Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection

A system consisting of one UV-A (365 nm) and two UV-C (265 nm) light-emitting diodes (LEDs) was built to evaluate the effect of single and combined exposures to UV-A and UV-C LEDs on Klebsiella pneumoniae and Escherichia coli inactivation and subsequent reactivation. The dose was measured by actinom...

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Autores principales:	María-Angélica Galezzo, Manuel Rodríguez Susa
Formato:	article
Lenguaje:	EN
Publicado:	IWA Publishing 2021
Materias:	drinking water klebsiella pneumoniae photo/dark repair point-of-use systems uv disinfection water treatment Environmental technology. Sanitary engineering TD1-1066
Acceso en línea:	https://doaj.org/article/f757d7192f864b99a0fa7eb63ae076b7
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spelling	oai:doaj.org-article:f757d7192f864b99a0fa7eb63ae076b72021-11-23T18:23:08ZEffect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection2043-90832408-936210.2166/washdev.2021.105https://doaj.org/article/f757d7192f864b99a0fa7eb63ae076b72021-11-01T00:00:00Zhttp://washdev.iwaponline.com/content/11/6/1071https://doaj.org/toc/2043-9083https://doaj.org/toc/2408-9362A system consisting of one UV-A (365 nm) and two UV-C (265 nm) light-emitting diodes (LEDs) was built to evaluate the effect of single and combined exposures to UV-A and UV-C LEDs on Klebsiella pneumoniae and Escherichia coli inactivation and subsequent reactivation. The dose was measured by actinometry using potassium ferrioxalate. Of laboratory prepared samples, 10 mL were irradiated for 20, 30, 45, 60 and 90 s. Logarithmic inactivation and percentages of photoreactivation and dark repair were calculated. E. coli and K. pneumoniae were reduced by more than 7 and 4 logs, respectively, at a dose of 21.5 mJ cm−2 using UV-C. No positive synergistic effect on the inactivation of the two bacteria was observed when using a simultaneous combination of UV-C and UV-A, probably due to a reactivation of the bacteria in the presence of UV-A light, which was not observed in irradiated samples under an individual exposure of 265 nm. For E. coli under 265 nm, the percentage of photoreactivation amounted to 10%, 3 h after irradiation. The results of this study demonstrated the capacity to inactivate E. coli and K. pneumoniae up to a considerable level and provide information for the application of UV LEDs in point-of-use systems. HIGHLIGHTS kD was calculated for K. pneumoniae, under exposure to 265 nm UV light-emitting diode (LEDs).; K. pneumoniae is more resistant than E. coli under 265 nm exposition.; 265, 365 and 265/365 nm were effective to inactivate E. coli and K. pneumoniae.; No positive synergistic effect for inactivation from the 265/365 nm LED combinations.; Photoreactivation was the dominant mechanism of reactivation of E. coli.;María-Angélica GalezzoManuel Rodríguez SusaIWA Publishingarticledrinking waterklebsiella pneumoniaephoto/dark repairpoint-of-use systemsuv disinfectionwater treatmentEnvironmental technology. Sanitary engineeringTD1-1066ENJournal of Water, Sanitation and Hygiene for Development, Vol 11, Iss 6, Pp 1071-1082 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	drinking water klebsiella pneumoniae photo/dark repair point-of-use systems uv disinfection water treatment Environmental technology. Sanitary engineering TD1-1066
spellingShingle	drinking water klebsiella pneumoniae photo/dark repair point-of-use systems uv disinfection water treatment Environmental technology. Sanitary engineering TD1-1066 María-Angélica Galezzo Manuel Rodríguez Susa Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection
description	A system consisting of one UV-A (365 nm) and two UV-C (265 nm) light-emitting diodes (LEDs) was built to evaluate the effect of single and combined exposures to UV-A and UV-C LEDs on Klebsiella pneumoniae and Escherichia coli inactivation and subsequent reactivation. The dose was measured by actinometry using potassium ferrioxalate. Of laboratory prepared samples, 10 mL were irradiated for 20, 30, 45, 60 and 90 s. Logarithmic inactivation and percentages of photoreactivation and dark repair were calculated. E. coli and K. pneumoniae were reduced by more than 7 and 4 logs, respectively, at a dose of 21.5 mJ cm−2 using UV-C. No positive synergistic effect on the inactivation of the two bacteria was observed when using a simultaneous combination of UV-C and UV-A, probably due to a reactivation of the bacteria in the presence of UV-A light, which was not observed in irradiated samples under an individual exposure of 265 nm. For E. coli under 265 nm, the percentage of photoreactivation amounted to 10%, 3 h after irradiation. The results of this study demonstrated the capacity to inactivate E. coli and K. pneumoniae up to a considerable level and provide information for the application of UV LEDs in point-of-use systems. HIGHLIGHTS kD was calculated for K. pneumoniae, under exposure to 265 nm UV light-emitting diode (LEDs).; K. pneumoniae is more resistant than E. coli under 265 nm exposition.; 265, 365 and 265/365 nm were effective to inactivate E. coli and K. pneumoniae.; No positive synergistic effect for inactivation from the 265/365 nm LED combinations.; Photoreactivation was the dominant mechanism of reactivation of E. coli.;
format	article
author	María-Angélica Galezzo Manuel Rodríguez Susa
author_facet	María-Angélica Galezzo Manuel Rodríguez Susa
author_sort	María-Angélica Galezzo
title	Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection
title_short	Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection
title_full	Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection
title_fullStr	Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection
title_full_unstemmed	Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection
title_sort	effect of single and combined exposures to uv-c and uv-a leds on the inactivation of klebsiella pneumoniae and escherichia coli in water disinfection
publisher	IWA Publishing
publishDate	2021
url	https://doaj.org/article/f757d7192f864b99a0fa7eb63ae076b7
work_keys_str_mv	AT mariaangelicagalezzo effectofsingleandcombinedexposurestouvcanduvaledsontheinactivationofklebsiellapneumoniaeandescherichiacoliinwaterdisinfection AT manuelrodriguezsusa effectofsingleandcombinedexposurestouvcanduvaledsontheinactivationofklebsiellapneumoniaeandescherichiacoliinwaterdisinfection
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Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection

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