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Pino-Sandoval DA, Cantú-Cárdenas ME, Rodríguez-González V, Patrón-Soberano OA, Rosas-Castor JM, Murillo-Sierra JC, Hernández-Ramírez A. Solar heterogeneous photo-Fenton for complete inactivation of Escherichia coli and Salmonella typhimurium in secondary-treated wastewater effluent. CHEMOSPHERE 2023; 342:140132. [PMID: 37690560 DOI: 10.1016/j.chemosphere.2023.140132] [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: 04/09/2023] [Revised: 08/17/2023] [Accepted: 09/07/2023] [Indexed: 09/12/2023]
Abstract
In this work, complete elimination of Escherichia coli and Salmonella typhimurium was achieved in 120 min using a heterogeneous photo-Fenton process under sunlight at pH 6.5 in distilled water. A face-centered composite central design 22 with one categoric factor and three replicates at the central point was used to evaluate the effect of iron (III) oxide concentration (0.8-3.4 mg L-1), H2O2 (2-10 mg L-1), and the type of iron oxide phase (maghemite and hematite) on the inactivation of both bacteria. The results showed that the amount of catalyst, H2O2 concentration and their interaction were significant factors (p < 0.05) in the elimination of the microorganisms. Thus, under the best conditions (3.4 mg L-1 of iron (III) oxide and 10 mg L-1 of H2O2) in the experimental ranges, complete inactivation of E. coli and S. typhimurium was achieved (6-log reduction) in 120 min using the photo-Fenton treatment with both iron-oxide phases. Furthermore, the photocatalytic elimination of both bacteria by the photo-Fenton process using hematite and maghemite in secondary-treated wastewater effluent was performed obtaining slower inactivation rates (1.2-5.9 times) than in distilled water due to the matrix effect of the effluent from a wastewater treatment plant. Nevertheless, the process continued to be effective in the effluent, achieving complete bacterial elimination in 150 min using the hematite phase. Additionally, the SEM images of the bacterial cells showed that the heterogeneous photo-Fenton treatment generated permanent and irreversible cell damage, resulting in complete cell death.
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Affiliation(s)
- Diego A Pino-Sandoval
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de Los Garza, C.P. 66455, Nuevo León, Mexico; Universidad Politécnica de Apodaca, Av. Politécnica No. 2331, El Barretal, Apodaca, C. P. 66600, Nuevo León, Mexico
| | - M Elena Cantú-Cárdenas
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de Los Garza, C.P. 66455, Nuevo León, Mexico
| | - Vicente Rodríguez-González
- IPICyT, Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, División de Materiales Avanzados, Camino a La Presa San José 2055, Lomas 4a. Sección, 78216, San Luis Potosí, S.L.P., Mexico
| | - O Araceli Patrón-Soberano
- IPICyT, Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, División de Materiales Avanzados, Camino a La Presa San José 2055, Lomas 4a. Sección, 78216, San Luis Potosí, S.L.P., Mexico
| | - J Martín Rosas-Castor
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de Los Garza, C.P. 66455, Nuevo León, Mexico
| | - J Camilo Murillo-Sierra
- Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Concepción, Chile
| | - Aracely Hernández-Ramírez
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de Los Garza, C.P. 66455, Nuevo León, Mexico.
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Li X, Huang G, Li Y, Chen X, Yao Y, Liang Y, Huang J, Zhao K, Yin J. Low-Cost ceramic disk filters coated with Graphitic carbon nitride (g-C3N4) for drinking water disinfection and purification. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.120999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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3
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Reducing the Impacts of Biofouling in RO Membrane Systems through In Situ Low Fluence Irradiation Employing UVC-LEDs. MEMBRANES 2020; 10:membranes10120415. [PMID: 33322250 PMCID: PMC7764532 DOI: 10.3390/membranes10120415] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 01/04/2023]
Abstract
Biofouling is a major concern for numerous reverse osmosis membrane systems. UV pretreatment of the feed stream showed promising results but is still not an established technology as it does not maintain a residual effect. By conducting accelerated biofouling experiments in this study, it was investigated whether low fluence UV in situ treatment of the feed using UVC light-emitting diodes (UVC-LEDs) has a lasting effect on the biofilm. The application of UVC-LEDs for biofouling control is a novel hybrid technology that has not been investigated, yet. It could be shown that a low fluence of 2 mJ∙cm-2 delays biofilm formation by more than 15% in lab-scale experiments. In addition, biofilms at the same feed channel pressure drop exhibited a more than 40% reduced hydraulic resistance. The delay is probably linked to the inactivation of cells in the feed stream, modified adsorption properties or an induced cell cycle arrest. The altered hydraulic resistance might be caused by a change in the microbial community, as well as reduced adenosine triphosphate levels per cells, possibly impacting quorum sensing and extracellular polymeric substances production. Due to the observed biofilm attributes, low fluence UV-LED in situ treatment of the feed stream seems to be a promising technology for biofouling control.
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Nelson KL, Boehm AB, Davies-Colley RJ, Dodd MC, Kohn T, Linden KG, Liu Y, Maraccini PA, McNeill K, Mitch WA, Nguyen TH, Parker KM, Rodriguez RA, Sassoubre LM, Silverman AI, Wigginton KR, Zepp RG. Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:1089-1122. [PMID: 30047962 PMCID: PMC7064263 DOI: 10.1039/c8em00047f] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Health-relevant microorganisms present in natural surface waters and engineered treatment systems that are exposed to sunlight can be inactivated by a complex set of interacting mechanisms. The net impact of sunlight depends on the solar spectral irradiance, the susceptibility of the specific microorganism to each mechanism, and the water quality; inactivation rates can vary by orders of magnitude depending on the organism and environmental conditions. Natural organic matter (NOM) has a large influence, as it can attenuate radiation and thus decrease inactivation by endogenous mechanisms. Simultaneously NOM sensitizes the formation of reactive intermediates that can damage microorganisms via exogenous mechanisms. To accurately predict inactivation and design engineered systems that enhance solar inactivation, it is necessary to model these processes, although some details are not yet sufficiently well understood. In this critical review, we summarize the photo-physics, -chemistry, and -biology that underpin sunlight-mediated inactivation, as well as the targets of damage and cellular responses to sunlight exposure. Viruses that are not susceptible to exogenous inactivation are only inactivated if UVB wavelengths (280-320 nm) are present, such as in very clear, open waters or in containers that are transparent to UVB. Bacteria are susceptible to slightly longer wavelengths. Some viruses and bacteria (especially Gram-positive) are susceptible to exogenous inactivation, which can be initiated by visible as well as UV wavelengths. We review approaches to model sunlight-mediated inactivation and illustrate how the environmental conditions can dramatically shift the inactivation rate of organisms. The implications of this mechanistic understanding of solar inactivation are discussed for a range of applications, including recreational water quality, natural treatment systems, solar disinfection of drinking water (SODIS), and enhanced inactivation via the use of sensitizers and photocatalysts. Finally, priorities for future research are identified that will further our understanding of the key role that sunlight disinfection plays in natural systems and the potential to enhance this process in engineered systems.
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Affiliation(s)
- Kara L Nelson
- Civil and Environmental Engineering, University of California, Berkeley, CA, USA.
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5
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Odling G, Chatzisymeon E, Robertson N. Sequential ionic layer adsorption and reaction (SILAR) deposition of Bi4Ti3O12 on TiO2: an enhanced and stable photocatalytic system for water purification. Catal Sci Technol 2018. [DOI: 10.1039/c7cy02549a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new method to produce bismuth titanate – titanium dioxide composites by modification of a TiO2 film deposited on a variety of different glass substrates is reported.
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Affiliation(s)
- Gylen Odling
- School of Chemistry
- University of Edinburgh
- Edinburgh
- UK
| | - Efthalia Chatzisymeon
- School of Engineering
- Institute for Infrastructure and Environment
- University of Edinburgh
- Edinburgh
- UK
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6
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Zhang B, Sun Z, Bai Y, Zhuang H, Ge D, Shi W, Sun Y. One-step deposition of a melanin-like polymer on individual Escherichia coli cells exhibiting a special UV resistance effect. RSC Adv 2016. [DOI: 10.1039/c6ra12307d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Melanin-like polydopamine encapsulated E. coli cells could retained cells viability, inhibited cell division and protected cells from UV radiation. These provide both fundamental research and applications of cell encapsulation for UV resistance.
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Affiliation(s)
- Bai Zhang
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Zhou Sun
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Yuting Bai
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Hanqiong Zhuang
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Dongtao Ge
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Wei Shi
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
| | - Yanan Sun
- Department of Biomaterials
- Fujian Key Laboratory of Materials Genome
- College of Materials
- Xiamen University
- Xiamen 361005
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7
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Ndounla J, Pulgarin C. Solar light (hv) and H2O2/hv photo-disinfection of natural alkaline water (pH 8.6) in a compound parabolic collector at different day periods in Sahelian region. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:17082-17094. [PMID: 26122565 DOI: 10.1007/s11356-015-4784-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 05/26/2015] [Indexed: 06/04/2023]
Abstract
The photo-disinfection of natural alkaline surface water (pH 8.6 ± 0.3) for drinking purposes was carried out under solar radiation treatments. The enteric bacteria studied were the wild total coliforms/Escherichia coli (10(4) CFU/ml) and Salmonella spp. (10(4) CFU/ml) naturally present in the water. The photo-disinfection of a 25-l water sample was carried out in a solar compound parabolic collector (CPC) in the absence and in the presence of hydrogen peroxide (H2O2). The addition of H2O2 (10 mg/L) to the sample water was sufficient to enhance the photo-disinfection and ensure an irreversible lethal action on the wild enteric bacteria contents of the sample. The inactivation kinetic of the system was significantly enhanced compared to the one carried out without H2O2 addition. The effect of the solar radiation parameters on the efficiency of the photo-disinfection were assessed. The pH has increased during the treatment in all the photo-disinfection processes (hv and H2O2/hv). The Salmonella spp strain has shown the best effective inactivate time in alkaline water than the one recorded under acidic or near-neutral conditions. The evolution of some physico-chemical parameters of the water (turbidity, NO2(-), NO3(-), NH4(+), HPO4(2-), and bicarbonate (HCO3(-))) was monitored during the treatment. Finally, the possible mechanistic process involved during the enteric bacteria inactivation was suggested.
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Affiliation(s)
- J Ndounla
- Ecole Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering GPAO, Station 6, 1015, Lausanne, Switzerland.
- Laboratoire Eau, Dépollution, Ecosystème et Santé (LEDES), Institut International d'Ingénierie de l'Eau et de l'Environnement, 01 BP 594, Ouagadougou 01, Burkina Faso.
| | - C Pulgarin
- Ecole Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering GPAO, Station 6, 1015, Lausanne, Switzerland.
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8
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Solar Disinfection of Viruses in Polyethylene Terephthalate Bottles. Appl Environ Microbiol 2015; 82:279-88. [PMID: 26497451 DOI: 10.1128/aem.02897-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/16/2015] [Indexed: 11/20/2022] Open
Abstract
Solar disinfection (SODIS) of drinking water in polyethylene terephthalate (PET) bottles is a simple, efficient point-of-use technique for the inactivation of many bacterial pathogens. In contrast, the efficiency of SODIS against viruses is not well known. In this work, we studied the inactivation of bacteriophages (MS2 and ϕX174) and human viruses (echovirus 11 and adenovirus type 2) by SODIS. We conducted experiments in PET bottles exposed to (simulated) sunlight at different temperatures (15, 22, 26, and 40°C) and in water sources of diverse compositions and origins (India and Switzerland). Good inactivation of MS2 (>6-log inactivation after exposure to a total fluence of 1.34 kJ/cm(2)) was achieved in Swiss tap water at 22°C, while less-efficient inactivation was observed in Indian waters and for echovirus (1.5-log inactivation at the same fluence). The DNA viruses studied, ϕX174 and adenovirus, were resistant to SODIS, and the inactivation observed was equivalent to that occurring in the dark. High temperatures enhanced MS2 inactivation substantially; at 40°C, 3-log inactivation was achieved in Swiss tap water after exposure to a fluence of only 0.18 kJ/cm(2). Overall, our findings demonstrate that SODIS may reduce the load of single-stranded RNA (ssRNA) viruses, such as echoviruses, particularly at high temperatures and in photoreactive matrices. In contrast, complementary measures may be needed to ensure efficient inactivation during SODIS of DNA viruses resistant to oxidation.
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9
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Disinfection of urban effluents using solar TiO2 photocatalysis: A study of significance of dissolved oxygen, temperature, type of microorganism and water matrix. Catal Today 2015. [DOI: 10.1016/j.cattod.2014.03.026] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Mattle MJ, Vione D, Kohn T. Conceptual model and experimental framework to determine the contributions of direct and indirect photoreactions to the solar disinfection of MS2, phiX174, and adenovirus. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:334-42. [PMID: 25419957 DOI: 10.1021/es504764u] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Sunlight inactivates waterborne viruses via direct (absorption of sunlight by the virus) and indirect processes (adsorption of sunlight by external chromophores, which subsequently generate reactive species). While the mechanisms underlying these processes are understood, their relative importance remains unclear. This study establishes an experimental framework to determine the kinetic parameters associated with a virus' susceptibility to solar disinfection and proposes a model to estimate disinfection rates and to apportion the contributions of different inactivation processes. Quantum yields of direct inactivation were determined for three viruses (MS2, phiX174, and adenovirus), and second-order rate constants associated with indirect inactivation by four reactive species ((1)O2, OH(•), CO3(•-), and triplet states) were established. PhiX174 exhibited the greatest quantum yield (1.4 × 10(-2)), indicating that it is more susceptible to direct inactivation than MS2 (2.9 × 10(-3)) or adenovirus (2.5 × 10(-4)). Second-order rate constants ranged from 1.7 × 10(7) to 7.0 × 10(9) M(-1) s(-1) and followed the sequence MS2 > adenovirus > phiX174. A predictive model based on these parameters accurately estimated solar disinfection of MS2 and phiX174 in a natural water sample and approximated that of adenovirus within a factor of 6. Inactivation mostly occurred by direct processes, though indirect inactivation by (1)O2 also contributed to the disinfection of MS2 and adenovirus.
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Affiliation(s)
- Michael J Mattle
- Laboratory of Environmental Chemistry, School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
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11
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Ndounla J, Pulgarin C. Evaluation of the efficiency of the photo Fenton disinfection of natural drinking water source during the rainy season in the Sahelian region. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 493:229-238. [PMID: 24950496 DOI: 10.1016/j.scitotenv.2014.05.139] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 05/29/2014] [Accepted: 05/29/2014] [Indexed: 06/03/2023]
Abstract
The photo-disinfection of water from two different wells (W1, pH: 4.6-5.1 ± 0.02) and (W2 pH: 5.6-5.7 ± 0.02) was carried out during the rainy season at Ouagadougou-Burkina Faso, West Africa. The weather variation during the rainy season significantly affects the photo-disinfection processes (solar disinfection and photo-Fenton). The dilution of the water by rainwater highly affected the chemical composition of the wells' water used in this study; very low iron contents Compared to the ones recorded during the dry season were recorded in all water samples. Both photo-disinfection processes were used to treat 25 L of water in a compound parabolic collector (CPC). None of them have shown the total inactivation of both wild enteric bacteria strains (total coliforms/E. coli and Salmonella spp.) involved in the treatment. However, the total coliforms/E. coli strains were totally inactivated during the exposure under most of the photo-Fenton treatment. Also, the remaining strains, especially those of Salmonella spp. were achieved during the subsequent 24h of dark storage under the action of the Fenton process. Under uniquely solar radiation, total inactivation was recorded only in the total coliforms/E. coli strains. The impact of the available irradiance on the efficiency of the photo-Fenton disinfection of natural water was highlighted during the exposure under high intermittent solar radiation. The impact of the HCO3(-) concentration of both wells' water on the evolution of the pH during the photo-disinfection was recorded. Drastic decrease was noticed after the initial fast increase in presence of low HCO3(-) concentration while a steady state was observed after the increase in presence of higher concentration. The redox activities of the nitrogen components of the water during both photo-disinfection processes have led to increased concentration of nitrite in all the cases and variations were noticed in that of nitrate and ammonia.
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Affiliation(s)
- J Ndounla
- Ecole Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering GPAO, Station 6, CH 1015 Lausanne, Switzerland; Institut International d'Ingénierie de l'Eau et de l'Environnement, Laboratoire Eau, Dépollution, Ecosystème et Santé (LEDES), 01 BP 594 Ouagadougou 01, Burkina Faso.
| | - C Pulgarin
- Ecole Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering GPAO, Station 6, CH 1015 Lausanne, Switzerland.
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12
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Lui GY, Roser D, Corkish R, Ashbolt N, Jagals P, Stuetz R. Photovoltaic powered ultraviolet and visible light-emitting diodes for sustainable point-of-use disinfection of drinking waters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 493:185-196. [PMID: 24946032 DOI: 10.1016/j.scitotenv.2014.05.104] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/23/2014] [Accepted: 05/23/2014] [Indexed: 06/03/2023]
Abstract
For many decades, populations in rural and remote developing regions will be unable to access centralised piped potable water supplies, and indeed, decentralised options may be more sustainable. Accordingly, improved household point-of-use (POU) disinfection technologies are urgently needed. Compared to alternatives, ultraviolet (UV) light disinfection is very attractive because of its efficacy against all pathogen groups and minimal operational consumables. Though mercury arc lamp technology is very efficient, it requires frequent lamp replacement, involves a toxic heavy metal, and their quartz envelopes and sleeves are expensive, fragile and require regular cleaning. An emerging alternative is semiconductor-based units where UV light emitting diodes (UV-LEDs) are powered by photovoltaics (PV). Our review charts the development of these two technologies, their current status, and challenges to their integration and POU application. It explores the themes of UV-C-LEDs, non-UV-C LED technology (e.g. UV-A, visible light, Advanced Oxidation), PV power supplies, PV/LED integration and POU suitability. While UV-C LED technology should mature in the next 10 years, research is also needed to address other unresolved barriers to in situ application as well as emerging research opportunities especially UV-A, photocatalyst/photosensitiser use and pulsed emission options.
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Affiliation(s)
- Gough Yumu Lui
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - David Roser
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Richard Corkish
- School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Nicholas Ashbolt
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia; School of Public Health , Room 3-57D, South Academic Building, University of Alberta, Edmonton, Alberta, T6G 2G7, Canada.
| | - Paul Jagals
- School of Population Health, University of Queensland, Brisbane, 4006, Australia.
| | - Richard Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
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Elucidating bacterial regrowth: Effect of disinfection conditions in dark storage of solar treated secondary effluent. J Photochem Photobiol A Chem 2014. [DOI: 10.1016/j.jphotochem.2014.05.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Nguyen MT, Silverman AI, Nelson KL. Sunlight inactivation of MS2 coliphage in the absence of photosensitizers: modeling the endogenous inactivation rate using a photoaction spectrum. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:3891-8. [PMID: 24575954 DOI: 10.1021/es405323p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The endogenous sunlight inactivation rates of MS2 coliphage in photosensitizer-free water were measured (kobs) under different light conditions and compared to modeled inactivation rates (kmod) computed using a previously published action spectrum. Experiments were conducted under simulated and natural sunlight. There was generally good agreement between modeled and observed MS2 sunlight inactivation rates in the summer and winter, suggesting that the action spectrum can be used to predict changes in the inactivation rate caused by diurnal and seasonal changes in natural sunlight irradiance. However, we show that a major source of uncertainty in the predictions is the ability to accurately measure or model the comparatively weak and highly variable solar irradiance between 280 and 300 nm, a range to which the inactivation rate is very sensitive. The action spectrum was also used to predict the endogenous inactivation rates of MS2 at different depths in a column of strongly humic-colored [i.e., solar ultraviolet (UV)-attenuating] wetland water under simulated sunlight; we observed fairly good agreement between kobs and kmod, suggesting that the action spectrum can be used to estimate the decrease in the endogenous inactivation rate caused by spectrally selective sunlight attenuation in the water column.
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Affiliation(s)
- Mi T Nguyen
- Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt) Engineering Research Center (ERC)
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15
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The antagonistic and synergistic effects of temperature during solar disinfection of synthetic secondary effluent. J Photochem Photobiol A Chem 2014. [DOI: 10.1016/j.jphotochem.2014.02.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Carter BH, Friend TH, Garey SM, Sawyer JA, Alexander MB, Tomazewski MA. Efficacy of reflective insulation in reducing heat stress on dairy calves housed in polyethylene calf hutches. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2014; 58:51-59. [PMID: 23325042 DOI: 10.1007/s00484-012-0623-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 08/02/2012] [Accepted: 08/03/2012] [Indexed: 06/01/2023]
Abstract
The objective of this study was to determine the ability of radiant insulation hutch covers to moderate the effect of ambient temperature and radiant energy on calves housed in polyethylene hutches. The insulation had a double layer of polyethylene bubble film laminated between a layer of aluminum foil and white polyethylene (reflectance = 95%, R value (ft(2) · °F ·h/Btu) = 2.7). In each of two experiments (exp.), hutches were either uninsulated (control) or covered with reflective insulation across the top and sides of the hutch leaving the front, back, and pen exposed. Each hutch had a 1.2 × 1.8-m attached outdoor wire pen. In both exp., rate of increase of interior hutch temperature relative to ambient temperature was lower in insulated hutches (P < 0.001) indicating they were warmer at low THI and cooler at high THI. In exp. 1, increase in respiration rate and ear canal temperature of the calves, relative to THI, were moderated in insulated hutches (P < 0.001). In Exp. 2, respiration rate was not affected by treatment (P = 0.50), but increased with increasing THI (P < 0.001). Mean ADG did not differ among treatments in either exp. (P > 0.21). Insulating calf hutches with reflective insulation moderated hutch microclimate, and improved calf comfort, but did not translate to improvements in economically relevant variables such as ADG.
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Affiliation(s)
- B H Carter
- Department of Animal Science, Texas A&M University, College Station, TX, USA
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17
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Silverman AI, Peterson BM, Boehm AB, McNeill K, Nelson KL. Sunlight inactivation of human viruses and bacteriophages in coastal waters containing natural photosensitizers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1870-1878. [PMID: 23384052 DOI: 10.1021/es3036913] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Sunlight inactivation of poliovirus type 3 (PV3), adenovirus type 2 (HAdV2), and two bacteriophage (MS2 and PRD1) was investigated in an array of coastal waters to better understand solar inactivation mechanisms and the effect of natural water constituents on observed inactivation rates (k(obs)). Reactor scale inactivation experiments were conducted using a solar simulator, and k(obs) for each virus was measured in a sensitizer-free control and five unfiltered surface water samples collected from different sources. k(obs) values varied between viruses in the same water matrix, and for each virus in different matrices, with PV3 having the fastest and MS2 the slowest k(obs) in all waters. When exposed to full-spectrum sunlight, the presence of photosensitizers increased k(obs) of HAdV2, PRD1 and MS2, but not PV3, which provides evidence that the exogenous sunlight inactivation mechanism, involving damage by exogenously produced reactive intermediates, played a greater role for these viruses. While PV3 inactivation was observed to be dominated by endogenous mechanisms, this may be due to a masking of exogenous k(obs) by significantly faster endogenous k(obs). Results illustrate that differences in water composition can shift absolute and relative inactivation rates of viruses, which has important implications for natural wastewater treatment systems, solar disinfection (SODIS), and the use of indicator organisms for monitoring water quality.
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Affiliation(s)
- Andrea I Silverman
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California, USA
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Khan SJ, Reed RH, Rasul MG. Thin-film fixed-bed reactor for solar photocatalytic inactivation of Aeromonas hydrophila: influence of water quality. BMC Microbiol 2012. [PMID: 23194331 PMCID: PMC3556150 DOI: 10.1186/1471-2180-12-285] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Controlling fish disease is one of the major concerns in contemporary aquaculture. The use of antibiotics or chemical disinfection cannot provide a healthy aquaculture system without residual effects. Water quality is also important in determining the success or failure of fish production. Several solar photocatalytic reactors have been used to treat drinking water or waste water without leaving chemical residues. This study has investigated the impact of several key aspects of water quality on the inactivation of the pathogenic bacterium Aeromonas hydrophila using a pilot-scale thin-film fixed-bed reactor (TFFBR) system. RESULTS The level of inactivation of Aeromonas hydrophila ATCC 35654 was determined using a TFFBR with a photocatalytic area of 0.47 m(2) under the influence of various water quality variables (pH, conductivity, turbidity and colour) under high solar irradiance conditions (980-1100 W m(-2)), at a flow rate of 4.8 L h(-1) through the reactor. Bacterial enumeration were obtained through conventional plate count using trypticase soy agar media, cultured in conventional aerobic conditions to detect healthy cells and under ROS-neutralised conditions to detect both healthy and sub-lethally injured (oxygen-sensitive) cells. The results showed that turbidity has a major influence on solar photocatalytic inactivation of A. hydrophila. Humic acids appear to decrease TiO(2) effectiveness under full sunlight and reduce microbial inactivation. pH in the range 7-9 and salinity both have no major effect on the extent of photoinactivation or sub-lethal injury. CONCLUSIONS This study demonstrates the effectiveness of the TFFBR in the inactivation of Aeromonas hydrophila under the influence of several water quality variables at high solar irradiance, providing an opportunity for the application of solar photocatalysis in aquaculture systems, as long as turbidity remains low.
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Affiliation(s)
- Sadia J Khan
- Centre for Plant and Water Sciences, Central Queensland University, Rockhampton, QLD 4701, Australia
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McGuigan KG, Conroy RM, Mosler HJ, du Preez M, Ubomba-Jaswa E, Fernandez-Ibañez P. Solar water disinfection (SODIS): a review from bench-top to roof-top. JOURNAL OF HAZARDOUS MATERIALS 2012; 235-236:29-46. [PMID: 22906844 DOI: 10.1016/j.jhazmat.2012.07.053] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 07/27/2012] [Accepted: 07/28/2012] [Indexed: 05/12/2023]
Abstract
Solar water disinfection (SODIS) has been known for more than 30 years. The technique consists of placing water into transparent plastic or glass containers (normally 2L PET beverage bottles) which are then exposed to the sun. Exposure times vary from 6 to depending on the intensity of sunlight and sensitivity of the pathogens. Its germicidal effect is based on the combined effect of thermal heating of solar light and UV radiation. It has been repeatedly shown to be effective for eliminating microbial pathogens and reduce diarrhoeal morbidity including cholera. Since 1980 much research has been carried out to investigate the mechanisms of solar radiation induced cell death in water and possible enhancement technologies to make it faster and safer. Since SODIS is simple to use and inexpensive, the method has spread throughout the developing world and is in daily use in more than 50 countries in Asia, Latin America, and Africa. More than 5 million people disinfect their drinking water with the solar disinfection (SODIS) technique. This review attempts to revise all relevant knowledge about solar disinfection from microbiological issues, laboratory research, solar testing, up to and including real application studies, limitations, factors influencing adoption of the technique and health impact.
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Grant SB, Saphores JD, Feldman DL, Hamilton AJ, Fletcher TD, Cook PLM, Stewardson M, Sanders BF, Levin LA, Ambrose RF, Deletic A, Brown R, Jiang SC, Rosso D, Cooper WJ, Marusic I. Taking the "Waste" Out of "Wastewater" for Human Water Security and Ecosystem Sustainability. Science 2012; 337:681-6. [DOI: 10.1126/science.1216852] [Citation(s) in RCA: 403] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Eby DM, Harbaugh S, Tatum RN, Farrington KE, Kelley-Loughnane N, Johnson GR. Bacterial sunscreen: layer-by-layer deposition of UV-absorbing polymers on whole-cell biosensors. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:10521-10527. [PMID: 22694254 DOI: 10.1021/la3014514] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
UV-protective coatings on live bacterial cells were created from the assembly of cationic and UV-absorbing anionic polyelectrolytes using layer-by-layer (LbL) methodology. A cationic polymer (polyallylamine) and three different anionic polymers with varying absorbance in the UV range (poly(vinyl sulfate), poly(4-styrenesulfonic acid), and humic acid) were used to encapsulate Escherichia coli cells with two different green fluorescent protein (GFP) expression systems: constitutive expression of a UV-excitable GFP (GFPuv) and regulated expression of the intensely fluorescent GFP from amphioxus (GFPa1) through a theophylline-inducible riboswitch. Riboswitches activate protein expression after specific ligand-RNA binding events. Hence, they operate as a cellular biosensor that will activate reporter protein synthesis after exposure to a ligand target. E. coli cells coated with UV-absorbing polymers demonstrated enhanced protection of GFP stability, metabolic activity, and viability after prolonged exposure to radiation from a germicidal lamp. The results show the effectiveness of LbL coatings to provide UV protection to living cells for biotechnological applications.
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Affiliation(s)
- D Matthew Eby
- Universal Technology Corporation and Air Force Research Laboratory, Materials and Manufacturing Directorate, Tyndall Air Force Base, 139 Barnes Drive, Building 1117, Tyndall AFB, Florida 32403, United States.
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Loo SL, Fane AG, Krantz WB, Lim TT. Emergency water supply: a review of potential technologies and selection criteria. WATER RESEARCH 2012; 46:3125-51. [PMID: 22521949 DOI: 10.1016/j.watres.2012.03.030] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 02/09/2012] [Accepted: 03/13/2012] [Indexed: 05/26/2023]
Abstract
Access to safe drinking water is one of the first priorities following a disaster. However, providing drinking water to the affected population (AP) is challenging due to severe contamination and lack of access to infrastructure. An onsite treatment system for the AP is a more sustainable solution than transporting bottled water. Emergency water technologies (WTs) that are modular, mobile or portable are suitable for emergency relief. This paper reviews WTs including membrane technologies that are suitable for use in emergencies. Physical, chemical, thermal- and light-based treatment methods, and membrane technologies driven by different driving forces such as pressure, temperature and osmotic gradients are reviewed. Each WT is evaluated by ten mutually independent criteria: costs, ease of deployment, ease of use, maintenance, performance, potential acceptance, energy requirements, supply chain requirements, throughput and environmental impact. A scoring system based on these criteria is presented. A methodology for emergency WT selection based on compensatory multi-criteria analysis is developed and discussed. Finally, critical research needs are identified.
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Affiliation(s)
- Siew-Leng Loo
- Singapore Membrane Technology Centre, Nanyang Technological University, Singapore 639798, Singapore
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Fabbricino M, d'Antonio L. Use of solar radiation for continuous water disinfection in isolated areas. ENVIRONMENTAL TECHNOLOGY 2012; 33:539-544. [PMID: 22629627 DOI: 10.1080/09593330.2011.584570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This study involved investigation of solar water disinfection in continuously working treatment plants with the aim of producing safe drinking water in isolated areas. Results were obtained from experimental work carried out on a pilot plant operating in different configurations. The use of a simple device to increase solar radiation intensity (solar concentrator) was tested, with results showing that it facilitated better performance. A comparison between transparent and black-painted glass reactors was also made, showing no difference between the two casings. Further, the effect of an increase in water temperature was analysed in detail. Temperature was found to play an important role in the disinfection process, even in cases of limited solar radiation intensities, although a synergistic effect of water heating and solar radiation for effective microbial inactivation was confirmed. Reactor design is also discussed, highlighting the importance of having a plug flow to avoid zones that do not contribute to the overall effectiveness of the process.
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Affiliation(s)
- M Fabbricino
- Department of Hydraulics, Geotechnics and Environmental Engineering, University of Naples Federico II, Naples, Italy.
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Khan SJ, Reed RH, Rasul MG. Thin-film fixed-bed reactor (TFFBR) for solar photocatalytic inactivation of aquaculture pathogen Aeromonas hydrophila. BMC Microbiol 2012; 12:5. [PMID: 22243515 PMCID: PMC3274425 DOI: 10.1186/1471-2180-12-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 01/13/2012] [Indexed: 11/29/2022] Open
Abstract
Background Outbreaks of infectious diseases by microbial pathogens can cause substantial losses of stock in aquaculture systems. There are several ways to eliminate these pathogens including the use of antibiotics, biocides and conventional disinfectants, but these leave undesirable chemical residues. Conversely, using sunlight for disinfection has the advantage of leaving no chemical residue and is particularly suited to countries with sunny climates. Titanium dioxide (TiO2) is a photocatalyst that increases the effectiveness of solar disinfection. In recent years, several different types of solar photocatalytic reactors coated with TiO2 have been developed for waste water and drinking water treatment. In this study a thin-film fixed-bed reactor (TFFBR), designed as a sloping flat plate reactor coated with P25 DEGUSSA TiO2, was used. Results The level of inactivation of the aquaculture pathogen Aeromonas hydrophila ATCC 35654 was determined after travelling across the TFFBR under various natural sunlight conditions (300-1200 W m-2), at 3 different flow rates (4.8, 8.4 and 16.8 L h-1). Bacterial numbers were determined by conventional plate counting using selective agar media, cultured (i) under conventional aerobic conditions to detect healthy cells and (ii) under conditions designed to neutralise reactive oxygen species (agar medium supplemented with the peroxide scavenger sodium pyruvate at 0.05% w/v, incubated under anaerobic conditions), to detect both healthy and sub-lethally injured (oxygen-sensitive) cells. The results clearly demonstrate that high sunlight intensities (≥ 600 W m-2) and low flow rates (4.8 L h-1) provided optimum conditions for inactivation of A. hydrophila ATCC 3564, with greater overall inactivation and fewer sub-lethally injured cells than at low sunlight intensities or high flow rates. Low sunlight intensities resulted in reduced overall inactivation and greater sub-lethal injury at all flow rates. Conclusions This is the first demonstration of the effectiveness of the TFFBR in the inactivation of Aeromonas hydrophila at high sunlight intensities, providing proof-of-concept for the application of solar photocatalysis in aquaculture systems.
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Affiliation(s)
- Sadia J Khan
- Centre for Plant and Water Sciences, Faculty of Sciences, Engineering and Health, CQUniversity, Rockhampton, QLD 4702, Australia
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Love DC, Silverman A, Nelson KL. Human virus and bacteriophage inactivation in clear water by simulated sunlight compared to bacteriophage inactivation at a southern California beach. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:6965-6970. [PMID: 20726507 DOI: 10.1021/es1001924] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Few quantitative data exist on human virus inactivation by sunlight and the relationship between human and indicator viruses under sunlit conditions. We investigated the effects of sunlight on human viruses (adenovirus type 2, poliovirus type 3) and bacteriophages (MS2, Q-Beta SP, Fi, M13, PRD1, Phi-X174, and coliphages isolated from Avalon Bay, California). Viruses were inoculated into phosphate buffered saline or seawater, exposed to a laboratory solar simulator for ≤12 h, and enumerated by double agar layer or cell culture to derive first-order inactivation rate constants (k(obs), h(-1)). The viruses most resistant to sunlight were adenovirus type 2 (k(obs)= 0.59 ± 0.04 h(-1)) and bacteriophage MS2 (k(obs)= 0.43 ± 0.02 h(-1)), which suggests MS2 may be a conservative indicator for sunlight resistant human viruses in clear water when sunlight inactivation is the main removal mechanism. Reasonable agreement was observed between somatic coliphage inactivation rates measured in the solar simulator (k(mean) = 1.81 h(-1)) and somatic coliphages measured in the surf zone during a field campaign at Avalon Bay during similar sunlight intensity (k = 0.75 h(-1) at log-RMSE minimum; k(range) = 0.54 h(-1) to >1.88 h(-1); Boehm, A. B. et al. Environ. Sci. Technol. 2009, 43, (21), 8046-8052). Hence, measuring sunlight inactivation rates of viruses in the laboratory can be used to estimate inactivation in the environment under similar sunlight and water quality conditions.
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Affiliation(s)
- David C Love
- Department of Civil and Environmental Engineering, University of California Berkeley, Berkeley, California 94720, USA.
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Sharan R, Chhibber S, Attri S, Reed RH. Inactivation and sub-lethal injury of Escherichia coli in a copper water storage vessel: effect of inorganic and organic constituents. Antonie van Leeuwenhoek 2010; 98:103-15. [PMID: 20358286 DOI: 10.1007/s10482-010-9435-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 03/22/2010] [Indexed: 01/11/2023]
Abstract
This study provides information on the effects of inorganic and organic constituents on inactivation and sub-lethal injury of Escherichia coli in water stored in a copper vessel. E. coli suspensions were stored for up to 24 h in copper vessels containing one of the following dissolved constituents at 1 g/l: salts of inorganic ions, carbohydrates, proteins and complex natural organic mixtures. Samples were surface plated onto (i) nutrient agar, incubated under standard aerobic conditions to provide conventional counts for uninjured bacteria count and onto (ii) nutrient agar plates with 0.5 g/l sodium pyruvate incubated under anaerobic conditions to enumerate sub-lethally injured (oxygen-sensitive) bacteria alongside their healthy counterparts. The concentration of dissolved copper in the stored water was determined using atomic absorption spectrophotometry. The addition of chloride salts resulted in a faster inactivation of E. coli compared to pure water with no dissolved additives, irrespective of the counterion. In contrast, a slower inactivation was observed in the presence of Na(2)SO(4), NaNO(3) and NaNO(2) when compared to NaCl. Addition of the carbohydrates glucose, lactose and starch gave broadly similar results to those obtained using unsupplemented water. However, the addition of amino acids, proteins, humic acid or complex organic mixtures caused a dramatic decrease in inactivation of E. coli, with evidence of a greater number of sub-lethally injured bacteria than was seen with other added constituents. The amount of copper was highest in stored water containing amino acids and complex organic constituents, with the slow inactivation most likely to be due to complex formation between leached copper and these organic constituents. The present study clearly demonstrates that water composition, particularly natural organic constituents, has a substantial impact on the antibacterial effectiveness and dissolved copper concentration of water stored in copper vessels and that both aspects will need to be considered in terms of their impact on the practical use of copper-based systems for small-scale water treatment.
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Affiliation(s)
- Riti Sharan
- Centre for Plant & Water Science, CQUniversity, Brisbane, Australia
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Davies CM, Roser DJ, Feitz AJ, Ashbolt NJ. Solar radiation disinfection of drinking water at temperate latitudes: inactivation rates for an optimised reactor configuration. WATER RESEARCH 2009; 43:643-652. [PMID: 19041999 DOI: 10.1016/j.watres.2008.11.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 11/10/2008] [Accepted: 11/12/2008] [Indexed: 05/27/2023]
Abstract
Solar radiation-driven inactivation of bacteria, virus and protozoan pathogen models was quantified in simulated drinking water at a temperate latitude (34 degrees S). The water was seeded with Enterococcus faecalis, Clostridium sporogenes spores, and P22 bacteriophage, each at ca 1x10(5) mL(-1), and exposed to natural sunlight in 30-L reaction vessels. Water temperature ranged from 17 to 39 degrees C during the experiments lasting up to 6h. Dark controls showed little inactivation and so it was concluded that the inactivation observed was primarily driven by non-thermal processes. The optimised reactor design achieved S90 values (cumulative exposure required for 90% reduction) for the test microorganisms in the range 0.63-1.82 MJ m(-2) of Global Solar Exposure (GSX) without the need for TiO2 as a catalyst. High turbidity (840-920 NTU) only reduced the S(90) value by <40%. Further, when all S90 means were compared this decrease was not statistically significant (prob.>0.05). However, inactivation was significantly reduced for E. faecalis and P22 when the transmittance of UV wavelengths was attenuated by water with high colour (140 PtCo units) or a suboptimally transparent reactor lid (prob.<0.05). S90 values were consistent with those measured by other researchers (ca 1-10 MJ m(-2)) for a range of waters and microorganisms. Although temperatures required for SODIS type pasteurization were not produced, non-thermal inactivation alone appeared to offer a viable means for reliably disinfecting low colour source waters by greater than 4 orders of magnitude on sunny days at 34 degrees S latitude.
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Affiliation(s)
- C M Davies
- Centre for Water and Waste Technology, Department of Civil and Environmental Engineering, University of New South Wales, Kensington, NSW 2052, Australia.
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Effectiveness of solar disinfection using batch reactors with non-imaging aluminium reflectors under real conditions: Natural well-water and solar light. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2008; 93:155-61. [DOI: 10.1016/j.jphotobiol.2008.08.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 07/01/2008] [Accepted: 08/25/2008] [Indexed: 11/22/2022]
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Sökmen M, Değerli S, Aslan A. Photocatalytic disinfection of Giardia intestinalis and Acanthamoeba castellani cysts in water. Exp Parasitol 2008; 119:44-8. [DOI: 10.1016/j.exppara.2007.12.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 12/13/2007] [Accepted: 12/17/2007] [Indexed: 10/22/2022]
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Josset S, Keller N, Lett MC, Ledoux MJ, Keller V. Numeration methods for targeting photoactive materials in the UV-A photocatalytic removal of microorganisms. Chem Soc Rev 2008; 37:744-55. [PMID: 18362981 DOI: 10.1039/b711748p] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This tutorial review reports on the different numeration methods for evaluating the efficiency of the photocatalytic action on microorganisms. Here we put forward the advantages and drawbacks of the standard methods such as the plate count, the fluorescence techniques and the Most Probable Number method for determining the biocidal photocatalytic activity and thus selecting efficient photocatalytic materials among complex systems. We highlight that bacterial spores are a representative and suitable tool for meeting the restrictive requirements resulting from the complex use of living matter instead of chemical targets.
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Affiliation(s)
- Sébastien Josset
- Laboratoire des Matériaux, Surfaces et Procédés pour la Catalyse, European Laboratory for Catalysis and Surface Sciences, CNRS, Louis Pasteur University, 25 rue Becquerel, 67087 Strasbourg, France
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Absence of E. coli regrowth after Fe3+ and TiO2 solar photoassisted disinfection of water in CPC solar photoreactor. Catal Today 2007. [DOI: 10.1016/j.cattod.2007.03.039] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Rincón AG, Pulgarin C. Fe3+ and TiO2 solar-light-assisted inactivation of E. coli at field scale. Catal Today 2007. [DOI: 10.1016/j.cattod.2007.01.028] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Berney M, Weilenmann HU, Simonetti A, Egli T. Efficacy of solar disinfection of Escherichia coli, Shigella flexneri, Salmonella Typhimurium and Vibrio cholerae. J Appl Microbiol 2006; 101:828-36. [PMID: 16968294 DOI: 10.1111/j.1365-2672.2006.02983.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To determine the efficacy of solar disinfection (SODIS) for enteric pathogens and to test applicability of the reciprocity law. METHODS AND RESULTS Resistance to sunlight at 37 degrees C based on F99 values was in the following order: Salmonella Typhimurium>Escherichia coli>Shigella flexneri>Vibrio cholerae. While F90 values of Salm. Typhimurium and E. coli were similar, F99 values differed by 60% due to different inactivation curve shapes. Efficacy seemed not to be dependent on fluence rate for E. coli stationary cells. Sensitivity to mild heat was observed above a temperature of 45 degrees C for E. coli, Salm. Typhimurium and Sh. flexneri, while V. cholerae was already susceptible above 40 degrees C. CONCLUSIONS Salmonella Typhimurium was the most resistant and V. cholerae the least resistant enteric strain. The reciprocity law is applicable for stationary E. coli cells irradiated with sunlight or artificial sunlight. SIGNIFICANCE AND IMPACT OF THE STUDY Escherichia coli might not be the appropriate indicator bacterium to test the efficacy of SODIS on enteric bacteria and the physiological response to SODIS might be different among enteric bacteria. The applicability of the reciprocity law indicates that fluence rate plays a secondary role in SODIS efficacy. Stating inactivation efficacy with T90 or F90 values without showing original data is inadequate for SODIS studies.
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Affiliation(s)
- M Berney
- Swiss Federal Institute of Aquatic Science and Technology, Eawag, Dübendorf, Switzerland
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Heaselgrave W, Patel N, Kilvington S, Kehoe SC, McGuigan KG. Solar disinfection of poliovirus and Acanthamoeba polyphaga cysts in water – a laboratory study using simulated sunlight. Lett Appl Microbiol 2006; 43:125-30. [PMID: 16869893 DOI: 10.1111/j.1472-765x.2006.01940.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To determine the efficacy of solar disinfection (SODIS) in disinfecting water contaminated with poliovirus and Acanthamoeba polyphaga cysts. METHODS AND RESULTS Organisms were subjected to a simulated global solar irradiance of 850 Wm(-2) in water temperatures between 25 and 55 degrees C. SODIS at 25 degrees C totally inactivated poliovirus after 6-h exposure (reduction of 4.4 log units). No SODIS-induced reduction in A. polyphaga cyst viability was observed for sample temperatures below 45 degrees C. Total cyst inactivation was only observed after 6-h SODIS exposure at 50 degrees C (3.6 log unit reduction) and after 4 h at 55 degrees C (3.3 log unit reduction). CONCLUSIONS SODIS is an effective means of disinfecting water contaminated with poliovirus and A. polyphaga cysts, provided water temperatures of 50-55 degrees C are attained in the latter case. SIGNIFICANCE AND IMPACT OF THE STUDY This research presents the first SODIS inactivation curve for poliovirus and provides further evidence that batch SODIS provides effective protection against waterborne protozoan cysts.
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Affiliation(s)
- W Heaselgrave
- Department of Infection, Immunity and Inflammation, School of Medicine, University of Leicester, UK
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Mani SK, Kanjur R, Bright Singh IS, Reed RH. Comparative effectiveness of solar disinfection using small-scale batch reactors with reflective, absorptive and transmissive rear surfaces. WATER RESEARCH 2006; 40:721-7. [PMID: 16427118 DOI: 10.1016/j.watres.2005.11.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 11/07/2005] [Accepted: 11/23/2005] [Indexed: 05/06/2023]
Abstract
This study investigated the enhancement of solar disinfection using custom-made batch reactors with reflective (foil-backed) or absorptive (black-backed) rear surfaces, under a range of weather conditions in India. Plate counts of Escherichia coli ATCC11775 were made under aerobic conditions and under conditions where reactive oxygen species (ROS) were neutralised, i.e. in growth medium supplemented with 0.05% w/v sodium pyruvate plus incubation under anaerobic conditions. While the addition of either an absorptive or a reflective backing enhanced reactor performance under strong sunlight, the reflective reactor was the only system to show consistent enhancement under low sunlight, where the process was slowest. Counts performed under ROS-neutralised conditions were slightly higher than those in air, indicating that a fraction of the cells become sub-lethally injured during exposure to sunlight to the extent that they were unable to grow aerobically. However, the influence of this phenomenon on the dynamics of inactivation was relatively small.
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Affiliation(s)
- Shibu K Mani
- Environmental Microbiology Laboratory, School of Environmental Studies, Cochin University of Science and Technology, Kochi 682-016, Kerala, India
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Tandon P, Chhibber S, Reed RH. Inactivation of Escherichia coli and coliform bacteria in traditional brass and earthernware water storage vessels. Antonie van Leeuwenhoek 2005; 88:35-48. [PMID: 15928975 DOI: 10.1007/s10482-004-7366-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2004] [Accepted: 12/08/2004] [Indexed: 10/25/2022]
Abstract
The detection and enumeration of indicator bacteria such as Escherichia coli is used to assess the extent of faecal contamination of drinking water. On the basis of this approach, the effectiveness of storing water contaminated with faecal indicator bacteria in brass or earthern vessels (mutkas) of the type used in rural India have been investigated. Suspensions of bacteria in sterile distilled water were maintained for up to 48 h in each vessel and enumerated by surface plate counts on nutrient agar (non-selective) and several selective coliform media at 37 degrees C either under standard aerobic conditions, or under conditions designed to neutralise reactive oxygen species (ROS), e.g. using an anaerobic cabinet to prepare plates of pre-reduced growth medium or by inclusion of sodium pyruvate in the growth medium, with incubation of aerobically-prepared plates in an anaerobic jar. The counts obtained for E. coli decreased on short-term storage in a brass mutka; counts for selective media were lower than for equivalent counts for non-selective medium, with ROS-neutralised conditions giving consistently higher counts than aerobic incubation. However, after 48 h, no bacteria were cultivable under any conditions. Similar results were obtained using water from environmental sources in the Panjab, and from rural households where brass and earthern mutkas are used for storage of drinking water, with enumeration on selective coliform media (presumptive total coliforms). In all cases results indicated that, while storage of water in a brass mutka can inactivate E. coli and coliforms over a 48 h period, standard aerobic plate counting using selective media may not be fully effective in enumerating sub-lethally damaged bacteria.
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Affiliation(s)
- Puja Tandon
- Division of Biomedical Sciences, Northumbria University, Ellison Place, NE1 8ST, Newcastle upon Tyne, Tyne and Wear, UK
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Abstract
AIMS To establish the influence of oxygen on Escherichia coli before, during and after exposure to UVA or simulated sunlight. METHODS AND RESULTS Bacterial suspensions were exposed either to UVA or simulated sunlight. Conventional aerobic plate counts of illuminated cell suspensions were consistently lower than those obtained under conditions where reactive oxygen species (ROS) were neutralized, either (i) by the addition of the peroxide scavenger sodium pyruvate (0.05% w/v) to the medium with subsequent incubation in an anaerobic jar or (ii) by culturing on a prereduced medium within an anaerobic cabinet, indicating that a substantial proportion of such cells are sublethally injured. While the presence of oxygen during the growth period resulted in a greater resistance of aerobically grown cells to simulated sunlight compared with their anaerobic counterparts, the extent of inactivation during illumination was directly related to the dissolved oxygen content of the water. CONCLUSIONS The results show that, at each stage, oxygen has a marked influence on the observed colony count. SIGNIFICANCE AND IMPACT OF THE STUDY Overall, the results indicate that future studies of bacteria exposed to UVA or sunlight should consider the effects of oxygen at every stage in the procedure, and especially during enumeration, where the inhibitory effects of ROS must be neutralized in order to obtain a valid count. An investigation of the effects of ROS neutralization on the counts of faecal bacteria under field conditions in natural waters is now required to establish the significance of these finding to solar water treatment.
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Affiliation(s)
- R Khaengraeng
- Division of Biomedical Sciences, Northumbria University, Newcastle upon Tyne, UK
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