criterion for grouping the water-quality parameters normally used is highly subjective and often based on data that are not correctly identified. In this paper, a cluster analysis based on fuzzy logic is applied. The advantage of the proposed procedure is that it allows a user to identify (in an automatic way and without any specific assumption) the zonation of the network and easily calibrate the unknown parameters. An analysis of the correlation between the sampling sites for the residual chlorine has been used to assess the applicability of the procedure.

scholarly journals Whole metagenome sequencing of chlorinated drinking water distribution systems

2018 ◽  
Vol 4 (12) ◽  
pp. 2080-2091 ◽  
Author(s):  
Isabel Douterelo ◽  
Carolina Calero-Preciado ◽  
Victor Soria-Carrasco ◽  
Joby B. Boxall
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Quality And Safety ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
Chlorinated Drinking Water ◽  
Metagenome Sequencing

This research highlights the potential of whole metagenome sequencing to help protect drinking water quality and safety.

scholarly journals Trihalomethanes formation in Iranian water supply systems: predicting and modeling

2015 ◽  
Vol 13 (3) ◽  
pp. 859-869 ◽  
Author(s):  
Ali Akbar Babaei ◽  
Leila Atari ◽  
Mehdi Ahmadi ◽  
Kambiz Ahmadiangali ◽  
Mirzaman Zamanzadeh ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Temperature ◽  
Distribution Systems ◽  
Water Distribution ◽  
Pearson Correlation ◽  
Multiple Linear Regression Model ◽  
Residual Chlorine ◽  
Water Supply Systems ◽  
Drinking Water Distribution Systems ◽  
Bromide Ion

Trihalomethanes (THMs) were the first disinfection by-products discovered in drinking water and are classified as probable carcinogens. This study measures and models THMs formation at two drinking water distribution systems (WDS1 and WDS2) in Ahvaz City, Iran. The investigation was based on field-scale investigations and an intensive 36-week sampling program, from January to September 2011. The results showed total THM concentrations in the range 17.4–174.8 μg/L and 18.9–99.5 μg/L in WDS1 and WDS2, respectively. Except in a few cases, the THM concentrations in WDS1 and WDS2 were lower than the maximum contaminant level values. Using two-tailed Pearson correlation test, the water temperature, dissolved organic carbon, UV254, bromide ion (Br−), free residual chlorine, and chlorine dose were identified as the significant parameters for THMs formation in WDS2. Water temperature was the only significant parameter for THMs formation in WDS1. Based on the correlation results, a predictive model for THMs formation was developed using a multiple regression approach. A multiple linear regression model showed the best fit according to the coefficients of determination (R2) obtained for WDS1 (R2 = 0.47) and WDS2 (R2 = 0.54). Further correlation studies and analysis focusing on THMs formation are necessary to assess THMs concentration using the predictive models.

Influence factors of organic compounds leaching from PE pipes and the potential toxic effects on E. coli and rat C6 glioma cell

2015 ◽  
Vol 16 (2) ◽  
pp. 402-409 ◽  
Author(s):  
Jingqing Liu ◽  
Hongxi Peng ◽  
Shengwei Tan ◽  
Jianmin Wu ◽  
Hamid Bastani ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Glioma Cell ◽  
Distribution Systems ◽  
Water Distribution ◽  
Influence Factors ◽  
C6 Glioma ◽  
Residual Chlorine ◽  
C6 Glioma Cell ◽  
Rat C6 Glioma

Water quality safety is always a hot topic. Recently there has been a great increase in the use of polyethylene (PE) pipes in drinking water distribution systems in China. Some organics can leach from PE pipes into drinking water, which is undoubtedly harmful for consumers. In this study, potential organics leaching from two Chinese brands of PE pipe were investigated in order to determine the potential risk to both consumers and water quality. Their released amounts are characterized by UV254 instead of total organic carbon (TOC). Organics are identified by means of gas chromatography coupled with mass spectrometry (GC-MS). Influencing factors such as types of water, time, pH, residual chlorine are discussed. The cytotoxicity of leaching organics is first put forward in this study, and rat C6 glioma cell is used to assess the effect of leaching organics; the increasing dosage of soaking solution negatively affects morphology and relative viability of rat C6 glioma cell. The results show that residual chlorine, time and temperature have a positive effect on organics release, while pH plays an opposite role.

scholarly journals Effects of residual disinfectants on the redox speciation of lead(ii)/(iv) minerals in drinking water distribution systems

2021 ◽  
Author(s):  
Sumant Avasarala ◽  
John Orta ◽  
Michael Schaefer ◽  
Macon Abernathy ◽  
Samantha Ying ◽  
...  
Keyword(s):  
Drinking Water ◽  
Reaction Kinetics ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Free Chlorine ◽  
Oxidative Transformation ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
Free Bromine

This study investigated the reaction kinetics on the oxidative transformation of lead(ii) minerals by free chlorine (HOCl) and free bromine (HOBr) in drinking water distribution systems.

Biofilms in copper plumbing systems: sensitivity to copper and chlorine and implications for corrosion

2002 ◽  
Vol 2 (4) ◽  
pp. 81-87
Author(s):  
M.M. Critchley ◽  
N.J. Cromar ◽  
N. McClure ◽  
H.J. Fallowfield
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Copper Ions ◽  
Free Chlorine ◽  
Drinking Water Distribution Systems ◽  
Microbial Biofilms ◽  
Drinking Water Distribution ◽  
Plumbing Systems ◽  
Viable Bacteria

Microbial biofilms have been implicated as a major contributor to the corrosion of metals in drinking water distribution systems. This study investigated the sensitivity of biofilm bacteria with previously established cuprosolvency activity, isolated from domestic copper plumbing pipes, to chlorine and copper and assessed their potential to adsorb aqueous copper. Bacterial suspensions were exposed to free chlorine residuals of 0.1, 0.2 and 0.5 mg/L and viable bacteria enumerated at times 0, 1, 2, 5 and 10 minutes. Disinfection curves showed the isolated bacteria were more resistant to free chlorine in comparison to the indicator organism Escherichia coli. Disc diffusion assays demonstrated high resistance by all bacteria to copper, with a Corynebacteria sp. showing no growth inhibition at concentrations up to 4 gCu/L. The isolated bacteria showed the ability to bind aqueous copper ions from solution in adsorption experiments. Significantly higher adsorption of copper was shown by a species of Pseudomonas. The results of this research will provide a greater understanding of causes of biofilm accumulation and copper contamination of drinking water, aiding in health risk assessment and risk management.

Amoebae-resisting bacteria in drinking water: risk assessment and management

2008 ◽  
Vol 58 (3) ◽  
pp. 571-577 ◽  
Author(s):  
J. F. Loret ◽  
M. Jousset ◽  
S. Robert ◽  
G. Saucedo ◽  
F. Ribas ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Control Strategies ◽  
Water Production ◽  
Water Safety ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
Drinking Water Production

Free-living amoebae have been detected in a large number of man-made water systems, including drinking water distribution systems. Some of these amoebae can host amoebae-resisting bacteria, and thus act potentially as reservoirs and vehicles for a number of pathogens. The objectives of this study were to characterize the amoebae and amoebae-resisting bacteria present in different raw waters used for drinking water production, and to assess the efficiency of different treatments applied for drinking water production in removing or inactivating these amoebae. The preliminary results of this study confirm the presence of amoebae and amoebae-resisting bacteria in raw waters used for drinking water production. Due to their capacity to encyst, most of these amoebae are extremely resistant to disinfection processes. In these conditions, preventing the dissemination of these micro-organisms through drinking water will mainly require their physical removal by clarification and filtration processes. The particular hazard that amoebae-resisting bacteria represent in drinking water production should be taken into account in any risk assessment conducted in the framework of a water safety plan, and control strategies based on physical removal rather than disinfection should be adopted where necessary.

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