A Comparative Study on the Pulsed UV and the Low‐Pressure UV Inactivation of a Range of Microbial Species in Water

Abstract

: Research into alternative methods of disinfecting water and wastewater has proven necessary due to the emergence of chlorine‐resistant organisms and the disinfection byproducts associated with chlorine use. The use of UV light to inactivate microbial species has proven effective, however; standard UV lamps have proven to be less effective in their ability to inactivate parasites and bacterial endospores in water treatment settings. Pulsed UV (PUV) light may potentially provide a novel alternative to water and wastewater disinfection. Research outlined in this study assesses the potential of a novel PUV system for the rapid and reproducible inactivation of a range of test species including Bacillus endospores. In comparison to standard low‐pressure (LP) UV lamps, this PUV system provided significantly higher levels of inactivation for all test species. Furthermore, there was a remarkable decrease in time needed to obtain significant inactivation rates following treatment with PUV compared to LP‐UV. With the PUV system, a 70‐second treatment time (7.65 μJ/cm2) resulted in similar inactivation rates of Bacillus endospores to that of the LP‐UV inactivation of their vegetative counterpart. Also, at PUV doses exceeding 4.32 J/cm2, there was not a significant difference in the PUV inactivation of Bacillus endospores in the absence or presence of 10 ppm organic matter. However, the presence of organic matter resulted in a significant reduction in microbial inactivation for all treatment doses using the LP‐UV system. The findings of this study suggest that PUV technology may provide a rapid effective method for the disinfection of water and wastewater.

Recent findings in pulsed light disinfection

“…() and Garvey et al . (). Another potential application of liquid treatment other than beverages is the decontamination of sugar syrup where a 3 log reduction in different spores was reported by Chaine et al .…”

“…Similar to the results of PL-treated produce or meat, a product-specific quality assessment as well as optimized treatment conditions are necessary in case of beverage treatment. Besides the decontamination of beverages, PL may also be used for disinfection in municipal wastewater, which has been proposed by Uslu et al (2014) and Garvey et al (2014). Another potential application of liquid treatment other than beverages is the decontamination of sugar syrup where a 3 log reduction in different spores was reported by Chaine et al (2012).…”

“…Its efficiency is higher compared to continuous UV irradiation because a high fluence can be applied within short time (Garvey et al . ). PL has already been used for several years on industrial scale for disinfection of packaging material.…”

“…The initiated intense light flashes exhibit a broad spectrum ranging from about 200 to 1100 nm with about 25% in the UV range (Kramer and Muranyi 2014). Its efficiency is higher compared to continuous UV irradiation because a high fluence can be applied within short time (Garvey et al 2014). PL has already been used for several years on industrial scale for disinfection of packaging material.…”

Pulsed light for the inactivation of fungal biofilms of clinically important pathogenicCandidaspecies

“…Due to the delivery mechanism of short‐duration pulses, PUV also has a better penetration depth than LPUV. Additionally, PUV has proved effective for the inactivation of numerous microbial species, bacterial endospores, biofilms and parasite species in a shorter treatment time than LP‐ or MP‐UV, leading to a reduction in operation costs (Garvey et al, ). Considering these important advantages of PUV over LP‐UV, the aim of this study was to determine the potential of a PUV light system for the inactivation of clinically important Candida species in both planktonic and biofilm form on surfaces commonly found in the health care setting.…”