Legionella species are the etiological agent of Legionnaires' disease, a pathology easily contracted from water circuits and by the inhalation of aerosol droplets. This bacterium mainly proliferates in water: Legionella pneumophila is the most commonly isolated specie in water environments and consequently in water system, although further Legionella species have frequently been isolated, including Legionella dumoffii. The simultaneous presence of the two species in the water system can therefore lead to the simultaneous infection of several people, giving rise to harmful outbreaks. Ultraviolet inactivation of waterborne microorganisms offers a rapid and effective treatment technique and recently is getting more attention mostly to eliminate unsafe level of contamination. To tackle the issue, the inactivation of the two species of Legionella spp., namely L. pneumophila and L. dumoffii, by means of UV-A light emitting diodes (UV-A LED) system is explored. We used a commercially available UV-A LED at 365 nm wavelength, and the UV-A dose is given incrementally to the Legionellae with a concentration of 106 CFU/mL in 0.9% NaCl (aq) solution. In this study, with a UV-A-dose of 1700 mJ/cm2, the log-reduction of 3-log (99.9% inactivation) for L. pneumophila and 2.1-log (99.1% inactivation) for L. dumoffii of the contaminated water are achieved. The Electrical Energy per Order (EEO) is evaluated and showed this system is more economic and efficient in comparison with UV-C and UV-B LEDs. Following the support of this preliminary study with additional tests, aiming to validate the technology, we expect this device may be installed in water plants such as cooling systems or any water purification station in either industrial or home scales to reduce the risk of this infectious disease, preventing consumers' health.

A sequential utilization of the UV-A (365 nm) fluence rate for disinfection of water, contaminated with Legionella pneumophila and Legionella dumoffii / Allahyari, E.; Carraturo, F.; De Risi, A.; Nappo, A.; Morelli, M.; Cajora, A.; Guida, M.. - In: ENVIRONMENTAL POLLUTION. - ISSN 0269-7491. - 304:(2022), p. 119224. [10.1016/j.envpol.2022.119224]

A sequential utilization of the UV-A (365 nm) fluence rate for disinfection of water, contaminated with Legionella pneumophila and Legionella dumoffii

Allahyari E.;Carraturo F.;De Risi A.;Nappo A.;Morelli M.;Guida M.
2022

Abstract

Legionella species are the etiological agent of Legionnaires' disease, a pathology easily contracted from water circuits and by the inhalation of aerosol droplets. This bacterium mainly proliferates in water: Legionella pneumophila is the most commonly isolated specie in water environments and consequently in water system, although further Legionella species have frequently been isolated, including Legionella dumoffii. The simultaneous presence of the two species in the water system can therefore lead to the simultaneous infection of several people, giving rise to harmful outbreaks. Ultraviolet inactivation of waterborne microorganisms offers a rapid and effective treatment technique and recently is getting more attention mostly to eliminate unsafe level of contamination. To tackle the issue, the inactivation of the two species of Legionella spp., namely L. pneumophila and L. dumoffii, by means of UV-A light emitting diodes (UV-A LED) system is explored. We used a commercially available UV-A LED at 365 nm wavelength, and the UV-A dose is given incrementally to the Legionellae with a concentration of 106 CFU/mL in 0.9% NaCl (aq) solution. In this study, with a UV-A-dose of 1700 mJ/cm2, the log-reduction of 3-log (99.9% inactivation) for L. pneumophila and 2.1-log (99.1% inactivation) for L. dumoffii of the contaminated water are achieved. The Electrical Energy per Order (EEO) is evaluated and showed this system is more economic and efficient in comparison with UV-C and UV-B LEDs. Following the support of this preliminary study with additional tests, aiming to validate the technology, we expect this device may be installed in water plants such as cooling systems or any water purification station in either industrial or home scales to reduce the risk of this infectious disease, preventing consumers' health.
2022
A sequential utilization of the UV-A (365 nm) fluence rate for disinfection of water, contaminated with Legionella pneumophila and Legionella dumoffii / Allahyari, E.; Carraturo, F.; De Risi, A.; Nappo, A.; Morelli, M.; Cajora, A.; Guida, M.. - In: ENVIRONMENTAL POLLUTION. - ISSN 0269-7491. - 304:(2022), p. 119224. [10.1016/j.envpol.2022.119224]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/884645
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 7
  • ???jsp.display-item.citation.isi??? 5
social impact