Role of hot water temperature and water system use on Legionella control in a tertiary hospital: An 8-year longitudinal study

2019 ◽  
Vol 149 ◽  
pp. 460-466 ◽  
Author(s):  
Laura Gavaldà ◽  
Marian Garcia-Nuñez ◽  
Sara Quero ◽  
Carmen Gutierrez-Milla ◽  
Miquel Sabrià
Keyword(s):  
Longitudinal Study ◽  
Water Temperature ◽  
Water System ◽  
Tertiary Hospital ◽  
Hot Water ◽  
System Use

Effect of heat flushing on the concentrations of Legionella pneumophila and other heterotrophic microbes in hot water systems of apartment buildings

1996 ◽  
Vol 42 (8) ◽  
pp. 811-818 ◽  
Author(s):  
Outi M. Zacheus ◽  
Pertti J. Martikainen
Keyword(s):  
Water Temperature ◽  
Legionella Pneumophila ◽  
Heterotrophic Bacteria ◽  
Water System ◽  
Water Systems ◽  
Hot Water ◽  
Circulating Water ◽  
Heterotrophic Microbes ◽  
Before And After ◽  
Circulating Water System

The decontamination of Legionella pneumophila and other heterotrophic microbes by heat flushing in four legionellae-positive hot water systems was studied. Before the decontamination procedure, the concentration of legionellae varied from 3.0 × 10−3 to 3.5 × 10−5 cfu/L and the hot water temperature from 43.6 to 51.5 °C. During the contamination the temperature was raised to 60–70 °C. All taps and showers were cleaned from sediments and flushed with hot water twice a day for several minutes. The decontamination lasted for 2–4 weeks. In a few weeks the heat-flushing method reduced the concentration of legionellae below the detection limit (50 cfu/L) in the hot circulating water system just before and after the heat exchanger. The high hot water temperature also decreased the viable counts of heterotrophic bacteria, fungi, and total microbial cells determined by the epifluorescent microscopy. However, the eradication of legionellae failed in a water system where the water temperature remained below 60 °C in some parts of the system. After the decontamination, the temperature of hot water was lowered to 55 °C. Thereafter, all the studied hot water systems were recolonized by legionellae within a few months, showing that the decontamination by heat flushing was temporary. Also, the contamination of other bacteria increased in a few months to the level before decontamination.Key words: legionellae, hot water system, decontamination, water temperature, heterotrophic bacteria.

scholarly journals Experimental determination of cold water temperature at the inlet to solar water storage tanks

2019 ◽  
Vol 116 ◽  
pp. 00106 ◽  
Author(s):  
Miroslaw Zukowski
Keyword(s):  
Water Temperature ◽  
Cold Water ◽  
Tap Water ◽  
Water System ◽  
District Heating ◽  
Hot Water ◽  
Storage Tanks ◽  
Climate Conditions ◽  
Cold Water Temperature

In the present work, results of experimental research on the mains water temperature supplying the Solar Domestic Hot Water system in the period from 2016 to 2018 are shown. The test object is located in the Hotel for Research Assistants on Bialystok University of Technology campus in Poland. One of the elements that will guarantee the correct energy balance of a hot tap-water system is the exact determination of the cold water temperature. The aim of this study is estimation of the temperature of the mains water flowing into the district heating substation and the water feeding directly the heat storage tanks. The research results showed that the average value of the cold water was 14.09°C during the 3 years of measurements. Moreover, it was shown that this temperature increased by about 0.4°C as a result of heat exchange with the air inside the substation. In the article, the author proposed modifications of coefficients in a commonly used model developed by National Renewable Energy Laboratory for determining the temperature of mains water in energy simulations. The proposed changes allow for accurate modelling of the cold water temperature under the climate conditions of north-eastern Poland.

A Preliminary Research on Operation Mode of Condensing Heat Recovery Hot Water Supply System for Water-Cooled Chillers

2011 ◽  
Vol 55-57 ◽  
pp. 618-623
Author(s):  
Wei Cai ◽  
Xiao Man Du ◽  
Zhao Hui Wu
Keyword(s):  
Water Temperature ◽  
Heat Recovery ◽  
High Efficiency ◽  
Operation Mode ◽  
Water System ◽  
Hot Water ◽  
Recovery System ◽  
Heat Recovery System ◽  
Hot Water Supply System ◽  
System Designs

The objective of the present paper is to investigate the condenser heat recovery in water-cooled chiller system. According to the technology characteristics of vapor compression refrigerating cycle, the viewpoint of condensing heat reclaim was proposed, and heat recovery system can be used in buildings. Air-cooled and water-cooled chillers with heat reclaim capability were discussed. Three optimized water system designs were introduced for more heat recovery or higher heating water temperature. The results show that it is very useful for designing and developing the new heat recovery unit with high efficiency, energy conservation, and environmental protection by analyzing the feature feasibility of condenser heat recovery system. The control of entering-condenser water temperature is recommended for higher chiller efficiency and operating steadily, the water system designs of preferential loading and side stream are for more heat recovery.

Peracetic Acid in the Disinfection of a Hospital Water System Contaminated With Legionella Species

2005 ◽  
Vol 26 (5) ◽  
pp. 490-493 ◽  
Author(s):  
Savina Ditommaso ◽  
Cinzia Biasin ◽  
Monica Giacomuzzi ◽  
Carla Maria Zotti ◽  
Alberto Cavanna ◽  
...  
Keyword(s):  
Water Temperature ◽  
Peracetic Acid ◽  
Distribution Systems ◽  
Water Distribution ◽  
Bacterial Load ◽  
Water System ◽  
Hot Water ◽  
Production Plant ◽  
Small Hospital ◽  
Emergency Situations

AbstractObjective:To assess the efficacy of an alternative disinfection method for hospital water distribution systems contaminated with Legionella.Methods:Disinfection with peracetic acid was performed in a small hospital contaminated with L. pneumophila serotype 1. The disinfectant was used at concentrations of 50 ppm (first three surveillance phases) and 1,000 ppm (fourth surveillance phase) for 30 minutes.Results:Environmental monitoring revealed that disinfection was maintained 1 week after treatment; however, levels of recontamination surpassing baseline values were detected after approximately 1 month. Comparison of water temperatures measured at the distal outlets showed a statistically significant association between temperature and bacterial load. The circulating water temperature was found to be lower in the two wards farthest away from the hot water production plant than in other wards. It was thought that the lower water temperature in the two wards promoted the bacterial growth even after disinfection.Conclusion:Peracetic acid may be useful in emergency situations, but does not provide definitive protection even if used monthly.

scholarly journals Energy Conservation and the Promotion ofLegionella pneumophilaGrowth: The Probable Role of Heat Exchangers in a Nosocomial Outbreak

2016 ◽  
Vol 37 (12) ◽  
pp. 1475-1480 ◽  
Author(s):  
Emilie Bédard ◽  
Simon Lévesque ◽  
Philippe Martin ◽  
Linda Pinsonneault ◽  
Kiran Paranjape ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Water Samples ◽  
Heat Exchangers ◽  
Gel Electrophoresis ◽  
Water System ◽  
Pulsed Field Gel Electrophoresis ◽  
Hot Water ◽  
Nosocomial Outbreak ◽  
Hospital Acquired

OBJECTIVETo determine the source of aLegionella pneumophilaserogroup 5 nosocomial outbreak and the role of the heat exchanger installed on the hot water system within the previous year.SETTINGA 400-bed tertiary care university hospital in Sherbrooke, Canada.METHODSHot water samples were collected and cultured forL. pneumophilafrom 25 taps (baths and sinks) within wing A and 9 taps in wing B. Biofilm (5) and 2 L water samples (3) were collected within the heat exchangers forL. pneumophilaculture and detection of protists. Sequence-based typing was performed on strain DNA extracts and pulsed-field gel electrophoresis patterns were analyzed.RESULTSFollowing 2 cases of hospital-acquired legionellosis, the hot water system investigation revealed a large proportion ofL. pneumophilaserogroup 5 positive taps (22/25 in wing A and 5/9 in wing B). High positivity was also detected in the heat exchanger of wing A in water samples (3/3) and swabs from the heat exchanger (4/5). The outbreak genotyping investigation identified the hot water system as the source of infections. Genotyping results revealed that all isolated environmental strains harbored the same related pulsed-field gel electrophoresis pattern and sequence-based type.CONCLUSIONSTwo cases of hospital-acquired legionellosis occurred in the year following the installation of a heat exchanger to preheat hospital hot water. No cases were reported previously, although the sameL. pneumophilastrain was isolated from the hot water system in 1995. The heat exchanger promotedL. pneumophilagrowth and may have contributed to confirmed clinical cases.Infect. Control Hosp. Epidemiol.2016;1475–1480

scholarly journals Factors Influencing Legionella Contamination of Domestic Household Showers

Pathogens ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 27 ◽  
Author(s):  
Deanna Hayes-Phillips ◽  
Richard Bentham ◽  
Kirstin Ross ◽  
Harriet Whiley
Keyword(s):  
Risk Factors ◽  
Water Temperature ◽  
Legionella Pneumophila ◽  
Public Awareness ◽  
Water System ◽  
South Australia ◽  
Hot Water ◽  
Factors Associated ◽  
Potential Source ◽  
Legionnaires Disease

Legionnaires’ disease is a potentially fatal pneumonia like infection caused by inhalation or aspiration of water particles contaminated with pathogenic Legionella spp. Household showers have been identified as a potential source of sporadic, community-acquired Legionnaires’ disease. This study used qPCR to enumerate Legionella spp. and Legionella pneumophila in water samples collected from domestic showers across metropolitan Adelaide, South Australia. A survey was used to identify risk factors associated with contamination and to examine awareness of Legionella control in the home. The hot water temperature was also measured. A total of 74.6% (50/68) and 64.2% (43/68) showers were positive for Legionella spp. and L. pneumophila, respectively. Statistically significant associations were found between Legionella spp. concentration and maximum hot water temperature (p = 0.000), frequency of shower use (p = 0.000) and age of house (p = 0.037). Lower Legionella spp. concentrations were associated with higher hot water temperatures, showers used at least every week and houses less than 5 years old. However, examination of risk factors associated with L. pneumophila found that there were no statistically significant associations (p > 0.05) with L. pneumophila concentrations and temperature, type of hot water system, age of system, age of house or frequency of use. This study demonstrated that domestic showers were frequently colonized by Legionella spp. and L. pneumophila and should be considered a potential source of sporadic Legionnaires’ disease. Increasing hot water temperature and running showers every week to enable water sitting in pipes to be replenished by the municipal water supply were identified as strategies to reduce the risk of Legionella in showers. The lack of public awareness in this study identified the need for public health campaigns to inform vulnerable populations of the steps they can take to reduce the risk of Legionella contamination and exposure.

Sporadic Legionnaires' disease: the role of domestic electric hot-water tanks

2011 ◽  
Vol 140 (1) ◽  
pp. 172-181 ◽  
Author(s):  
S. F. DUFRESNE ◽  
M. C. LOCAS ◽  
A. DUCHESNE ◽  
C. RESTIERI ◽  
J. ISMAÏL ◽  
...  
Keyword(s):  
Potable Water ◽  
Water System ◽  
Water Systems ◽  
Pulsed Field Gel Electrophoresis ◽  
Hot Water ◽  
Clinical Isolates ◽  
Domestic Hot Water ◽  
Legionnaires Disease ◽  
Water Tanks

SUMMARYSporadic community-acquired legionellosis (SCAL) can be acquired through contaminated aerosols from residential potable water. Electricity-dependent hot-water tanks are widely used in the province of Quebec (Canada) and have been shown to be frequently contaminated withLegionellaspp. We prospectively investigated the homes of culture-proven SCAL patients from Quebec in order to establish the proportion of patients whose domestic potable hot-water system was contaminated with the sameLegionellaisolate that caused their pneumonia. Water samples were collected in each patient's home. Environmental and clinical isolates were compared using pulsed-field gel electrophoresis. Thirty-six patients were enrolled into the study.Legionellawas recovered in 12/36 (33%) homes. The residential and clinical isolates were found to be microbiologically related in 5/36 (14%) patients. Contaminated electricity-heated domestic hot-water systems contribute to the acquisition of SCAL. The proportion is similar to previous reports, but may be underestimated.

scholarly journals A Novel Dynamic Approach to Cost-Optimal Energy Performance Calculations of a Solar Hot Water System in an nZEB Multi-Apartment Building

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 509
Author(s):  
Filip Patrčević ◽  
Damir Dović ◽  
Ivan Horvat ◽  
Petar Filipović
Keyword(s):  
Water Temperature ◽  
Storage Tank ◽  
Water System ◽  
Optimal Solution ◽  
Energy Performance ◽  
Hot Water ◽  
Solar Collectors ◽  
Apartment Building ◽  
Calculation Algorithm ◽  
Optimal Energy

This paper presents the methodology for conducting a cost-optimal energy performance calculation of a solar hot water system, used for space heating and domestic hot water needs. The calculation is based on dynamic hourly methods, according to the new Energy Performance of Buildings’ (EPB) set of standards EN 15316:2017, and a revision of the standard EN 15316-5:2017 from the year 2021, dealing with storage-tank water temperature calculations. The paper provides proposals for modifications to these newly introduced standards, in order to overcome the observed ambiguities and shortcomings. The calculation of annual energy performance of a building was performed on an hourly basis over a year for the reference of an nZEB multi-apartment building, for a climate area of the city of Zagreb, taking into account water temperature change in the layers of the storage tank connected to solar collectors and hot water boilers. The cost-optimal solution was then determined by varying individual parameters of the building technical system. The influence of these parameters on the energy efficiency of the building was analyzed in detail. Furthermore, the results were compared against those obtained by the Croatian calculation algorithm based on the previous set of EPB standards, EN 15316:2008, currently used EU-wide for the energy performance certification of buildings. The results indicated that the calculation methods of the present algorithm underestimated the consumption of building primary energy by 12%. The energy delivered by solar collectors was underestimated by 18%.

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