Evaluation of Legionella spp. Colonization in Residential Buildings Having Solar Thermal System for Hot Water Production

Despite an increase of literature data on Legionella spp. presence in private water systems, epidemiological reports assert a continuing high incidence of Legionnaires’ disease infection in Italy. In this study, we report a survey on Legionella spp. colonization in 58 buildings with solar thermal systems for hot water production (TB). In all buildings, Legionella spp. presence was enumerated in hot and cold water samples. Microbiological potability standards of cold water were also evaluated. Legionella spp. was detected in 40% of the buildings. Moreover, we detected correlations between the count of Legionella spp. and the presence of the optimal temperature for the microorganism growth (less than 40 °C). Our results showed that cold water was free from microbiological hazards, but Legionella spp., was detected when the mean cold water temperature was 19.1 ± 2.2 °C. This may considered close to the suboptimal value for the Legionella growth (more then 20 °C). In conclusion, we observed the presence of a Legionnaires’ disease risk and the need of some strategies aimed to reduce it, such as the application of training programs for all the workers involved in water systems maintenance.

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Colonization of Legionella spp. in Hot and Cold Water Networks of Residential Buildings in Pisa District (Tuscany, Italy): A Five-Years Survey

10.20944/preprints201905.0186.v1 ◽

2019 ◽

Author(s):

Michele Totaro ◽

Anna Laura Costa ◽

Lorenzo Frendo ◽

Erica De Vita ◽

Serena Giorgi ◽

...

Keyword(s):

Cold Water ◽

Disease Risk ◽

Residential Buildings ◽

Hot Water ◽

Coliform Bacteria ◽

Published Data ◽

Water Production ◽

Water Networks ◽

Cold Water Temperature ◽

Solar Thermal System

Literature data on Legionella spp. presence in houses water networks have been increasing during the last years, but epidemiological reports assert a high incidence of Legionnaires’ disease infection in Italy. Updating our previously published data, we report a five-year survey on Legionella spp. colonization in 235 buildings with an independent hot water production (IB); 82 buildings with a central hot water production (CB); and 58 buildings with a solar thermal system for hot water production (TB). In all the 375 buildings Legionella spp. was researched in hot and cold water samples and microbiological potability standards of cold water were evaluated. Legionella spp. was detected in 27% of the water networks, mostly in CB and TB. We detected correlations between the presence of bacteria and some physical-chemical parameters (low chlorine level and optimal temperature for Legionella spp. growth). Cold water resulted free from microbiological hazards, except for coliform bacteria isolated in three separate cases, and Legionella spp., detected when cold water temperature was about 20°C. After a five-year survey we confirm the presence of a Legionnaires’ disease risk and the need of training programs for all the workers involved in residential water systems management.

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Computational framework for evaluating risk trade-offs in costs associated with Legionnaires’ Disease risk, energy, and scalding risk for hospital hot water systems

Environmental Science Water Research & Technology ◽

10.1039/d1ew00397f ◽

2021 ◽

Author(s):

Ashley Heida ◽

Alexis Mraz ◽

Mark Hamilton ◽

Mark Weir ◽

Kerry A Hamilton

Keyword(s):

Legionella Pneumophila ◽

Disease Risk ◽

Disease Outbreaks ◽

Febrile Illness ◽

Water Systems ◽

Hot Water ◽

Computational Framework ◽

Trade Offs ◽

Pontiac Fever ◽

Legionnaires Disease

Legionella pneumophila are bacteria that when inhaled cause Legionnaires’ Disease (LD) and febrile illness Pontiac Fever. As of 2014, LD is the most frequent cause of waterborne disease outbreaks due...

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Presence of Legionella spp. in Hot Water Networks of Different Italian Residential Buildings: A Three-Year Survey

10.20944/preprints201710.0058.v1 ◽

2017 ◽

Author(s):

Michele Totaro ◽

Paola Valentini ◽

Anna Laura Costa ◽

Lorenzo Frendo ◽

Alessia Cappello ◽

...

Keyword(s):

Legionella Pneumophila ◽

Water Samples ◽

Cold Water ◽

Residential Buildings ◽

Hot Water ◽

Water Production ◽

Water Networks ◽

Legionella Species ◽

Solar Thermal System ◽

And Control

Although the European reports highlight an increase in community-acquired Legionnaires’ disease cases, the risk of Legionella spp. in private houses is underestimated. In Pisa (Italy) we performed a three-year survey on Legionella presence in 121 buildings with an independent hot water production (IB); 64 buildings with a central hot water production (CB); and 35 buildings with a solar thermal system for hot water production (TB). From all the 220 buildings Legionella spp. was researched in two hot water samples collected either at the recirculation point or at on the first floor and on the last floor, while the potable water quality was analyzed in three cold water samples collected at the inlet from the aqueduct network, at the exit from the autoclave, and at the most remove remote? tap. Legionella pneumophila sg1, Legionella pneumophila sg2-16 and not-pneumophila Legionella species were detected in 26% of the hot water networks, mostly in CB and TB. In these buildings we detected correlations between the presence of Legionella and the total chlorine concentration decrease or/and the increase of the temperature. Cold water resulted free from microbiological hazards, with the exception of Serratia liquefaciens and Enterobacter cloacae isolated at the exit from two different autoclaves. We observed an increase in total microbial counts at 22 and 37°C between the samples collected at the most remote taps compared to the ones collected at the inlet from the aqueduct. The study highlights a condition of potential risk for susceptible categories of population and supports the need for measures of risk assessment and control.

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Legionella spp. Colonization in Water Systems of Hotels Linked with Travel-Associated Legionnaires’ Disease

Water ◽

10.3390/w13162243 ◽

2021 ◽

Vol 13 (16) ◽

pp. 2243

Author(s):

Antonios Papadakis ◽

Maria Keramarou ◽

Dimosthenis Chochlakis ◽

Vassilios Sandalakis ◽

Varvara A. Mouchtouri ◽

...

Keyword(s):

Water Supply ◽

Legionella Pneumophila ◽

Cold Water ◽

Water Systems ◽

Hot Water ◽

Water Supply Systems ◽

Surveillance Network ◽

Legionnaires Disease ◽

Hot Water Supply ◽

Supply Systems

Hotel water systems colonized with Legionella spp. have been the source of travel-associated Legionnaires’ disease, and cases, clusters and outbreaks continue to be reported worldwide each year. A total of 132 hotels linked with travel-associated Legionnaires’ disease, as reported through the European Legionnaires’ Disease Surveillance Network, were inspected and tested for Legionella spp. during 2000–2019 by the public health authorities of the island of Crete (Greece). A total of 3311 samples were collected: 1885 (56.93%) from cold water supply systems, 1387 (41.89%) from hot water supply systems, 37 (1.12%) were swab samples and two (0.06%) were soil. Of those, 685 (20.69%), were collected from 83 (62.89%) hotels, testing positive (≥50 CFU/L) for Legionella pneumophila) serogroups 1–10, 12–14 and non-pneumophila species (L. anisa, L. erythra, L. tusconensis, L. taurinensis, L. birminghamensis, L. rubrilucens, L. londiniesis, L. oakridgensis, L. santicrusis, L. brunensis, L. maceacherii). The most frequently isolated L. pneumophila serogroups were 1 (27.92%) and 3 (17.08%). Significantly higher isolation rates were obtained from hot water supply systems (25.96%) versus cold water systems (16.98%) and swab samples (13.51%). A Relative Risk (R.R.) > 1 (p < 0.0001) was calculated for hot water temperature <55 °C (R.R.: 4.43), chlorine concentrations <0.2 mg/L (R.R.: 2.69), star ratings <4 (R.R.: 1.73) and absence of Water Safety Plan implementation (R.R.: 1.57).

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Dynamic modeling of solar thermal collectors for domestic hot water production using TRNSYS

Euro-Mediterranean Journal for Environmental Integration ◽

10.1007/s41207-020-00223-6 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Intissar Harrabi ◽

Mohamed Hamdi ◽

Amira Bessifi ◽

Majdi Hazami

Keyword(s):

Dynamic Modeling ◽

Hot Water ◽

Solar Thermal ◽

Water Production ◽

Domestic Hot Water ◽

Solar Thermal Collectors

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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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Non-residential water demand model validated with extensive measurements and surveys

Drinking Water Engineering and Science ◽

10.5194/dwes-6-99-2013 ◽

2013 ◽

Vol 6 (2) ◽

pp. 99-114 ◽

Cited By ~ 3

Author(s):

E. J. Pieterse-Quirijns ◽

E. J. M. Blokker ◽

E. van der Blom ◽

J. H. G. Vreeburg

Keyword(s):

Water Demand ◽

Cold Water ◽

Residential Buildings ◽

Water System ◽

Hot Water ◽

Demand Model ◽

Water Heater ◽

Peak Demand ◽

Demand Equations ◽

Proper Estimation

Abstract. Existing Dutch guidelines for the design of the drinking water and hot water system of non-residential buildings are based on outdated assumptions on peak water demand or on unfounded assumptions on hot water demand. They generally overestimate peak demand values required for the design of an efficient and reliable water system. Recently, a procedure was developed based on the end-use model SIMDEUM to derive design-demand-equations for peak demand values of both cold and hot water during various time steps for several types and sizes of non-residential buildings, viz. offices, hotels and nursing homes. In this paper, the design-demand-equations are validated with measurements of cold and hot water patterns on a per second base and with surveys. The good correlation between the simulated water demand patterns and the measured patterns indicates that the basis of the design-demand-equations, the SIMDEUM simulated standardised buildings, is solid. Surveys were held to investigate whether the construction of the standardised buildings based on the dominant variable corresponds with practice. Surveys show that it is difficult to find relationships to equip the standardised buildings with users and appliances. However, the validation proves that with a proper estimation of the number of users and appliances in only the dominant functional room of the standardised buildings, SIMDEUM renders a realistic cold and hot water diurnal demand pattern. Furthermore, the new design-demand-equations based on these standardised buildings give a better prediction of the measured peak values for cold water flow than the existing guidelines. Moreover, the new design-demand-equations can predict hot water use well. In this paper it is illustrated that the new design-demand-equations lead to reliable and improved designs of building installations and water heater capacity, resulting in more hygienic and economical installations.

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