Relationship between bacterial regrowth and some physical and chemical parameters within Sydney's drinking water distribution system

Power, Kaye; Nagy, L.

doi:10.1016/s0043-1354(98)00251-6

Cited by 58 publications

(35 citation statements)

References 24 publications

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“…No Klebsiella isolates (based on 16S rRNA PCR) were obtained during sampling four, while the fewest positive samples (based on genus-specific PCR) were observed during sampling three (24%). Klebsiella oxytoca has been isolated on numerous occasions from Australian drinking water sources (55). Kaushik et al (56) also reported recently that, of the 50 rainwater samples they tested in Singapore, 12% were positive for Klebsiella spp.…”

Section: Discussionmentioning

confidence: 98%

Distribution of Indigenous Bacterial Pathogens and Potential Pathogens Associated with Roof-Harvested Rainwater

Dobrowsky

Kwaadsteniet

Cloete

et al. 2014

Appl Environ Microbiol

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The harvesting of rainwater is gaining acceptance among many governmental authorities in countries such as Australia, Germany, and South Africa, among others. However, conflicting reports on the microbial quality of harvested rainwater have been published. To monitor the presence of potential pathogenic bacteria during high-rainfall periods, rainwater from 29 rainwater tanks was sampled on four occasions (during June and August 2012) in a sustainable housing project in Kleinmond, South Africa. This resulted in the collection of 116 harvested rainwater samples in total throughout the sampling period. The identities of the dominant, indigenous, presumptive pathogenic isolates obtained from the rainwater samples throughout the sampling period were confirmed through universal 16S rRNA PCR, and the results revealed that Pseudomonas (19% of samples) was the dominant genus isolated, followed by Aeromonas (16%), Klebsiella (11%), and Enterobacter (9%). PCR assays employing genusspecific primers also confirmed the presence of Aeromonas spp. In addition, on one sampling occasion, Giardia spp. were detected in 25% of the eight tank water samples analyzed. This study highlights the diverse array of pathogenic bacteria that persist in harvested rainwater during high-rainfall periods. The consumption of untreated harvested rainwater could thus pose a potential significant health threat to consumers, especially children and immunocompromised individuals, and it is recommended that harvested rainwater be treated for safe usage as an alternative water source. R ainwater harvesting (RWH) has been described as an alternative improved water source, as this technology could assist in the provision of water directly to households for drinking and domestic purposes (1). Communities are also able to capture and store rainwater for utilization in small-scale productive activities, such as vegetable gardening, which could make a positive contribution toward food security for individuals from lower socioeconomic groups (2). In addition, low economic growth and the effects of climate change have compelled many governments and water authorities worldwide to rely on the process of harvesting rainwater as an alternative source of water (3).A limited number of qualitative studies (4) have been conducted on the usage of rainwater for domestic and potable purposes, and while some studies have determined that harvested rainwater is safe for drinking purposes without prior treatment (5, 6), a few studies have, however, shown that harvested rainwater is, in fact, not suitable for potable purposes (7, 8, 9, 10, 11). As rainwater is collected from roof surfaces, pathogenic organisms that are found in bird feces, insects, mammals, reptiles, and other debris may be flushed into the tanks via the gutters and the tank inlet systems. This phenomenon could pose serious human health risks (12), and between 1978 and 2006, six incidents of disease related to rainwater were reported (10,13,14).Indicator organisms, such as fecal coliforms and Escherichia coli, ...

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Section: Discussionmentioning

confidence: 98%

Distribution of Indigenous Bacterial Pathogens and Potential Pathogens Associated with Roof-Harvested Rainwater

Dobrowsky

Kwaadsteniet

Cloete

et al. 2014

Appl Environ Microbiol

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“…From studies in the USA, it was concluded that coliform regrowth was significantly reduced in chlorinated supplies at AOC (Assimilable Organic Carbon) values below 50-100 µg carbon/litre [23,24], indicating that AOC is much more influential than water age or temperature [25]. Some correlation was found between some types of HPC numbers in the DWDS and temperature and distance from the water treatment works (WTW) [26]. Even though the meaning of HPC is not very clear, it is widely used and much data is available.…”

Section: Hypotheses On Factors Influencing Microbial Water Quality Datamentioning

confidence: 99%

Relating Water Quality and Age in Drinking Water Distribution Systems Using Self-Organising Maps

et al. 2016

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Understanding and managing water quality in drinking water distribution system is essential for public health and wellbeing, but is challenging due to the number and complexity of interacting physical, chemical and biological processes occurring within vast, deteriorating pipe networks. In this paper we explore the application of Self Organising Map techniques to derive such understanding from international data sets, demonstrating how multivariate, non-linear techniques can be used to identify relationships that are not discernible using univariate and/or linear analysis methods for drinking water quality. The paper reports on how various microbial parameters correlated with modelled water ages and were influenced by water temperatures in three drinking water distribution systems.

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“…This is because free residual chlorine dissipates in the distribution network and decreases with increasing levels of contamination (Power and Nagy, 1999). Although the water was chlorinated before distribution, the increase in contamination resulting from the lengthening of the supply interval causes rapid depletion of residual chlorine, further increasing the risk of contamination of the water (Ecura et al, 2011).…”

Section: General Water Qualitymentioning

confidence: 99%

Water Quality at Supply Source and Point of Use in the Kathmandu Valley

Shrestha

Aihara

et al. 2013

J. of Wat. ^|^ Envir. Tech.

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Water scarcity is a major issue in the Kathmandu Valley. Also, from a health perspective, it is important to evaluate the relationship between the quantity and quality of available water. In this study, we identified the water source used, and its availability and quality at the source and point of use. This was done by conducting a questionnaire survey and measuring the level of indicator bacteria and free residual chlorine in domestic water sampled at households. The results showed that most households used mixed water sources, with piped water being preferred for consumption. Nonparametric statistical tests showed that the total coliform was significantly high in source water with a longer supply interval and also high in stored water. In addition, but not of statistical significance, Escherichia coli was mostly detected in source water with a longer supply interval and also in stored water. In contrast, the proportion of samples with free residual chlorine was lower in water with a longer supply interval. Partial correlations showed that a longer cleaning interval of water storage vessels was associated with lower water availability and might lead to contamination of stored water. Therefore, safe storage of water should be promoted at the household level, and water supply services should be improved at the regional scale.

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Relationship between bacterial regrowth and some physical and chemical parameters within Sydney's drinking water distribution system

Cited by 58 publications

References 24 publications

Distribution of Indigenous Bacterial Pathogens and Potential Pathogens Associated with Roof-Harvested Rainwater

Distribution of Indigenous Bacterial Pathogens and Potential Pathogens Associated with Roof-Harvested Rainwater

Relating Water Quality and Age in Drinking Water Distribution Systems Using Self-Organising Maps

Water Quality at Supply Source and Point of Use in the Kathmandu Valley

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