Increased resistance of environmental anaerobic spores to inactivation by UV

Hijnen, W.A.M.; Veer, A.J. van der; Beerendonk, E.F.; Medema, Gerriet Jan

doi:10.2166/ws.2004.0028

Cited by 8 publications

(6 citation statements)

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“…The inactivation rate constant of E. coli and B. subtilis bacteria in water has been reported by several investigators (17,(28)(29)(30)(31)(32) and is summarized in ref. 33.…”

Section: Resultsmentioning

confidence: 99%

A tryptophan synchronous and normal fluorescence study on bacteria inactivation mechanism

Dhankhar

Chen

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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The UV photodissociation kinetics of tryptophan amino acid, Trp, attached to the membrane of bacteria, Escherichia coli and Bacillus subtilis, have been studied by means of normal and synchronous fluorescence. Our experimental data suggest that the fluorescence intensity of Trp increases during the first minute of irradiation with 250 nm to ∼ 280 nm, 7 mW/cm2 UV light, and subsequently decreases with continuous irradiation. During this short, less than a minute, period of time, 70% of the 107 cell per milliliter bacteria are inactivated. This increase in fluorescence intensity is not observed when tryptophan is in the free state, namely, not attached to a protein, but dissolved in water or saline solution. This increase in fluorescence is attributed to the additional fluorescence of tryptophan molecules formed by protein unfolding, the breakage of the bond that attaches Trp to the bacterial protein membrane, or possibly caused by the irradiation of 2 types of tryptophan residues that photolyze with different quantum yields.

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“…The inactivation rate constant of E. coli and B. subtilis bacteria in water has been reported by several investigators (17,(28)(29)(30)(31)(32) and is summarized in ref. 33.…”

Section: Resultsmentioning

confidence: 99%

A tryptophan synchronous and normal fluorescence study on bacteria inactivation mechanism

Dhankhar

Chen

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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“…The tests were carried out with the bench unit and the pilot unit using calibrated Bacillus subtilis spores (ATCC 6633) from the University of Vienna as described by Hijnen et al (2004). The tests were carried out with the bench unit and the pilot unit using calibrated Bacillus subtilis spores (ATCC 6633) from the University of Vienna as described by Hijnen et al (2004).…”

Section: Methodsmentioning

confidence: 99%

By-product formation during ultraviolet disinfection of a pretreated surface water

Ijpelaar¹,

Veer²,

Medema³

et al. 2005

Journal of Environmental Engineering and Science

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A low-pressure (LP-UV) and medium-pressure UV lamp (MP-UV) were compared for the formation of nitrite, assimilable organic carbon (AOC), and genotoxicity using pretreated surface water in a bench UV unit. The results have been compared with the by-products formed in pretreated surface water using a pilot unit equipped with four mediumpressure lamps identical to the one used in the bench unit. It was found that although significant nitrite formation occurred in the MP-UV bench tests, it remained well below the European standard (0.1 mg/L NO − 2 ) in the pilot unit. The LP-UV gave no or very low amounts of nitrite (bench unit). The AOC and genotoxicity increase with LP-UV was negligible. The AOC content and genotoxicity after MP-UV irradiation in the bench unit was significant as well, whereas AOC was formed limitedly in the pilot unit. Genotoxicity was elevated but not significant. Résumé :Une lampe UV à basse pression (LP-UV) et une lampe UV à pression moyenne (MP-UV) ont été comparées quant à la formation de nitrite, de COA (carbone organique assimilable) et pour la génotoxicité en utilisant de l'eau de surface prétraitée dans une unité UV de laboratoire. Les résultats ont été comparés aux sous-produits formés dans l'eau de surface prétraitée en utilisant une unité pilote équipée de 4 lampes à pression moyenne, identiques à celle utilisée dans l'unité de laboratoire. Bien que des quantités importantes de nitrite aient été formées dans les essais MP-UV en laboratoire, il a été trouvé que le niveau demeurait bien en deçà de la norme européenne (0,1 mg/L NO − 2 ) dans l'unité pilote. La lampe LP-UV ne donnait pas de nitrite ou seulement en très faibles quantités (unité de laboratoire). L'augmentation de la teneur en COA et de la génotoxicité avec la lampe LP-UV était négligeable. Après une irradiation MP-UV dans l'unité de laboratoire, la teneur en COA et la génotoxicité étaient aussi significatives, alors que la formation de COA était limitée dans l'unité pilote. La génotoxicité était élevée mais pas significative.

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“…The reasons for the differences in the performance of the full-scale system to the bench-scale reactor at the higher UVT may have been: fine-scale fluence differences in the reactors due to the distribution of the hydraulic residence time, orientation of UV-LEDS, adsorption, reflection and refraction of the UV light through water, and the LED and lamp intensity profile [16]. It is well established that the calculated fluence data obtained on scale-up with continuous-flow systems rarely mirrors the biodosimetry obtained using collimated beam experiments for conventional UV lamp systems [31]. For example, lower inactivation rate constants have been found for E. coli in continuous flow compared to collimated beam systems.…”

Section: Uv-led Bench-and Full-scale Comparisonmentioning

confidence: 99%

“…Havelaar [33] showed similar performance is achievable in LPUV systems operated continuously, with inactivation efficiencies of 0.168 (R 2 = 0.53) for E. coli. In addition, the reduction equivalent dose of one pilot scale system was 60% lower than the calculated fluence for Clostridia spores compared to equivalent collimated beam systems [16,31,34]. Initial microbial resistance has been suggested as one reason for an offset in performance between completely mixed flow-through reactors and collimated beam systems [35].…”

Section: Uv-led Bench-and Full-scale Comparisonmentioning

confidence: 99%

Application of Ultraviolet Light-Emitting Diodes (UV-LED) to Full-Scale Drinking-Water Disinfection

Jarvis

Autin²,

Goslan

et al. 2019

Water

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Ultraviolet light-emitting diodes (UV-LEDs) have recently emerged as a viable technology for water disinfection. However, the performance of the technology in full-scale drinking-water treatment systems remains poorly characterised. Furthermore, current UV disinfection standards and protocols have been developed specifically for conventional mercury UV systems and so do not necessarily provide an accurate indication of UV-LED disinfection performance. Hence, this study aimed to test the hypothesis that a full-scale UV-LED reactor can match the Cryptosporidium inactivation efficiency of conventional mercury UV reactors. Male-specific bacteriophage (MS2) was used as the Cryptosporidium spp. surrogate microorganism. The time-based inactivation efficiency of the full-scale reactor was firstly compared to that of a bench-scale (batch-type) UV-LED reactor. This was then related to mercury UV reactors by comparing the fluence-based efficiency of the bench-scale reactor to the USEPA 90% prediction interval range of expected MS2 inactivation using mercury UV lamps. The results showed that the full-scale UV-LED reactor was at least as effective as conventional mercury UV reactors at the water-quality and drive-current conditions considered. Nevertheless, comparisons between the bench- and full-scale UV-LED reactors indicated that improvements in the hydraulic flow profile and power output of the full-scale reactor could help to further improve the efficiency of UV-LED reactors for municipal drinking water disinfection. This represents the world’s first full-scale UV-LED reactor that can be applied at municipal water treatment works for disinfection of pathogenic microorganisms from drinking water.

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Increased resistance of environmental anaerobic spores to inactivation by UV

Cited by 8 publications

References 0 publications

A tryptophan synchronous and normal fluorescence study on bacteria inactivation mechanism

A tryptophan synchronous and normal fluorescence study on bacteria inactivation mechanism

By-product formation during ultraviolet disinfection of a pretreated surface water

Application of Ultraviolet Light-Emitting Diodes (UV-LED) to Full-Scale Drinking-Water Disinfection

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