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1
Kim, Jin-Gab. "Ozone, as an antimicrobial agent in minimally processed foods." Connect to resource, 1998. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1120751688.
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Thesis (Ph. D.)--Ohio State University, 1998.Advisor: Ahmed E. Yousef, Dept. of Food Science and Nutrition. Includes bibliographical references (leaves 200-225). Available online via OhioLINK's ETD Center
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Perry, Jennifer Jean. "Ozone based treatments for inactivation of Salmonella enterica serovar Enteritidis in shell eggs." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1282680734.
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Dev, Kumar Govindaraj. "Effect of Ozone and Ultraviolet Irradiation Treatments on Listeria monocytogenes Populations in Chill Brines." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35954.
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The efficacy of ozone and ultraviolet light, used in combination, to inactivate Listeria monocytogenes in fresh (9% NaCl, 91.86% transmittance at 254 nm) and spent chill brines (20.5% NaCl, 0.01% transmittance at 254 nm) was determined. Preliminary studies were conducted to optimize parameters for the ozonation of â freshâ and â spentâ brines. These include diffuser design, comparison of kit to standard methods to measure residual ozone, studying the effect of ozone on uridine absorbance and determining presence of residual listericidal activity post ozonation.
An ozone diffuser was designed using 3/16 inch PVC tubing for the ozonation of brines. The sparger was designed to facilitate better diffusion and its efficiency was tested. The modified sparger diffused 1.44 ppm of ozone after 30 minutes of ozonation and the solution had an excess of 1 ppm in 10 minutes of ozonating fresh brine solution (200ml). Population levels of L. monocytogenes were determined at various time intervals post-ozonation (0, 10, 20, 60 min) to determine the presence of residual listericidal activity. The population post ozonation (0 minutes) was 5.31 Log CFU/ml and was 5.08 Log CFU/ml after a 60 minute interval. Therefore, residual antimicrobial effect was weak. Accuracy of the Vacu-vial Ozone analysis kit was evaluated by comparing the performance of the kit to the standard indigo colorimetric method for measuring residual ozone. The kit was inaccurate in determining residual ozone levels of spent brines and 1% peptone water. Uridine was evaluated as a UV actinometric tool for brine solutions that were ozonated before UV treatment. The absorbance of uridine (A262) decreased after ozonation from 0.1329 to 0.0512 for standard 10 minutes UV exposure duration. Absorbance of uridine was influenced by ozone indicating that the presence of ozone may hamper UV fluence determination accuracy in ozone-treated solutions.
Upon completion of diffuser design and ozone/UV analysis studies, the effect of ozone-UV combination on L. monocytogenes in fresh and spent brines was evaluated. Ozonation, when applied for 5 minutes, caused a 5.29 mean Log reduction while 5 minutes of UV exposure resulted in a 1.09 mean Log reduction of L. monocytogenes cells in fresh brines. Ten minutes of ozonation led to a 7.44 mean Log reduction and 10 minutes of UV radiation caused a 1.95 mean Log reduction of Listeria in fresh brine.
Spent brines required 60 minutes of ozonation for a 4.97 mean Log reduction in L. monocytogenes counts, while 45 minutes resulted in a 4.04 mean Log reduction. Ten minutes of UV exposure of the spent brines resulted in 0.30 mean Log reduction in Listeria cells. A combination of 60 minutes ozonation and 10 minute UV exposure resulted in an excess of 5 log reduction in cell counts. Ozonation did not cause a sufficient increase in the transmittance of the spent brine to aid UV penetration but resulted in apparent color change as indicated by change in L*a*b* values. Ozonation for sufficient time had considerable listericidal activity in fresh brines and spent brines and when combined with UV treatment, is effective reducing L. monocytogenes to undetectable levels in fresh brines.Master of Science in Life Sciences
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Kniel, Kalmia Elisabeth. "Evaluation of chemical treatments and ozone on the viability of Cryptosporidium parvum oocysts in fruit juices." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/27243.
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Cryptosporidium parvum is a protozoan parasite historically associated with waterborne and more recently foodborne outbreaks of diarrheal illness. Contamination of certain foods, such as unpasteurized apple cider, with infective oocysts may occur as oocysts are shed in the feces of common ruminants like cattle and deer that graze in and around orchards. Cryptosporidiosis can result in a severe illness for previously healthy individuals and a life-threatening illness in immunocompromised individuals. Disease occurs after the ingestion of small infective oocysts (4 to 5 mm in size). The relatively thick membrane of the oocysts allows them to be resistant to chlorine and many other environmental pressures, making oocysts difficult to inactivate.
In this study, alternative treatments to pasteurization were evaluated for their ability to inhibit C. parvum oocyst viability in fruit juices. Oocyst viability was analyzed with a cell culture infectivity assay, using a human illeocecal cell line (HCT-8) that is most similar to human infection. The percent inhibition of infection by each treatment was determined along with the corresponding log reduction for the treatments found to be most effective. Infection by treated oocysts was compared to that of control untreated oocysts. Cell monolayers were infected with 10⁶ treated oocysts or a series of 10-fold dilutions. Parasitic life stages were visualized using an immunohistochemistry system and 100 microscope fields counted per monolayer. Organic acids and H₂O₂ were added on a wt/vol basis to apple cider, orange juice, and grape juices. Malic, citric, and tartaric acids at concentrations from 1%-5% inhibited C. parvum infectivity of HCT-8 cells by up to 88%. Concentrations ranging from 0.025%-3% H₂O₂ were evaluated where addition of 0.025% H₂O₂ to each juice resulted in a >5 log reduction of C. parvum infectivity as determined with an MPN-based cell culture infectivity assay. Treating apple cider, orange juice, and grape juice with ozone for a time period of 30 seconds up to 15 minutes at 6° and 22°C (0.9 g/L flow rate) inhibited C. parvum viability to > 90% as monitored in the cell culture assay. It is hypothesized that oocyst wall proteins that are necessary for infection are oxidized by the reactive oxygen species generated from the decomposition of the ozone and hydrogen peroxide treatments. These treatments or combinations thereof may offer potential alternatives to traditional pasteurization for fruit juices to successfully inhibit C. parvum viability.Ph. D.
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Borikar, Devendra Dhondu. "Evaluations of conventional, slow sand filtration, ozone, ozone/H2O2 and UV/H2O2 treatments for decontamination of the selected PPCPs and EDCs and their effect on THMs formation potential." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/49949.
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Pharmaceuticals, personal care products (PPCPs), endocrine disrupting compounds (EDCs), and disinfectant by-products (DBPs) in drinking water are all associated with potential health implications that warrant their removal and formation prevention during drinking water treatment. This work presents the results of several pilot scale studies carried out using; a) dual train conventional treatment processes of coagulation, flocculation, sedimentation, filtration (conventional); and b) (multistage) slow sand filtration (SSF); both coupled with ozone and advanced oxidation processes (AOPs) such as ozone/H₂O₂ and UV/H₂O₂ using natural water from three different sources.
Removal of selected PPCPs and EDCs (as a group) was limited (on average 30%) by conventional treatment. On the contrary, ozone/H₂O₂ plus conventional was the most effective process (average of about 97%) to remove the selected PPCPs and EDCs, followed closely by ozone along with conventional treatment which was also very effective; however, at a slightly lower percent (average 95%) removal. Overall, ozone/H₂O₂ or ozone followed by conventional was very effective, irrespective of the raw water quality. However, the effectiveness of conventional treatment plus UV/H₂O₂ AOP was varied by raw water quality, resulting in reduced efficiency for lower raw water quality containing higher organics, bicarbonates, carbonates and particles. The average removal of PPCPs and EDCs with conventional plus UV/H₂O₂ treatment was about 86%. Experiments involving ozone or ozone/H₂O₂ followed by SSF also showed relatively high removals of target contaminants. On average, the removal rates of PPCPs and EDCs were around 95-100% for the combined processes. In comparison, stand-alone ozone or ozone/H₂O₂ showed removals of around 77% of PPCPs and EDCs.
Reduction of disinfection by-products formations, measured as THM-FP (trihalomethanes formation potential), was also investigated over the course of all pilot studies and for each of the treatment scenarios. In most experiments, application of ozone/H₂O₂ and ozone alone upstream of the conventional led to additional reductions in THM-FPs as compared to that of the standalone conventional treatment. However, in most experiments, UV/H₂O₂, when applied downstream of the conventional process, increased THM-FPs of the conventionally treated water. SSF process showed to be effective and reduced 71% of THM-FPs.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Metivier, Romain. "Ecologie microbienne de produits végétaux : Adaptation de traitements assainissants pour la valorisation de ces produits." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0419/document.
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L’utilisation de coproduits en tant que matière première provenant d’une autre voie industrielle, fait qu’il n’est plus considéré comme « déchet ». Leur valorisation est donc un axe de développement pour les entreprises agronomiques et agroalimentaires. Cependant, leur nouveau statut de « matière première » entraîne des contraintes pour les industriels.Celles-ci sont diverses selon les voies de destination : sanitaires, toxicologiques …Ce travail s’intéresse à deux coproduits issus de filières différentes de transformation végétale :(1) l’épiderme de pomme, comme source d’antioxydants. Leur valorisation passe par l’emploi de matières premières peu traitées d’un point de vue phytosanitaire qui pourront être a priori plus contaminées par des flores diverses.(2) Les broyats de végétaux issus de la culture céréalière comme matière première de produits biosourcés. Ils présentent naturellement de fortes contaminations en microorganismes sporulés.La valorisation de ces deux coproduits nécessite donc des traitements assainissants adaptés.Ainsi, il était indispensable de déterminer la nature, la variabilité et l’évolution des écologies microbiennes présentes sur ces coproduits par des techniques rapides de dénombrement ainsi que d’identification par biologie moléculaire. L’étude de différents procédés assainissants a également été réalisé pour combiner l’efficacité de désinfection à la préservation des qualités nutritionnelles (pomme) ou des propriétés physiques (broyats)The use of byproduct as raw material from another industrial sector, facts that it is not considered any more as "waste". Their valuation is thus an axis of development for the agronomic and food-processing industry. However, their new consideration of "raw material" entails constraints for the industrialists. These constraints are diverse according to the destination ways of the byproduct: sanitary, toxicological… This work focus on two byproducts resulting from different vegetable process: (1) apple peels, as antioxidant source. Their valuation needs to use raw materials with low phytosanitary treatment, so these materials may be more contaminated by different floras. (2) Crushed vegetable matter stemming from cereal crop as raw material of biosourced products. They occur naturally a strong microbial spore contamination. The valuation of these two byproducts requires adapted cleaning treatments. So, it was the main thing to determine nature, variability and evolution of the present microbial ecologies of these byproducts by fast techniques of enumeration and identification by molecular biology. The study of different cleaning process was also realized to combine efficiency of disinfection with the preservation of nutritional qualities (apple) or physical properties (crushed vegetable matter)
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Robertson, Louise. "Optimising coagulation and ozone pre-treatments and comparing the efficacy of differently pre-treated grain distillery wastewaters in an upflow anaerobic sludge blanket (UASB) reactor." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86286.
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Thesis (MScFoodSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Large volumes of high strength wastewater are generated annually by distilleries. Treatment of this wastewater is essential to increase its reuse potential. Anaerobic digestion (AD) has been widely applied as high strength wastewater treatment. Additionally, grain distillery wastewater (GDWW) is high in fats, oils and grease (FOG) which can cause problems during AD. Pre-treatment is therefore often required to make the AD process more efficient. The overall objective of this study was to investigate the operational efficiency of upflow anaerobic sludge blanket (UASB) reactors while treating GDWW as substrate. The first aim was to investigate the pre-treatment of the GDWW specifically for the removal of FOG by evaluating the effect of pH adaption, coagulant concentration and ozone (O3) dosages on the FOG reduction efficiency. Secondly, the effect of two different pre-treatments (only coagulant and coagulant and ozone) on the subsequent UASB treatment step was investigated. The pH of raw GDWW (pH 3.4) was adapted to three different pH values (5.0, 6.0, and 7.0) and the coagulant, aluminium chlorohydrate (ACH) (140 mg.L-1), was added. To make the process more economically viable, the lowering the coagulant concentration (to 100 mgACH.L-1) was also investigated. Optimal reductions for chemical oxygen demand (COD) (33.2% ± 4.93), total suspended solids (TSS) (91.9% ± 1.73) and FOG (84.1% ± 1.98) were, however, achieved at a higher coagulant concentration of 140 mgACH.L-1, and at a wastewater pH of 7.0. The effect of additional ozone treatment was also investigated. Maximum reductions for the ozone treatment were obtained at 100 mgO3.L-1 for COD (3.6% ± 4.08), and at 900 mgO3.L-1 for TSS (27.7% ± 5.58) and FOG (23.9% ± 1.83). The ozone treatment was most efficient for FOG reduction (in terms of mg FOG reduced per mg ozone) at 100 mgO3.L-1. An ozone dosage of 300 mgO3.L-1, was decided on based on economic feasibility, findings in literature on toxicity of ozone and the potential degradation of recalcitrant compounds at this dosage. The final pre-treatment thus included pH adaption to 7.0, coagulant dosage of 140 mgACH.L-1, and an ozone dosage of 300 mgO3.L-1. The second part of this study involved the operation of two 2 L laboratory scale UASB reactors for 277 days. The substrate of the first reactor contained GDWW that had only undergone coagulant pre-treatment (Rcontrol), while the substrate of the second UASB reactor consisted of GDWW that had undergone coagulant and ozone pre-treatment (Rozone). Both reactors treated the pre-treated GDWW successfully at ca. 9 kgCOD.m-3d-1. COD reductions of 96% for Rcontrol and 93% for Rozone, were achieved. FOG reductions (%) showed variations throughout the study and maximum reductions of 88% and 92% were achieved for Rcontrol and Rozone, respectively. The Rozone produced more biogas, but the methane content was similar for both reactors. The additional ozone pre-treatment did not show any added benefits to the reactor performance results. UASB granule washout in Rcontrol did, however, suggest possible toxicity of unsaturated fatty acids present in the non-ozonated substrate. The feasibility of FOG removal was shown as both reactors successfully treated pre-treated GDWW. Ozonation, after a coagulant dosage, which resulted in further reduction in the FOG content of the GDWW, is thus not essential to ensure the success of an anaerobic digestion step. Ozonation of the pre-treated GDWW could, however, be beneficial to gas production and the efficiency of a tertiary biological process.
AFRIKAANSE OPSOMMING: Groot volumes hoë-sterkte afloopwater word jaarliks deur distilleerderye opgelewer. Die behandeling van hierdie afloopwater is noodsaaklik om die hergebruiksmoontlikheid daarvan te verhoog. Die toepassing van anaërobiese vertering (AV) is wydverspreid in hoë-sterkte afloopwaterbehandeling. Graandistillerings-afloopwater (GDAW) is boonop hoog in vette, olies en ghries (VOG), wat probleme kan veroorsaak tydens AV. Voorbehandeling word dus dikwels verlang om die AV meer doeltreffend te maak. Die oorhoofse doelstelling van hierdie studie was om die doeltreffendheid van opvloei-anaërobieseslykkombers- (OAS-) reaktore wat GDAW as substraat behandel, te ondersoek. Die eerste mikpunt was om die voorbehandeling van die GDAW, te ondersoek vir die verwydering van VOG. Dit is uitgevoer deur die uitwerking van pH aanpassing, koagulantkonsentrasie en osoon(O3)dosis op VOG vermindering te evalueer. Tweedens is die uitwerking van twee verskillende voorbehandelings (slegs koagulant asook koagulant en osoonbehandeling) op die opvolgende OAS-behandelingsstap ondersoek. Die pH van rou GDAW (pH 3.4) is aangepas tot drie verskillende pH waardes (5.0, 6.0 en 7.0) en die koagulant, aluminium-chlorohidraat (ACH), is bygevoeg (140 mg.L-1). Om die proses meer ekonomies uitvoerbaar te maak is ‘n verlaagde koagulantkonsentrasie (verlaag tot 100 mgACH.L-1) ook ondersoek. Die optimale afnames vir chemiese suurstofvereiste (CSV) (33.2% ± 4.93), totale oplosbare vastestowwe (TOV) (91.9% ± 1.73) en VOG (84.1% ± 1.98) is egter bereik teen ‘n hoër koagulant konsentrasie van 140 mgACH.L-1, en teen ‘n afloopwater-pH van 7.0. Die uitwerking van ‘n bykomende osoonbehandeling is ook ondersoek. Die hoogste afnames tydens die osoonbehandeling is bereik teen 100 mgO3.L-1 vir CSV (3.6% ± 4.08), en teen 900 mgO3.L-1 vir TOV (27.7% ± 5.58) en VOG (23.9% ± 1.83). Die osoonbehandeling was mees doeltreffend vir VOG (in terme van mg VOG verwyder per mg osoon) teen 100 mgO3.L-1. Daar is besluit op ‘n van 300 mgO3.L-1, as gevolg van die ekonomiese uitvoerbaarheid, bevindinge in literatuur vir die toksisiteit van osoon, en die moontlike afbraak van moeilik-afbreekbare komponente teen hierdie dosis. Die finale voorbehandeling het dus bestaan uit ‘n aanpassing van die afloopwater-pH na 7.0, ‘n koagulantdosis van 140 mgACH.L-1, en ‘n osoondosis van 300 mgO3.L-1. Tydens die tweede gedeelte van hierdie studie is twee 2 L laboratoriumskaal OAS reaktore bedryf vir 277 dae. Die substraat van die eerste reaktor het GDAW bevat wat slegs ‘n koagulant-voorbehandeling ondergaan het (Rkontrole), terwyl die substraat van die tweede OAS-reaktor GDAW bevat het wat koagulant- en osoon-voorbehandeling ondergaan het (Rosoon). Beide reaktore het die voorbehandelde-GDAW suksesvol behandel teen ‘n organieseladingstempo van ca. 9 kgCSV.m-3d-1. Afnames in CSV van 96% vir Rkontrole en 93% vir Rosoon, is bereik. Tydens die studie is deurlopende wisseling in VOG verwydering (%) waargeneem, en die hoogste verwyderings wat bereik is, is onderskeidelik 88% en 92% vir Rkontrole en Rosoon. Die Rosoon het meer biogas geproduseer, maar die metaanpersentasie was soortgelyk vir beide reaktore. Die osoon-voorbehandeling het nie enige toegevoegde voordele getoon in die reaktorprestasie resultate nie. Die uitwas van die OAS-granules vir die Rkontrole het egter moontlike toksisiteit van onversadigdevetsure aangedui, wat moontlik teenwoordig kon wees in die nie-geösoneerde substraat. Die uitvoerbaarheid van VOG verwydering is getoon aangesien beide reaktore voorbehandelde GDAW suksesvol behandel het. Osonering, wat verdere afname in die VOG inhoud van GDAW teweeggebring het (na ‘n koagulant dosis), is dus nie noodsaaklik vir die suksesvolle verloop van ‘n anaërobiese-verteringsstap nie. Osonering van die voorbehandelde GDAW kan egter voordelig wees vir gasvorming, en kan ook verder die doeltreffendheid van ‘n tersiêre biologiese behandeling verhoog.
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Siddiqui, Mohamed Shakeel. "Ozone-bromide interactions in water treatment." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185847.
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Ozonation of drinking waters, particularly as a preoxidant, is becoming a widespread practice. Ozone is a powerful oxidant and reacts with many of the natural constituents present in water. The presence of bromide ion in water can lead to the formation of brominated disinfection by-products upon ozonation. The existence of brominated by-products in a public water supply could be of public health concern since some of them have been shown to be mutagenic. Production of both organic and inorganic by-products upon ozonation of waters containing bromide ion was investigated. Organic by-products identified include bromoform, dibromoacetonitrile (DBAN), and 1,1(DBAA); inorganic by-products identified include bromate, hypobromous acid and hypobromite ion. Formation of by-products is a function of bromide ion concentration, the source and concentration of humic substances, pH, ozone dose, temperature, alkalinity and reaction time. Bromoform concentration ranged from 5 to 60 $\mu$g/L and total organic bromine (TOBr) concentration varied from 15 to 150 $\mu$g/L for a bromide concentration ranging from 0.5 to 1.5 mg/L. TOBr concentrations were much higher than bromoform indicating that bromoform constitutes only a fraction of the pool of brominated DBP material. Bromate threshold levels were shown to vary according to precursor source and pH level. At pH 7.5 bromide threshold concentrations for bromate were higher than at pH 8.5; the exact opposite case was observed for bromoform. Ionic strength had no significant effect on the formation of by-products whereas an increase in alkalinity resulted in decreased amounts of by-products. Temperature effects are manifested in two different ways: (i) the water temperature at which ozonation was carried out versus (ii) the subsequent incubation temperature. While enhanced precursor oxidation was observed at higher ozonation temperatures, the partial oxidation by-products varied in their reactivity in forming brominated by-products upon incubation. An increase in incubation temperature from 20 to 30$\sp\circ$C produced about a 30% increase in bromoform where as an increase in ozonation temperature resulted in a 20% increase in bromoform. Results of this research indicate that control of by-products can be effected by using PEROXONE (hydrogen peroxide plus ozone) or ammonia. PEROXONE produced 55% less organic by-products at the cost of a 25% increase in bromate. Ammonia addition resulted in a 30% decrease of both organic and inorganic by-products.
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Zakaria, Khalid. "Industrial wastewater treatment using electrochemically generated ozone." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2596.
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The remediation of industrial wastewater is highly challenging, difficult task, and demands highly efficient technologies. Electrochemical and ozonation technologies are among the most efficient methods in treating the industrial wastewater. The electrochemical generation of ozone can provide very high concentrations of the reagent in both the gas phase and solution. The aim of the research reported in this thesis was to develop durable and highly efficient Ni/Sb – SnO2 anodes to generate ozone and to investigate their efficiency in treating industrial wastewater. Different anode sizes were studied: 0.64 cm2, 6.25 cm2 and 24 cm2 using Ti mesh as substrate. With respect to the 0.64 cm2 anodes, replacing Sb and Ni chlorides with their respective oxides and adding Au or Pb had little or no effect upon the anodes electrochemical properties. The research showed that all 0.64 cm2 anodes were porous with dimensionalities < 2. However, the presence of the Au in the precursors reduced the ozone current efficiency. The 0.64 cm2 anodes achieved ozone current efficiencies of ca. 30% at cell voltages of 2.7 V routinely. Using 6.25 cm2 anodes prepared with the Sb and Ni oxides in the precursor solution and annealed at 550 oC gave electrodes which were durable for more than 200 h operation at a current density of 100 mA cm-2 (corresponding to cell voltages of ca. 3 V) in 1 M HClO4. These current densities and service life are the highest reported for Ni/Sb – SnO2 anodes. A service life of more than 600 h was achieved in a later investigation. The 6.25 cm2 anodes achieved current efficiencies up to 38%, with 25 -30% routinely achievable. The presence of Ni is crucial for ozone generation with optimum Ni content (in the precursor solution) of ca. 1.04 at % Ni. The optimum annealing temperature was 460 oC. In terms of the 24 cm2 anodes, they were employed to prepare membrane electrode assemblies (MEA’s) for ozone generation from deionised (Millipore) water. MEA’s with air breathing cathodes suffered from flooding of the cathode pores, resulting in limited current densities. MEA’s with hydrogen – evolving cathodes did not suffer from flooding or low current densities. Overall, current efficiency of ca. 36 % at cell voltage of 1.6 V (40 mA cm-2) with Millipore water as anolyte was obtained using MEA’s with air breathing Preface vii cathodes; corresponding to a power consumption of 16.7 kWh (kg O3)-1 which is the lowest reported for electrochemical ozone generation of any description, MEA’s with H2 cathodes achieved a current efficiency of 33% at ca. 25 mA cm-2 and a cell voltage of 2.5 V, corresponding to ca. 25 kWh (kg O3)-1. The 0.64 cm2 anodes were used to decolourise solutions containing : Reactive Blue 50 (RB50), Naphthol Green B (NGB) and Congo Red (CR) dyes. The operational conditions of the decolourisation process were investigated and the optimum conditions were: 3 g dm-3 Na2CO3 as electrolyte, 50 mA cm-2 and 200 mg dm-3 dye in Millipore water. RB50 solutions could be decolourised completely within 20 min, with 90% of the COD removal after 60 min, NGB and CR proved more refractory. Indirect oxidation mediated by OH radicals was the main decolourisation mechanism at the Ni/Sb – SnO2 anodes. Ozonation, UV254 irradiation and O3/UV were used to decolourise the dye solutions for comparison with electrochemical decolourisation at the Ni/Sb – SnO2 anodes. Ozone was generated by MEA – based electrochemical cells and ozonation occurred in a bubble column reactor (BCR). The O3/UV combination was the most efficient, achieving 100 % decolourisation of RB50 and NGB solutions within 20 and 35 min, respectively, with 33% and 64% COD removal after 60 min.
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Grima, N. M. M. "Kinetic and mass transfer studies of ozone degradation of organics in liquid/gas-ozone and liquid/solid-ozone systems." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/3351.
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This work was concerned with the determination of mass transfer and kinetic parameters of ozone reactions with four organic compounds from different families, namely reactive dye RO16, triclocarban, naphthalene and methanol. In order to understand the mechanisms of ozone reactions with the organic pollutants, a radical scavenger (t-butanol) was used and the pH was varied from 2 to 9. Ozone solubility (CAL*) is an important parameter that affects both mass transfer rates and chemical reaction kinetics. In order to determine accurate values of the CAL* in the current work, a set of experiments were devised and a correlation between CAL* and the gas phase ozone concentration of the form CAL*(mol/L) = 0.0456 CO3 (g/m3 NTP) was obtained at 20°C. This work has also revealed that t-butanol did not only inhibit hydroxyl radical reactions but also increased mass transfer due to it increasing the specific surface area (aL). Values of the aL were determined to be 2.7 and 3.5 m2/m3 in the absence and presence of t-butanol respectively. It was noticed that the volumetric mass transfer coefficient (kLa) has increased following the addition of t-butanol. Ozone decomposition was studied at pH values of 2 to 9 in a 500 mL reactor initially saturated with ozone. Ozone decomposition was found to follow a second order reaction at pH values less than 7 whilst it was first order at pH 9. When the t-butanol was added, the decomposition of ozone progressed at a lower reaction order of 1.5 for pH values less than 7 and at the same order without t-butanol at pH 9. Ozone decomposition was found significant at high pHs due to high hydroxide ion concentration, which promotes ozone decomposition at high pHs. The reaction rate constant (k) of RO16 ozonation in the absence of t-butanol was determined. The result suggests that RO16 degradation occurs solely by molecular ozone and indirect reactions by radicals are insignificant. The chemical reaction of triclocarban with ozone was found to follow second order reaction kinetics. The degradation of naphthalene using the liquid/gas-ozone (LGO) system was studied. This result showed that hydroxyl radicals seemed to have limited effect on naphthalene degradation which was also observed when a radical scavenger (t-butanol) was used. Reaction rate constants were calculated and were found around 100 times higher than values reported in the literature due to differences in experimental conditions. From the results of the experimental investigation on the degradation of methanol by ozone it was found that the rate constant (k) of the degradation reaction increased at pH 9. The reaction stoichiometry was found to have a value of 1 mol/mol. The two steps of the liquid/solid-ozone (LSO) system were studied on beds of silica gel and a zeolitic material (D915) and the ozone adsorption process was modeled and found that particle rate controls ozone adsorption step but liquid rate controls the water treatment step. Ozone desorption with pure deionised water was studied. The water flow rate was found to accelerate the desorption rates but pH was found to decrease the desorption rates. In contrast, the effect of pH was insignificant in the presence of t-butanol. Determination of the adsorption isotherms for RO16, naphthalene and methanol revealed that RO16 did not exhibit adsorption on silica gel, but both naphthalene and methanol showed adsorption on D915 described by Langmuir model.
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Muz, Melis. "Ozone Treatment Of Excess Biological Sludge And Xenobiotics Removal." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614310/index.pdf.
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novel ozone-assisted aerobic sludge digestion process to stabilize and decrease the amount of excess sludge produced during biological treatment is presented in this study.
Excess sludge production is a well known burden for the treatment plants both legally and financially. Moreover, with the arise in the knowledge in recalcitrant compounds it is understood that it can act as a significant secondary pollutant.
With the developed pulse ozonation method, waste activated sludge samples from Ankara Tatlar and other Wastewater Treatment Plants (WWTP) were ozonated for different periods in Erlenmeyer flasks once a day on each of four consecutive days. Flasks were continuously aerated between ozone applications on an orbital shaker. The MLVSS, MLSS, COD and OUR parameters were measured routinely during the course of four days of digestion in order to optimize the process. Also pH, CST(capillary suction time) and SVI (sludge volume index) were followed. As a result MLVSS reductions of up to 95% were achieved with an ozone dose of only 0.0056 kg O3/kg-initial MLSS, at the end of the fourth day.
In another experimental set, ozone dose was increased on the last day in order to destroy the selected endocrine disrupting compounds, namely diltiazem, carbamazepine, butyl benzyl phthalate and acetaminophen and two natural hormones estrone and progesterone, which accumulated onto the sludge. Over 99%
removal of these contaminants were achieved on the fourth day. The analyses were conducted by using LC(ESI) MS/MS after solid phase extraction (SPE).
By this process it became possible to save on contact time, as well as achieving a bio-solids digestion far exceeding the standard aerobic process at the expense of a minimum of ozone dose with the additional micropollutants removal. The developed process is deemed superior over side-stream ozonation of activated sludge in that it does not cause any reduction in active biomass amount that should be maintained in the aeration tank.
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Paraskeva, Panagiota. "The treatment of a secondary municipal effluent by ozone." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298426.
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Beaman, Melanie Simone. "Management of landfill leachates by ozone treatment and recycle." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300538.
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Luz, Nélia Fialho Valente da. "Estudo do efeito da aplicação intrauterina de ozono sobre a taxa de gestação, após inseminação artificial, em vacas repetidoras de raça Frísia Holstein." Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2013. http://hdl.handle.net/10400.5/6323.
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Dissertação de Mestrado Integrado em Medicina VeterináriaNos bovinos, a saúde uterina no pós-parto encontra-se facilmente comprometida. O ambiente uterino, durante o puerpério, é um dos principais factores que influencia a fertilidade das vacas e, desta forma, qualquer alteração da saúde uterina pode induzir a síndrome da vaca repetidora. Esta definição compreende um grupo heterogéneo de vacas subférteis, sem anomalias anatómicas ou infecciosas, que exibem uma variedade de desequilíbrios reprodutivos, num padrão constante, durante três ou mais ciclos éstricos consecutivos, de duração normal (17-25 dias). O objectivo principal deste trabalho experimental foi o de avaliar o efeito da aplicação intrauterina de ozono (Ripromed® palhinhas; Novagen, Itália), 10 horas antes da IA, sobre alguns índices reprodutivos de vacas repetidoras de raça Frísia Holstein. Foram utilizados dois grupos de vacas repetidoras: um dos grupos foi sujeito a tratamento (n=23) e o outro serviu de grupo controlo (n=31), não tendo sido tratado. Foram avaliadas nos dois grupos a taxa de gestação à 1ª IA do ensaio e da 2ª IA do ensaio. Também foi avaliada a incidência de afecções no pós-parto das vacas de ambos os grupos e a taxa de gestação à 1ª IA do ensaio, tendo em conta essas afecções. Após a análise estatística dos resultados, verificou-se não haver diferenças significativas (p>0,05) entre os dois grupos, muito possivelmente devido ao reduzido número da amostra (n=54). Ainda assim, no que diz respeito à taxa de gestação à 1ª IA do ensaio, verificou-se que os resultados foram numericamente superiores para o grupo dos animais tratados, relativamente ao dos não tratados (43% vs. 26%, p>0,05). Relativamente ao número de animais gestantes após a 2ª IA do ensaio (animais que fizeram retorno ao cio – 40%) registaram-se resultados menos favoráveis nas vacas tratadas (0% vs. 37%, p>0,05). No entanto, pouco se pôde concluir àcerca deste resultado, dada a pequenez da amostra. Observou-se, da mesma forma, que a retenção placentária (46,6%) e a endometrite clínica (53,3%) foram as afecções de maior incidência em ambos os grupos e que, os resultados do tratamento foram favoráveis tanto para as vacas que apresentaram patologia no puerpério ( 45% vs. 37%, p>0,05), como para as que tiveram um pós-parto aparentemente normal (42% vs. 8%, p>0,05). Deste modo, e como pouco se poderá efectivamente concluir, com base no tratamento estatístico acerca dos efeitos desta terapêutica sobre os índices reprodutivos analisados, outros estudos prospectivos deverão ser realizados.
ABSTRACT - STUDY OF THE EFFECT OF INTRAUTERINE OZONE TREATMENT ON REPEAT-BREEDERS HOLSTEIN-FRIESIAN COWS PREGNANCY RATE AFTER ARTIFICIAL INSEMINATION - In cattle, postpartum uterine health is easily compromised. The uterine environment during the puerperium influences cows’ fertility and its perturbation can induce the repeat-breeder syndrome. The repeat-breeders cows are an heterogeneous group of subfertile cows without anatomical abnormalities or infectious diseases. Those females exhibit reproductive imbalances in a constant pattern, for three or more consecutive estrous cycles (17-25 days). The main objective of this study was to evaluate the effect of intrauterine ozone treatment (Ripromed® straws; Novagen, Italy), given 10 hours before the AI on a few reproductive parameters of repeat-breeders Holstein-Friesian dairy cows. The study was conducted on two different groups: treatment group (n = 23) and control group (n = 31). It was evaluated in both groups: the pregnancy rate (1st and 2nd AI), the incidence of postpartum diseases and the pregnancy rate, taking into account those diseases. After statistical analysis, it was found no significant differences (p>0.05) between the two groups, most likely due to the small sample size (n = 54). Still, with regard to the pregnancy rate at 1st AI, the results were numerically higher for the treated group compared to the untreated one (43% vs 26%, p>0.05). Regarding the number of pregnant animals after the 2nd AI (animals that return to oestrus - 40%) it was found lower results in treated group (0 % vs 37 %, p>0.05). It was observed that retained placenta (46.6%) and clinical endometritis (53.3%) had higher incidence in both groups and the treatment results were favorable for the cows that had postpartum diseases (45% vs 37%, p>0.05) and for those that had an apparently normal postpartum (42% vs 8%, p>0.05). Therefore, based on the statistical treatment, it was not possible to conclude much. Other prospective studies should be conducted.
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Storlie, Leslee. "An Investigation into Bromate Formation in Ozone Disinfection Systems." Thesis, North Dakota State University, 2013. https://hdl.handle.net/10365/26896.
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Ozonation is used as an alternative disinfection process to chlorination but unfortunately has a potential of oxidizing bromide, a natural component of water sources, to bromate. Bromate is a possible carcinogen with a maximum contaminant level of 10 ppb. To understand bromate formation in full-scale systems, a comprehensive study was conducted at the Moorhead Water Treatment Plant (WTP). Bromide concentrations in source waters were monitored. Water samples from locations in the ozonation chambers were collected and analyzed for bromate and other parameters. Results showed that bromate formation was increased through increases in pH, bromide, and ozone dose during high temperatures and was decreased by increases in organics. The impact of the bromate influential parameters was minimized at low temperatures. To assist Moorhead WTP on developing bromate control strategies, a modeling approach was adopted to predict bromate formation at various operational conditions using temperature, pH, ozone dose, bromide, and TOC.MWH Global, AWWA Scholarship
American Water Works Association (AWWA), Minnesota and North Dakota sections
North Dakota Water Resources Research Institute
Department of Civil Engineering, North Dakota State University
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Fornander, Erik. "Ozone Treatment Targeting Pharmaceutical Residues : Validation and Process Control in a Wastewater Treatment Plant." Thesis, Linköpings universitet, Teknisk biologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-154012.
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Major studies conducted in Europe and North America has concluded that the current processes in wastewater treatment plants insufficiently degrade micropollutants e.g. pharmaceutical residues. Several sorption and oxidation methods has therefore been investigated with the purpose of removing or degrading micropollutants in wastewater. The main purpose of this project was, firstly, to validate the results from a pilot study conducted by Tekniska verken i Linköping AB (2014) which investigated the use of ozone to degrade pharmaceutical residues. Secondly, to investigate and design a suitable process control strategy for the ozonation process. Four different tests were conducted during the project, a dose-response test, step-response tests, a trace test, and a performance test. A poorer average reduction of pharmaceutical residues was observed in this project compared to the pilot study. An average reduction of approximately 80% was observed at the highest tested dose, 0.67 mg O3/mg DOC, N corr. Whilst an average reduction of 90% was observed at approximately 0.46 mg O3/mg DOC, N corr, in the pilot study. However, the quality of the wastewater was worse during this project compared to the pilot study. ΔUVA254 and offgas concentration of ozone were found to be suitable control parameters for process control. A control strategy based on a combination of these parameters was designed, where ΔUVA254 was used as the main control parameter and the off-gas concentration of ozone was used as a limiting controller to ensure a sufficient mass transfer in the system. In conclusion, a suitable flow proportional base ozone dose valid for current water conditions has been identified, 10 mg/L. Differences in wastewater quality which heavily influence the ozonation process have been identified. Lastly, a control strategy for process control of the ozonation have been identified, designed and is ready for implementation.
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Patania, Nancy L. 1959. "A parametric study of ozone treatment of Colorado River water." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/191935.
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The Central Arizona Project is a water delivery system which will bring Colorado River water to urban and agricultural areas in central and southern Arizona via a 330-mile canal. Colorado River water is a high quality source but will minimally require treatment for turbidity removal and disinfection in order to meet federal, state and municipal standards. In this research, ozone treatment of CAP canal water was investigated. A parametric study was conducted to evaluate the effects of Ozone dose, aluminum sulfate dose and mixing conditions on turbidity and particle removal, organic carbon removal and filtration characteristics. Fluctuations in raw water quality were substantial over the sampling period of several months. At a 95% confidence level, turbidity removal by filtration depended on alum dose and rapid mix duration. Particle removal and TOC removal by filtration depended on ozone and alum doses as well as mixing time. Substantial removal of organic carbon, did not occur, but the mechanism of removal was found to be adsorption and subsequent filtration. In pressurized filtration tests, volume throughput was found to be dependent on ozone and alum doses, with higher alum doses resulting in decreased filtration.
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Van, der Merwe Werner. "Ozone treatment of chromium waste materials / Werner van der Merwe." Thesis, North-West University, 2011. http://hdl.handle.net/10394/9392.
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Ozonation, or advanced oxidation processes (utilising ozone decomposition products as oxidants) are widely used in industrial waste water and drinking water treatment plants. In these applications the use of ozone is based on ozone and its decomposition by-products being strong oxidants. A case study revealed that several waterworks in South Africa successfully utilise ozone as a pre-oxidant for the treatment of raw waters.
South Africa holds more than three quarters of the world’s viable chromium ore (chromite) reserves. Subsequently the Cr-related industry-within is considerable in size and a major producer of large volumes of waste materials. Chromium also occurs commonly in other industrial waste materials (e.g. fly ash and clinkers originating from coal combustion) and is a natural occurring element in natural sediments, since chromium is the 21st most abundant element in the earth’s crust with an average concentration of approximately 100 ppm. Considering the abundance of natural and anthropogenic Cr-containing materials in South Africa the possibility exists that some of these materials might be suspended in raw water entering water treatment facilities.
In this dissertation, the possible oxidation of non-Cr(VI) Cr-containing materials suspended in water during ozonation, is presented within the context of water treatment applications (Chapter 4). The results indicate that in situ formation of hazardous Cr(VI) is possible during aqueous ozonation. pH had a significant influence, since the decomposition products of aqueous O3, i.e. hydroxyl radicals that form at higher pH levels, were found to be predominantly responsible for Cr(VI) formation. Increased ozonation contact time, water temperature and solid loading also resulted in elevated Cr(VI) concentrations being formed. Occasionally these values exceeded the drinking water standard 50 ppb Cr(VI). The results therefore indicate the importance of removing suspended particulates from water prior to ozonation. Additionally, pH-control could be used to mitigate the possible formation of Cr(VI) during ozonation.
In Chapter 5, exploratory work is presented on the possibility of utilising Cr(VI) formation via ozonation as a means of recovering chromium from Cr-containing waste materials. Such a study is of particular interest within the local context, considering the large volumes of waste produced by the Cr-related industry in South Africa. This exploratory work is based on the fact that unlike Cr(0) and Cr(III), most Cr(VI) compounds are relatively soluble in water. Cr(VI) is a carcinogen if inhaled, however the probability of negative health effects are substantially reduced if it occurs in solution. Thus a hydrometallurgical route of recovering Cr-units via Cr(VI) generation represents the safest route with regard to Cr(VI) exposure. Such a hydrometallurgical route could also addresses the limitations of the physical separation methods currently applied, which fails to recover fine Cr-containing solids. The degree of Cr2O3-liberation achieved in this exploratory work was relatively low. However, the Cr2O3-liberation achieved for the ferrochromium slag (15%) indicated some promise, considering the limitations of this exploratory work. Several steps can be considered in future studies, which would in all likelihood improve the Cr2O3-liberation further.Thesis (MSc (Chemistry))--North-West University, Potchefstroom Campus, 2012
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Alawadi, Jameela Mohammed Ali Senkais. "Assessment of the use of ozone in root canal treatment." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491991.
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Healing and non-healing in the periapical region after endodontic treatment in humans was first studied radiographically by Strindberg (1956). Subsequent reports (Bergenhoitz et af.1979, Ehnevid et af. 1993, Caliskan & Sen 1996, Waltimo et af. 2001, Huumonen et af. 2003) have published radiographic studies of the periapical healing process. They all report a high percentage of failures after endodontic treatment. Furthermore, in a bacteriological and radiographic study, Engstrom (1964) found a higher healing rate after endodontic treatment when bacteriological samples from the root canal showed no traces of bacteria before root filling. Therefore,the use of antiseptic irrigation is an important part of chemomechanical root canal preparation. It enhances elimination of microbiota and facilitates removal of necrotic tissue and dentine debris from the root canal system. Based on its unique capacity to dissolve necrotic tissue remnants, NaOCI remains the most widely recommended irrigating solution in endodontics (Zehnder 2006). A novel concept for the treatment of dental caries using ozone gas, as a potent microbicide, has recently been introduced (Baysan et af. 2000, Baysan & Lynch 2004, 2006, 2007). A number of studies have been undertaken on the effects of ozone on treating dental caries and the reduction of oral microorganisms (Holmes 2003, Abu-Salem 2004, Nagayoshi et af. 2004a, b, Huth et af. 2005, Huth et af. 2006, Huth et af. 2007, Estrela et af. 2007, Baysan & Beighton 2007). Previous data had suggested that ozone delivered as a gas on root carious lesions or as ozonatcd water to bacteria in vitro (Baysan et af. 2000) was extremely bactericidal. Such effects would also be expected if the gaseous ozone became dissoived in water since ozonated water is well established as an antimicrobial in many industrial situations (Kim et af.. 1999). Aims: The study aims at the following: to investigate the quality of the first and second root canal fillings performed by undergraduate dental students at the School of Dentistry, Belfast, UK; to investigate the efficacy of ozone for removal of the smear layer and to kil1 microorganisms including E. faecalis in-vitro; to examine clinically the ability of ozone to reduce the number ofbacteria in root canals and its effect on postoperative pain after root canal therapy in an in-vivo study and to assess radiographic the effect ofthc use of ozone into NaOCI on periapical radiolucencies after 6 months recall. I\Iaterials and Methods: 230 postoperative periapical radiographs were assessed. All the radiographs were interpreted using strict criteria. EntercocclIs faecalis microorganisms and 80 extracted single rooted tceth were used to assess the ability ofozone to remove the smear layer as well as to kill microorganisms in an in-vitro study. One hundred patients were enrolled and subjected to clinical examination of the root treated tooth and a periapical radiograph and a sample was taken for microbiological analysis and the postoperative pain scores were quantified (no pain to severe). Eighty periapical x-ray where examined at the baseline and at 6 months recall using strict criteria. Results: There was no statistically significant difference between the quality of the first and second root canal fillings performed by undergraduate dental students. The application of ozone for 40s, 60s or 120s was able to kill all the E. faecalis in an in-vitro study. The irrigation of ozonated NaOCI and Sterilox with ozone significantly improved the removal of the smear layer in-vitro. The application of ozone for a period of lOs at each stage was capable of reducing the number of colony forming units in-vivo with no adverse side effects. The ozone delivery system was easy to use. Conclusions: Radiographic examination of endodontically treated teeth demonstrated that there was no statistically significant difference in the first and second root canal fillings performed by undergraduate dental students. From the obtained data, it can be concluded that the introduction of ozone in routine root canal disinfection when used with NaOCI and with Sterilox in-vitro helped to removc thc smear layer. Ozone gas~kill more E. faecalis in vitro than NaOCI with air. The use ofozone is capable of reducing microorganisms with~for less postoperative pain in one session RCT using ozone. Two cases, which were treated with NaOCI and air, got worse and both cases had x-ray scores of one at baseline and were two at 6 months, whilst in the ozonated NaOCI group no case got worse. Supplied by The British Library - 'The world's knowledge'
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Hill, Ryan. "Green ozone technology for water and wastewater treatment : an energy-efficient, cost effective and sustainable solution." Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680079.
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Barberis, K. "Ozone and the spinning disc reactor in water and wastewater treatment." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378295.
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Khurana, Aakash. "Ozone treatment for prevention of microbial growth in air conditioning systems." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001326.
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Wijnbladh, Erik. "Ozone Technology for Sludge Bulking Control." Thesis, Uppsala University, Department of Earth Sciences, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88830.
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Slamsvällning orsakar stora problem i avloppsreningsverk med biologisk rening i aktivt slamprocesser. Slamsvällning orsakas av filamentösa (trådformiga) bakterier, som inverkar negativt på slammets sedimenteringsegenskaper.
Himmerfjärdens vattenreningsverk har drabbats av detta problem som leder till ett stabilt lager av slam på ytan av sedimenteringsbassängen som inte sedimenterar.
För att lösa detta problem behandlades returslammet från sedimenteringsbassängen med ozon för att minska mängden filamentösa bakterier i returslamflödet. Ozon är en starkt oxiderande gas, som är väl användbar för icke-specifik bekämpning av slamsvällning. När ozon kommer i kontakt med den filamentösa bakteriens cellvägg penetreras det in i cellen, varvid cellen lyserar.
Ozonbehandlingen resulterade i en förminskning av antalet filamentösa bakterier. Ozonbehandling av returslam förbättrade sedimenteringsegenskaperna hos svällande slam utan att påverka andra viktiga mikrobiologiska processer t.ex. nitrifikation.
Bulking sludge causes major problems in wastewater treatment plants that deal with biological nutrient removal in activated sludge processes. Bulking sludge is caused by filamentous bacteria, which have a negative impact on the sludge settling properties.
Himmerfjärden wastewater treatment plant suffers from this type of problem with bulking sludge which creates a stable layer at the surface that does not settle in the clarifier.
In order to solve this problem, on site generated ozone was used to decrease the amount of filamentous bacteria in the return activated sludge flow. Ozone is a strong oxidant is suitable for non-specific bulking control. It stresses the filamentous bacteria causing inactivation through cell wall disintegration.
The ozone treatment resulted in decreased abundance of filamentous bacteria. Ozone treatment of the recycled activated sludge improves the settling properties of bulking sludge, without interfering with other important microbiological processes e.g. nitrification.
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Sandu, Simonel Ioan. "Evaluation of ozone treatment, pilot-scale wastewater treatment plant, and nitrogen budget for Blue Ridge Aquaculture." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11271.
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Sustainable tilapia production at Blue Ridge Aquaculture (BRA) is constrained by availability of high quality replacement water. I developed a pilot-scale wastewater treatment system to treat and reuse effluent presently discharged. An initial study was conducted to determine the response of the BRA waste stream to ozone application. Dosages of 6.9, 4.8 and 2.4 g O3 were applied for 30 minutes to 35 L of settled effluent. Optimum ozone dosage and reaction time, ozone transfer efficiency, ozone yield coefficient, degree of pollutant removal, and other ozone and water quality parameters were determined. Most results suggested that the maximum process feasibility limit for ozone contact time was approximately 9 minutes at an applied ozone concentration of 23g/m3 (6.9 g O3 dose). Formation of foam increased solids and COD removal up to three times. Poor removal or accumulation of DOC and TAN was observed, indicating the need for biological treatment following ozonation.
Next, I evaluated a pilot station treatment train including sedimentation, microscreen filtration, fluidized bed denitrification, ozonation, aerobic biological oxidation in a trickling filter, and jar-test chemical flocculation. Significant improvements were found regarding solids, COD, cBOD5, NO3--N, TKN, and turbidity. Removal of foam after ozonation improved ozonation efficacy and pollutant removal.
A nitrogen budget for the BRA facility was derived, indicating that 35% of the nitrogen applied in feed was assimilated in fish. I evaluated the possible impact of residual inorganic nitrogen forms from treated effluent upon fish in the recirculating systems. I found that less than 1% of the TAN produced would return the recovered stream, and that the existing biological contactors can remove it. Evaluation of TAN fate indicated that 84% was oxidized in biofilters, 14% was oxidized by passive nitrification, and 1% was removed by water exchange. For NO3-N, I determined that 56% was removed by passive denitrification and 44% by daily water exchange.
The pilot station design was effective for removing organics and nutrients, and can serve as the basis for scale-up for treating and reusing the entire BRA effluent stream.Ph. D.
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Al-Shamasi, Amna. "Assessment of enamel changes during fixed orthodontic treatment with and without ozone." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446141.
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Gurgel, Monique de Moura. "Processo de ozon?lise aplicado ao aproveitamento tecnol?gico de res?suos de coco verde." Universidade Federal Rural do Rio de Janeiro, 2016. https://tede.ufrrj.br/jspui/handle/jspui/1472.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
The chemical analysis and structural analyzes of tropical biomass products has become a potential interest for the production of biofuels. Residues from coconut is promising because it doesn`t compete with the food industry and it can be transformed into a higher product added value due the lignocellulosic origin. Green coconuts had been separated between fiber and parenchyma following by anatomical characterization which it could better be understood and visualized the effect of pretreatment delignification; ozonolysis, with the chemical and compositional changes in the cell wall. To access the carbohydrates, lignin must be removed, thus it had been explored the changes induced by ozone under pH conditions; with addition of acetic acid and sodium hydroxide, and treatment time in milli-Q water. The ozonolysis was carried out at pH 3, 5 and 8 for 2; 4 and 6 hours at 25 ? C. Analyses were performed before and after the ozonolysis reaction to investigate the change of polysaccharides and lignin with the following techniques: SEM, Py-GC/MS, HPLC, FT-IR and TGA. With Scanning electron microscope and infrared spectroscopy, it was possible to observe the degradation of structural components of the fibers, in the form of "spring", from 4 hours of oxidation and changes in the intensities of the bands. According to the Py-GC/MS results, compounds resulting from lignin had been identified and stablished S/G ratio as 0,73. With a lignin Klason content of 26.28% from green coconut fiber and 25.45% from parenchyma. The best conditions of ozone treatment were determined to be the fiber with no addition of reagents for 4 hours under oxidation as determined by the increase of glucose content in the hydrolysate to 45.96 % after acid hydrolysis of ozone treated fibers.
An?lises qu?micas e estruturais dos produtos de biomassa tropical tem se tornado um potencial interesse para produ??o de novos produtos que agreguem valores sustent?veis, dentre eles, os biocombust?veis. Res?duos de coco se tornam promissores pois n?o competem com a ind?stria aliment?cia e podem ser transformados em um produto de maior valor agregado visto serem de origem lignocelul?sica. Nesse contexto, os cocos verdes foram separados entre fibra e par?nquima e por conseguinte, caracterizados a n?vel anat?mico para que melhor pudesse ser compreendido a rela??o do tratamento utilizado para deslignifica??o; no caso, a ozon?lise, assim como as altera??es qu?micas e composicionais da parede celular. Para acessar os carboidratos, a lignina precisa ser removida, portanto foi explorado as mudan?as induzidas pelo oz?nio sob condi??es de pH; atrav?s adi??o de ?cido ac?tico e hidr?xido de s?dio, e tempo. O tratamento com oz?nio em solu??o de ?gua biodeionizada foi conduzido em pH 3, 5 e 8 por 2, 4 e 6 horas a temperatura de 25?C. As an?lises foram realizadas com amostras anteriores e posteriores ? rea??o de ozon?lise, investigando as altera??es dos polissacar?deos e da lignina com as seguintes t?cnicas: MEV, Pi-GC/MS, CLAE, FT-IR e TGA. De acordo com a Microscospia eletr?nica de varredura e Espectroscopia de infravermelho, foi poss?vel observar a degrada??o dos componentes estruturais das fibras, em forma de ?mola?, a partir de 4 horas de oxida??o e altera??es nas intensidades das bandas respecivamente. De acordo com a Pi-GC/MS, os derivados da lignina foram identificados e estabelecido uma rela??o S/G de 0,73 para fibra. O teor de lignina de Klason foi de 26,28% para a fibra e 25,45% para o par?nquima. Em visto disso, chegou-se a conclus?o que a melhor condi??o de tratamento com oz?nio foi obtido com as fibras sem adi??o de reagente sob 4 horas de exposi??o ao agente oxidante, determinado pelo aumento do teor de glicose a 45,96%.
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Stříteský, Luboš. "Využití oxidačních procesů (AOP) pro odstraňování mikropolutantů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226161.
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This thesis deals with advanced oxidation processes (AOPs) and it’s use for removal of micropollutants from wastewater. The first chapter explains the need AOPs, water quality, pollution and substances that are present in the water. Further, the first chapter outlines approach of the current legislation to micropollutants. The second chapter explains the theory and principle of operation of AOPs. This chapter is divided into two sections. The first section describes AOPs, which were tested at selected WWTP. In the second section, there are described some other AOPs. The third chapter is a literature retrieval of AOPs dealing with the removal of micropollutants. This chapter is focused on the removal of hormones by AOPs using ozone-based AOPs. The fourth chapter describes the actual testing of selected AOPs. The chapter describes selected WWTP, pilot-scale AOP unit and test results. In the last chapter there is designed and described full-scale AOP tertiary unit for removing of micropollutants. The last chapter also contains economic analysis of the proposed tertiary unit.
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Marcé, Escalé Mireia. "Ozonation of Municipal Wastewater for Water Reuse." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/402548.
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Water is essential for life in all the levels: humans, animals and plants depend on it for their existence. The unsustainable growth, the changes in the consumption pattern and the climate change have positioned water resources under pressure. In this scenario where the water quality and quantity are a worldwide concern, research and development have analyzed and generated various emerging technologies that can promote the use of alternative sources of water.
Commonly, the Municipal WWTPs are organized in four stages that include physical, chemical and biological processes. Wastewater treatment plants (WWTPs) will have an important role in the future eco-cities since will provide energy by means of a system characterized by the smallest possible ecological footprint. However, several ecological effects have been observed downstream of WWTP outfalls, probably due to the incomplete removal of pollutants by the conventional WWTPs. The analysis and understanding of the pollutants fate in Conventional WWTPs is fully necessary to create measures to reduce their release in the environment.
Even though, conventional WWTPs are designed to treat solid wastes, suspended solids and biodegradable dEfOM, many micropollutants are also affected by the treatment train. Hence, half of the micropollutant load is eliminated either by sorption to the sludge, biological degradation, volatilization and abiotic degradation. Despite this fact, some hydrophilic compounds are neither adsorbed into the sludge nor eliminated in the discharge effluents. Consequently, some of these micropollutants can end up in the aquatic environment generating negative effects, including long-term and short-term toxicity.
In the problematic water pollution scenario mentioned before, advanced oxidation processes (AOPs) emerge as a possible alternative to treat the biologically persistent wastewater improving water quality and therefore restoring the aquatic environment. These processes degrade organic pollutants by forming hydroxyl radicals (OH·) which are highly reactive and non- selective. Nowadays, AOPs include also the processes that involve other radicals as sulfate radicals (SO4 ·).
Ozone application is used in wastewater, disinfection and air treatment to minimize the pollution. This process has two main strengths: on one hand, the strong oxidant potential and secondly, the lack of residues after its application. Ozone can react directly, via molecular pathway or indirectly via hydroxyl radical.
In this work, ozone has been applied to different non-conventional points of the treatment line, to check if its action could promote the enhancement of the whole treatment. Thus, it has been applied at the outlet of the primary effluent leading us to an improvement in the water quality parameters and in the removal of micropollutants. Moreover, other significant parameters for ozone application as the ozone demand and mass transfer have been studied.
Afterwards, the study was focus in the application of ozone on the activated sludge matrix. In this case, ozone showed good performance too, improving the settleability, increasing the solubility of sludge and eliminating micropollutants in both phases (sludge and supernatant).
Finally, the combination of ozone application with biological treatments was tested. Thus, ozone was applied to the primary effluent which was lately treated by an aerobic biological treatment.
In this case, good performances were observed at the level of micropollutants. Lately, ozone was applied to the conventional activated sludge matrix which was subsequently introduced in an anaerobic process to check the enhancement of biogas production. In this case, only two ozone doses showed better performances than the initial sludge without ozone pretreatment. Biodegradability and acute toxicity was studied for the primary effluent before and after ozonation, showing an improvement when the transfer ozone dose increased.L’aigua es essencial per la vida en tots els nivells: humans, animals i plantes depenen d’ella per la seva pròpia existència. El creixement insostenible, els canvis en el patró de consum i el canvi climàtic han situat els recursos hídrics sota pressió. En aquest escenari on la qualitat de l’aigua i la quantitat són una preocupació mundial, la recerca i el desenvolupament analitzen actualment les tecnologies que promoguin el ús alternatiu dels recursos hídrics. En l’escenari de la problemàtica de l’aigua, els processos d’oxidació avançada emergeixen com a possible alternativa per tractar els compostos recalcitrants que trobem en l’aigua, millorant la qualitat de l’aigua i per tant, restaurant el medi aquàtic. Aquests processos, degraden els contaminants orgànics formant radicals hidroxils (·OH) que són altament reactius i no són selectius. L’ozó s’utilitza en el tractament d’aigües residuals, desinfecció i tractament de l’aire per minimitzar la contaminació. Aquest procés té dos punts forts: per una banda, el fort potencial oxidant i en segon lloc, la manca de residus després de la seva aplicació. L’Ozó pot reaccionar directament, via molecular o indirectament via el radical hidroxil. En aquest projecte, l’ozó s’ha aplicat a diferents punts de la cadena de tractament, per tal de comprovar si la seva acció pot promoure una millora en el tractament global. Així, s’ha aplicat a l’efluent de la sortida del tractament primari millorant els paràmetres de l’efluent primari tant a nivell de la qualitat de l’aigua i de l’eliminació dels microcontaminants. A més, altres paràmetres importants relacionats amb l’aplicació de l’ozó i la demanda d’ozó han estat estudiats. Després, l’estudi es va centrar en l’aplicació de l’ozó en una matriu de Fangs Activats. En aquest cas, ozó va mostrar bons resultats millorant la sedimentació, incrementant la solubilitat dels fangs i l’eliminant els microcontaminants. Finalment, l’ozó es va combinar amb tractaments biològics, aeròbics i anaeròbics. Bones eliminacions es van observar a nivell de microcontaminants. Tot i així, només dues dosis van afavorir una millora en la producció del biogàs.
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Mao, Huazhong. "Development and evaluation of the ozone/immobilized fungal process for pulp mill effluent treatment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22155.pdf.
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Di, Domizio Thomas John. "Treatment of Colorado River water with ozone, ferric chloride and Cat-Floc T-2." Thesis, The University of Arizona, 1990. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1990_607_sip1_w.pdf&type=application/pdf.
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Chittrakorn, Sasivimon. "Use of ozone as an alternative to chlorine for treatment of soft wheat flours." Diss., Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/575.
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Di, Domizio Thomas John 1963. "Treatment of Colorado River water with ozone, ferric chloride and Cat-Floc T-2." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/192043.
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Colorado River water (CRW) is a traditionally high quality source but it will require treatment for turbidity removal and disinfection in order to meet existing and future water treatment regulations. In this research, a treatment process consisting of preozonation followed by chemical coagulation, flocculation, and direct filtration was investigated. The effects of ozone, ferric chloride, and Cat-Floc T-2 doses on turbidity, UV absorbance at 254 nm, and total organic carbon (TOC) removal were statistically evaluated in order to determine the optimum chemical combinations required to achieve the treatment objectives. The ozone dose employed had the most significant impact (>99% confidence level) on turbidity removal. At a 99% confidence level, ozone and Cat-Floc T-2 were found to be statistically significant in reducing UV absorbance. There were no significant decreases in TOC observed with any of the treatment combinations studied. This was attributed to the low ozone doses employed. A second part of this research involved a study on the effects of the treatment chemicals on CRW after kaolinite had been added to artificially increase its turbidity.
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Alvares, A. Brenda C. "Ozone pretreatment to improve the biodegradation of recalcitrant textile azo dyes during wastewater treatment." Thesis, Cranfield University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391572.
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Liang, He. "Control of surface interactions with ultra-violet/ozone modification at polystyrene surface." Thesis, Robert Gordon University, 2014. http://hdl.handle.net/10059/948.
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Surface interactions and reactivity are of critical importance in current biomedical technologies, for example, satisfactory cell attachment and long term viability are essential for optimal in vitro tissue culture and for successful implantation and stability of cardiovascular medical implants such as stents and grafts. To achieve this, the control of fundamental forces and the resulting molecular interactions between the relevant surface and absorbing or adhering species in the physiological system is compulsory. This work utilised the surface modification technique of Ultra-Violet/ Ozone to improve the polystyrene biocompatibility by oxidising the surface with additional polar oxygen functional groups without damaging the surface bulk property. UV/Ozone treatment utilised throughout this study produced controllable oxygen functional groups and led to an increase in surface atomic oxygen level to 41% on unwashed and 35% on washed polystyrene surfaces, washing resulted in the removal of low molecular weight oxidised materials. Surface energy was increased by the addition of oxygen functional groups with the combination of alcohol (C-OR), carbonyl (C=O) and carboxyl (O-C=O); Saturation state was reached after 300s of UV/Ozone treatment where no more oxygen functionalities were incorporated to the surface. Moreover, UV/ozone treatment did not show an effect on the surface roughness studied by atomic force microscopy. The biological responses of human endothelial umbilical vein cells (HUVECs) were studied at the different level of UV/Ozone treated surfaces. HUVEC adhesion, proliferation and migration were significantly improved by the treatment compared to untreated and tissue cultures plastics (TCPs). Among the levels of UV/ozone treatment studied, 120s and 180s were found to be the most effective and HUVEC proliferation did not seem to be affected by the high level of oxygen. Similarly, the surface oxygen level did not affect the migration over UV/Ozone treated over 60s. Hypoxic condition significantly increased HUVECs migration on UV/Ozone treated, TCPs and untreated surfaces compared to normoxia, the oxygen rich surface did not favour to HUVECs that underwent regulatory process to enable the cells to increase migration. Under laminar flow conditions, HUVECs did not only grow, proliferate and migrate but also showed standard responses on UV/Ozone treated polystyrene surface. A decrease in cell size was observed at all shear stress intensities studied (1 dyn/cm2, 9 dyn/cm2 and 25 dyn/cm2) and the decrease was more obvious at higher shear stress. High shear stress intensity also induced high cell turnovers, which may be related to air bubbles induced at high flow rate. The overall findings of this study clearly illustrate that UV/Ozone surface treatment can be applied on polystyrene to improve human endothelial cells functionalities in term of adhesion, proliferation and migration in both static and laminar flow environment.
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Hung, Isaac, and Isaac Hung. "Ultrafine Bubble-Enhanced Ozonation For Water Treatment." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/621853.
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Ultrafine bubbles, often referred to as nanobubbles, have been used in various applications from environmental remediation to medicine. Even though the technology to generate ultrafine bubbles has been around for many years, the full potential of its applications has not been completely studied. This project seeks to study the use of ultrafine bubble technology for water treatment in combination with ozone gas. A factorial design experiment was chosen to test the effects of ultrafine bubbles on the concentration of an indicator organism, E. coli, in water as well as their effects on ozone gas being injected into water. Ozone gas or nitrogen gas was injected into water contaminated with E. coli as either ultrafine bubbles or fine bubbles as treatments for up to 60 minutes. Ultrafine bubbles were found to not have any significant effect on the concentration of E. coli in water. However, ultrafine bubbles did provide benefits when used in conjunction with ozone gas that regular, fine bubbles did not provide. The benefits included allowing the concentration of dissolved ozone in the water to decrease at a slower rate as well as allowing more ozone to dissolve into water at a higher rate than conventional methods of bubbling in ozone. While in this particular set of experiments the concentration of dissolved ozone in water didn't surpass 2 mg/L, which didn't allow for rapid disinfection and treatment of water, it is believed that with a more powerful ozone generator better results can be achieved. This project demonstrates the benefits and potential of injecting ozone gas as ultrafine bubbles into water as a way to effectively and efficiently disinfect and treat water.
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Shalluf, Milad A. "Effect of post-harvest treatment on ripening and quality of tomato fruit using ozone : application of different ozone doses as controlled atmosphere storage for delay ripening and maintaining the quality of tomatoes and effect of ozone on antioxidant and sugar compounds at different stages of tomato fruit ripening." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4448.
Full textAbstract:
Tomatoes are widely produced and consumed due to their nutritional content and versatility. However, the tomato is a soft fruit liable to damage and flavour deterioration. Hence, the main challenge for the tomato producing industry is to prevent the high loss incurred during harvest, handling and transportation of the crops. The objective of this study was to investigate the overall nutritional implication of controlled storage of tomatoes using ozone on the ripening process and the basic nutritional components of tomatoes. This investigation was also designed to focus on the effect of different ozone doses on the basic components and properties (carotenoids, ascorbic acid, total antioxidant activity and soluble sugars content) of the quality and dynamic maturity of tomatoes. Green tomatoes (Rio Grande) were treated in glass chambers with ozone enriched air [(air + 2, 7 and 21 mg O3/g tomato) and control (air only)] under humidity and temperature of 90-95% and 14-17 oC respectively. Tomatoes were sampled after 14 days of ozone treatment in the storage chamber and analyzed for different quality parameters (appearance, weight loss, Total Soluble Solids (TSS), titratable acidity, total ascorbic acid and carotene) of the ripening. The variety Elegance tomatoes were selected and the fruits were graded by colour and subjected to treatment with ozone (in doses 0 (clean air), 0.25, 0.50, and1.00 mg O3/g tomatoes) during storage for 6 days under the same humidity and temperature conditions. The fruits were analysed for carotenoids, ascorbic acid content, total antioxidant activity and soluble sugars. Analysis of the fruits clearly showed that ozone significantly delayed the development of colour on the surface, particularly in the low doses, and caused black spots on the surface of the tomatoes, particularly in higher ozone doses. Ozone did not affect the ascorbic acid and titratable acidity content. However ozone did reduce the Total Soluble Solids (TSS) by about 10% at the lowest ozone dose. A high inhibition of accumulation of carotenoids, particularly at low dose, of the tomatoes (Rio Grande) was also observed. Tomatoes (Elegance) under ozone treatments contained higher ß-carotene than those under the control treatment and lycopene content increased during storage in the red stage of tomato fruits. Ascorbic acid (AsA), dehydroascorbic acid (DHA) and the total of AsA and DHA concentrations, and ratios of redox (ASA/ (ASA + DHA) and DHA/AsA in pericarp and pulp of tomatoes tissue, did not show clear differences between the different treatments. The concentrations of the glucose and fructose increased in the tomatoes which were subjected to ozone treatments. Results from this study show that controlled atmosphere storage of tomatoes using ozone is a viable technique which warrants further study.
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Janna, Hussein. "Occurrence and removal of emerging contaminants in wastewaters." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6097.
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Over the past decade, the occurrence and removal of emerging contaminants in the environment has received much attention. Both natural and synthetic progestogens, which are hormones, and also benzotriazoles are two examples of such emerging contaminants. Sewage treatment works are recognised as one of the main routes of these compounds to the environment. Low concentrations (nanograms per litre) of biologically active chemicals may exhibit an impact on aquatic organisms and human health. This study was undertaken to determine the occurrence and removal of these two classes of chemicals at sewage treatment works, along with an evaluation of the performance of advanced treatment and also to investigate their fate in the aquatic environment. Therefore, field-based sampling campaigns were undertaken at a sewage treatment works, rivers and potable water to achieve these aims. Solid phase extraction and LC/MS/MS were used in order to analyse the samples from these different locations, along with catchment modelling and assessment of how the use of benzotriazoles may contribute to their presence in the environment. The results have demonstrated that progestogens and benzotriazoles are in the sewage system; the natural hormone (progesterone) was the most predominant compound entering the sewage treatment work (46.9 ng/l) among the progestogens while concentrations of the benzotriazoles were two orders of magnitude higher than the progestogens. The conventional sewage treatment works were, to some extent, able to remove these compounds from wastewaters. However, this may not be adequate to afford protection to the environment. The investigation of advanced treatments, ozone, granular activated carbon and chlorine dioxide, indicated no further significant removal of progestogens, probably as a result of concentrations being close to method detection limits. However, there were indications that benzotriazoles were removed. A degradation study demonstrated that the natural hormone (progesterone) was degraded rapidly while benzotriazoles were not degraded. Catchment modelling indicated that high (up to 2,000 ng/l) concentrations of benzotriazoles would be present in surface waters used for potable supply, and consequently benzotriazoles were found in the tap water with mean concentrations of 30.9 ng/l (benzotriazole) and 15.1 ng/l for tolyltriazole. It is therefore apparent that although conventional treatment may be seen as effective, achieving over 90% removal, this may not be good enough. However, before investing in tertiary treatment, a number of factors, such as the effectiveness at different sites, the presence of degradation products and costs, both financial and in relation to energy use, need to be considered.
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Derdar, Mawaheb M. Zarok. "Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase. Experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitatated semi-batch gas/liquid reactor." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4872.
Full textAbstract:
Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study.
Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas¿liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa.
The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used.
ii
These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17¿-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17¿-estradiol (E2) converted to estrone (E1) at the beginning of the reaction.
A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.Ministry of Higher Education in Libya and the Libyan Cultural Centre and Educational Bureau in London.
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Derdar, Mawaheb M. Zarok. "Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase : experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitated semi-batch gas/liquid reactor." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4872.
Full textAbstract:
Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas-liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa. The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used. ii These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17β-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17β-estradiol (E2) converted to estrone (E1) at the beginning of the reaction. A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.
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Van, Huu Tap, Van Tuyen Trinh, and Xuan Hien Dang. "Treatment of leachate by combining PAC and UV/O3 processes." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-99370.
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The landfill leachate is commonly treated for non-biodegradable organic matters, ammonia and colour. Experimental investigations using polyaluminium chlorite (PAC) and UV/O3 have been conducted for the determination of optimal pH value, reaction time and PAC concentration for the removal of chemical oxygen demand (COD) and colour. In pre-treatment coagulation stages, the highest COD and colour removal efficiencies were observed at the concentration of PAC ≥ 3,000 mglG1 and pH values between 7 and 8. However, these experiments also indicated significant removal efficiency for PAC starting with concentrations of 1,500 mglG1. The efficiency of COD and colour removal were approximately 30% and 70%, respectively. Similar efficiencies have been observed also during the second treatment stage where UV/O3 processes were used to treat coagulated leachate. After UV/O3 application, the pH of leachate reached the optimum value of 7.5 whereas the highest COD and colour removal efficiency was 55% and 72%, respectively, and the optimal reaction time was achieved after 80 minNước rỉ rác sinh ra từ bãi chôn lấp chất thải rắn cần được xử lý các thành phần chất hữu cơ khó phân hủy sinh học, xử lí amoni và độ màu. Một số kết quả thử nghiệm về xử lý COD và màu của nước rỉ rác bằng việc sử dụng phương pháp keo tụ với PAC và quá trình UV/O3 đã được thực hiện cùng với việc xác định các giá trị pH tối ưu, thời gian phản ứng và nồng độ PAC tối ưu. Hiệu suất xử lý cao nhất đạt được khi nồng độ của PAC ≥ 3.000 mg/l, pH trong khoảng từ 7 đển 8 trong giai đoạn tiền xử lý. Tuy nhiên, hiệu quả loại bỏ COD và màu bắt đầu tăng rõ khi nồng độ PAC từ 1.500 mg/l trở lên. Hiệu quả loại bỏ COD và màu tương ứng là khoảng 30% và 70%. Các giá trị pH này phù hợp cho quá trình phản ứng UV/O3 được sử dụng sau giai đoạn keo tụ. Sau quá trình xử lý bằng hệ UV/O3, pH của nước rỉ rác tối ưu được xác định là 7,5 (hiệu suất xử lý COD và màu cao nhất tương ứng là 55% và 72%), thời gian phản ứng tối ưu là 80 phút
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Bales, Dustin William. "Optimization of an Advanced Water Treatment Plant: Bromate Control and Biofiltration Improvement." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4286.
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The David L. Tippin Water Treatment Facility (DLTWTF) serving the city of Tampa, Florida is an advanced drinking water treatment facility consisting of coagulation/flocculation, ozonation, granular activated carbon biofiltration, and disinfection by chloramine. New regulations and the recent economic crisis pushed the facility to investigate methods to decrease costs and meet regulatory requirements easier.
The two major issues identified as priorities for investigation were the optimization of the biofiltration system and the use of a novel process to reduce the formation of bromate during ozonation.
Optimization of the biofiltration system is needed to remove more of the assorted particles that cause biofilms, nitrification in the distribution system, and high chloramine demand. Previous work improved the removal of particles that cause biofilms and nitrification, but was not able address the removal of particles that cause high chloramine demand to a satisfactory degree. Possible factors affecting this high chloramine decay were identified and evaluated at the pilot scale, including filter depth, chloramination of filter backwash water, media material, and nutrient addition. Non-chlorinated backwash water reduced chloramine demand by approximately 30% for GAC filters, and by approximately 50% for anthracite. Generally, anthracite performed slightly worse than GAC. Nutrient addition showed no effect. Filter depth improved chloramine decay, but not significantly enough to warrant the increased material required
Bromate control is necessary to prevent the formation of bromate, a regulated carcinogen. Traditional bromate control methods use pH depression. While effective, at the DLTWTF, this forces the increased use of more expensive caustic soda over lime for raising the pH of process water. A novel process known as the chlorine-ammonia process was investigated at the bench scale to identify the ideal ratio of chlorine and ammonia to decrease the formation of bromate to ensure regulatory compliance and allow greater use of lime to decrease costs. The best ratio in this study is 0.45 mg/L NH3 to 0.75 mg/L Cl2 which produced 1.09 ppb bromate at a CT of 6.8 min*mg/L, representing a 84% improvement over the control.
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Lamoureux, Tara. "Ozone and GAC Treatment of a Central Florida Groundwater for Sulfide and Disinfectant By-Product Control." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5656.
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This study evaluated the combination of ozone and granular activated carbon (GAC) treatment for the removal of sulfide and disinfection byproduct (DBP) precursors in drinking water at the pilot-scale. The research conducted was performed at the Auxiliary (Aux) and Main Water Treatment Plants (WTPs) in Sanford, Florida. Both WTPs rely upon groundwater sources that contain total sulfide ranging from 0.02 to 2.35 mg/L and total organic carbon (TOC) ranging from 0.61 to 2.20 mg/L. The Aux WTP’s raw water contains, on average, 88% more sulfide and 24% more TOC than the Main WTP. Haloacetic acids (HAA5) and total trihalomethanes (TTHMs) comprise the regulated forms of DBPs. HAA5 are consistently below the maximum contaminant level (MCL) of 60 μg/L, while TTHM ranges from 70 to 110 μg/L, at times exceeding the MCL of 80 μg/L in the distribution system. Ozone alone removed total sulfide and reduced UV-254 by about 60% at the Aux Plant and 35% at the Main Plant. Producing an ozone residual of 0.50 mg/L prevented the formation of bromate while removing approximately 35 to 60% concentration of DBP precursors as measured by UV-254. Operating the GAC unit at an empty bed contact time (EBCT) of 10 minutes for the Aux Plant and 5.5 minutes for the Main Plant resulted in 75% and 53% of UV-254 reduction, respectively. The average 120 hour TTHM formation potential for the Aux and Main Plants were 66 μg/L and 52 μg/L, respectively, after treatment by ozone and GAC. GAC exhaustion was deemed to have occurred after seven weeks for the Aux Plant and eleven weeks for the Main Plant. The GAC columns operated in three phases: an adsorption phase, a transitional phase, and a biologically activated carbon (BAC) phase. The GAC adsorption phase was found to produce the lowest TTHMs; however, TTHMs remained less than 80 μg/L during the BAC stage at each plant. BAC exhaustion did not occur during the course of this study. Ozone-GAC reduced chlorine demand by 73% for the Aux Plant and 10% for the Main Plant.M.S.Env.E.
Masters
Civil, Environmental and Construction Engineering
Engineering and Computer Science
Environmental Engineering
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Manoto, SL, MJ Maepa, and SK Motaung. "Medical ozone therapy as a potential treatment modality for regeneration of damaged articular cartilage in osteoarthritis." Elsevier, 2015. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001856.
Full textAbstract:
Abstract
Osteoarthritis (OA) is the most common degenerative joint disease and a growing health
problem affecting more than half of the population over the age of 65. It is characterized by inflammation
in the cartilage and synovium, resulting in the loss of joint structure and progressive damage
to the cartilage. Many pro-inflammatory mediators are elevated in OA, including reactive oxygen
species (ROS) such as nitric oxide (NO) and hydrogen peroxide (H2O2). Damaged articular cartilage
remains a challenge to treat due to the limited self-healing capacity of the tissue and unsuccessful
biological interventions. This highlights the need for better therapeutic strategies to heal
damaged articular cartilage. Ozone (O3) therapy has been shown to have positive results in the
treatment of OA; however the use of O3 therapy as a therapeutic agent is controversial. There is
a perception that O3 is always toxic, whereas evidence indicates that when it is applied following
a specified method, O3 can be effective in the treatment of degenerative diseases. The mechanism
of action of O3 therapy in OA is not fully understood and this review summarizes the use of O3
therapy in the treatment of damaged articular cartilage in OA.
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Herbst, Jennifer Lynn. "The effects of ozone treatment on chemical parameters of a recirculating aquaculture system producing hybrid striped bass." Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/40666.
Full textAbstract:
The hypothesis tested in this study is that the application of ozone to reuse aquaculture water provides more favorable conditions for hybrid striped bass at production levels. Evaluation of water quality in fish culture systems being treated with ozone was made during a production trial (1200 fish/14,OOO 1). Originally, a control and four ozonated systems with doses of 3, 13, 25, and 45 g O3/kg feed/day supported fish for experimentation but, due to mechanical failure, only the control, the 13 and 25 g O3/kg feed/day treatments completed the full 35 week study. On an equal feeding basis, concentrations of dissolved organic carbon (DOC), carbonaceous biochemical oxygen demand (CBODs), and chemical oxygen demand (COD) were lowest in the most heavily ozonated systems. Ozone increased the biodegradation of DOC. Total suspended solids, particle size and distributions were impacted by ozone's flocculating properties. The percentages of particles in the smallest size range, 5-20 microns, were greater in the control system than the ozonated systems during weeks of equal feeding rates. When feeding rates differed, the control system maintained a larger number total particles per kilogram of feed administered. The pH of the ozonated systems was lower than the control which favored the ionized (less toxic) form of ammonia. Enhanced biodegradation of organics in the ozonated systems may have increased carbon dioxide production and caused a decline in pH. Greater nitrification in the ozonated systems may have also decreased the pH. Higher total ammonia nitrogen (TAN) levels were produced in the control on an equal feeding basis. Average weekly TAN t unionized ammonia (NH3), nitrite and nitrate concentrations remained at acceptable levels across treatments and throughout the production trial. Overall, the major indication of improved system conditions due to ozone treatment was that fish raised in the ozonated systems fed steadily throughout the growth trial while the control system's culture experienced periods of reduced feeding.Master of Science
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Murney, Grant. "The reaction of ozone with sodium sulphide and its application to the treatment of tannery waste waters." Thesis, University of the West of Scotland, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336898.
Full textAbstract:
Leather production results in large volumes of waste water containing high levels of sodium sulphide, which has to be treated before disposal. The use of ozone to facilitate this oxidation was considered by first studying ozone-sodium sulphide reaction. The sodium sulphide solutions were found to be adequate models for the tannery effluent. The reaction order was found to be second order overall (first order in both sulphide and ozone). The true reaction order was found to be 0.33 for sulphide in the initial stages of the reaction. The use of ozone in conjunction with either UV radiation or a manganese catalyst was found to have no benefit to the rate of sulphide oxidation. The reaction products were thiosulphate, sulphite and sulphate. A mathematical model based on a first order consecutive reaction scheme was developed. The liquid phase mass transfer coefficient for physical absotption of ozone into water was estimated to be k'La=4.76 x 10-3 S-I, while the overall transfer coefficient during the ozone-sulphide reaction was estimated to be Kt.a=().0719 S-I. This gave an enhancement factor of 15.1 which indicates that ozone decomposition reactions may be negligable. It was estimated that a full scale ozone system would require the application of 120 kg of ozone per hour for 12 hours to treat 200 Itt waste water. An economic comparison of this proposed system indicates that operating costs for ozone would be approximately 6 times greater per m3 waste water than the costs for the current aeration treatment
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Högner, Erik, and Joakim Lindgren. "Kompletterande reningstekniker för läkemedelsrester för Duvbackens avloppsreningsverk." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-21716.
Full textAbstract:
Stora mängder receptbelagda- och receptfria läkemedel brukas årligen. Farmaceutiska föreningar såsom exempelvis preventivmedel, antibiotikum och smärtstillande läkemedel når reningsverk via urin och fekalier. Traditionella reningsverk saknar förmågan att helt reducera dessa föreningar och de släpps ut via det utgående vattnet till en recipient där de kan medföra en negativ påverkan i miljön. Duvbackens reningsverk i Gävle har en traditionell uppbyggnad och det behandlade spillvattnet släpps ut i Inre Fjärden. Syftet med denna studie är att utifrån Duvbackens avloppsreningsverks förhållanden föreslå en rekommenderad kompletterande reningsmetod för att reducera läkemedelsrester ifrån spillvattnet. För att kunna föreslå en kompletterande reningsmetod har en provtagning efter läkemedelssubstanser på det inkommande och det utgående spillvattnet genomförts i Duvbackens reningsverk. Detta för att se vilka substanser reningsverket reducerar och vilka som släpps ut i Inre Fjärden. En litteraturstudie har genomförts där aktivt kol och ozons reduktionsförmåga av läkemedelsrester granskats, samt vart i reningsverket de bör implementeras. Kostnader av aktivt kol och ozon har ställs i förhållande till varandra genom en ekonomisk undersökning. Duvbackens reningsverk är dimensionerat för 100 000 personekvivalenter och är beläget mellan stadsdelarna Brynäs och Bomhus i Gävle. Reningsverket använder sig av mekanisk, biologisk och vid behov kemisk rening. Resultaten från provtagningen visade att av de 22 läkemedelssubstanser vilka granskats reducerades sex substanser med mindre än 45 % och två substanser fick en förhöjd halt efter de passerat Duvbackens reningsverk. Både ozon och aktivt kol har i tidigare pilotförsök visat god förmåga att reducera läkemedelssubstanser från avloppsvatten. Variation av reduktionsgrader har visats bero på kolförbrukning och dosering av ozon. En skillnad mellan de kompletterande reningsmetoderna är att aktivt kols reduktionsförmåga försämras med tiden medan ozon har en mer konstant reduktion av läkemedelssubstanser. Ozon bör implementeras efter slutsedimenteringen följt av ett sandfilter för att reducera reaktiva biprodukter. Vid användning av aktivt kol bör reningsmetoden implementeras efter slutsedimenteringen, då det är av stor vikt att spillvattnet inte har för höga halter av suspenderade ämnen som mättar kolet. När aktivt kol och ozons kostnader jämförts under samma förhållanden har aktivt kol visats vara marginellt dyrare. Energikostnader utgör de stora kostnaderna för ozonrening medan kolförbrukningen visats utgöra den stora kostnaden för rening med aktivt kol.Large amounts of prescription- and non-prescription pharmaceutical drugs are used annually. Pharmaceutical compounds such as contraception, antibiotics and analgesic drugs end up in sewage treatment plants via urine and feces. The traditional sewage treatment plant lacks the ability to completely reduce pharmaceutical compounds and they are emitted via efflux to a recipient, where they can have a negative impact on the environment. The sewage treatment plant Duvbacken in Gävle has a traditional structure and the treated effluent end up in Inre Fjärden. The purpose of this study is to recommend a complementary treatment method to reduce pharmaceutical compounds based on the sewage treatment plant Duvbacken’s circumstances. In order to recommend a complementary treatment method samples of the incoming and outgoing efflux have been tested for pharmaceutical substances. The samples were taken to see what substances the sewage treatment plant reduces and what substances end up in Inre Fjärden. A literature review was conducted to examine activated carbon and ozone’s ability to reduce pharmaceutical compounds, it also researched where the treatment methods should be implemented. An economical investigation was done to show the costs for activated carbon and ozone in relation to each other. The sewage treatment plant Duvbacken in Gävle is constructed for 100 000 persons and is located between the suburban areas Brynäs and Bomhus. The sewage treatment plant uses mechanical, biological and if necessary chemical treatment. The results from the samples of the 22 substances that were examined showed that six pharmaceuticals were reduced by less than 45 % and two substances had an increased concentration after treatment in the sewage treatment plant. Both ozone and activated carbon have in previous studies shown good ability to reduce pharmaceutical substances from the municipal efflux. Variations in the ability to reduce pharmaceuticals depends on carbon consumption and ozone dosage. One difference between the complementary treatment methods are that activated carbons ability to reduce pharmaceuticals decreases with time, while ozone has a more constant reduction. Ozone should be implemented after the traditional treatment followed by a sand filter to reduce reactive byproducts. Activated carbon should also be implemented after the traditional treatment due to an efflux with high content of suspended substances can saturate the carbon. When the costs of activated carbon and ozone are compared under the same circumstances it has been shown that activated carbon is marginally more expensive. The energy use represents the major costs for ozone treatment while carbon consumption has shown to be the major cost for activated carbon.
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Das, Elif. "Effect Of Controlled Atmosphere Storage, Modified Atmosphere Packaging And Gaseous Ozone Treatment On The Survival Characteristics Of Salmonella Enteritidis At Cherry Tomatoes." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605337/index.pdf.
Full textAbstract:
iv
In recent years, outbreaks of infections associated with raw and
minimally processed fruits and vegetables have been reported. Possible
sources for contamination are irrigation water, manure, wash water, handling
by workers and contact with contaminated surfaces. Pathogens can occur on
raw and minimally processed produce at populations ranging from 103 to 109
CFU/g and able to survive and sometimes grow under various storage
conditions. The objective of this study was to analyse the growth/survival of
Salmonella Enteritidis at spot-inoculated or stem-injected cherry tomatoes
during passive modified atmosphere packaging (MAP), controlled
atmosphere (CA) and air storage at 7 and 22°C. Low density polyethylene (LDPE) with a package size of 10x10 cm2 for 25±
2 g tomatoes was used for MAP storage in which the gas composition equilibrated to 6% O2/ 4% CO2 and a carbon dioxide incubator was used for CA storage in which the CO2 level was monitored and maintained as 5% through the term of storage at 7 and 22°
C. During the research, the effect of ozone treatment (5-30 mg/L ozone gas for 0-20 min) was also considered for surface sanitation. The results demonstrate that S.Enteritidis can survive and/or grow during the storage of tomatoes depending on the location site of the pathogen on fruit, suspension cell density and storage temperature. During MAP, CA and air storage, S.Enteritidis with initial population of 7.0 log10 CFU/tomato survived on tomato surfaces with an approximate decrease of 4.0-5.0 log10 CFU/tomato in population within the storage period
however, in the case of initial population of 3.0 log10 CFU/tomato, cells died completely on day 4 during MAP storage and on day 6 during CA and air storage. The death rate of S.Enteritidis on the surfaces of tomatoes that were stored in MAP was faster than that of stored in air. Storage temperature was effective on the survival of S.Enteritidis for the samples stored at ambient atmosphere
cells died completely on day 6 at 7°
C and on day 8 at 22°
C. Stem scars provided protective environments for Salmonella
an approximate increase of 1.0 log10 CFU/tomato in stem-scar population was observed during MAP, CA and air storage at 22°
C within the period of 20 days. Cells survived with no significant change in number at 7°
C. The development of the microbial association in tomatoes was dominated by lactic acid bacteria (LAB). The pH values of the tomatoes changed approximately from 4.0 to 3.0 during the storage period. LAB grew well under all atmospheric conditions with or without the presence of S.Enteritidis. Gaseous ozone treatment has bactericidal effect on S.Enteritidis, inoculated on the surface of the tomatoes. 5 mg/L ozone gas treatment was not effective. 30 mg/L ozone gas treatment affected surface color.
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Karat, Irma. "Advanced Oxidation Processes for removal of COD from pulp and paper mill effluents : A Technical, Economical and Environmental Evaluation." Thesis, KTH, Industriell ekologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121350.
Full textAbstract:
In Sweden, the dominating source for emissions of degradable organic substances to water is the pulp and paper industry. The organic substances increase oxygen consumption in the recipient which subsequently threatens aquatic species. Improved process engineering, process closures and use of external treatments have in recent years drastically lowered the Biological Oxygen Demand (BOD). However, the Chemical Oxygen Demand (COD) has not been reduced to the same extent, as some organic substances are more persistent and must be treated with more advanced techniques. Chemical precipitation, which can bind large parts of the remaining COD into solid matter, making it possible to be removed from the effluent by various separation technologies, contributes to an efficient COD removal. However, the direct operating cost for the treatment is high as large amount of chemicals are used in the process, and large quantities of sludge generated. In the near future EU pulp and paper industry will have to meet new regulatory demands on COD discharges, and pulp mills in Asia, South-America and Oceania will meet stringent discharge demands. It is therefore of interest to review alternative treatments in regards to technical, environmental and economical feasibility in the treatment of pulp and paper mill wastewaters. Much interest has been shown for Advanced Oxidation Processes (AOP), which is why these techniques have been evaluated in this thesis. The first part of the report consists of a literature review where processes with the following oxidants have been reviewed: 1. Ozone (O3); 2. Ozone + Hydrogen peroxide (O3/H2O2); 3. Fenton’s reagent (Fe2+/ H2O2); 4. Ozone + Ultraviolet light (O3/UV); 5. Hydrogen peroxide + Ultraviolet light (H2O2/UV); 6. Photo-Fenton’s reagent (Fe2+/ H2O2/UV); 7. Titanium dioxide + Ultraviolet light (TiO2/UV). Ozone treatment (1) and ozone in combination with hydrogen peroxide (2) were chosen for further experimental studies. The experiments were conducted at Wedecos (Xylem Water Solutions) laboratory in Germany and tested on wastewater from three different Swedish mills: A, B and C. The experimental results indicate that treatment with ozone is an efficient method for elimination of COD from pulp and paper mill wastewaters. A relatively high COD reduction (41 % for Mill A, 31% for Mill B and 53% for Mill C) was achieved for all wastewaters with an applied ozone dosage of 0.2g O3/L, without an appreciable impact on other parameters such as pH, N-tot, NO2-, NO3-, NH4+, P-tot and PO43-. There are indications that the nature of the wastewater has an impact on the COD removal efficiency and that TMP wastewater is easier to oxidize in comparison to wastewater from sulphate mills. The combination with hydrogen peroxide did not show any further COD reduction compared to ozone treatment alone, thus confirming the results Ko et al. showed in their study in 2009. Oxidation with ozone is seen as more environmental alternative in comparison to chemical treatment (precipitation/flocculation) because contaminants in the wastewater are destructed rather than concentrated or transferred into a different phase, which leads to the decrease of COD, colour and toxicity without the need to handle large amounts of sludge. However, a subsequent biological treatment may be necessary for removal of BOD as a BOD increase is registered for all wastewater treated in this study. The costs are on the other hand higher in comparison to chemical treatment even though there are indications of cases when treatment with ozone can be profitable (e.g. if the cost for sludge handling increases in the future, price for chemicals increases and electricity price decreases). There are some uncertainties regarding the system and there is no clear evidence that toxic by-products are not formed. More research must be done and more full-scale installations must be reported before the pulp and paper industry is willing to invest in oxidation technology.I Sverige, är massa- och pappersindustrin den dominerande utsläppskällan av nedbrytbart organiskt material till vatten. När det organiska materialet når recipienten ökar syreförbrukningen eftersom stora mängder syre erfordras för nedbrytningen av materialet. Detta leder i sin tur till att de vattenlevande organismerna hotas och utsätts för syrebrist. Förbättrad processteknik, ökad processlutning och utbyggnad av extern avloppsvattenrening har under de senaste åren drastiskt sänkt den biokemiska syreförbrukningen (BOD). Däremot har den kemiska syreförbrukningen (COD) inte reducerats i samma utsträckning då delar av det organiska materialet är mer persistent och måste behandlas med mer avancerad teknik. Kemisk fällning kan idag binda stora delar av det kvarvarande COD till fast material som sedan kan avlägsnas via olika separationsmetoder. En stor nackdel med den här typen av rening är att stora mängder kemikalier används som i sin tur genererar stora mängder slam som måste tas om hand, vilket introducerar höga driftkostnader. Inom en snar framtid kommer massa- och pappersbruk inom EU att möta nya regulatoriska krav för COD utsläpp, och bruk i Asien, Sydamerika och Oceanien kommer även de att möta väldigt hårda utsläppskrav. Det är därför av intresse att granska alternativa reningsmetoder och utvärdera dess tekniska, miljömässiga och ekonomiska genomförbarhet vid behandling av avloppsvatten från massa- och pappersbruk. Mycket intresse har visats för Avancerade Oxidationsprocesser (AOP), varför dessa tekniker valts att utvärderas i detta examensarbete. Första delen av rapporten innefattar en litteraturstudie där processer med följande oxidanter studerats: 1. Ozon (O3); 2. Ozon + Väteperoxid (O3/H2O2); 3. Fenton’s reagens (Fe2+/ H2O2); 4. Ozon + Ultraviolett ljus (O3/UV); 5. Väteperoxid + Ultraviolett ljus (H2O2/UV); 6. Foto-Fenton’s reagens (Fe2+/ H2O2/UV); 7. Titaniumdioxid + Ultraviolett ljus (TiO2/UV). Utav dessa valdes ozon behandling (1) och ozon i kombination med väteperoxid (2) för vidare experimentella studier. Behandlingarna har utförts vid Wedecos (Xylem Water Solutions) laboratorium i Tyskland och undersökts på avloppsvatten från tre olika svenska bruk; A , B och C. Experimentella resultat tyder på att ozonering är effektiv behandlingsmetod för reducering av COD i avloppsvatten från massa- och pappersbruk. En relativt hög COD reducering (41% för bruk A, 31% för bruk B, och 53% för bruk C) uppvisades för samtliga avloppsvatten med en tillämpad ozondosering på 0.2 g O3/L, utan någon märkbar inverkan på andra parametrar så som pH, N-tot, NO2-, NO3-, NH4+, P-tot och PO43-. Det förekommer indikationer om att typ av avloppsvatten har en inverkan på COD reduktionen och att TMP avloppsvatten är lättare att oxidera i jämförelse mot avloppsvatten från sulfatmassabruk. Kombinationen av ozon och väteperoxid uppvisade ingen ytterligare COD reduktion i jämförelse mot ozon som enda oxidant, och bekräftade därmed de resultat Ko et al. uppvisade i sin studie 2009. Ozonering ses som ett miljövänligare alternativ till kemisk rening (fällning/flockning) eftersom föroreningarna i vattnet destrueras istället för att koncentreras, vilket innebär att COD, färg och toxicitet kan minskas utan att stora mängder slam genereras. Dock kan en efterföljande biologisk behandling vara nödvändig för avskiljning av BOD då en BOD ökning uppvisats för samtliga avloppsvatten i denna studie i takt med att COD brutits ned till lättnedbrytbart biologisk material. Kostnaderna är däremot höga i jämförelse mot kemisk fällning även om det förekommer indikationer på fall när behandlingen kan vara lönsam (t ex om slamhanteringskostnaderna blir högre i framtiden, inköpspriset för kemikalier ökar och elpriset sjunker). Det råder vissa tveksamheter gällande systemet och det finns inga konkreta bevis på att toxiska biprodukter inte bildas. Mer forskning måste utföras och fler fullskaliga installationer måste rapporteras och innan massa- och pappersindustrin är villig att investera i oxidationstekniken.
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RAMAKRISHNAN, BALAJI. "TREATMENT OF MTBE CONTAMINATED WATERS USING AIR STRIPPING AND ADVANCED OXIDATION PROCESSES." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1131024170.
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Ferreira, Marina Beloti. "Efeito na reparação óssea periapical da ozonioterapia como coadjuvante ao tratamento endodôntico. Estudo clínico-radiográfico." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/23/23145/tde-11092012-131848/.
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A reparação dos tecidos periapicais testemunha o êxito da terapia endodôntica. Por intervir de forma favorável na reparação tecidual, a ozonioterapia é reconhecida como um importante coadjuvante ao protocolo terapêutico, sendo oportuno verificar sua eficácia no caso da terapia endodôntica. Para isso, foi avaliada, in vivo a influência do gás ozônio, da água ozonizada e óleo ozonizado na reparação tecidual em situações de necrose pulpar com alterações ósseas periapicais, diagnosticado e caracterizado como quadros de infecção primária. Foram feitas radiografias previamente e ao final do tratamento e novamente no terceiro e no sexto mês após a conclusão da terapia endodôntica. Respeitando-se os critérios de inclusão, 36 pacientes da Clínica Odontológica da Faculdade de Odontologia da Universidade de São Paulo foram divididos aleatoriamente em 3 grupos: Grupo I (12 dentes) Controle: tratamento endodôntico segundo protocolo da Disciplina de Endodontia da FOUSP; Grupo II (12 dentes) protocolo terapêutico empregado pelo Grupo I e associado ao final com irrigação de 10 mL de água bidestilada ozonizada na concentração de 8 g/mL; e, Grupo III (12 dentes) protocolo terapêutico empregado pelo Grupo I e associado ao final do preparo do canal da aplicação de 10 mL do gás ozônio na concentração de 40 g/mL. Foi utilizado como medicação intracanal o hidróxido de cálcio veiculado em PRP no Grupo I e o óleo de girassol ozonizado (Philozon, Santa Catarina, SC, Brasil) nos Grupos II e III. As medicações permaneceram por um período de 15 dias e em seguida foi feita obturação com cimento AH-Plus. A avaliação da reparação óssea periapical foi realizada analisando as radiografias digitalizadas no programa ImageLab. Após a delimitação e quantificação de pixels das lesões periapicais, as radiografias finais e controles de 3 e 6 meses foram comparadas, indicando o quanto de redução da radiolucência periapical. Paralelamente, foi feita a análise de sensibilidade pós-operatória utilizando uma Escala Visual Analógica. Os pacientes foram questionados com relação à sensibilidade previamente ao início do tratamento, 72 horas após consulta inicial e nos controles de 3 e 6 meses, devendo associá-la com uma nota de 0 a 10 de acordo com a intensidade. Os dados foram submetidos à análise de variância, complementado pelo teste de Tukey, com significância de 5%. Os três protocolos terapêuticos instituídos promoveram redução da imagem radiolúcida periapical sem diferença estatística significante. Na análise da sensibilidade, o Grupo III apresentou os melhores resultados, com diferença estatística significante em relação aos demais grupos. Com base nos dados obtidos e na análise estatística executada, foi possível concluir que a ozonioterapia, por meio do emprego do gás ozônio e água ozonizada na fase do preparo químico cirúrgico e do óleo ozonizado como medicação intracanal, interviu de maneira favorável na reparação, em situações de necrose pulpar com alterações ósseas periapicais, sendo o gás mais efetivo que a água ozonizada, com diferenças estatísticas significantes. Os 2 grupos experimentais de ozonioterapia comparado ao grupo controle (protocolo FOUSP) apresentaram padrão de reparação óssea semelhante. A utilização da água ozonizada como irrigante e do óleo ozonizado como medicação intracanal mostrou a melhor eficácia do ponto de vista sintomatológico.The success of the endodontic treatment is related to the repair of the periapical tissues. The ozone therapy is known for its therapeutic usefulness, favorable tissue healing, thus it seems suitable for evaluating its efficiency in the endodontic therapy. The aim of this study was to evaluate in vivo the influence of ozone gas, ozonated water and oil in bone repair in cases of pulpar necrosis with radiographic evidence of periapical bone loss associated with primary endodontic infection. Radiographs (Xrays) were taken prior and after the completion of the endodontic treatment, three and six months later. According to the enclosure criteria, 36 patients of the Dental Clinic of the School of Dentistry, University of Sao Paulo, were selected and randomly divided in three groups: Group I (12 teeth) Control: endodontic treatment protocol according to the discipline of Endodontics FOUSP, Group II (12 teeth): endodontic protocol associated with final irrigation with 10 mL of bidestilated ozonated water at concentration of 8 g/mL and Group III (12 teeth): endodontic protocol associated with application of 10 mL of ozone gas at concentration of 40 g/mL. Calcium Hydroxide was used as intracanal medication for 15 days. In Group I it was associated with anesthetic solution and in the Groups II and III associated with ozonated oil (Philozon, Santa Catarina, SC, Brazil). After this period, all teeth were obturated with AH-Plus root canal sealer. Evaluation of periapical bone repair was performed with Image Lab software after image digitalization. After delimitation and pixel quantification of the periapical lesion area of the images immediately after the endodontic treatment, 3 and 6-months follow up, the obtained data were compared indicating the quantum reduction of the periapical radiolucency. In parallel, a postoperative sensitivity analysis was performed using a Visual Analog Scale. Patients were asked to score the sensitivity from 0 to 10 according to its intensity prior to first appointment, 72 hours later the first visit, 3 and 6 months later. Data were submitted to analysis of variance (ANOVA), complemented by the Tukey test at 5% of significance. All the three groups promoted a reduction of the apical radiolucent image without statistical difference. In the sensitivity analysis, Group III showed the best results with statistically significant difference compared to the other groups. Based on the statistical data analysis we concluded that ozone therapy through the use of ozone gas and ozonated water during the root canal instrumentation and ozonated oil as intracanal medication, positively intervene in the repair of periapical bone loss. The ozone gas was more effective than the ozonated water with significant statistical difference. Group II and III (experimental groups) compared to Group I (endodontic protocol FOUSP) showed a similar pattern of bone repair. The use of ozonated water as irrigant and ozonated oil as intracanal dressing showed better efficacy in terms of symptomatology.