Ozonation is an integral process in ozone-biofiltration treatment systems and is beginning to be widely adopted worldwide for water reuse applications. Ozone is effective for pathogenic inactivation and organics oxidation: both increasing assimilable organic carbon for biofiltration and eliminating trace organic contaminants which may pose a threat to human health. However, ozone can also form disinfection byproducts such as bromate from the oxidation of naturally occurring anion bromide. Bromate is a known human carcinogen and is regulated by the EU, WHO, and USEPA to a maximum limit of 10µg/L. In waters high in bromide, especially above 100µg/L, bromate formation becomes a major concern. In the secondary wastewater effluent studied, bromide concentration may exceed 500µg/L. Several bromate suppression techniques have been devised in previous work, including free ammonia addition, monochloramination, and the chlorine-ammonia process. While free ammonia addition was not found to adequately reduce bromate formation below the required MCL, monochloramine addition and the chlorine-ammonia process were found to be effective. However, the impact of these chemical suppression techniques on organics oxidation and disinfection has not been fully studied. This study explored the impact of these bromate suppression techniques at a wide range of ozone doses on bromate formation, pathogenic inactivation, ozone-refractory organics oxidation through the surrogate 1,4-dioxane, and N-nitrosodimethylamine (NDMA) formation. Additionally, bromate suppression mechanisms of monochloramine were explored further through a variety of different water quality parameters, such as through hydroxyl radical exposure and ultraviolet absorption spectrum measurements, which were correlated and utilized to develop a hydroxyl radical exposure predictive model. / Master of Science / Ozone is a powerful oxidant used in water treatment in order to degrade contaminants of emerging concern into less harmful moieties and to inactivate pathogens. Upon application to process water, ozone quickly reacts with constituents in the water to form hydroxyl radicals: the most powerful oxidant in water treatment. These hydroxyl radicals, though with extremely short half-lives, are able to degrade ozone-recalcitrant organics, such as 1,4-dioxane through a process called advanced oxidation. Ozone itself also has the capability of inactivating a multitude of pathogenic organisms, including viruses Giardia and Cryptosporidium parvum when specific contacts times are met. However, ozone does have the potential to form disinfection byproducts such as Nnitrosodimethylamine (NDMA) and bromate. NDMA, though not currently regulated by the United States’ Environmental Protection Agency (USEPA), has a drinking water health advisory limit of 10ng/L in the State of California. Bromate, on the other hand, is a known human carcinogen regulated to 10µg/L by the USEPA. Formed within the ozone system from the naturally occurring ion bromide, bromate can be limited through various chemical treatments such as ammonia addition, pH adjustment, monochloramination, and the chlorine-ammonia process. To date, these methods of bromate suppression have not been comprehensively studied in terms of bromate suppression as well as disinfection and organics oxidation in water reuse systems. The purpose of this research was to minimize bromate formation while ensuring NDMA formation was minimized, and disinfection and organics oxidation were maximized. Through this study, system efficiencies were improved and water quality for future generations will be improved.

A Dispersion model for ozone inside the rectangular duct of an indoor air quality pilot plant was simulated. Using this the concentration profiles of ozone at several points downstream of ozone insertion were simulated and they matched well with experimental results. Recommendations for future work are cited. A thermodynamic study was conducted to check the levels of concentration in which certain toxic compounds could be present due to the oxidation of pre-determined chlorinated compounds. STANJAN, a package which solves for equilibrium concentrations using the element potential method, was used. Recommendations for future work are cited. A Reaction model was developed for the global oxidation reactions occurring in the catalyst bed which is situated downstream of the ozone insertion. Once this was done, the effect of moisture and temperature were studied qualitatively and recommendations for further work are Cited. / Master of Science

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 "fresh" and "spent" 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

No / In the search for an efficient and economical method to treat a leachate generated from a controlled municipal solid waste landfill site (Jebel Chakir) in the region of greater Tunis in Tunisia, ozone alone and ozone combined with hydrogen peroxide were studied. The leachate was characterised by high COD, low biodegradability and intense dark colour. A purpose-built reactor, to avoid foaming, was used for the study. It was found that ozone efficacy was almost doubled when combined with hydrogen peroxide at 2 g/L but higher H2O2 concentrations gave lower performances. Enhancement in the leachate biodegradability from about 0.1 to about 0.7 was achieved by the O3/H2O2 system. Insignificant changes in pH that may due to buffering effect of bicarbonate was found. A small decrease in sulphate concentrations were also observed. In contrast, chloride concentration declined at the beginning of the experiment then increased to reach its initial value. Estimates of the operating costs were made for comparison purposes and it was found that the O3/H2O2 system at 2 g/L H2O2 gave the lowest cost of about 3.1 TND (2.3 USD)/kg COD removed.

One-year-old seedlings of red spruce, loblolly pine, yellow-poplar, and sweetgum were exposed to ozone (0.0 or 0.1 ppm, 4 hr d⁻¹, 3 d wk⁻¹) in combination with simulated acidic rain (pH 5.6 or 3.0, 1 h d⁻¹, 2 d wk⁻¹, 0.75 cm hr⁻¹) for ten weeks. After the ten-week treatment with ozone and simulated acidic rain, the seedlings were submitted to two drought cycles, and water potential, net photosynthesis (Pn), stomatal conductance (Cs), and transpiration (Ts) were measured. Whole-plant fresh weight increment (FWT) and dry weight were significantly reduced in red spruce seedlings after the ten-week treatment with ozone. Ozone also significantly reduced shoot height growth (SHG) and increased the apparent plastochron duration (APD) of sweetgum seedlings. Treatment with simulated rain at pH 3.0 significantly increased FWT and SHG of red spruce compared to pH 5.6 as well as FWT and relative growth rate (RGR) of loblolly pine. The APD was significantly reduced in sweetgum seedlings exposed to simulated acid rain at pH 3.0 compared to 5.6. Significant interactions between ozone and simulated acidic rain occurred in all species except red spruce, and they were additive. The SHG was significantly lower in loblolly seedlings exposed to 0.1 ppm ozone + pH 5.6 than in seedlings exposed to either 0.1 ppm ozone + pH 3.0 or 0.0 ppm ozone + pH 5.6. The APD was significantly increased in yellow-poplar and sweetgum seedlings exposed to 0.1 ppm ozone + pH 5.6 compared to any other treatment. Visible symptoms appeared on the adaxial leaf surface of yellow-poplar seedlings submitted to acid rain at pH 3.0 regardless of ozone treatment. Visible foliar symptoms were also observed on the adaxial surface of sweetgum seedlings exposed to 0.1 ppm ozone. The symptoms were characterized by premature red pigmentation with small brown necrotic lesions. Foliar concentrations of P and S were significantly increased in all seedlings exposed to simulated rain at pH 3.0 compared with pH 5.6 except for red spruce which exhibited the increases of K and S. In general, there were neither significant effects of ozone nor interactions between ozone and rain pH on foliar nutrient concentrations. There were no significant effects of ozone on Pn, Cs, Ts, or water-use efficiency (WUE) prior to the drought cycles for all species. However, after the first drought cycle, Pn and Cs were significantly changed in loblolly pine and sweetgum pre-exposed to 0.1 ppm ozone compared with controls. The ten-week treatment of simulated acidic rain at pH 3.0 significantly increased Pn and Ts of loblolly pine and reduced Cs of yellow-poplar. After the first drought cycle, yellow-poplar treated with pH 3.0 rain showed lower Pn and WUE than seedlings exposed to pH 5.6 solution. A 0.5 MPa shift in the response of net photosynthesis (Pn) to decreasing water potential occurred in red spruce seedlings across all air pollutant treatments after the drought cycles indicating photosynthetic acclimation to drought stress. During the second drought cycle, Pn was more sensitive to water potential in red spruce and loblolly pine seedlings exposed to 0.10 ppm ozone + pH 3.0 solution compared with seedlings exposed to 0.0 ppm ozone + pH 5.6 solution. This increased sensitivity of Pn to water potential might be explained through a change in root hydraulic conductivity (Lp). In general, Lp showed significant effects of ozone and simulated acidic rain after moisture stress. After the first drought cycle, Lp was decreased in yellow-poplar and sweetgum seedlings exposed to 0.10 ppm ozone. After the second drought cycle, Lp was decreased in yellow-poplar and red spruce seedlings exposed to 0.1 ppm ozone. Significant interactions between ozone and simulated acidic rain occurred in the Lp of red spruce and yellow-poplar seedlings after the first drought cycle. The results from this dissertation indicate that ozone and/or simulated acidic rain can alter the growth and drought susceptibility of forest tree species under laboratory conditions. Forest trees which are periodically exposed to ambient ozone and acidic rain in natural forest ecosystems probably have a response similar to the results from this study. Additional research is necessary to determine if such effects are occurring in natural forest ecosystems. / Ph. D.

Les éclosions virales constituent des menaces persistantes pour les établissements de soins. En plus de compromettre la santé des usagers, du personnel et des visiteurs, ces éclosions représentent d'énormes défis de gestion des ressources humaines, matérielles et financières. La pandémie de SRAS-CoV-2 sévissant depuis plus d'une année a mis en lumière la méconnaissance du rôle de l'air dans la transmission des virus. Des technologies de traitement de l'air pourraient contribuer au contrôle des virus aérosolisés et éventuellement à la protection des occupants des milieux de soins. Dans le cadre de ce doctorat, une stratégie de traitement de l'air utilisant l'ozone a été testée pour inactiver des bioaérosols viraux. Afin d'obtenir un portrait de la contamination aérienne en milieu hospitalier, une campagne d'échantillonnage a été menée lors de trois éclosions d'influenza. Enfin, la production d'aérosols pendant le traitement d'échantillons en laboratoire clinique a été examinée. Dans la première étude, le norovirus murin ainsi que les bactériophages PhiX174, Phi6, PR772 et MS2 ont été nébulisés dans une chambre d'aérosols rotative et exposés à un traitement de l'air utilisant l'ozone à différents niveaux d'humidité relative. Le norovirus murin a été exposé à 0,23 ppm d'ozone et à 20% et 85% d'humidité relative alors que les bactériophages ont été exposés à 1,13 ppm d'ozone et à trois humidités relatives, soit 20%, 55% et 85%. Pour tous les virus, des temps d'exposition de 10, 40 et 70 minutes ont été évalués. Ce traitement a été comparé à une condition de référence, qui consistait en une exposition à l'air. Les aérosols ont été récupérés à l'aide d'un échantillonneur d'air et les virus ont été quantifiés en culture et par biologie moléculaire. Des ratios infectieux ont été calculés afin de déterminer la réduction de l'infectiosité virale attribuable au traitement à l'ozone. Une inactivation d'au moins deux ordres de grandeur a été observée après 40 minutes d'exposition à l'ozone à 85% d'humidité relative pour PhiX174, MS2 et MNV-1. Une exposition à la condition de référence à 20% d'humidité relative pendant 10 minutes a été suffisante pour une inactivation similaire des bactériophages PR772 et Phi6. Ce même traitement de l'air a ensuite été évalué pour l'inactivation d'aérosols d'influenza et du virus respiratoire syncytial. Toutefois, dans le cas de ce second virus, la perte d'infectiosité lors des procédés d'aérosolisation et d'échantillonnage était trop importante pour pouvoir l'exposer à l'ozone. Concernant l'influenza, des concentrations d'ozone de 0,23 et 1,70 ppm ont été testées à des niveaux faibles et élevés d'humidité relative. Deux suppléments, l'un de nature lipidique et l'autre de nature protéique, ont été ajoutés au lysat viral afin de quantifier l'effet protecteur qu'ils pourraient procurer aux virus aérosolisés. Une condition sans supplément a aussi été testée à des fins de comparaison. Une exposition pendant 80 minutes à une concentration d'ozone de 1,70 ppm combinée à une humidité relative élevée a engendré la meilleure inactivation, soit une réduction de quatre ordres de grandeur, pour les aérosols sans supplément ou additionnés de supplément protéique Lors de la troisième étude, l'air d'un milieu hospitalier en contexte d'éclosion grippale a été échantillonné à trois reprises. L'efficacité de récupération de trois appareils, dont deux fonctionnant à haut débit et un à bas débit, a été évaluée. Cette campagne a révélé une variabilité des concentrations aériennes d'influenza A et B entre les éclosions. Bien que des concentrations maximales de l'ordre de 10⁵ copies d'ARN/m³ aient été détectées, aucun virus infectieux n'a été quantifié. Finalement, la génération d'aérosols pendant le traitement d'échantillons sanguins et urinaires dans un laboratoire clinique de biochimie a été examinée. Les employés redoutaient de produire des aérosols contenant du SRAS-CoV-2 infectieux à partir d'échantillons récoltés chez des patients infectés par la COVID-19. Pour ce projet, une culture liquide d'une bactérie modèle a été employée en remplacement des échantillons cliniques. Trois méthodes de collecte ont été utilisées pour évaluer la production d'aérosols, soit le prélèvement d'air par un appareil standard, l'emploi de boîtes indicatrices et l'écouvillonnage de surfaces. Aucune bactérie n'a été récupérée par ces trois méthodes d'échantillonnage, ce qui indique que les procédures de traitement étudiées n'ont produit qu'une faible quantité d'aérosols. / Viral outbreaks are recurring threats to healthcare facilities. While putting the health of users, staff and visitors at risk, these outbreaks represent enormous challenges in the management of human, material and financial resources. The SARS-CoV-2 pandemic. The SARS-CoV-2 pandemic, which has been raging for more than a year, has highlighted the misunderstanding of the role of air in the transmission of viruses. Air treatment technologies could contribute to the control of airborne viruses and eventually to the protection of healthcare occupants. During this doctoral program, an air treatment strategy using ozone was assessed for the inactivation of viral bioaerosols. To obtain a global portrait of airborne contamination in a hospital environment, an air sampling campaign was conducted during three influenza outbreaks. At last, the aerosol production during sample treatment in a clinical laboratory was examined. In the first study, murine norovirus and bacteriophages PhiX174, Phi6, PR772 and MS2 were nebulized in a rotative aerosol chamber and exposed to an air treatment using ozone at different relative humidity levels. The murine norovirus was exposed to 0.23 ppm of ozone and 20% and 85% of relative humidity while the bacteriophages were exposed to 1.13 ppm of ozone and three relative humidity: 20%, 55% and 85%. For all viruses, exposure times of 10, 40 and 70 minutes were evaluated. This treatment was compared to a reference condition, which was air exposure. The aerosols were collected with an air sampler and viruses were quantified using both culture and molecular biology. Infectious ratios were calculated to determine the viral infectivity reduction that was attributable to ozone. An inactivation of at least two orders of magnitude was obtained for an ozone exposure of 40 minutes at 85% of relative humidity for PhiX174, MS2 and MNV-1. Exposure to the reference condition at 20% of relative humidity for 10 minutes was sufficient for a similar inactivation of bacteriophages PR772 and Phi6. The same air treatment was then evaluated for the inactivation of influenza or respiratory syncytial virus aerosols. However, the infectivity loss of the respiratory syncytial virus during aerosolization and sampling processes was too elevated for ozone exposure. For influenza, ozone concentrations of 0.23 and 1.70 ppm were tested at low and high relative humidity levels. Two supplements, one lipid-based and the other protein-based were added to the viral lysate to quantify their protective effect for airborne viruses. A condition without a supplement was also tested for comparison purposes. Exposure to 1.70 ppm of ozone at high relative humidity for 80 minutes yielded the greatest inactivation, which was a reduction of four orders of magnitude for aerosols without supplement or with the protein-based supplement. In the third study, the air in a hospital environment during influenza outbreaks was sampled three times. The collection efficiency of three air samplers, two high flowrate and one low flowrate, was evaluated. This campaign revealed a variability between outbreaks in regards to airborne influenza A and B concentrations. While concentrations of up to 10⁵ RNA copies/m³ were detected, no infectious virus could be quantified. Lastly, aerosol generation during blood and urine sample treatment in a clinical biochemistry laboratory was examined. Employees feared producing infectious SARS-CoV-2 containing aerosols from samples collected from COVID-19 infected patients. For this project, a liquid culture of a model bacteria was employed to replace clinical samples. The sampling methods were used to evaluate aerosol production: air sampling using a standard device, the use of settling plates and surface swabbing. No bacteria were recovered by these three sampling methods, which indicates that the studied sample treatment procedures produce low quantities of aerosols.

La très forte croissance de la population mondiale recensée au siècle dernier s'est accompagnée d'une migration des populations vers les zones urbanisées, créant en quelques décennies et sur tous les continents de véritables mégapoles dont la population excède - pour 50 d'entre elles - 7 millions d'habitants. Mais la population de ces villes a très souvent augmenté trop rapidement pour que les infrastructures existantes (réseaux routiers, transports en communs...) puissent le supporter : la prise en charge des problèmes environnementaux (qualité de l'air, gestion des déchets et des ressources...) y reste donc un vrai défi. En parallèle, les observations comme les modèles numériques relèvent la nécessité de gérer conjointement la problématique de la pollution locale dans les grandes villes et les politiques climatiques, via la prise en compte des transferts de polluants depuis l'échelle locale jusqu'à l'échelle globale. La tendance croissante des concentrations de fond en ozone sur l'Europe - et qui pose un également un problème de gestion du climat - serait ainsi en grande partie dépendante de l'augmentation des émissions des grandes villes de l'hémisphère Nord en croissance économique rapide (Monks et al., 2009).Que connaît-on de l'impact réel de ces mégapoles sur la qualité de l'air ? Peu de choses. Les travaux de recherche visant à comprendre les déterminants de la pollution oxydante ont jusqu'à présent principalement ciblé les échelles locale et régionale. Et si les interactions entre mégapoles et échelle globale ont fait l'objet de plusieurs études (Wild et Akimoto, 2001; Stohl tt al., 2002; Lawrence et al., 2003, 2007) de modélisation, il existe peu de travaux centrés sur les interactions des mégapoles avec leur environnement continental. Mes travaux de thèse se sont donc attachés à caractériser ces impacts à l'aide de la modélisation eulérienne. Mes principaux questionnements ont reposé sur la nature, l'ampleur, la portée, l'impact direct et indirect et enfin la variabilité des flux de polluants exportés par les mégapoles européennes. Mais je me suis également intéressé à la nature même de ces grands centres émetteurs, en me posant la question de la sensibilité de leurs impacts à leur structure urbaine (dense ou étalée). Le développement de nouvelles fonctionnalités dans le modèle, ainsi que son adaptation à des questionnements spécifiques (calcul de flux, nouveau schéma chimique, test d'une version dédiée à l'étude des interactions d'échelles) se sont révélés nécessaires pour apporter des réponses à mes questionnements / The important increase in worldwide population identified during the last century led to a human migration toward urban areas. As a consequence, 50 high populated areas called megacities, reaching more than 7 millions of people, appeared in the last decades. This huge increase happened so fast that existing infrastructures (such as roads network, public transport) is not suitable anymore. Taking into account environmental issues (air quality, supply and waste management) in this context is then a real challenge. In the meantime, observations and numerical models highlight the need to deal with local pollution in megacities as well as climate policy, through the consideration of pollutants transfer from local scale to global scale. The increase of ozone background in Europe, which also is a climate issue, could depend of the increase of the megacities emissions in the north hemisphere, due to the economical development (Monks et al., 2009).What do we know of the megacities real impact on air quality? Scientific studies aiming to understand the key parameters of oxidizing pollution have mainly focus on the local and regional scales. Interactions between megacities and global scale have been the subject of many modelling studies (Wild et Akimoto, 2001; Stohl et al., 2002; Lawrence et al., 2003, 2007). However, there are still few works concerning interactions between megacities and their continental environment. My thesis works were then aiming at identifying theses impacts using eulerian modelling. My main interrogations concerned the nature, the magnitude, the scope, direct and indirect impact, and finally the pollutants exported by European megacities flux variations. In addition, I also investigated the nature of these high emission areas, through the sensitivity of the urban structure on their impacts (compact or spread cities). New tools developments in the model (flux calculation, new chemical scheme, implementation of an upgraded tool dedicated to scales interaction) were necessary to answer the problematic

La réaction de formation de l’ozone O+O2+M→O3+M est un exemple unique de réaction chimique qui mène à une composition isotopique anormale des produits, probablement due à une brisure de symétrie. L’existence d’autres réactions chimiques présentant des effets isotopiques similaires est encore controversée malgré des études affirmant que de telles réactions existent. Ainsi, deux études sur la réaction O+CO+M → CO2+M indiquent un fractionnement indépendant de la masse de 8% environ. Néanmoins, la présence d’ozone dans ces expériences soulève des questions en ce qui concerne la validité des résultats. Nous avons donc étudié à nouveau la réaction O+CO+M dans le photoréacteur installé au CCAR (Université de Copenhague) où les réactifs et les contaminants sont surveillés par spectroscopie FTIR. Cette étude, combinée avec l’analyse de la distribution spectrale des lampes utilisées et la modélisation cinétique des isotopes, mène à une réinterprétation complète des expériences précédentes. Nous concluons que les mesures disponibles sont plus compatibles avec l’hypothèse qu’aucune anomalie isotopique indépendante de la masse n’a lieu dans la réaction O+CO et que toutes les observations peuvent être complètement expliquées par un transfert isotopique à partir de l’ozone.Nous présentons également une méthode pour produire des échantillons d’ozone à haute pureté et déterminer une limite supérieure des contaminations par les oxydes d’azote basée sur des mesures par spectrométrie de masse. Ces valeurs pourront être utilisées comme référence pour de futures études sur les sections efficaces d’absorption de l’ozone dans l’IR et l’UV. / The ozone formation reaction O+O2+M→O3+M is a unique example of a chemical reaction that leads to an anomalous isotopic composition of the products, most likely due to symmetry – breaking effects. So far, results on other chemical systems that might show similar effects are spurious, even though such claims concerning reactions other than the formation of ozone have been made repeatedly.This applies in particular to the spin forbidden O+CO+M→CO2+M reaction, where two studies report a mass-independent fractionation of about 8%. Nevertheless, the presence of ozone in these experiments raises questions as to the validity of this assertion. We thus make a new attempt to study the O+CO+M reaction in the photoreactor at CCAR (University of Copenhagen) where reagents and contaminants are monitored on-line by FTIR spectroscopy. This study combined with the analysis of the spectral distribution of the employed lamps and isotope kinetic modeling lead to a complete re-interpretation of previous experiments. We conclude that available measurements are more compatible with the hypothesis that there is no mass-independent isotope fractionation in the O+CO reaction. We propose that all observations can be completely explained by an isotope transfer from ozone, involving photolytic production of O(1D) that in turn leads to OH radicals, which then rapidly form CO2 from reaction with CO. We also present a method to produce pure ozone samples and derive an upper limit on nitrogen oxide contaminations based on mass spectrometer measurements. These values will serve as benchmarks values for future studies of ozone absorption cross sections in the IR and UV.

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.

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.