Modeling Heterotrophic Bacteria in Plumbing System of Drinking Water

2014 ◽  
Vol 86 (6) ◽  
pp. 504-512
Author(s):  
Shakhawat Chowdhury ◽  
Muhammad Al-Zahrani
Keyword(s):  
Drinking Water ◽  
Heterotrophic Bacteria ◽  
Plumbing System

scholarly journals Degradation of Bacterial Water Quality in Drinking Water after Bottling

2020 ◽  
Vol 14 (1) ◽  
pp. 78-83
Author(s):  
Ali Shahryari ◽  
Charlotte D. Smith ◽  
Abolfazl Amini
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Heterotrophic Bacteria ◽  
Positive Association ◽  
Ambient Air ◽  
Bottled Water ◽  
Plate Count ◽  
Biochemical Tests ◽  
Storage Duration

Background: The consumption of bottled water globally, including Iran, has increased tremendously in recent years. This study was designed to assess the bacteriological quality of bottled water and its compliance with the drinking water regulations. In addition, we evaluated bottled waters for the presence of a variety of genera of bacteria and the effect of storage duration on the extent of bacterial contamination. Methods: Four hundred samples of bottled water belonging to ten different Iranian brands with various production dates were purchased from supermarkets in Gorgan, Iran, from 2017 to 2018. Bacterial quality of bottled water was assessed using heterotrophic plate count (HPC) followed by usual biochemical tests for identification of bacterial genera, and by the API system. Results: The average HPC of bottled water was 9974 colony-forming units per milliliter (CFU/ml). Twelve genera were isolated, among which Bacillus spp. and Escherichia coli were the most and least abundant, respectively. Statistical analysis showed that there was a positive association between water quality and storage duration so that the highest microbial load occurred within the first to third months after bottling. Furthermore, the highest rate of contamination was observed in May when ambient air temperatures commonly reached 40 °C. Conclusion: The bacterial quality of bottled water was not according to the standard of drinking water quality. This study demonstrated the variation in bacterial levels after bottling, which indicates the presence of waterborne heterotrophic bacteria, some of which can pose severe health risks to consumers.

scholarly journals Determination of cytotoxicity and invasiveness of heterotrophic plate count bacteria isolated from drinking water

2002 ◽  
Vol 2 (3) ◽  
pp. 115-122 ◽  
Author(s):  
D. Pavlov ◽  
C.M.E. de Wet ◽  
W.O.K. Grabow ◽  
M.M. Ehlers
Keyword(s):  
Drinking Water ◽  
Health Risk ◽  
Heterotrophic Bacteria ◽  
Penicillin G ◽  
Plate Count ◽  
Heterotrophic Plate Count ◽  
Water Supplies ◽  
Plate Counts ◽  
Study Support ◽  
Heterotrophic Plate Counts

Evidence has been presented that some heterotrophic bacteria often detected in drinking water supplies possess features associated with pathogenicity. This suggests that even the low numbers of heterotrophic bacteria considered acceptable by drinking water specifications may constitute a health risk, particularly to immunocompromised consumers. In this study, 339 bacteria were isolated at random from routine heterotrophic plate count (HPC) tests on selected drinking water supplies in South Africa. In a first screen for potentially pathogenic properties, 188 of the isolates (55.5%) displayed a- or b-haemolysis on blood agar. Further analysis of the haemolytic isolates for enzymes associated with virulence revealed the presence of chondroitinase (5.3%), coagulase (16.0%), DNase (60.6%), elastase (33.0%), fibrinolysin (53.7%), gelatinase (62.2%), hyaluronidase (21.3%), lecithinase (47.9%), lipase (54.8%) and proteinase (64.4%) of the isolates. No fluorescein or pyocyanin was detected in any of the isolates. Among the haemolytic isolates 68.6% were resistant to oxacillin (1 μg), 59.6% to penicillin G (2 units), 47.3% to penicillin G (10 units), 53.7% to ampicillin (10 μg) and 42.6% to ampicillin (25 μg). Cytotoxicity, invasiveness and adherence properties of the haemolytic isolates was determined on HEp-2 and Caco2 cell lines. Among the haemolytic isolates 96% were cytolytic on the HEp-2 cell line. All the haemolytic isolates adhered to HEp-2 and Caco2 cells but gram-negative isolates tended to adhere in larger numbers than gram-positive isolates. HEp-2 cells were invaded by 42% of the haemolytic isolates. Heterotrophic bacteria, which most frequently revealed the above features associated with pathogenicity included species of the following genera: Aeromonas, Acinetobacter, Aureobacterium, Bacillus, Klebsiella, Moraxella, Pseudomonas, Staphylococcus, Tsukamurella and Vibrio. The results obtained in this study support earlier indications that bacteria detected by routine heterotrophic plate counts on drinking water supplies may include bacteria associated with potentially pathogenic properties. The extent to which these bacteria in drinking water supplies may constitute a health risk remains to be investigated.

scholarly journals Quality assessment of roof-harvested rainwater in the West Bank, Palestinian Authority

2011 ◽  
Vol 9 (3) ◽  
pp. 525-533 ◽  
Author(s):  
A. K. Daoud ◽  
K. M. Swaileh ◽  
R. M. Hussein ◽  
M. Matani
Keyword(s):  
Drinking Water ◽  
Health Risk ◽  
Human Health ◽  
Heterotrophic Bacteria ◽  
West Bank ◽  
Human Health Risk ◽  
Fecal Coliforms ◽  
The West ◽  
Guideline Values

Rain harvesting is becoming more common in the Palestinian Territories as a result of drinking water scarcity. Although it might pose serious human health risk, this water is being consumed without treatment in many areas of the West Bank. The present study evaluates the physicochemical and microbial quality of harvested rainwater that is used as potable water in the West Bank. Samples from roof-harvested rainwater storage tanks (n = 42) were collected in summer (SS) 2006/winter (WS) 2007. Physicochemical parameters measured were: temperature, pH, electrical conductivity, salinity, total dissolved solids, turbidity, nitrate, copper and lead. With few exceptions, all these parameters were within WHO guideline values. All samples (100%) were found to contain coliforms and to be heavily contaminated with heterotrophic bacteria. About 67% of all samples were contaminated with fecal coliforms. Specific PCR technique confirmed the presence of five pathogenic microorganisms that can be ordered according to their prevalence as: Citrobacter (83%) > Acinetobacter (78%) > Aeromonas (52%) > Pseudomonas and Campylobacter (7%). Prevalence of microorganisms in SS was higher than in WS. Although the physicochemical quality of most harvested rainwater samples was in accordance with WHO guidelines for drinking water, stored rainwater was significantly contaminated with bacteria resulting in significant human health risk from infectious diseases.

scholarly journals The health-related microbiological quality of bottled drinking water sold in Dar es Salaam, Tanzania

2006 ◽  
Vol 5 (1) ◽  
pp. 179-185 ◽  
Author(s):  
Gabriel R. Kassenga
Keyword(s):  
Drinking Water ◽  
Heterotrophic Bacteria ◽  
Tap Water ◽  
Microbiological Quality ◽  
Total Coliform ◽  
Dar Es Salaam ◽  
Bottled Water ◽  
Faecal Coliform ◽  
Coliform Bacteria

The consumption of bottled and plastic-bagged drinking water in Tanzania has increased largely because of the deteriorating quality of tap water. It is uncertain whether these water products are safe for drinking. In this study, the microbiological quality of bottled and plastic-bagged drinking water sold in Dar es Salaam, Tanzania, was investigated. One hundred and thirty samples representing 13 brands of bottled water collected from shops, supermarkets and street vendors were analysed for total coliform and faecal coliform organisms as well as heterotrophic bacteria. These were compared with 61 samples of tap water. Heterotrophic bacteria were detected in 92% of the bottled water samples analysed. Total and faecal coliform bacteria were present in 4.6% and 3.6%, respectively, of samples analysed with a tendency for higher contamination rates in plastic-bagged drinking water. Microbiological quality of tap water was found to be worse compared with bottled water, with 49.2% and 26.2% of sampling points showing the presence of total coliform and faecal coliform organisms, respectively. The results suggest caution and vigilance to avert outbreaks of waterborne diseases from these types of drinking water.

scholarly journals Microbiological quality of well water from Koprivnica-Križevci County in 2018

2021 ◽  
Vol 8 (1-2) ◽  
pp. 11-16
Author(s):  
Sanja Furmeg ◽  
Lana Feher Turković ◽  
Ana Mojsović-Ćuić ◽  
Vesna Jaki Tkalec ◽  
Maja Kiš
Keyword(s):  
Drinking Water ◽  
Heterotrophic Bacteria ◽  
Microbiological Quality ◽  
Well Water ◽  
The Public ◽  
Enterococcus Spp ◽  
High Incidence ◽  
Microbiological Parameters ◽  
Private Wells

In this study, microbiological quality of drinking water deriving from the private wells from Koprivnica-Križevci County was investigated. A total of 287 samples from different locations were collected during 2018 and analysed for the following microbiological parameters: total coliforms, Escherichia coli, Enterococcus spp., Clostridium perfringens, Pseudomonas aeruginosa, and the number of aerobic heterotrophic bacteria at 36 °C and 22 °C. The results showed that 24 % of the analysed water samples were of unsatisfactory microbiological quality, with high incidence of faecal contamination. Well water is still the main source of drinking water for many residents of this County, especially in its rural parts, so continuous monitoring and disinfection of drinking water deriving from private wells is of exceptional importance for the public health.

Establishing minimum free chlorine residual concentration for microbial control in a municipal drinking water distribution system

2014 ◽  
Vol 9 (4) ◽  
pp. 491-501 ◽  
Author(s):  
Jennie L. Rand ◽  
Graham A. Gagnon ◽  
Alisha Knowles
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Heterotrophic Bacteria ◽  
Full Scale ◽  
Free Chlorine ◽  
Source Analysis ◽  
Plate Count ◽  
Similar Data ◽  
Residual Concentration ◽  
Chlorine Residual

Distribution system data from a Nova Scotia municipal drinking water supply was collected over four years, including free chlorine residual concentration, heterotrophic plate count (HPC) bacteria, and temperature. These data were analyzed for occurrences of HPC bacteria greater than 500 colony forming units (CFU)/mL. The municipality was interested in determining if secondary chlorination practices were sufficient in maintaining microbial health in their distribution system. Coliform data were non-detect (total coliforms and Escherichia coli) in the distribution system over this period and thus heterotrophic bacteria were used to assess microbial health. Results were compared to similar data collected from pilot-scale studies that had been carried out using the same municipal water as the source. Analysis showed that a similar trend was observed between pilot- and full-scale samples. Full-scale data analysis revealed that the minimum disinfection requirement of 0.2 mg/L did not consistently control occurrences of heterotrophic bacteria from being greater than 500 CFU/mL. By comparison, maintaining a concentration of 0.3 mg/L or above, particularly in warm-weather systems, maintained the number of heterotrophic bacteria at below 500 CFU/mL. Fortunately the majority of samples collected in the full-scale distribution system (>89%) had a free chlorine residual concentration of greater than 0.30 mg/L. While it is recognized that this system had 100% compliance for E. coli, the goal of this work will help utilities understand how to utilize microbial data to inform operational disinfection targets for their distribution system.

scholarly journals A biochemical multi-species quality model of a drinking water distribution system for simulation and design

2013 ◽  
Vol 23 (3) ◽  
pp. 571-585 ◽  
Author(s):  
Krzysztof Arminski ◽  
Tomasz Zubowicz ◽  
Mietek A. Brdys
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Heterotrophic Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Large Set ◽  
Monitoring And Control ◽  
Quality Model ◽  
Drinking Water Distribution

Abstract Drinking Water Distribution Systems (DWDSs) play a key role in sustainable development of modern society. They are classified as critical infrastructure systems. This imposes a large set of highly demanding requirements on the DWDS operation and requires dedicated algorithms for on-line monitoring and control to tackle related problems. Requirements on DWDS availability restrict the usability of the real plant in the design phase. Thus, a proper model is crucial. Within this paper a DWDS multi-species quality model for simulation and design is derived. The model is composed of multiple highly inter-connected modules which are introduced to represent chemical and biological species and (above all) their interactions. The chemical part includes the processes of chloramine decay with additional bromine catalysis and reaction with nitrogen compounds. The biological part consists of both heterotrophic and chemo-autotrophic bacteria species. The heterotrophic bacteria are assumed to consume assimilable organic carbon. Autotrophs are ammonia oxidizing bacteria and nitrite oxidizing bacteria species which are responsible for nitrification processes. Moreover, Disinfection By-Products (DBPs) are also considered. Two numerical examples illustrate the derived model’s behaviour in normal and disturbance operational states.

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