Investigation of opportunistic pathogens in municipal drinking water under different supply and treatment regimes

2004 ◽  
Vol 50 (1) ◽  
pp. 83-90 ◽  
Author(s):  
M. Pryor ◽  
S. Springthorpe ◽  
S. Riffard ◽  
T. Brooks ◽  
Y. Huo ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Microbiological Quality ◽  
Opportunistic Pathogens ◽  
Treatment Regimes ◽  
Point Of Use ◽  
Deep Wells ◽  
Before And After ◽  
Legionella Species ◽  
Biofilm Bacteria

Changing regulations to lower disinfectant byproducts in drinking water is forcing utilities to switch disinfection from chlorine to monochloramine. It is generally unknown whether this will impact positively or negatively on the microbiological quality of drinking water. A utility in Florida, using water with relatively high organic carbon levels from deep wells in several wellfields, made the decision to change its disinfection regime from chlorine to chloramine in order to meet the new regulations. To assess the impacts of such a change on the microbiology of its water supplies, it undertook a number of studies before and after the change. In particular, the presence of the opportunistic pathogens Legionella and Mycobacterium, and also the composition of drinking-water biofilms, were examined. A preliminary synthesis and summary of these results are presented here. Legionella species were widely distributed in source waters and in the distribution system when chlorine was the disinfectant. In some samples they seemed to be among the dominant biofilm bacteria. Following the change to monochloramine, legionellae were not detected in the distribution system during several months of survey; however, they remained detectable at point of use, although with less species diversity. A variety of mycobacteria (21 types) were widely distributed in the distribution system when chlorine was the disinfectant, but these seemed to increase in dominance after chloramination was instituted. At point of use, only four species of mycobacteria were detected. Other changes occurring with chloramination included (a) an altered biofilm composition, (b) increased numbers of total coliforms and heterotrophs and (c) nitrification of water storage tanks. The results suggested that consideration should be given to the microbiological effects of changing disinfection regimes in drinking-water and distribution system biofilms.

The effect of distribution system biofilm bacteria on copper concentrations in drinking water

2002 ◽  
Vol 2 (1) ◽  
pp. 319-324
Author(s):  
M.M. Critchley ◽  
N.J. Cromar ◽  
N. McClure ◽  
H.J. Fallowfield
Keyword(s):  
Public Health ◽  
Drinking Water ◽  
Distribution System ◽  
Xanthomonas Maltophilia ◽  
Biofilm Bacteria ◽  
Rhodococcus Sp

This study investigated the potential for distribution system biofilm bacteria to elevate copper concentrations in drinking water. Biofilms were sampled from household copper reticulation pipes and grown on R2A agar. Laboratory coupon experiments were used to determine the effect of single isolate biofilms on aqueous copper concentrations. The majority of biofilm bacteria did not affect copper concentrations in comparison to sterile controls. However, several bacteria including Acidovorax delafieldii, Cytophaga johnsonae and Micrococcus kristinae were shown to significantly elevate copper concentrations in drinking water. In contrast, the bacteria Rhodococcus sp. and Xanthomonas maltophilia were shown to significantly decrease copper levels in comparison to controls. The significance of biofilm bacteria to increase copper concentrations in drinking water has implications for public health by increasing concentrations to levels toxic to humans.

scholarly journals Point-of-Use Water Treatment Methods and the Microbiological Quality of Drinking Water in a Peri-Urban Community of Bonendale, Douala IV, Cameroon

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ngouakam H ◽  
◽  
Fru Cho J ◽  
Tientche B ◽  
◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Microbiological Quality ◽  
Coliform Bacteria ◽  
Cross Sectional ◽  
Potential Health ◽  
Coliform Count ◽  
Point Of Use ◽  
Dug Wells

Background: The study aimed at assessing the knowledge of Bonendale populations related to safe drinking water; determine the microbiological quality and the household treatment practices of drinking water at the point of use (PoU). Methods: The study was descriptive and cross-sectional, conducted between November 2017 and November 2018 in Bonendale, Douala IV. A systematic random sampling method was used to select 237 households. Results: The main source of drinking water in the study population was dug wells (64.9%). The major activity around the boreholes was agriculture 50% (6/12) while agriculture and livestock rearing were practiced around 34.3% (12/35) and 42.8% (15/35) of dug wells respectively. Nearly half 110 (46.4%) of respondents had a good knowledge of physical properties of drinking water. Fifty-nine water samples out of a total of 60 tested (98.3%) were contaminated by coliform bacteria. Analysis of water samples indicated that 47.6% (10/21) of dug wells, 37.0% (10/27) of Camwater, and 41.2% (5/12) of boreholes had a total coliform count varying between 101-1000 CFU/100mL. And only a single Camwater water sample 1 (137%) had a coliform count of 0 CFU/100mL. Conclusion: These findings indicated the poor microbiological quality of point water used by Bonendale populations representing an important potential health risk of water-borne diseases. The results also reveal that a very high proportion of households treat their PoU before drinking.

scholarly journals The efficacy of chlorine-based disinfectants against planktonic and biofilm bacteria for decentralised point-of-use drinking water

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gillian E. Clayton ◽  
Robin M. S. Thorn ◽  
Darren M. Reynolds
Keyword(s):  
Antimicrobial Activity ◽  
Drinking Water ◽  
Hypochlorous Acid ◽  
Drinking Water Treatment ◽  
Distribution Networks ◽  
Free Chlorine ◽  
Biofilm Reactor ◽  
E Coli ◽  
Point Of Use ◽  
Biofilm Bacteria

AbstractChlorine solutions are used extensively for the production of biologically safe drinking water. The capability of point-of-use [POU] drinking water treatment systems has gained interest in locations where centralised treatment systems and distribution networks are not practical. This study investigated the antimicrobial and anti-biofilm activity of three chlorine-based disinfectants (hypochlorite ions [OCl-], hypochlorous acid [HOCl] and electrochemically activated solutions [ECAS]) for use in POU drinking water applications. The relative antimicrobial activity was compared within bactericidal suspension assays (BS EN 1040 and BS EN 1276) using Escherichia coli. The anti-biofilm activity was compared utilising established sessile Pseudomonas aeruginosa within a Centre for Disease Control [CDC] biofilm reactor. HOCl exhibited the greatest antimicrobial activity against planktonic E. coli at >50 mg L−1 free chlorine, in the presence of organic loading (bovine serum albumen). However, ECAS exhibited significantly greater anti-biofilm activity compared to OCl- and HOCl against P. aeruginosa biofilms at ≥50 mg L−1 free chlorine. Based on this evidence disinfectants where HOCl is the dominant chlorine species (HOCl and ECAS) would be appropriate alternative chlorine-based disinfectants for POU drinking water applications.

Decision support system to select sustainable point-of-use/point-of-entry treatment systems (D4SPOUTS)

2013 ◽  
Vol 49 (2) ◽  
pp. 104-113
Author(s):  
Mohamed A. Hamouda ◽  
William B. Anderson ◽  
Peter M. Huck
Keyword(s):  
Drinking Water ◽  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Distribution System ◽  
Sustainability Assessment ◽  
Engineering Practice ◽  
Point Of Entry ◽  
Point Of Use ◽  
Treated Drinking Water

Point-of-use (POU) and point-of-entry (POE) devices are, in some situations, considered to be a viable solution for drinking water suppliers and consumers alike to deal with site specific drinking water issues. This paper introduces a newly developed decision support system (DSS) that employs decision making techniques to select among the various devices based on their characterization and sustainability assessment. Careful illustration of the various aspects and components of the DSS is provided and the decision process is explained. Aspects of validity, usability and sensitivity analysis are demonstrated through a hypothetical case study for removing lead introduced in the distribution system of municipally treated drinking water. The output of the DSS helps to determine the more sustainable treatment devices which should have positive implications for the application of POU and POE devices. Other potential uses of the DSS are described to illustrate its versatility and usefulness. The DSS is not intended to replace common engineering practice in selecting POU and POE treatment systems, but rather to give support to the users by providing the necessary information about all possible solutions.

Comparing health outcomes and point-of-use water quality in two rural indigenous communities of Baja California, Mexico before and after receiving new potable water infrastructure

2014 ◽  
Vol 4 (4) ◽  
pp. 672-680 ◽  
Author(s):  
Paula Stigler-Granados ◽  
Penelope J. E. Quintana ◽  
Richard Gersberg ◽  
María Luisa Zúñiga ◽  
Thomas Novotny
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Baja California ◽  
Indigenous Communities ◽  
Gastrointestinal Illness ◽  
Source Water ◽  
Water Infrastructure ◽  
Safe Water ◽  
Point Of Use ◽  
Before And After

One of the United Nations Millennium Development Goals is to reduce the global proportion of people who do not have access to safe drinking water. In the past, the typical strategy to reach this goal has been the use of investment-intensive centralized infrastructure development for water supplies. However, there is increasing evidence suggesting that improving water quality at the source does not guarantee safe water at point-of-use. This study examined water quality, waterborne disease incidence and water system use over time in two small rural indigenous communities of Baja California, Mexico, before and after drinking-water infrastructure improvements. Community Promotoras collected data on the incidence of gastrointestinal illness through face-to-face surveys. Concurrently, water samples from the old and new water sources and household water storage containers were analyzed for fecal coliforms. Although source water quality was significantly improved in both communities (p < 0.05), neither community had a significant decrease in the level of contaminated drinking water sampled at the household level. No significant decrease in gastrointestinal illness was found after the improvements to the source water supply. These results indicate that point-of-use contamination and acceptance of the new sources may be a critical point for intervention when attempting to assure access to safe water, especially in rural communities.

scholarly journals The microbial colonization of activated carbon block point-of-use (PoU) filters with and without chlorinated phenol disinfection by-products

2017 ◽  
Vol 3 (5) ◽  
pp. 830-843 ◽  
Author(s):  
Chia-Chen Wu ◽  
Sudeshna Ghosh ◽  
Kelly J. Martin ◽  
Ameet J. Pinto ◽  
Vincent J. Denef ◽  
...  
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Bacterial Community Structure ◽  
Microbial Colonization ◽  
Opportunistic Pathogens ◽  
Absolute Abundance ◽  
Carbon Block ◽  
Point Of Use ◽  
Water Filters ◽  
By Products

Activated carbon based point-of-use drinking water filters change the bacterial community structure and increase the absolute abundance of genera, including those associated with opportunistic pathogens.

scholarly journals Away-from-home drinking water consumption practices and the microbiological quality of water consumed in rural western Kenya

2011 ◽  
Vol 9 (4) ◽  
pp. 628-636 ◽  
Author(s):  
W. Onyango-Ouma ◽  
Charles P. Gerba
Keyword(s):  
Drinking Water ◽  
Water Consumption ◽  
Microbiological Quality ◽  
Cross Sectional ◽  
Western Kenya ◽  
Household Level ◽  
Point Of Use ◽  
Quality Of Water ◽  
Consumption Practices

A cross-sectional descriptive study was conducted to examine away-from-home drinking water consumption practices and the microbiological quality of water consumed in rural western Kenya. The study involved adults and schoolchildren. Data were collected using focus group discussions, questionnaire survey, observations, diaries and interviews. The findings suggest that away-from-home drinking water consumption is a common practice in the study area; however, the microbiological quality of the water consumed is poor. While some respondents perceive the water to be safe for drinking mainly because of the clear colour of the water, others are forced by circumstances to drink the water as it is owing to a lack of alternative safe sources. It is concluded that there is a need for new innovative approaches to address away-from-home drinking water consumption in resource-poor settings in order to complement and maximize the benefits of point-of-use water treatment at the household level.

The effect of distribution system bacterial biofilms on copper concentrations in drinking water

2001 ◽  
Vol 1 (4) ◽  
pp. 247-252 ◽  
Author(s):  
M.M. Critchley ◽  
H.J. Fallowfield
Keyword(s):  
Public Health ◽  
Drinking Water ◽  
Distribution System ◽  
Bacterial Biofilms ◽  
Xanthomonas Maltophilia ◽  
Biofilm Bacteria ◽  
Rhodococcus Sp

This study investigated the potential for distribution system biofilm bacteria to elevate copper concentrations in drinking water. Biofilms were sampled from household copper reticulation pipes and grown on R2A agar. Laboratory coupon experiments were used to determine the effect of single isolate biofilms on aqueous copper concentrations. The majority of biofilm bacteria did not affect copper concentrations in comparison to sterile controls. However, several bacteria including Acidovorax delafieldii, Cytophaga johnsonae and Micrococcus kristinae were shown to significantly elevate copper concentrations in drinking water. In contrast, the bacteria Rhodococcus sp. and Xanthomonas maltophilia were shown to significantly decrease copper levels in comparison to controls. The significance of biofilm bacteria to increase copper concentrations in drinking water has implications for public health by increasing concentrations to levels toxic to humans.

scholarly journals Nontuberculous Mycobacteria, Fungi, and Opportunistic Pathogens in Unchlorinated Drinking Water in the Netherlands

2012 ◽  
Vol 79 (3) ◽  
pp. 825-834 ◽  
Author(s):  
Paul W. J. J. van der Wielen ◽  
Dick van der Kooij
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
The Netherlands ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Distribution System ◽  
Nontuberculous Mycobacteria ◽  
Opportunistic Pathogens ◽  
Content Type ◽  
Premise Plumbing

ABSTRACTThe multiplication of opportunistic pathogens in drinking water supplies might pose a threat to public health. In this study, distributed unchlorinated drinking water from eight treatment plants in the Netherlands was sampled and analyzed for fungi, nontuberculous mycobacteria (NTM), and several opportunistic pathogens by using selective quantitative PCR methods. Fungi and NTM were detected in all drinking water samples, whereasLegionella pneumophila,Pseudomonas aeruginosa,Stenotrophomonas maltophilia, andAspergillus fumigatuswere sporadically observed.Mycobacterium aviumcomplex andAcanthamoebaspp. were not detected. Season had no influence on the occurrence of these organisms, except for NTM andS. maltophilia, which were present in higher numbers in the summer. Opportunistic pathogens were more often observed in premise plumbing water samples than in samples from the distribution system. The lowest number of these organisms was observed in the finished water at the plant. Thus, fungi, NTM, and some of the studied opportunistic pathogens can multiply in the distribution and premise plumbing systems. Assimilable organic carbon (AOC) and/or total organic carbon (TOC) had no clear effects on fungal and NTM numbers or onP. aeruginosa- andS. maltophilia-positive samples. However,L. pneumophilawas detected more often in water with AOC concentrations above 10 μg C liter−1than in water with AOC levels below 5 μg C liter−1. Finally, samples that containedL. pneumophila,P. aeruginosa, orS. maltophiliawere more frequently positive for a second opportunistic pathogen, which shows that certain drinking water types and/or sampling locations promote the growth of multiple opportunistic pathogens.

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