Effects of FLONLIZER®, Ultraviolet Sterilizer, on <i>Legionella</i> Species Inhabiting Cooling Tower Water

Yamamoto, Hiroyuki; Urakami, Itsuo; Nakano, Koji; Ikedo, Masanari; Yabuuchi, Eiko

doi:10.1111/j.1348-0421.1987.tb03136.x

Cited by 14 publications

(3 citation statements)

References 15 publications

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“…pneumophila has been obtained by U.V. doses of 2.8-6.2 mWs cm-2 (Antopol and Ellner 1979;Yamamoto et al 1987). Thus, in the field experiment reported here, the elimination of legionellas in the radiator was not as efficient as in the laboratory studies mentioned above.…”

Section: Discussioncontrasting

confidence: 57%

Growth of legionella and other heterotrophic bacteria in a circulating cooling water system exposed to ultraviolet irradiation

Kusnetsov

Keskitalo

Ahonen³

et al. 1994

Journal of Applied Bacteriology

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The effect of ultraviolet irradiation on the growth and occurrence of legionella and other heterotrophic bacteria in a circulating cooling water system was studied. Water of the reservoir was circulated once in 28 h through a side-stream open channel u.v. radiator consisting of two lamps. Viable counts of legionellas and heterotrophic bacteria in water immediately after the u.v. treatment were 0-12 and 0.7-1.2% of those in the reservoir, respectively. U.v. irradiation increased the concentration of easily assimilable organic carbon. In the u.v. irradiated water samples incubated in the laboratory the viable counts of heterotrophic bacteria reached the counts in reservoir water within 5 d. The increase in viable counts was mainly due to reactivation of bacterial cells damaged by u.v. light, not because of bacterial multiplication. Despite u.v. irradiation the bacterial numbers in the reservoir water, including legionellas, did not decrease during the experimental period of 33 d. The main growth of bacteria in the reservoir occurred in biofilm and sediment, which were never exposed to u.v. irradiation.

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Section: Discussioncontrasting

confidence: 57%

Growth of legionella and other heterotrophic bacteria in a circulating cooling water system exposed to ultraviolet irradiation

Kusnetsov

Keskitalo

Ahonen³

et al. 1994

Journal of Applied Bacteriology

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“…There is no residual effect, and chemicals are not added once the water leaves the UV reactor [20]. Yamamoto et al [21] confirmed the killing rate of Legionella, based on a dose of UV light when a UV sterilizer generating a wave length of 254 nm was used. The results of the experiments confirmed that a UV sterilizer could be used to control Legionella in a cooling tower.…”

Section: Introductionmentioning

confidence: 99%

Impact of an Ultraviolet Reactor on the Improvement of Air Quality Leaving a Direct Evaporative Cooler

et al. 2018

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The purpose of this study is to improve microbial air quality by improving water quality, particularly concerning microbiological aspects, by applying an ultraviolet water purifier system to a direct evaporative cooling (DEC) system. A direct evaporative cooler is an air cooling technique that uses the evaporation of water. Most DECs recirculate water to reduce water use. Evaporative cooling pads and water are biologically contaminated by recirculating water. This contamination can develop into air contamination and cause respiratory illnesses in occupants. It is necessary to use sterilized water in a DEC to prevent respiratory diseases and maintain air quality. In this study, we examine whether improvements in water quality in a DEC affect air quality by dividing experiments into a control group (Control) and a treated group (UV-treated). In the control group, the degree of contamination was measured when a DEC operated for four weeks without ultraviolet water treatment. In UV-treated, the degree of contamination was measured when UV water treatment was applied to a DEC for four weeks. In both Control and UV-treated, microbes were sampled from the water, the evaporative cooling pad surface, and the DEC inlet and outlet air samples in order to compare the levels of contamination. The surface was measured once at four points, and the air was measured four times at two points. A comparison of the two experiments indicated that the degree of microbial contamination of water and air was significantly reduced in the UV-treated group when compared to that in the control group. When the pollution degree of the evaporative cooling pad was compared to the degree of air pollution, it was difficult to obtain a correlation between the two factors, although the results confirmed that the contamination of the evaporative cooling pad caused water pollution. Therefore, it is necessary to operate a water treatment system to maintain the clean air in DECs.

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“…Even cooling-tower water contaminated with dirt could be sterilized effectively by a UV sterilizer at an optimum flow rate (10). UV sterilizers tested have set up the optimum flow rate for killing microorganisms in cooling-tower water.…”

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confidence: 99%

Effects of Biocidal Treatments to Inhibit the Growth of Legionellae and Other Microorganisms in Cooling Towers

Yamamoto

Ezaki

Ikedo

et al. 1991

Microbiology and Immunology

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The effects of biocidal treatments for cooling towers were examined through the use of chemicals and ultraviolet irradiation to inhibit the growth of legionellae and other microorganisms. In the water of cooling towers without continuous biocidal treatments, heterotrophic bacteria and bacterivorous protozoan first appeared, and then legionellae increased up to 104 CFU/100 ml. When a UV sterilizer was connected to the cooling tower, the legionellae count was 1/10 or 1/100 of that in the nontreated tower water. In the water of towers supplemented continuously with the biocidal chemicals, legionellae were not found during a 4-month period. The biocidal treatments tested were proved to suppress the increase of legionellae in cooling-tower water, and thus are useful in preventing the outbreak of legionellosis due to inhalation of contaminated aerosol from the cooling tower system.

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Effects of FLONLIZER®, Ultraviolet Sterilizer, on Legionella Species Inhabiting Cooling Tower Water

Cited by 14 publications

References 15 publications

Growth of legionella and other heterotrophic bacteria in a circulating cooling water system exposed to ultraviolet irradiation

Growth of legionella and other heterotrophic bacteria in a circulating cooling water system exposed to ultraviolet irradiation

Impact of an Ultraviolet Reactor on the Improvement of Air Quality Leaving a Direct Evaporative Cooler

Effects of Biocidal Treatments to Inhibit the Growth of Legionellae and Other Microorganisms in Cooling Towers

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