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Wei S, Chen T, Hou H, Xu Y. Recent Advances in Electrochemical Sterilization. J Electroanal Chem (Lausanne) 2023. [DOI: 10.1016/j.jelechem.2023.117419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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2
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Enhancement of superoxide evolution by nickel-doped for the removal of organic pollutants and cyanobacteria. J Taiwan Inst Chem Eng 2020. [DOI: 10.1016/j.jtice.2020.08.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Azaki M, Uda A, Tian D, Nakazato K, Hotta A, Kawai Y, Ishijima K, Kuroda Y, Maeda K, Morikawa S. Effective methods for the inactivation of Francisella tularensis. PLoS One 2019; 14:e0225177. [PMID: 31725770 PMCID: PMC6855423 DOI: 10.1371/journal.pone.0225177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/29/2019] [Indexed: 11/19/2022] Open
Abstract
Francisella tularensis (F. tularensis) is highly pathogenic to humans and must be handled under biosafety level 3 conditions. Samples used for the diagnosis and experimental analysis must be completely inactivated, although methods for the inactivation of F. tularensis are limited. In this study, effective methods for the inactivation of F. tularensis SCHU P9 and five other strains were determined by comparisons of colony-forming units between treated and control samples. The results showed that F. tularensis SCHU P9 was denatured by heat treatment (94°C for 3 min and 56°C for 30 min), filtration with a 0.22 μm filter, and the use of various solutions (i.e. >70% ethanol, methanol, acetone, and 4% paraformaldehyde). F. tularensis SCHU P9 remained viable after treatment with 50% ethanol for 1 min, filtration with a 0.45 μm filter, and treatments with detergents (i.e. 1% lithium dodecyl sulfate buffer, 1% Triton X-100 and 1% Nonidet P-40) at 4°C for 24 h. Additionally, F. tularensis SCHU P9 suspended in fetal bovine serum in plastic tubes was highly resistant to ultraviolet radiation compared to suspensions in water and chemically defined medium. The methods for inactivation of F. tularensis SCHU P9 was applicable to the other five strains of F. tularensis. The data presented in this study could be useful for the establishment of guidelines and standard operating procedures (SOP) to inactivate the contaminated samples in not only F. tularensis but also other bacteria.
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Affiliation(s)
- Mika Azaki
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo Japan
- Department of Correlative Study in Physics and Chemistry, Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan
| | - Akihiko Uda
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo Japan
- * E-mail:
| | - Deyu Tian
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Katsuyoshi Nakazato
- Department of Correlative Study in Physics and Chemistry, Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan
| | - Akitoyo Hotta
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo Japan
| | - Yasuhiro Kawai
- Division of Biosafety Control and Research, National Institute of Infectious Diseases, Tokyo, Japan
| | - Keita Ishijima
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo Japan
- Laboratory of Veterinary Microbiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Yudai Kuroda
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo Japan
- Laboratory of Veterinary Microbiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Ken Maeda
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo Japan
- Laboratory of Veterinary Microbiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Shigeru Morikawa
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo Japan
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Thwaites BJ, Short MD, Stuetz RM, Reeve PJ, Alvarez Gaitan JP, Dinesh N, van den Akker B. Comparing the performance of aerobic granular sludge versus conventional activated sludge for microbial log removal and effluent quality: Implications for water reuse. WATER RESEARCH 2018; 145:442-452. [PMID: 30189399 DOI: 10.1016/j.watres.2018.08.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/14/2018] [Accepted: 08/18/2018] [Indexed: 06/08/2023]
Abstract
The application of aerobic granular sludge (AGS) technology has increased in popularity, largely due to the smaller physical footprint, enhanced biological nutrient removal performance and ability to perform with a more stable operation when compared to conventional activated sludge (CAS) systems. To date, the ability of AGS to remove microbial pathogens such as; Escherichia coli, Giardia, and Cryptosporidium has not been reported. This study compared the log10 removal performance of commonly used pathogen surrogates (sulfite-reducing clostridia spores, f-RNA bacteriophage, E. coli and total coliforms) by AGS and CAS during the start-up phase, through to maturation. Results showed that AGS performed as well as CAS for the log10 removal performance of all microbial surrogates, except for spores which were removed more effectively by AGS most likely due to greater adherence of spores to the AGS biomass compared to CAS mixed liquor. Results suggest that AGS is capable of meeting or exceeding CAS-equivalent health-based targets for pathogen removal in the context of water recycling as well as not adversely affecting the secondary effluent water quality (suspended solids, turbidity and particle size) in terms of ultraviolet light transmissivity (254 nm). These findings confirmed for the first time that the adoption of AGS operation would not adversely impact downstream tertiary disinfection processes from altered water quality, nor would it require further pathogen treatment interventions in addition to what is already required for CAS systems.
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Affiliation(s)
- Benjamin J Thwaites
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Michael D Short
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, 5095, South Australia, Australia
| | - Richard M Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Petra J Reeve
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Juan-Pablo Alvarez Gaitan
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Nirmala Dinesh
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia; Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042, South Australia, Australia; School of Natural and Built Environments, University of South Australia, Mawson Lakes, 5095, South Australia, Australia
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Zakaria F, Harelimana B, Ćurko J, van de Vossenberg J, Garcia HA, Hooijmans CM, Brdjanovic D. Effectiveness of UV-C light irradiation on disinfection of an eSOS(®) smart toilet evaluated in a temporary settlement in the Philippines. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2016; 26:536-553. [PMID: 27666295 DOI: 10.1080/09603123.2016.1217313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/30/2016] [Indexed: 06/06/2023]
Abstract
Ultraviolet germicidal (short wavelength UV-C) light was studied as surface disinfectant in an Emergency Sanitation Operation System(®) smart toilet to aid to the work of manual cleaning. The UV-C light was installed and regulated as a self-cleaning feature of the toilet, which automatically irradiate after each toilet use. Two experimental phases were conducted i.e. preparatory phase consists of tests under laboratory conditions and field testing phase. The laboratory UV test indicated that irradiation for 10 min with medium-low intensity of 0.15-0.4 W/m(2) could achieve 6.5 log removal of Escherichia coli. Field testing of the toilet under real usage found that UV-C irradiation was capable to inactivate total coliform at toilet surfaces within 167-cm distance from the UV-C lamp (UV-C dose between 1.88 and 2.74 mW). UV-C irradiation is most effective with the support of effective manual cleaning. Application of UV-C for surface disinfection in emergency toilets could potentially reduce public health risks.
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Affiliation(s)
- Fiona Zakaria
- a Department of Environmental Engineering and Environmental Technology , UNESCO-IHE , Delft , The Netherlands
| | - Bertin Harelimana
- a Department of Environmental Engineering and Environmental Technology , UNESCO-IHE , Delft , The Netherlands
| | - Josip Ćurko
- b Faculty of Food Technology and Biotechnology , University of Zagreb , Zagreb , Croatia
| | - Jack van de Vossenberg
- a Department of Environmental Engineering and Environmental Technology , UNESCO-IHE , Delft , The Netherlands
| | - Hector A Garcia
- a Department of Environmental Engineering and Environmental Technology , UNESCO-IHE , Delft , The Netherlands
| | - Christine Maria Hooijmans
- a Department of Environmental Engineering and Environmental Technology , UNESCO-IHE , Delft , The Netherlands
| | - Damir Brdjanovic
- a Department of Environmental Engineering and Environmental Technology , UNESCO-IHE , Delft , The Netherlands
- c Faculty of Applied Sciences, Department of Biotechnology , Delft University of Technology , Delft , The Netherlands
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Paulino-Lima IG, Fujishima K, Navarrete JU, Galante D, Rodrigues F, Azua-Bustos A, Rothschild LJ. Extremely high UV-C radiation resistant microorganisms from desert environments with different manganese concentrations. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 163:327-36. [PMID: 27614243 DOI: 10.1016/j.jphotobiol.2016.08.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 08/10/2016] [Indexed: 12/25/2022]
Abstract
Desiccation resistance and a high intracellular Mn/Fe ratio contribute to ionizing radiation resistance of Deinococcus radiodurans. We hypothesized that this was a general phenomenon and thus developed a strategy to search for highly radiation-resistant organisms based on their natural environment. While desiccation is a typical feature of deserts, the correlation between radiation resistance and the intracellular Mn/Fe ratio of indigenous microorganisms or the Mn/Fe ratio of the environment, has not yet been described. UV-C radiation is highly damaging to biomolecules including DNA. It was used in this study as a selective tool because of its relevance to early life on earth, high altitude aerobiology and the search for life beyond Earth. Surface soil samples were collected from the Sonoran Desert, Arizona (USA), from the Atacama Desert in Chile and from a manganese mine in northern Argentina. Microbial isolates were selected after exposure to UV-C irradiation and growth. The isolates comprised 28 genera grouped within six phyla, which we ranked according to their resistance to UV-C irradiation. Survival curves were performed for the most resistant isolates and correlated with their intracellular Mn/Fe ratio, which was determined by ICP-MS. Five percent of the isolates were highly resistant, including one more resistant than D. radiodurans, a bacterium generally considered the most radiation-resistant organism, thus used as a model for radiation resistance studies. No correlation was observed between the occurrence of resistant microorganisms and the Mn/Fe ratio in the soil samples. However, all resistant isolates showed an intracellular Mn/Fe ratio much higher than the sensitive isolates. Our findings could represent a new front in efforts to harness mechanisms of UV-C radiation resistance from extreme environments.
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Affiliation(s)
| | - Kosuke Fujishima
- University Affiliated Research Center, NASA Ames Research Center, Moffett Field, CA, 94035-0001, USA
| | - Jesica Urbina Navarrete
- University Affiliated Research Center, NASA Ames Research Center, Moffett Field, CA, 94035-0001, USA
| | - Douglas Galante
- Brazilian Synchrotron Light Laboratory, Campinas, 13083-970, Brazil
| | - Fabio Rodrigues
- Institute of Chemistry, University of São Paulo, 05508-000, Brazil
| | - Armando Azua-Bustos
- Centro de Investigación Biomédica, UniversidadAutónoma de Chile, Santiago, 8910060, Chile
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Khandpur P, Gogate PR. Evaluation of ultrasound based sterilization approaches in terms of shelf life and quality parameters of fruit and vegetable juices. ULTRASONICS SONOCHEMISTRY 2016; 29:337-353. [PMID: 26585014 DOI: 10.1016/j.ultsonch.2015.10.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/11/2015] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
The present work evaluates the performance of ultrasound based sterilization approaches for processing of different fruit and vegetable juices in terms of microbial growth and changes in the quality parameters during the storage. Comparison with the conventional thermal processing has also been presented. A novel approach based on combination of ultrasound with ultraviolet irradiation and crude extract of essential oil from orange peels has been used for the first time. Identification of the microbial growth (total bacteria and yeast content) in the juices during the subsequent storage and assessing the safety for human consumption along with the changes in the quality parameters (Brix, titratable acidity, pH, ORP, salt, conductivity, TSS and TDS) has been investigated in details. The optimized ultrasound parameters for juice sterilization were established as ultrasound power of 100 W and treatment time of 15 min for the constant frequency operation (20 kHz). It has been established that more than 5 log reduction was achieved using the novel combined approaches based on ultrasound. The treated juices using different approaches based on ultrasound also showed lower microbial growth and improved quality characteristics as compared to the thermally processed juice. Scale up studies were also performed using spinach juice as the test sample with processing at 5 L volume for the first time. The ultrasound treated juice satisfied the microbiological and physiochemical safety limits in refrigerated storage conditions for 20 days for the large scale processing. Overall the present work conclusively established the usefulness of combined treatment approaches based on ultrasound for maintaining the microbiological safety of beverages with enhanced shelf life and excellent quality parameters as compared to the untreated and thermally processed juices.
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Affiliation(s)
- Paramjeet Khandpur
- Chemical Engineering Department, Institute of Chemical Technology, Matunga, Mumbai 400019, India
| | - Parag R Gogate
- Chemical Engineering Department, Institute of Chemical Technology, Matunga, Mumbai 400019, India.
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Skibinski B, Müller P, Uhl W. Rejection of submicron sized particles from swimming pool water by a monolithic SiC microfiltration membrane: Relevance of steric and electrostatic interactions. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2015.10.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Samstag RW, Ducoste JJ, Griborio A, Nopens I, Batstone DJ, Wicks JD, Saunders S, Wicklein EA, Kenny G, Laurent J. CFD for wastewater treatment: an overview. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2016; 74:549-563. [PMID: 27508360 DOI: 10.2166/wst.2016.249] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Computational fluid dynamics (CFD) is a rapidly emerging field in wastewater treatment (WWT), with application to almost all unit processes. This paper provides an overview of CFD applied to a wide range of unit processes in water and WWT from hydraulic elements like flow splitting to physical, chemical and biological processes like suspended growth nutrient removal and anaerobic digestion. The paper's focus is on articulating the state of practice and research and development needs. The level of CFD's capability varies between different process units, with a high frequency of application in the areas of final sedimentation, activated sludge basin modelling and disinfection, and greater needs in primary sedimentation and anaerobic digestion. While approaches are comprehensive, generally capable of incorporating non-Newtonian fluids, multiphase systems and biokinetics, they are not broad, and further work should be done to address the diversity of process designs. Many units have not been addressed to date. Further needs are identified throughout, but common requirements include improved particle aggregation and breakup (flocculation), and improved coupling of biology and hydraulics.
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Affiliation(s)
- R W Samstag
- Civil and Sanitary Engineer, PO Box 10129, Bainbridge Island, WA, USA E-mail:
| | - J J Ducoste
- North Carolina State University, Raleigh, NC, USA
| | | | - I Nopens
- BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, University of Ghent, Ghent, Belgium
| | | | | | | | | | - G Kenny
- R.V. Anderson Associates, Toronto, Canada
| | - J Laurent
- Icube, University of Strasbourg, Strasbourg, France
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Zhao JH, Chen W, Zhao Y, Liu C, Liu R. UV/TiO2 photocatalytic disinfection of carbon-bacteria complexes in activated carbon-filtered water: Laboratory and pilot-scale investigation. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2015; 50:1274-1281. [PMID: 26301854 DOI: 10.1080/10934529.2015.1055155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The occurrence of carbon-bacteria complexes in activated carbon filtered water has posed a public health problem regarding the biological safety of drinking water. The application of combined process of ultraviolet radiation and nanostructure titanium dioxide (UV/TiO2) photocatalysis for the disinfection of carbon-bacteria complexes were assessed in this study. Results showed that a 1.07 Lg disinfection rate can be achieved using a UV dose of 20 mJ cm(-2), while the optimal UV intensity was 0.01 mW cm(-2). Particle sizes ≥8 μm decreased the disinfection efficiency, whereas variation in particle number in activated carbon-filtered water did not significantly affect the disinfection efficiency. Photoreactivation ratio was reduced from 12.07% to 1.69% when the UV dose was increased from 5 mJ cm(-2) to 20 mJ cm(-2). Laboratory and on-site pilot-scale experiments have demonstrated that UV/TiO2 photocatalytic disinfection technology is capable of controlling the risk posed by carbon-bacteria complexes and securing drinking water safety.
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Affiliation(s)
- Jin Hui Zhao
- a College of Environment, Nanjing Tech University , Nanjing , P.R. China
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Omotade TO, Bernhards RC, Klimko CP, Matthews ME, Hill AJ, Hunter MS, Webster WM, Bozue JA, Welkos SL, Cote CK. The impact of inducing germination of Bacillus anthracis and Bacillus thuringiensis spores on potential secondary decontamination strategies. J Appl Microbiol 2014; 117:1614-33. [PMID: 25196092 DOI: 10.1111/jam.12644] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/03/2014] [Accepted: 09/03/2014] [Indexed: 12/22/2022]
Abstract
AIMS Decontamination and remediation of a site contaminated by the accidental or intentional release of fully virulent Bacillus anthracis spores are difficult, costly and potentially damaging to the environment. Development of novel decontamination strategies that have minimal environmental impacts remains a high priority. Although ungerminated spores are amongst the most resilient organisms known, once exposed to germinants, the germinating spores, in some cases, become susceptible to antimicrobial environments. We evaluated the concept that once germinated, B. anthracis spores would be less hazardous and significantly easier to remediate than ungerminated dormant spores. METHODS AND RESULTS Through in vitro germination and sensitivity assays, we demonstrated that upon germination, B. anthracis Ames spores and Bacillus thuringiensis Al Hakam spores (serving as a surrogate for B. anthracis) become susceptible to environmental stressors. The majority of these germinated B. anthracis and B. thuringiensis spores were nonviable after exposure to a defined minimal germination-inducing solution for prolonged periods of time. Additionally, we examined the impact of potential secondary disinfectant strategies including bleach, hydrogen peroxide, formaldehyde and artificial UV-A, UV-B and UV-C radiation, employed after a 60-min germination-induction step. Each secondary disinfectant employs a unique mechanism of killing; as a result, germination-induction strategies are better suited for some secondary disinfectants than others. CONCLUSIONS These results provide evidence that the deployment of an optimal combination strategy of germination-induction/secondary disinfection may be a promising aspect of wide-area decontamination following a B. anthracis contamination event. SIGNIFICANCE AND IMPACT OF THE STUDY By inducing spores to germinate, our data confirm that the resulting cells exhibit sensitivities that can be leveraged when paired with certain decontamination measures. This increased susceptibility could be exploited to devise more efficient and safe decontamination measures and may obviate the need for more stringent methods that are currently in place.
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Affiliation(s)
- T O Omotade
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
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Effect of repetitive ultraviolet irradiation on the physico-chemical properties and microbial stability of pineapple juice. INNOV FOOD SCI EMERG 2014. [DOI: 10.1016/j.ifset.2014.02.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Giardia duodenalis: Number and Fluorescence Reduction Caused by the Advanced Oxidation Process (H2O2/UV). INTERNATIONAL SCHOLARLY RESEARCH NOTICES 2014; 2014:525719. [PMID: 27379301 PMCID: PMC4897353 DOI: 10.1155/2014/525719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 11/04/2014] [Indexed: 11/30/2022]
Abstract
This study evaluated the effect of peroxidation assisted by ultraviolet radiation (H2O2/UV), which is an advanced oxidation process (AOP), on Giardia duodenalis cysts. The cysts were inoculated in synthetic and surface water using a concentration of 12 g H2O2 L−1 and a UV dose (λ = 254 nm) of 5,480 mJcm−2. The aqueous solutions were concentrated using membrane filtration, and the organisms were observed using a direct immunofluorescence assay (IFA). The AOP was effective in reducing the number of G. duodenalis cysts in synthetic and surface water and was most effective in reducing the fluorescence of the cyst walls that were present in the surface water. The AOP showed a higher deleterious potential for G. duodenalis cysts than either peroxidation (H2O2) or photolysis (UV) processes alone.
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Dos Santos LU, Alves DP, Guaraldo AMA, Cantusio Neto R, Durigan M, Franco RMB. Infectivity of Giardia duodenalis Cysts from UV Light-Disinfected Wastewater Effluent Using a Nude BALB/c Mouse Model. ISRN PARASITOLOGY 2013; 2013:713958. [PMID: 27335858 PMCID: PMC4890921 DOI: 10.5402/2013/713958] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 12/27/2012] [Indexed: 11/24/2022]
Abstract
Giardia duodenalis is a protozoan of public health interest that causes gastroenteritis in humans and other animals. In the city of Campinas in southeast Brazil, giardiasis is endemic, and this pathogen is detected at high concentrations in wastewater effluents, which are potential reservoirs for transmission. The Samambaia wastewater treatment plant (WWTP) in the city of Campinas employs an activated sludge system for sewage treatment and ultraviolet (UV) light for disinfection of effluents. To evaluate this disinfection process with respect to inactivating G. duodenalis cysts, two sample types were investigated: (i) effluent without UV disinfection (EFL) and (ii) effluent with UV disinfection (EFL+UV). Nude immunodeficient BALB/c mice were intragastrically inoculated with a mean dose of 14 cysts of G. duodenalis recovered from effluent from this WWTP, EFL, or EFL+UV. All animals inoculated with G. duodenalis cysts developed the infection, but animals inoculated with UV-exposed cysts released a lower average concentration of cysts in their faeces than animals inoculated with cysts that were not UV disinfected. Trophozoites were also observed in both groups of animals. These findings suggest that G. duodenalis cysts exposed to UV light were damaged but were still able to cause infection.
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Affiliation(s)
- Luciana Urbano Dos Santos
- Laboratory of Oxidation Processes, Department of Sanitation and Environment, School of Civil Engineering, Architecture and Urbanism, University of Campinas (UNICAMP), C.P. Box 6021, 13083-852 Campinas, SP, Brazil
| | - Delma Pegolo Alves
- CEMIB Multidisciplinary Centre for Biological Investigation, University of Campinas (UNICAMP), C.P. Box 6095, 13083-877 Campinas, SP, Brazil
| | - Ana Maria Aparecida Guaraldo
- Laboratory of Helminthology, Department of Parasitology, Institute of Biology, University of Campinas (UNICAMP), C.P. Box 6109, 13083-970 Campinas, SP, Brazil
| | - Romeu Cantusio Neto
- Laboratory of Microbiology, Society for Water Supply and Sanitation (SANASA), Street Abolição 2.375, 13045-750 Campinas, SP, Brazil
| | - Mauricio Durigan
- Laboratory of Genetic and Molecular Analysis, Center of Molecular Biology and Genetic Engineering (CBMEG), Institute of Biology, University of Campinas (UNICAMP), C.P. Box 6109, 13083-875 Campinas, SP, Brazil
| | - Regina Maura Bueno Franco
- Laboratory of Protozoology, Department of Animal Biology, Institute of Biology, University of Campinas (UNICAMP), C.P. Box 6109, 13083-970 Campinas, SP, Brazil
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Würtele MA, Kolbe T, Lipsz M, Külberg A, Weyers M, Kneissl M, Jekel M. Application of GaN-based ultraviolet-C light emitting diodes--UV LEDs--for water disinfection. WATER RESEARCH 2011; 45:1481-9. [PMID: 21115187 DOI: 10.1016/j.watres.2010.11.015] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 11/04/2010] [Accepted: 11/09/2010] [Indexed: 05/02/2023]
Abstract
GaN-based ultraviolet-C (UV-C) light emitting diodes (LEDs) are of great interest for water disinfection. They offer significant advantages compared to conventional mercury lamps due to their compact form factor, low power requirements, high efficiency, non-toxicity, and overall robustness. However, despite the significant progress in the performance of semiconductor based UV LEDs that has been achieved in recent years, these devices still suffer from low emission power and relatively short lifetimes. Even the best UV LEDs exhibit external quantum efficiencies of only 1-2%. The objective of this study was to investigate the suitability of GaN-based UV LEDs for water disinfection. The investigation included the evaluation of the performance characteristics of UV LEDs at different operating conditions as well as the design of a UV LED module in view of the requirements for water treatment applications. Bioanalytical testing was conducted using Bacillus subtilis spores as test organism and UV LED modules with emission wavelengths of 269 nm and 282 nm. The results demonstrate the functionality of the developed UV LED disinfection modules. GaN-based UV LEDs effectively inactivated B. subtilis spores during static and flow-through tests applying varying water qualities. The 269 nm LEDs reached a higher level of inactivation than the 282 nm LEDs for the same applied fluence. The lower inactivation achieved by the 282 nm LEDs was compensated by their higher photon flux. First flow-through tests indicate a linear correlation between inactivation and fluence, demonstrating a well designed flow-through reactor. With improved light output and reduced costs, GaN-based UV LEDs can provide a promising alternative for decentralised and mobile water disinfection systems.
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Affiliation(s)
- M A Würtele
- TU Berlin, Fachgebiet Wasserreinhaltung, Sekr. KF4, Strasse des 17, Juni 135, 10623 Berlin, Germany.
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Sauer A, Moraru CI. Inactivation of Escherichia coli ATCC 25922 and Escherichia coil O157:H7 in apple juice and apple cider, using pulsed light treatment. J Food Prot 2009; 72:937-44. [PMID: 19517718 DOI: 10.4315/0362-028x-72.5.937] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The main objective of this work was to evaluate the effectiveness of pulsed light (PL) treatment for the inactivation of Escherichia coli in liquids with different levels of clarity. Nonpathogenic E. coli ATCC 25922 and pathogenic E. coli O157: H7 were used as challenge organisms. Butterfield's phosphate buffer (BPB), tryptic soy broth (TSB), apple juice, and apple cider were used as substrates. The inoculated liquids were placed in a thin layer (1.3 mm) into glass chambers (23 by 53 by 11 mm) and exposed to PL doses of up to 13.1 J/cm2. PL treatments were performed in a Xenon RS-3000C PL unit, both in static mode and under turbulence. Survivors were determined by standard plate counting or the most-probable-number technique. For static treatments, reduction levels exceeding 8.5 log were obtained in BPB for all strains and reduction levels of about 3.5 log were obtained in TSB. For apple juice, inactivation levels of 2.66 +/- 0.10 log were obtained for E. coli ATCC 25922 and 2.52 +/- 0.19 log for E. coli O157:H7. In cider, inactivation levels of 2.32 +/- 0.16 log and 3.22 +/- 0.29 log were obtained for the nonpathogenic and pathogenic strains, respectively. Inactivation kinetics was characterized using the Weibull model. Turbulent treatments resulted in 5.76 +/- 0.06 log reduction in cider and 7.15 +/- 0.22 log reduction in juice, which satisfies the U.S. Food and Drug Administration requirement of 5-log reduction of E. coli. These results show promise for the use of PL for the effective reduction of E. coli in apple juice and cider.
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Affiliation(s)
- Anne Sauer
- Department of Food Science, Cornell University, Stocking Hall, Ithaca, New York 14853, USA
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