Getting into hot water: Water quality in tropical lakes in relation to their utilisation

There is a need for accessible and low-cost microbiological water quality testing in contexts where diarrheal illness is a major public health concern. In most cases, the quantification of Escherichia coli and other microbial indicators by conventional culture methods requires an incubation step for processed samples at specific temperatures for bacterial growth over a prescribed time. However, incubators can be the most expensive equipment required for such microbial analyses, limiting the number and scope of water quality testing available in low-resource contexts. In this study, a low-cost incubator was developed using a locally available expanded polystyrene (EPS) foam cooler, with two water bottles filled with hot water to heat incubator to a target of 35 °C. The EPS incubator performance was validated by processing 150 water samples in duplicates using the Colilert Quanti-tray/2000 system, incubated in either the EPS incubator or a standard laboratory incubator set at 35 °C. Statistically significant correlations of results indicated that the quantification of E. coli was comparable between both methods. Risk categorizations from standard and EPS incubation results agreed for 141 of 150 (94%) samples, with zero false negatives. In addition to being reasonably mobile the EPS incubator would reduce the cost of such water quality testing, thus potentially increasing the scope of water quality testing coverage.

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Water Quality as a Predictor of Legionella Positivity of Building Water Systems

Pathogens ◽

10.3390/pathogens8040295 ◽

2019 ◽

Vol 8 (4) ◽

pp. 295 ◽

Cited By ~ 4

Author(s):

David Pierre ◽

Julianne L. Baron ◽

Xiao Ma ◽

Frank P. Sidari ◽

Marilyn M. Wagener ◽

...

Keyword(s):

Water Quality ◽

Cold Water ◽

Water Systems ◽

Quality Parameters ◽

Free Chlorine ◽

Hot Water ◽

Water Quality Parameters ◽

Plate Count ◽

Poor Correlation ◽

Distal Site

Testing drinking water systems for the presence of Legionella colonization is a proactive approach to assess and reduce the risk of Legionnaires’ disease. Previous studies suggest that there may be a link between Legionella positivity in the hot water return line or certain water quality parameters (temperature, free chlorine residual, etc.) with distal site Legionella positivity. It has been suggested that these measurements could be used as a surrogate for testing for Legionella in building water systems. We evaluated the relationship between hot water return line Legionella positivity and other water quality parameters and Legionella colonization in premise plumbing systems by testing 269 samples from domestic cold and hot water samples in 28 buildings. The hot water return line Legionella positivity and distal site positivity only demonstrated a 77.8% concordance rate. Hot water return line Legionella positivity compared to distal site positivity had a sensitivity of 55% and a specificity of 96%. There was poor correlation and a low positive predictive value between the hot water return line and distal outlet positivity. There was no correlation between Legionella distal site positivity and total bacteria (heterotrophic plate count), pH, free chlorine, calcium, magnesium, zinc, manganese, copper, temperature, total organic carbon, or incoming cold-water chlorine concentration. These findings suggest that hot water return line Legionella positivity and other water quality parameters are not predictive of distal site positivity and should not be used alone to determine the building’s Legionella colonization rate and effectiveness of water management programs.

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IN AND OUT OF HOT WATER: A CASE STUDY OF DFW AIRPORT'S RECENT DEICING AND WATER QUALITY HISTORY

Proceedings of the Water Environment Federation ◽

10.2175/193864703784343640 ◽

2003 ◽

Vol 2003 (2) ◽

pp. 365-388

Author(s):

Sarah K. Walls ◽

Daniel Bergman ◽

Enos L. Stover

Keyword(s):

Water Quality ◽

Hot Water

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Managing Water Quality in Premise Plumbing: Subject Matter Experts’ Perspectives and a Systematic Review of Guidance Documents

Water ◽

10.3390/w12020347 ◽

2020 ◽

Vol 12 (2) ◽

pp. 347 ◽

Cited By ~ 3

Author(s):

Rajveer Singh ◽

Kerry A. Hamilton ◽

Md Rasheduzzaman ◽

Zhao Yang ◽

Saurajyoti Kar ◽

...

Keyword(s):

Water Quality ◽

Water Temperature ◽

Subject Matter ◽

Opportunistic Pathogen ◽

Hot Water ◽

Guidance Document ◽

Subject Matter Experts ◽

Water Heater ◽

Expert Opinions ◽

Guidance Documents

Although many guidance documents have been developed to inform the design and operation of building water systems to ensure safe water quality, there is a lack of consensus on some topics. This study interviewed 22 subject matter experts (SMEs) to identify topics of concern for managing water quality in buildings and compared SME views with information available on these topics in 15 systematically screened important guidance documents. The study found 18 design and 11 operational topics as critical for managing water quality in buildings. No one guidance document addressed all these topics, suggesting that a compendium of available guidance is needed. SMEs most frequently recommended temperature and residual disinfectant measurements as good parameters for monitoring overall building water quality. Both SME and guidance document recommendations for temperature for controlling opportunistic pathogen growth were reasonably consistent with water heater setpoint >60 °C. However, hot water temperature recommendations varied between 50 and 55 °C for other locations (i.e., the water temperature at the tap or end of the return loop). On the contrary, recommendations for disinfectant residual levels (0.2–2.0 mg/L), flushing frequency (1–14 days), and allowable time for hot water to reach the tap (10–60 s) were not consistent. While this study was able to reconcile diverging views on some of the water quality topics, such as identifying common guidance for water heater set point to at least 60 °C, it also highlights lack of definitive guidance on other critical topics, such as residual level, flushing frequency, hot water time to tap, and the use of thermostatic mixing valves, indicating that these are significant knowledge gaps that need further investigation. The study concludes that there is a need for developing evidence-based guidance, particularly on the topics where expert opinions diverged.

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Hydrodynamic and ecological 3D modeling in tropical lakes

SN Applied Sciences ◽

10.1007/s42452-021-04272-6 ◽

2021 ◽

Vol 3 (4) ◽

Author(s):

Lais F. Amorim ◽

José Rodolfo Scarati Martins ◽

Fabio F. Nogueira ◽

Fabio P. Silva ◽

Bárbara P. S. Duarte ◽

...

Keyword(s):

Water Quality ◽

High Frequency ◽

3D Model ◽

3D Models ◽

Tropical Lakes ◽

Hydrodynamic Behavior ◽

Frequency Monitoring ◽

Lakes And Reservoirs ◽

Bed Material ◽

Good Agreement

AbstractConservation and improvement of water quality in water bodies is an important matter to maintain all of its uses as well as other human necessities like microclimate regulation and leisure. Lakes and reservoirs have a complex circulation behavior with vertical temperature profiles changes along the time, resulting in differences in water density and a vertical stratification condition. This characteristic can directly affect the water quality conditions perturbing its main indicators. This study aims to evaluate the quasi-3D models' capacity to represent the hydrodynamic behavior of a tropical lake and its effects on the main variables that characterize its water quality. To achieve this objective, high-frequency monitoring data were collected, the lake was represented in a quasi-3D model, and the accuracy of the result was evaluated by applying statistical indices. The evaluation showed good agreement between field measures and simulated results when compared with other applications. The connections between hydrodynamic behavior and water quality were seen with the simulations results analysis, which showed that mixing events and long stratification periods perturb the water quality, the first with re-suspended bed material and the second blocking the surface and bottom exchanges. The application of a 3D model gives the capacity to reproduce the reservoir spatial variability and its vertical profiles, which is necessary to study the constituents' distributions across the water column. Therefore, the hydrodynamic and water quality behavior of lakes was accurately represented by the model, as well as the importance of improving high-frequency monitoring techniques.

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Exergy, economic and water quality analysis of solar pure water and hot water co-production system: an experimental investigation

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2021.117182 ◽

2021 ◽

pp. 117182

Author(s):

Xizheng Zhou ◽

Lang Wu ◽

Guohui Xiao Experiments ◽

Zhineng Tong ◽

Hao Li

Keyword(s):

Water Quality ◽

Experimental Investigation ◽

Production System ◽

Pure Water ◽

Hot Water ◽

Quality Analysis ◽

Water Quality Analysis

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Legionella sp. in water systems in public teaching and education facilities in Małopolskie voivodeship in 2016

Przeglad Epidemiologiczny ◽

10.32394/pe.73.21 ◽

2019 ◽

pp. 227-237

Author(s):

Jacek Żak ◽

Karolina Orlińska ◽

Magdalena Koperny ◽

Jarosław Foremny ◽

Katarzyna Bandoła ◽

...

Keyword(s):

Water Quality ◽

Water Supply ◽

Water Samples ◽

Distribution Systems ◽

Water Distribution ◽

Objective Assessment ◽

Water Systems ◽

Hot Water ◽

Water Spray ◽

Taking Action

INTRODUCTION. Bacteria Legionella sp. found in water distribution systems, especially warm, transferred to water spray devices for aerators and showers in the form of aerosols infected with them become a threat to the human inhaler. OBJECTIVE. Assessment of colonization of the water supply network with Legionella bacteria in teaching and education facilities in Małopolska in 2016 year. MATERIAL AND METHODS. The results of water samples taken from plumbing installations were analyzed in teaching and education facilities by employees of the State Sanitary Inspection of the Lesser Poland Voivodeship. RESULTS. The results of 366 testing hot water samples in 111 teaching and education centers in Małopolska have shown that in 123 testing samples (33,6%) in 48 centers (43,2%) the water sample was colonized with Legionella sp. and the water quality did not meet the requirements of the current ordinance of the Minister of Health. CONCLUSIONS. It is justified to periodically monitor the presence of Legionella sp. in water supply installations in teaching and education centers and taking action to reduce the colonization of these bacteria.

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Chemistry of the Interfaces of an Electric Water Heater: Implications from an Input-Output Analysis

Water Quality Research Journal ◽

10.2166/wqrj.2010.011 ◽

2010 ◽

Vol 45 (1) ◽

pp. 99-109

Author(s):

Martin B. Hocking

Keyword(s):

Water Quality ◽

Inductively Coupled Plasma ◽

Cold Water ◽

Water System ◽

Hot Water ◽

Water Heater ◽

Domestic Water ◽

Output Analysis ◽

Inductively Coupled ◽

Copper Zinc

Abstract In a case study, this paper responds to increasing public interest in water quality issues by investigating chemical changes as water passes through a domestic water hot water system. Elemental changes were measured by simultaneous analysis of the incoming and outgoing water streams and the deposited sediment from an electric water heater tank. The results may alter some long-held beliefs. The collected and dried sediment from the tank was analyzed for thirty common elements by inductively coupled plasma and atomic absorption techniques. Of the 25 elements found, the dominant seven in order of concentration were magnesium, aluminum, copper, zinc, manganese, iron, and sodium, as well as some surprising traces of other elements. The cold water input and the heated output were also analyzed for thirteen measurable elements. In the heated water output, magnesium had a massive 151% increase in concentration, followed by much more modest increases shown by arsenic, calcium, lead, potassium, silicon, and strontium. None of these mass balance changes compromised the potability of the water. The six elements, aluminum, boron, copper, iron, manganese, and sodium, showed decreases in aqueous concentrations on heating, thereby improving the water quality.

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