scholarly journals Opportunistic pathogens and faecal indicators in drinking water associated biofilms in Cluj, Romania

2012 ◽  
Vol 10 (3) ◽  
pp. 471-483 ◽  
Author(s):  
A. Farkas ◽  
M. Drăgan-Bularda ◽  
D. Ciatarâş ◽  
B. Bocoş ◽  
Ş. Ţigan
Keyword(s):  
Drinking Water ◽  
Human Health ◽  
Treatment Plant ◽  
Water System ◽  
Drinking Water Treatment ◽  
Microbial Consortia ◽  
Opportunistic Pathogens ◽  
Water Safety ◽  
Potential Threat ◽  
Faecal Indicators

Biofouling occurs without exception in all water systems, with undesirable effects such as biocorrosion and deterioration of water quality. Drinking water associated biofilms represent a potential risk to human health by harbouring pathogenic or toxin-releasing microorganisms. This is the first study investigating the attached microbiota, with potential threat to human health, in a public water system in Romania. The presence and the seasonal variation of viable faecal indicators and opportunistic pathogens were investigated within naturally developed biofilms in a drinking water treatment plant. Bacterial frequencies were correlated with microbial loads in biofilms as well as with physical and chemical characteristics of biofilms and raw water. The biofilms assessed in the current study proved to be extremely active microbial consortia. High bacterial numbers were recovered by cultivation, including Pseudomonas aeruginosa, Escherichia coli, Aeromonas hydrophila, intestinal enterococci and Clostridium perfringens. There were no Legionella spp. detected in any biofilm sample. Emergence of opportunistic pathogens in biofilms was not significantly affected by the surface material, but by the treatment process. Implementation of a water safety plan encompassing measures to prevent microbial contamination and to control biofouling would be appropriate.

scholarly journals Persistence of Nontuberculous Mycobacteria in a Drinking Water System after Addition of Filtration Treatment

2006 ◽  
Vol 72 (9) ◽  
pp. 5864-5869 ◽  
Author(s):  
Elizabeth D. Hilborn ◽  
Terry C. Covert ◽  
Mitchell A. Yakrus ◽  
Stephanie I. Harris ◽  
Sandra F. Donnelly ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Cold Water ◽  
Nontuberculous Mycobacteria ◽  
Treatment Plant ◽  
Water System ◽  
Drinking Water Treatment ◽  
Drinking Water System

ABSTRACT There is evidence that drinking water may be a source of infections with pathogenic nontuberculous mycobacteria (NTM) in humans. One method by which NTM are believed to enter drinking water distribution systems is by their intracellular colonization of protozoa. Our goal was to determine whether we could detect a reduction in the prevalence of NTM recovered from an unfiltered surface drinking water system after the addition of ozonation and filtration treatment and to characterize NTM isolates by using molecular methods. We sampled water from two initially unfiltered surface drinking water treatment plants over a 29-month period. One plant received the addition of filtration and ozonation after 6 months of sampling. Sample sites included those at treatment plant effluents, distributed water, and cold water taps (point-of-use [POU] sites) in public or commercial buildings located within each distribution system. NTM were recovered from 27% of the sites. POU sites yielded the majority of NTM, with >50% recovery despite the addition of ozonation and filtration. Closely related electrophoretic groups of Mycobacterium avium were found to persist at POU sites for up to 26 months. Water collected from POU cold water outlets was persistently colonized with NTM despite the addition of ozonation and filtration to a drinking water system. This suggests that cold water POU outlets need to be considered as a potential source of chronic human exposure to NTM.

scholarly journals The Impact of Extreme Weather Events on Bacterial Communities and Opportunistic Pathogens in a Drinking Water Treatment Plant

Water ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 54
Author(s):  
Wei Tang ◽  
Yunsi Liu ◽  
Qiuyan Li ◽  
Ling Chen ◽  
Qi Li ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Opportunistic Pathogens ◽  
Treatment Processes ◽  
Weather Events

Drinking water treatment processes are highly effective at improving water quality, but pathogens can still persist in treated water, especially after extreme weather events. To identify how extreme weather events affected bacterial populations in source and treated water, water samples were collected from the Yangtze River Delta area and a local full-scale drinking water treatment plant. Bacterial community structure and the occurrence of pathogens were investigated in samples using 16S rRNA sequencing and qPCR techniques. In this study, the results show that intense rainfall can significantly increase levels of bacteria and opportunistic pathogens in river and drinking water treatment processes (p < 0.05); in particular, the relative abundance of Cyanobacteria increased after a super typhoon event (p < 0.05). The biological activated carbon (BAC) tank was identified as a potential pathogen reservoir and was responsible for 52 ± 6% of the bacteria released downstream, according to Bayesian-based SourceTracker analysis. Our results provide an insight into the challenges faced by maintaining finished water quality under changing weather conditions.

Challenging drinking water disinfection: How to face up to emerging waterborne pathogens?

2006 ◽  
Vol 1 (2) ◽  
Author(s):  
C. de Traversay ◽  
C. Bourny ◽  
C. Boucherie ◽  
M. Djafer ◽  
J. Cavard
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Primary Objective ◽  
Water Disinfection ◽  
Waterborne Pathogens ◽  
Water Safety ◽  
Management Plans

The disinfection of drinking water remains the primary objective of drinking water treatment. The emergence of new waterborne pathogens has led to a growing need to develop a strategy for reducing the risks of illness. Based on the water safety plan concept, this paper reports on the system assessment, the effective operational monitoring for disinfection and the management plans. The results obtained on the surface water treatment plant of Neuilly-sur-Marne (106 MGD) which includes a full treatment with clarification, ozonation and chlorination, illustrate this paper.

Insights into the challenges of risk characterization using drinking water safety plans

2017 ◽  
Vol 44 (5) ◽  
pp. 321-328 ◽  
Author(s):  
Yvonne Post ◽  
Emma Thompson ◽  
Edward McBean
Keyword(s):  
Drinking Water ◽  
Water System ◽  
Drinking Water Treatment ◽  
Risk Scores ◽  
Water Safety ◽  
Drinking Water Safety ◽  
Water Safety Plan ◽  
Key Issues ◽  
Water Safety Plans ◽  
High Degree

Risk assessment methodologies, specifically water safety plans (WSPs), provide a water operator with a greater awareness of the drinking water system and the hazards that may occur. This brings key issues to the forefront and promotes a proactive approach to drinking water safety. This paper identifies the challenges in completing a WSP and evaluates the robustness of procedures. Experts knowledgeable in drinking water treatment were asked to complete Alberta’s Drinking Water Safety Plan template for a hypothetical community. Findings from use of a condensed version of the WSP are also described, and the resulting risk scores obtained from both methodologies are compared. A high degree of variability between experts’ responses was observed from both; however, trends between responses show that the condensed WSP makes it easier to compare hazards relative to each other, to determine key risk areas that warrant more attention.

Improving the biological stability of drinking water by ion exchange

2011 ◽  
Vol 11 (1) ◽  
pp. 107-112 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
S. A. Baghoth ◽  
E. R. Cornelissen ◽  
L. C. Rietveld
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
Ion Exchange ◽  
Biofilm Formation ◽  
Formation Rate ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Biological Stability ◽  
Biological Activated Carbon ◽  
Pre Treatment

To guarantee a good water quality at the consumer’s tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research is to measure the effect of NOM removal by ion exchange on the biological stability of drinking water. Experiments were performed in two lanes of the pilot plant of Weesperkarspel in the Netherlands. The lanes consisted of ozonation, softening, biological activated carbon filtration and slow sand filtration. Ion exchange in fluidized form was used as pre-treatment in one lane and removed 50% of the dissolved organic carbon (DOC); the other lane was used as reference. Compared to the reference lane, the assimilable organic carbon (AOC) concentration of the finished water in the lane pretreated by ion exchange was 61% lower. The biofilm formation rate of the finished water was decreased with 70% to 2.0 pg ATP/cm2.day. The achieved concentration of AOC and the values of the biofilm formation rate with ion exchange pre-treatment showed that the biological stability of drinking water can be improved by extending a treatment plant with ion exchange, especially when ozonation is involved as disinfection and oxidation step.

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