scholarly journals Demonstration and evaluation of germicidal UV-LEDs for point-of-use water disinfection

2010 ◽  
Vol 8 (3) ◽  
pp. 479-486 ◽  
Author(s):  
Christie Chatterley ◽  
Karl Linden
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Low Pressure ◽  
Water Disinfection ◽  
Light Emitting ◽  
E Coli ◽  
Point Of Use ◽  
One Year ◽  
Uv Lamps ◽  
Uv Leds

Ultraviolet (UV) irradiation is a common disinfection option for water treatment in the developed world. There are a few systems installed in developing countries for point-of-use treatment, but the low-pressure mercury lamps currently used as the UV irradiation source have a number of sustainability issues including a fragile envelope, a lifetime of approximately one year, and they contain mercury. UV light emitting diodes (LEDs) may offer solutions to many of the sustainability issues presented by current UV systems. LEDs are small, efficient, have long lifetimes, and do not contain mercury. Germicidal UV LEDs emitting at 265 nm were evaluated for inactivation of E. coli in water and compared to conventional low-pressure UV lamps. Both systems provided an equivalent level of treatment. A UV-LED prototype was developed and evaluated as a proof-of-concept of this technology for a point-of-use disinfection option, and the economics of UV-LEDs were evaluated.

scholarly journals 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

2021 ◽  
Author(s):  
María-Angélica Galezzo ◽  
Manuel Rodríguez Susa
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Water Disinfection ◽  
Dark Repair ◽  
Light Emitting ◽  
E Coli ◽  
Point Of Use ◽  
Combined Exposures ◽  
Uv Leds ◽  
Uv C

Abstract 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.

scholarly journals Fundamental Characteristics of Deep-UV Light-Emitting Diodes and Their Application To Control Foodborne Pathogens

2015 ◽  
Vol 82 (1) ◽  
pp. 2-10 ◽  
Author(s):  
Joo-Yeon Shin ◽  
Soo-Ji Kim ◽  
Do-Kyun Kim ◽  
Dong-Hyun Kang
Keyword(s):  
Foodborne Pathogens ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Bacterial Inactivation ◽  
Content Type ◽  
Light Emitting ◽  
E Coli ◽  
Deep Uv ◽  
Uv Lamps ◽  
Uv C

ABSTRACTLow-pressure mercury UV (LP-UV) lamps have long been used for bacterial inactivation, but due to certain disadvantages, such as the possibility of mercury leakage, deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative. Therefore, in this study, we examined the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating foodborne pathogens, includingEscherichia coliO157:H7,Salmonella entericaserovar Typhimurium, andListeria monocytogenes, on solid media, as well as in water. As the temperature increased, DUV-LED light intensity decreased slightly, whereas LP-UV lamps showed increasing intensity until they reached a peak at around 30°C. As the irradiation dosage and temperature increased,E. coliO157:H7 andS. Typhimurium experienced 5- to 6-log-unit reductions.L. monocytogeneswas reduced by over 5 log units at a dose of 1.67 mJ/cm2. At 90% relative humidity (RH), onlyE. coliO157:H7 experienced inactivation significantly greater than at 30 and 60% RH. In a water treatment study involving a continuous system, 6.38-, 5.81-, and 3.47-log-unit reductions were achieved inE. coliO157:H7,S. Typhimurium, andL. monocytogenes, respectively, at 0.5 liter per minute (LPM) and 200 mW output power. The results of this study suggest that the use of DUV-LEDs may compensate for the drawbacks of using LP-UV lamps to inactivate foodborne pathogens.

scholarly journals Comparison of standard light-emitting diode (LED) and 385 nm ultraviolet A LED (UVA-LED) for disinfection of Escherichia coli

2017 ◽  
Vol 13 (4-2) ◽  
pp. 430-437 ◽  
Author(s):  
Sameen Ahmed Malik ◽  
Tan Tian Swee ◽  
Nik Ahmad Nizam Nik Malek ◽  
Mohammed Rafiq Abdul Kadir ◽  
Takahiro Emoto ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Human Life ◽  
Light Emitting ◽  
Led Light ◽  
E Coli ◽  
Wide Range ◽  
Uva Light ◽  
Uv Lamps

UV light has become an integral part of human life especially in performing wide range of disinfection. Most of the research on UVLEDs is limited to UVC region because of comparison with mercury based UV lamps which work typically at 254 nm. Limited research is found on the use of UVA-LEDs for inactivation of microorganisms in healthcare. In this study a standard 3 mm LED has been compared with 385 nm UVA-LED for inactivation of Escherichia coli.  E. coli strains were swabbed on control, LED and UVA-LED petri dishes using cotton bud. The LED and UVA-LED samples were exposed to standard LED light and UVA light respectively for 1 h. The analysis of bacteria by determining Colony forming units (CFU) and log inactivation were carried out to calculate the number of colonies present in each sample. Result showed negligible to none disinfection properties in standard LED light. LED samples had  CFU/ml colonies compared to control which is  CFU/ml. UVA-LED samples achieved maximum inactivation and only had  CFU/ml. Log inactivation results showed that LED samples observed 0.1-log inactivation whereas the UVA-LED had significant inactivation of 3.8-log inactivation corresponding to approximately 99.99 % E. coli reduction. The results demonstrate that UVA-LED at 385 nm is capable of efficiently providing inactivation of bacteria E. coli. 

scholarly journals UV Light Application as a Mean for Disinfection Applied in the Dairy Industry

2021 ◽  
Vol 11 (16) ◽  
pp. 7285
Author(s):  
Arpit Chawla ◽  
Adriana Lobacz ◽  
Justyna Tarapata ◽  
Justyna Zulewska
Keyword(s):  
Uv Light ◽  
Dairy Industry ◽  
Microbial Inactivation ◽  
Microbial Pathogens ◽  
Great Promise ◽  
Market Demand ◽  
Light Emitting ◽  
Long Time ◽  
Uv Lamps ◽  
Uv Leds

Thermal treatment is the most popular decontamination technique used in the dairy industry to ensure food protection and prolong shelf life. But it also causes nutrient and aroma degradation, non-enzymatic browning, and organoleptic changes of dairy products. Non-thermal solutions, on the other hand, have been extensively explored in a response to rising market demand for more sustainable and safe goods. For a long time, the use of ultraviolet (UV) light in the food industry has held great promise. Irradiation with shortwave UV light has excellent germicidal properties, which can destroy a variety of microbial pathogens (for example bacteria, fungi, molds, yeasts, and viruses), at low maintenance and installation costs with minimal use of energy to preserve food without undesirable effects of heat treatment. The purpose of this review is to update the studies made on the possibilities of UV-C radiation while also addressing the essential processing factors involved in the disinfection. It also sheds light on the promise of UV light-emitting diodes (UV-LEDs) as a microbial inactivation alternative to conventional UV lamps.

Point-of-use water disinfection using UV light-emitting diodes to reduce bacterial contamination

2013 ◽  
Vol 20 (8) ◽  
pp. 5441-5448 ◽  
Author(s):  
Kristina Y. Nelson ◽  
Dena W. McMartin ◽  
Christopher K. Yost ◽  
Ken J. Runtz ◽  
Takaya Ono
Keyword(s):  
Bacterial Contamination ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Water Disinfection ◽  
Light Emitting ◽  
Point Of Use

Time dose reciprocity in UV disinfection of water

1998 ◽  
Vol 38 (12) ◽  
pp. 145-150 ◽  
Author(s):  
R. Sommer ◽  
T. Haider ◽  
A. Cabaj ◽  
W. Pribil ◽  
M. Lhotsky
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Water Disinfection ◽  
High Dose ◽  
E Coli ◽  
Dose Rates ◽  
Test Organisms ◽  
Irradiation Apparatus ◽  
Uv Dose ◽  
Time Dose

The microbicidal effect of UV light depends on the dose in both, disinfection processes and natural inactivation by the sunlight in surface water. Deviations of the time dose reciprocity are well known from chemical water disinfection whereas no data are available about this effect in UV inactivation in water. In a previous study we found that the UV inactivation behaviour of yeast strains does not follow the time dose reciprocity, insofar that longer exposure led to higher reduction of cultivable cells. In contrast, an earlier study about E coli B/r claimed a higher inactivation with single exposure compared with fractionated UV irradiation. To investigate this question we selected water-relevant microorganisms and studied their UV inactivation behaviour (253.7nm) by means of a specially designed UV irradiation apparatus (a) under standard irradiation conditions (2W/m2) and (b) with three levels of UV dose rate (2, 0.2 and 0.02W/m2). The test organisms were (i) three E coli strains (ATCC 25922, ATCC 11229 and an isolate from sewage) representing the routinely used faecal indicator, (ii) three bacterial viruses (MS2, ϕX174 and B40-8) proposed as indicators for viral contamination in water and (iii) spores of Bacillus subtilis because of their use as a biodosimeter in prototype testing of commercial UV plants for drinking water disinfection. We found, under standard inactivation conditions, that the E coli strains and phage ϕX174 are most UV susceptible, followed by B40-8 and finally MS2 and bacterial spores. The dose protraction experiments revealed for the E coli strains a higher inactivation with high dose rates compared to low dose rates at the same UV doses (difference of about 1 log10 at 80-100J/m2). The other test organisms did not deviate from the time dose reciprocity in the proven range of dose.

scholarly journals Using UVC Light-Emitting Diodes at Wavelengths of 266 to 279 Nanometers To Inactivate Foodborne Pathogens and Pasteurize Sliced Cheese

2015 ◽  
Vol 82 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Soo-Ji Kim ◽  
Do-Kyun Kim ◽  
Dong-Hyun Kang
Keyword(s):  
Foodborne Pathogens ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Content Type ◽  
Warm Up ◽  
Light Emitting ◽  
Uv Led ◽  
Serovar Typhimurium ◽  
Uv Lamps ◽  
Uv Leds

ABSTRACTUVC light is a widely used sterilization technology. However, UV lamps have several limitations, including low activity at refrigeration temperatures, a long warm-up time, and risk of mercury exposure. UV-type lamps only emit light at 254 nm, so as an alternative, UV light-emitting diodes (UV-LEDs) which can produce the desired wavelengths have been developed. In this study, we validated the inactivation efficacy of UV-LEDs by wavelength and compared the results to those of conventional UV lamps. Selective media inoculated withEscherichia coliO157:H7,Salmonella entericaserovar Typhimurium, andListeria monocytogeneswere irradiated using UV-LEDs at 266, 270, 275, and 279 nm in the UVC spectrum at 0.1, 0.2, 0.5, and 0.7 mJ/cm2, respectively. The radiation intensity of the UV-LEDs was about 4 μW/cm2, and UV lamps were covered with polypropylene films to adjust the light intensity similar to those of UV-LEDs. In addition, we applied UV-LED to sliced cheese at doses of 1, 2, and 3 mJ/cm2. Our results showed that inactivation rates after UV-LED treatment were significantly different (P< 0.05) from those of UV lamps at a similar intensity. On microbiological media, UV-LED treatments at 266 and 270 nm showed significantly different (P< 0.05) inactivation effects than other wavelength modules. For sliced cheeses, 4- to 5-log reductions occurred after treatment at 3 mJ/cm2for all three pathogens, with negligible generation of injured cells.

Application of GaN-based ultraviolet-C light emitting diodes – UV LEDs – for water disinfection

2011 ◽  
Vol 45 (3) ◽  
pp. 1481-1489 ◽  
Author(s):  
M.A. Würtele ◽  
T. Kolbe ◽  
M. Lipsz ◽  
A. Külberg ◽  
M. Weyers ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Water Disinfection ◽  
Light Emitting ◽  
Ultraviolet C ◽  
Uv Leds

scholarly journals Diarrhoea prevention in Bolivia through point-of-use water treatment and safe storage: a promising new strategy

1999 ◽  
Vol 122 (1) ◽  
pp. 83-90 ◽  
Author(s):  
R. E. QUICK ◽  
L. V. VENCZEL ◽  
E. D. MINTZ ◽  
L. SOLETO ◽  
J. APARICIO ◽  
...  
Keyword(s):  
Water Quality ◽  
Community Education ◽  
Water Disinfection ◽  
E Coli ◽  
Safe Storage ◽  
Point Of Use ◽  
Quality Testing ◽  
New Strategy ◽  
Diarrhoea Prevention ◽  
And Control

A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households had 44% fewer diarrhoea episodes than control households (P=0·002). Infants <1 year old (P=0·05) and children 5–14 years old (P=0·01) in intervention households had significantly less diarrhoea than control children. Campylobacter was less commonly isolated from intervention than control patients (P=0·02). Stored water in intervention households was less contaminated with Escherichia coli than stored water in control households (P<0·0001). Intervention households exhibited less E. coli contamination of stored water and less diarrhoea than control households. This promising new strategy may have broad applicability for waterborne disease prevention.

scholarly journals Effects of UV Radiation on Photolyase and Implications with Regards to Photoreactivation following Low- and Medium-Pressure UV Disinfection

2007 ◽  
Vol 74 (1) ◽  
pp. 327-328 ◽  
Author(s):  
Jiangyong Hu ◽  
Puay Hoon Quek
Keyword(s):  
Uv Radiation ◽  
Uv Irradiation ◽  
Flavin Adenine Dinucleotide ◽  
Low Pressure ◽  
Uv Disinfection ◽  
Medium Pressure ◽  
Uv Lamps

ABSTRACT Photolyase activity following exposure to low-pressure (LP) and medium-pressure (MP) UV lamps was evaluated. MP UV irradiation resulted in a greater reduction in photolyase activity than LP UV radiation. The results suggest that oxidation of the flavin adenine dinucleotide in photolyase may have caused the decrease in activity.

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