scholarly journals A pulsed light system for the disinfection of flow through water in the presence of inorganic contaminants

2014 ◽  
Vol 13 (2) ◽  
pp. 406-412 ◽  
Author(s):  
Mary Garvey ◽  
Neil Rowan
Keyword(s):  
Uv Light ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Limited Data ◽  
Inorganic Contaminants ◽  
Test Species ◽  
Bacterial Endospores ◽  
Effective Form ◽  
Pulsed Uv Light ◽  
Flow Through

The use of ultraviolet (UV) light for water disinfection has become increasingly popular due to on-going issues with drinking water and public health. Pulsed UV light has proved to be an effective form of inactivating a range of pathogens including parasite species. However, there are limited data available on the use of pulsed UV light for the disinfection of flowing water in the absence or presence of inorganic contaminants commonly found in water sources. Here, we report on the inactivation of test species including Bacillus endospores following pulsed UV treatment as a flow through system. Significant levels of inactivation were obtained for both retention times tested. The presence of inorganic contaminants iron and/or manganese did affect the rate of disinfection, predominantly resulting in an increase in the levels of inactivation at certain UV doses. The findings of this study suggest that pulsed UV light may provide a method of water disinfection as it successfully inactivated bacterial cells and bacterial endospores in the absence and presence of inorganic contaminants.

Inactivation of recalcitrant protozoan oocysts and bacterial endospores in drinking water using high-intensity pulsed UV light irradiation

2012 ◽  
Vol 12 (4) ◽  
pp. 513-522 ◽  
Author(s):  
J. C. Hayes ◽  
M. Garvey ◽  
A. M. Fogarty ◽  
E. Clifford ◽  
N. J. Rowan
Keyword(s):  
High Intensity ◽  
Uv Light ◽  
Waste Water Treatment ◽  
Scale Up ◽  
Clear Trend ◽  
E Coli ◽  
Log Reduction ◽  
Bacterial Endospores ◽  
Pulsed Uv Light ◽  
Uv Dose

This constitutes the first study to compare the use of high-intensity pulsed UV light (PUV) irradiation for the novel destruction of harmful protozoan (Cryptosporidium parvum Iowa isolate) oocysts and bacterial (Clostridium perfringens ATCC 13124 and Bacillus cereus ATCC 11178) endospores in artificially-spiked water where these organisms are resistant to conventional chlorination. Experimental results revealed that all three test organisms in their dormant recalcitrant state required extended levels of pulsing to achieve significant reductions in numbers compared to other similarly PUV-treated Escherichia coli ATCC 25922 that is a non-spore forming indicator of faecal pollution in water. 120 pulses at 900 V or 16.2 J per pulse (equivalent to a UV dose of 8.39 μJ cm−2) were required to achieve ca. 2 log C. perfringens spore numbers, whereas a similar level of PUV irradiation reduced both C. parvum oocysts and B. cereus endospores by ca. 5 log orders. A comparative ca. 5 log reduction of E. coli cell numbers was achieved after only 25 pulses at 900 V (equivalent to a UV dose of 1.74 μJ cm−2). A clear trend emerged where the order of resistance to PUV-irradiation observed was C. perfringens endospores > C. parvum oocysts, B. cereus endospores > E. coli cells. This study suggests disinfection kinetic data for the more resistant C. perfringens endospores can be used as a measure of estimating disinfection efficacy of PUV treatments for C. parvum oocysts in water, avoiding the need to use complex animal or cell culture infectivity models that are only available in specialised laboratories with highly trained technicians. This study will inform future studies exploring scale-up of PUV at waste-water treatment plants.

scholarly journals Comparison of UV-C and Pulsed UV Light Treatments for Reduction of Salmonella, Listeria monocytogenes, and Enterohemorrhagic Escherichia coli on Eggs

2017 ◽  
Vol 81 (1) ◽  
pp. 6-16 ◽  
Author(s):  
Askild L. Holck ◽  
Kristian H. Liland ◽  
Signe M. Drømtorp ◽  
Mats Carlehög ◽  
Anette McLeod
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Enteritidis ◽  
Uv Light ◽  
Enterohemorrhagic Escherichia Coli ◽  
Bacterial Cells ◽  
The European Union ◽  
Microscopy Imaging ◽  
Pulsed Uv Light ◽  
Uv C

ABSTRACT Ten percent of all strong-evidence foodborne outbreaks in the European Union are caused by Salmonella related to eggs and egg products. UV light may be used to decontaminate egg surfaces and reduce the risk of human salmonellosis infections. The efficiency of continuous UV-C (254 nm) and pulsed UV light for reducing the viability of Salmonella Enteritidis, Listeria monocytogenes, and enterohemorrhagic Escherichia coli on eggs was thoroughly compared. Bacterial cells were exposed to UV-C light at fluences from 0.05 to 3.0 J/cm2 (10 mW/cm2, for 5 to 300 s) and pulsed UV light at fluences from 1.25 to 18.0 J/cm2, resulting in reductions ranging from 1.6 to 3.8 log, depending on conditions used. Using UV-C light, it was possible to achieve higher reductions at lower fluences compared with pulsed UV light. When Salmonella was stacked on a small area or shielded in feces, the pulsed UV light seemed to have a higher penetration capacity and gave higher bacterial reductions. Microscopy imaging and attempts to contaminate the interior of the eggs with Salmonella through the eggshell demonstrated that the integrity of the eggshell was maintained after UV light treatments. Only minor sensory changes were reported by panelists when the highest UV doses were used. UV-C and pulsed UV light treatments appear to be useful decontamination technologies that can be implemented in continuous processing.

Application of UV light emitting diodes to batch and flow-through water disinfection systems

Desalination ◽  
2013 ◽  
Vol 328 ◽  
pp. 24-30 ◽  
Author(s):  
Kumiko Oguma ◽  
Ryo Kita ◽  
Hiroshi Sakai ◽  
Michio Murakami ◽  
Satoshi Takizawa
Keyword(s):  
Light Emitting Diodes ◽  
Uv Light ◽  
Water Disinfection ◽  
Light Emitting ◽  
Flow Through

Inactivation of Escherichia coli K-12 in Liquid Egg White By a Flow-through Pulsed Uv Light Treatment System

2020 ◽  
Vol 83 (3) ◽  
pp. 418-425 ◽  
Author(s):  
BEINING OUYANG ◽  
ALI DEMIRCI ◽  
PAUL H. PATTERSON
Keyword(s):  
Escherichia Coli ◽  
Flow Rate ◽  
Uv Light ◽  
Egg White ◽  
Treatment System ◽  
Significant Difference ◽  
Pulsed Uv Light ◽  
Flow Through ◽  
K 12 ◽  
The Impact

ABSTRACT Unpasteurized liquid egg can be contaminated with pathogenic microorganisms and may cause foodborne outbreaks. Thus, it is essential to decontaminate the liquid egg to ensure food safety. Pulsed UV light is one of the emerging technologies for food decontamination in recent years. This static treatment system has been studied previously in our laboratory. However, continuous processing using a flow-through treatment system needs to be evaluated for potential commercial applications. Therefore, in this study, a flow-through treatment system of pulsed UV light was evaluated and optimized for inactivation of Escherichia coli K12NSR for liquid egg white decontamination. Treatment factors including flow rate (40 to 80 mL/min), number of passes (one to three passes), and distance from the sample to the pulsed UV light strobe (5 to 13 cm) were optimized using response surface methodology. This methodology suggested three passes with 40 mL/min flow rate and a 5-cm distance as the optimum conditions. The model was then validated for the maximum reduction of E. coli K12NSR, which was measured as 1.57 log CFU/mL at the optimal conditions. The energy doses of the pulsed UV light and temperature changes of the liquid egg white during the treatment were measured. Furthermore, several quality parameters were assessed at the optimum treatment conditions to determine the impact of the flow-through pulsed UV processing on the quality of liquid egg white. The results showed significant differences in pH, lipid oxidation, turbidity, and color between control and pulsed UV light–treated samples (P < 0.05). However, there was no significant difference in foaming ability or foam stability between pulsed UV light–treated samples and the control. Overall, this study demonstrated the potential of flow-through pulsed UV light to decontaminate liquid egg white, but further research is needed for optimal enhancement. HIGHLIGHTS

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