Made available in DSpace on 2014-06-11T19:35:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-27Bitstream added on 2014-06-13T21:07:01Z : No. of bitstreams: 1 basso_mfm_dr_arafo.pdf: 618642 bytes, checksum: a30b4dfd3eaaae29f0c670dfb57dbd55 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A energia por microondas tem sido recomendada para desinfetar próteses totais. Entretanto, os ciclos de desinfecção podem afetar a estabilidade dimensional das bases de próteses. Assim, o objetivo deste estudo clínico foi avaliar o efeito de dois protocolos de desinfecção por microondas na estabilidade dimensional de próteses totais, analisando a estabilidade dimensional linear, o percentual de força oclusal obtido a partir dos contatos oclusais cêntricos e as ocorrências clínicas. Foram confeccionadas próteses totais para quarenta pacientes totalmente edêntulos. Todas as próteses foram prensadas com a resina Lucitone 550. Após a colocação, aguardou-se 30 dias para submeter as próteses às condições experimentais como a seguir: Grupo 1 (G1)- 20 pacientes tiveram as próteses maxilares submetidas a desinfecção por microondas (650 W / 3 minutos), uma vez por semana, durante 4 semanas. Grupo 2 (G2)- 20 pacientes tiveram as próteses maxilares submetidas a desinfecção por microondas (650 W / 3 minutos), três vezes por semana, durante 4 semanas. Para avaliar a estabilidade dimensional linear, mensurações foram realizadas entre quatro pontos de referência (primeiros pré-molares e segundos molares bilateralmente) antes da primeira desinfecção por microondas (baseline) e após cada semana de desinfecção. Um software foi utilizado para mensurar as distâncias entre os pontos de referência a partir de fotografias padronizadas. As dimensões médiolateral e anteroposterior e a área foram calculadas. Os dados foram analisados pelos testes ANOVA two-way, Tukey e t-Student (_=0,05). O sistema T-Scan III foi utilizado para avaliar o percentual de força oclusal obtido a partir dos contatos oclusais cêntricos. Os contatos oclusais cêntricos foram capturados, antes da primeira desinfecção por microondas (baseline) e após cada semana de desinfecção, por meio... / Microwave energy has been recommended for disinfecting complete dentures. However, the microwave disinfection cycles may affect the dimensional stability of denture bases. Therefore, the purpose of this clinical study was to evaluate the effect of two microwave disinfection protocols on the dimensional stability of complete dentures, analyzing the linear dimensional stability, the percent occlusal force obtained from centric occlusal contacts and the clinical events. Complete dentures were constructed for forty totally edentulous patients. All dentures were conventionally processed with heat-polymerized acrylic resin (Lucitone 550). After insertion of complete dentures, it was expected 30 days to submit the dentures to the experimental conditions as follows: Group 1 (G1)- 20 patients had the maxillary complete dentures submitted to microwave disinfection (650 W/ 3 minutes), once a week, for four weeks. Group 2 (G2)- 20 patients had the maxillary complete dentures submitted to microwave disinfection (650 W/ 3 minutes), three times a week, for four weeks. To evaluate the linear dimensional stability, measurements were taken across four reference points (first premolars and second molars bilaterally) before of first microwave disinfection (baseline) and after each week of disinfection. Software was used to measure distances between reference points from standardized photographs. Mediolateral and anteroposterior dimensions and area between reference points were calculated. The dimensional data obtained were analyzed using two-way ANOVA, Tukey test and t test (_ = .05). To evaluate the percent occlusal force obtained from centric occlusal contacts, the T-Scan III system was used. The centric occlusal contacts were measured, before of first microwave disinfection (baseline) and after each week of disinfection, using pressure-sensitive sheets and studied in T-Scan software. The occlusal data... (Complete abstract click electronic access below)

Les légionelles sont un enjeu de santé publique majeur car ces bactéries sont responsables des cas de légionellose, parfois mortels. Les tours aéroréfrigérantes (TAR) peuvent être incriminées car pouvant potentiellement émettre des aérosols contaminés. Un traitement de désinfection de ces eaux est donc nécessaire. Cependant les techniques actuelles conduisent très souvent à des injections importantes de réactifs induisant des rejets écotoxiques dans l'environnement qu'il est nécessaire de limiter. L'application du traitement d'oxydation avancée H2O2/UV – considéré comme innovant pour ce domaine et dont l'impact environnemental est limité (décomposition du peroxyde d'hydrogène en eau et oxygène, peu de production de composés toxiques) – a prouvé son efficacité de désinfection à la fois au sein d'un pilote de laboratoire sur une eau reconstituée, chargée en microorganismes et matière organique, mais aussi lors du traitement de l'eau d'une TAR du secteur tertiaire. Les ultraviolets ont été appliqués de manière continue (10 à 22 J.cm-2 sur le pilote ; 2 à 7 J.cm-2 sur la TAR) avec le maintien d'un résiduel constant en peroxyde d'hydrogène (10 à 50 mg.L-1 sur le pilote ; 3 à 10 mg.L-1 sur la TAR). Sur le pilote de laboratoire, le traitement H2O2/UV a montré une efficacité supérieure à l'application des UV ou du peroxyde d'hydrogène seul. Des abattements plus importants sur les paramètres microbiologiques de l'eau et des biofilms (ATP, bactéries cultivables et totales) et une modification profonde de la matière organique (minéralisation) ont pu être observés. Il a ainsi été conservé les avantages de chaque technique (désinfection reconnue des UV et action bactéricide de H2O2), tout en limitant leurs inconvénients (absence de rémanence des UV, fortes concentrations nécessaires en H2O2) grâce à la génération de radicaux hydroxyles pouvant agir sur les microorganismes et la matière organique. L'étude sur une TAR a confirmé ces résultats et a montré de bonnes performances de désinfection en comparaison avec celles obtenues pour le dioxyde de chlore. Cependant, lors les phases d'optimisation des essais, une adaptation des bactéries au peroxyde d'hydrogène a été observée indiquant la nécessité d'un contrôle régulier de cet oxydant afin de maintenir un résiduel conséquent et d'éviter la mise en place d'une dérive du système. De plus, il a été montré que le traitement n'a eu qu'une faible action sur les produits de conditionnement de l'eau (antitartre, anticorrosion). Une rapide évaluation économique a permis de placer le couplage H2O2/UV dans le même ordre de grandeur que les traitements habituels. / Legionella is a major public health issue as they are responsible for Legionnaires' disease, which can be fatal. Cooling towers are often incriminated because of their potential emission of contaminated aerosols. A disinfection process for treating water is then necessary. However, current techniques often need high concentrations of chemical products which lead to ecotoxic releases into the environment. UV-H2O2 is an advanced oxidation process with a limited environmental impact (hydrogen peroxide decomposition into oxygen and water, low production of toxic compounds). It was shown that this method is an effective technique of disinfection both in a laboratory pilot on water charged with microorganisms and organic matter, and in the water treatment of a cooling tower (service sector). UV irradiation was applied continuously (10 – 22 J.cm-2 on the pilot; 2 – 7 J.cm-2 on the cooling tower) with a constant residual of hydrogen peroxide (10 to 50 mg.L-1 on the pilot; 3 to 10 mg.L-1 on the cooling tower). On the laboratory pilot, UV-H2O2 showed a higher efficacy than UV or hydrogen peroxide treatments applied alone. A more important reduction of microbiological parameters in water and biofilms (ATP, heterotrophic plate and total bacteria counts) and a deep change in organic matter (mineralization) were observed. The advantages of each process (both well-known UV disinfection and bactericidal action of H2O2) were selected by limiting their disadvantages (no residual with UV, need for high concentrations of H2O2) through the generation of hydroxyl radicals, acting on microorganisms and organic matter. The study on a cooling tower confirmed these results and showed good disinfection performances compared with those obtained for chlorine dioxide. However, the optimization phases of the treatment highlighted a bacterial adaptation to hydrogen peroxide. A monitoring of this oxidant is required in order to maintain a residual, and therefore to avoid a drift of the system. Besides, UV-H2O2 showed little effect on scale and corrosion inhibitors. A rapid economic assessment allowed to placing UV-H2O2 in the same order of magnitude as usual treatments.

Orientador: Carlos Eduardo Vergani / Banca: Ana Lucia Machado / Banca: Marco Antonio Compagnoni / Banca: Marcelo Ferraz Mesquita / Banca: Rodrigues Nunes Rached / Resumo: O estudo avaliou o efeito do reembasamento, da ciclagem mecânica, da ciclagem térmica e da desinfecção por microondas sobre a força máxima de fratura, a deformação, a energia de ruptura e a estabilidade dimensional de bases de prótese. Os resultados evidenciaram que as variações intra-orais tais como os estresses térmico e mecânico aumentaram a degradação e diminuíram a vida útil das bases de prótese intactas e reembasadas com o material reembasador TRFII. A desinfecção por microondas produziu uma contração significativa das bases de prótese intactas e aquelas reembasadas com os materiais NTL e K. A desinfecção por microondas não afetou os valores de força máxima de fratura das bases de prótese intactas ou reembasadas com diferentes materiais reembasadores; porém, os valores de energia de ruptura e deformação das bases de prótese reembasadas com TR e NTL foram significativamente reduzidas após os ciclos de desinfecção por microondas e armazenamento em água por 7 dias. / Abstract: This study investigated the effect of relining, thermal stress, mechanical stress and microwave disinfection on the maximum fracture load, deflection at fracture, fracture energy and dimensional stability of intact denture bases and those relined with four autopolymerizing reline resins. Thermal and mechanical stresses adversely affect the strength of intact and/or relined denture bases; however, effects vary based upon the relining material used. Microwave disinfection produced increased shrinkage of intact specimens and those relined with New Truliner and Kooliner. The strength of the denture bases relined with New Truliner was not significantly affected by any of the experimental conditions, but comparing the control groups, New Truliner exhibited the lowest maximum fracture load values. The maximum fracture load of specimens was not affected by microwave disinfection. Microwave disinfection and water storage for 7 days decreased the deflection at fracture and fracture energy values of specimens relined with Tokuso Rebase Fast and New Truliner. The deflection at fracture and fracture energy values of specimens relined with Tokuso Rebase Fast and New Truliner were affected by microwave disinfection. / Doutor

Made available in DSpace on 2014-07-29T15:01:41Z (GMT). No. of bitstreams: 1 Dissertacao Waleska Fernanda F Morgado.pdf: 1282396 bytes, checksum: 4ca186add1105f1358d9922c71f2b024 (MD5) Previous issue date: 2008-08-25 / Latin-American countries are facing serious problems related to waterborne diseases due to the lack of basic sanitation, affecting in particular those people living in small and rural communities. Solar radiation for water disinfection, SODIS, seems a promising process for small communities since it does not require electric energy and it has low cost and easy operation. This work aimed to evaluate the inactivation of the pathogens Escherichia coli and Clostridium perfringens by SODIS in the Center-West region of Brazil, Goiânia-GO. The Colilert® and multiple tubes (NMP/100 mL) were used to determine the Escherichia coli and the Clostridium perfringens bacterias, respectively. The inactivation and the re-growth of these bioindicators, the physico-chemical parameters of the raw and disinfected waters were the main focus of this work. Raw water was collected from a well located at the Civil Engineering School (EEC) of Federal University of Goiás (UFG) and it was inoculated apart using pre-determined concentrations of these bio-indicators. Samples were put in transparent PET bottles with capacity of 2L and left under sunlight exposure between 9am and 3pm. Samples were collected and analyzed in the laboratory after 0, 2, 4 and 6 hours of exposure. The work was divided into two phases: the first evaluate the effect of the use of two water volumes (1.5 L and 2 L) on the pathogen inactivation. In addition, the re-growth of these pathogens in the PET bottles after 3 storage days at ambient temperature was also investigated. In the second phase, PET bottles containing 1.5 L of contaminated water were exposed to sunlight radiation with and without solar reflectors. The results showed that there was a small difference (0,25-Log to Clostridium perfringens and 0,5-Log to Escherichia coli) in the inactivation of both bioindicators between the two volumes evaluated in the first phase. The use of the solar reflector did not improve the inactivation of the Clostridium perfringens and their re-growth was proportional to the final concentration after 6 hours of sunlight exposure. / Os países latino-americanos enfrentam sérios problemas com a alta incidência de doenças relacionadas com a falta de saneamento básico, sendo mais afetadas as populações que vivem em localidades pobres, periféricas e em zonas rurais. A utilização da radiação solar no processo de desinfecção de água, SODIS, é introduzida nesse contexto como uma alternativa de desinfecção da água independente de insumos, que funciona sem fornecimento de energia elétrica, baixo custo e de fácil operação em comunidades pequenas. Este trabalho teve por objetivo avaliar a inativação dos patógenos Escherichia coli e o Clostridium perfringens através da SODIS na região Centro-Oeste do Brasil, na cidade de Goiânia GO. Para a determinação das bactérias Escherichia coli e Clostridium perfringens foi utilizado os métodos Colilert® e tubos múltiplos (NMP/100 mL), respectivamente. A inativação e o recrescimento destes bioindicadores, a análise dos parâmetros físico-químicos da água bruta e da água desinfetada pela SODIS foram os enfoques principais deste estudo. Água bruta foi coletada de um poço raso da Escola de Engenharia Civil (EEC) da Universidade Federal de Goiás (UFG) e inoculada com concentrações determinadas dos bioindicadores, separadamente, acondicionadas em garrafas de PET e expostas ao sol pelo período das 09:00 às 15:00 horas. Amostras de água foram coletadas e analisadas em laboratório após os tempos de exposição de 0, 2, 4 e 6 horas. O trabalho experimental foi dividido em duas etapas, a primeira considerou a diferença de volumes nas garrafas, 1,5 L e 2 L, para investigar o efeito das concentrações de oxigênio, a verificação do recrescimento após 3 dias de armazenamento na própria garrafa de PET em temperatura ambiente e a avaliação da água bruta antes e após a SODIS. Na segunda etapa, garrafas com volume padrão de 1,5 L foram usadas em combinação com e sem concentrador solar. Os resultados mostraram que houve uma pequena diferença, (0,25-Log para Clostridium perfringens e 0,5-Log Escherichia coli) nas inativações bacterianas em relação aos diferentes volumes, sendo maiores nas garrafas de 1,5 L para ambos os bioindicadores na etapa 1. O uso do concentrador solar não apresentou melhoria no processo em relação ao Clostridium perfringens e o recrescimento foi proporcional à concentração final dos bioindicadores após as 6 horas de exposição.

Resumo: A energia por microondas tem sido recomendada para desinfetar próteses totais. Entretanto, os ciclos de desinfecção podem afetar a estabilidade dimensional das bases de próteses. Assim, o objetivo deste estudo clínico foi avaliar o efeito de dois protocolos de desinfecção por microondas na estabilidade dimensional de próteses totais, analisando a estabilidade dimensional linear, o percentual de força oclusal obtido a partir dos contatos oclusais cêntricos e as ocorrências clínicas. Foram confeccionadas próteses totais para quarenta pacientes totalmente edêntulos. Todas as próteses foram prensadas com a resina Lucitone 550. Após a colocação, aguardou-se 30 dias para submeter as próteses às condições experimentais como a seguir: Grupo 1 (G1)- 20 pacientes tiveram as próteses maxilares submetidas a desinfecção por microondas (650 W / 3 minutos), uma vez por semana, durante 4 semanas. Grupo 2 (G2)- 20 pacientes tiveram as próteses maxilares submetidas a desinfecção por microondas (650 W / 3 minutos), três vezes por semana, durante 4 semanas. Para avaliar a estabilidade dimensional linear, mensurações foram realizadas entre quatro pontos de referência (primeiros pré-molares e segundos molares bilateralmente) antes da primeira desinfecção por microondas (baseline) e após cada semana de desinfecção. Um software foi utilizado para mensurar as distâncias entre os pontos de referência a partir de fotografias padronizadas. As dimensões médiolateral e anteroposterior e a área foram calculadas. Os dados foram analisados pelos testes ANOVA two-way, Tukey e t-Student (_=0,05). O sistema T-Scan III foi utilizado para avaliar o percentual de força oclusal obtido a partir dos contatos oclusais cêntricos. Os contatos oclusais cêntricos foram capturados, antes da primeira desinfecção por microondas (baseline) e após cada semana de desinfecção, por meio... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Microwave energy has been recommended for disinfecting complete dentures. However, the microwave disinfection cycles may affect the dimensional stability of denture bases. Therefore, the purpose of this clinical study was to evaluate the effect of two microwave disinfection protocols on the dimensional stability of complete dentures, analyzing the linear dimensional stability, the percent occlusal force obtained from centric occlusal contacts and the clinical events. Complete dentures were constructed for forty totally edentulous patients. All dentures were conventionally processed with heat-polymerized acrylic resin (Lucitone 550). After insertion of complete dentures, it was expected 30 days to submit the dentures to the experimental conditions as follows: Group 1 (G1)- 20 patients had the maxillary complete dentures submitted to microwave disinfection (650 W/ 3 minutes), once a week, for four weeks. Group 2 (G2)- 20 patients had the maxillary complete dentures submitted to microwave disinfection (650 W/ 3 minutes), three times a week, for four weeks. To evaluate the linear dimensional stability, measurements were taken across four reference points (first premolars and second molars bilaterally) before of first microwave disinfection (baseline) and after each week of disinfection. Software was used to measure distances between reference points from standardized photographs. Mediolateral and anteroposterior dimensions and area between reference points were calculated. The dimensional data obtained were analyzed using two-way ANOVA, Tukey test and t test (_ = .05). To evaluate the percent occlusal force obtained from centric occlusal contacts, the T-Scan III system was used. The centric occlusal contacts were measured, before of first microwave disinfection (baseline) and after each week of disinfection, using pressure-sensitive sheets and studied in T-Scan software. The occlusal data... (Complete abstract click electronic access below) / Orientador: Eunice Teresinha Giampaolo / Coorientador: Marco Antonio Compagnoni / Banca: Raphael Freitas de Souza / Banca: Claudia Helena Lovato da Silva / Banca: Ana Claudia Pavarina / Banca: João Neudenir Arioli Filho / Doutor

Orientadores: Ricardo de Lima Isaac, Regina Maura Bueno Franco / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-05T11:45:48Z (GMT). No. of bitstreams: 1 Tosetto_MarianadeSalles_M.pdf: 2211562 bytes, checksum: 608a86bf4dcf009813ef868c3b96d5c6 (MD5) Previous issue date: 2005 / Resumo: Este trabalho consistiu na análise da eficiência do tratamento terciário do efluente da Estação de Tratamento de Esgoto (ETE) Samambaia, no município de Campinas-SP, para fins de reuso em ambiente urbano. O sistema avaliado era composto das etapas de coagulação, pré-floculação em meio granular, filtração e desinfecção com radiação ultravioleta. O estudo experimental foi realizado em escala de bancada para otimização do processo de coagulação, e em escala piloto para avaliar as etapas de pré-floculação, filtração e desinfecção. Foram investigados, como coagulantes químicos, o sulfato férrico e o sulfato de alumínio, taxas de filtração de 120 e 300 m3/m2.dia, e dose de radiação UV de, aproximadamente, 95 mWs/cm2. O efluente terciário produzido na instalação piloto não foi considerado seguro sob o aspecto de saúde pública para aplicação em reuso urbano, como irrigação de parques e jardins, limpeza urbana, lavagem de veículos, combate a incêndio, entre outros, pois não atendeu as recomendações da Organização Mundial de Saúde ¿ OMS quanto à concentração de ovos de helmintos, e apresentou cistos de Giardia spp. ainda em concentrações elevadas, embora nenhuma das recomendações encontradas na literatura contemple limites para estes últimos. Os parâmetros turbidez, DBO, sólidos em suspensão, Coliformes Totais e E. coli atenderam as metas e padrões recomendados na literatura para reuso urbano / Abstract: This work consisted of efficiency analysis of tertiary treatment of effluent from a Wastewater Treatment Plant (WWTP Samambaia) that is located at the city of Campinas (São Paulo State, Brazil), for urban reuse. The system consisted of a physico-chemical treatment composed of coagulation, granular upflow flocculation, direct downflow filtration and ultraviolet disinfection. The experimental work was carried out using bench-scale tests to optimize chemical coagulation, and in a pilot installation to evaluate the flocculation, filtration and disinfection steps. Aluminum sulfate and ferric sulfate were evaluated as coagulants. Filtration rates of 120 and 300 m/day and UV doses of 95 mWs/cm2 were applied. The tertiary effluent obtained at the pilot plant was not considered safe, under the public health point of view, for urban reuse, like gardens and parks irrigation, urban cleaning, car-washing, fire protection and others, because the helminth eggs concentration, that did not comply to World Health Organization-WHO recommendation, and the high level of Giardia spp. cysts concentration detected at the tertiary-treated effluent, although the quality requirements for urban reuse do not limit this concentration. The turbidity, BOD, suspended solids and coliforms parameters were according to literature recommendation for urban reuse / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil

Orientadores: Peterson Bueno de Moraes, Edério Dino Bidóia / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia / Made available in DSpace on 2018-08-22T03:26:05Z (GMT). No. of bitstreams: 1 Claro_ElisMarinaTurini_M.pdf: 2348408 bytes, checksum: 866377db43cbdf888b73040dcfb89167 (MD5) Previous issue date: 2013 / Resumo: O uso de tecnologias alternativas de tratamento de água contribui para suprimir limitações e inconvenientes oriundos dos processos convencionais de tratamento. Dentre estas, destaca-se a fotocatálise heterogênea, a qual foi utilizada nesse trabalho visando redução da concentração de matéria orgânica, nitrito, inativação de coliformes totais e Escherichia coli da água do rio Piracicaba, para ser utilizada como água de entrada em uma ETA. Avaliou-se o processo fotocatalítico utilizando TiO2 P25 e ZnO comercial além de fotocatalisadores dopados sintetizados (SiZnO, N-SiZnO, F-N-SiZnO, N-SiZnO + NH4Cl, TiO2 + NaOH, TiO2 + NH4OH e TiO2 + NH4F) nas concentrações 1,0 g l-1 e 0,5 g l-1, submetidos à ação de três fontes de radiação distintas (lâmpada de vapor de mercúrio de 250 W, simulador solar e um reator utilizando LED UV de 0,12 W), avaliando-se a toxicidade com sementes de alface (Lactuca sativa). Os resultados demonstraram que em 0,5 g L-1 dos fotocatalisadores, melhor concentração estudada, todos apresentaram atividade fotocatalítica, sendo que nenhum dos sintetizados foram capazes de proporcionar degradação superior ao TiO2 e ao ZnO para tratamento da água do rio. Os melhores resultados dos fotocatalisadores sintetizados foram obtidos com o N-SiZnO para remoção de matéria orgânica em 60 minutos (37% para vapor de mercúrio) e inativação de micro-organismos maiores que 4,0 log para coliformes totais e E. coli, utilizando vapor de mercúrio em 30 minutos de tratamento, além de apresentar a menor fitotoxicidade para as três fontes de radiação. A lâmpada de vapor de mercúrio foi a que apresentou resultados mais satisfatórios em 60 minutos de tratamento. Para o nitrito, não houve redução nas concentrações em 60 minutos de tratamento em relação à inicial, porém, ocorreu aumento nos valores de nitrito em 15 minutos de tratamento, indicando provável oxidação a nitrato. A fotocatálise heterogênea poderia ser aplicada para utilização como tratamento de água de entrada de uma ETA convencional de ciclo completo, entretanto, devido à necessidade de separação dos fotocatalisadores da água e aumento da toxicidade, é recomendado uma minuciosa análise de custo x benefício / Abstract: The use of alternative technologies for water treatment contributes to suppress limitations and disadvantages of conventional processes. Among the promising technologies, there is heterogeneous photocatalysis which was used in this work in order to reduce the concentration of organic matter, nitrite, inactivation of total coliforms and Escherichia coli in samples of water from Piracicaba River, to be used as primary feed for a Municipal Water Treatment Plant (MWTP). We evaluated the photocatalytic process using TiO2 P25 (Degussa) and commercial ZnO as well as synthesized photocatalysts doped (SiZnO, N-SiZnO, F-N-SiZnO, N-SiZnO + NH4Cl, TiO2 + NaOH, TiO2 + NH4OH and TiO2 + NH4F) in concentrations of 1.0 g L-1 and 0.5 g L-1 irradiated under three different sources (high-pressure mercury vapor lamp, solar simulator and UVLED) and monitoring the toxicity with lettuce seeds (Lactuca sativa). The results showed that 0.5 g L-1 was the best concentration; at this value all photocatalysts presented photo-activity whereas none of the synthesized was able to overcome the degradation rates observed by the TiO2 and ZnO. The best results were obtained by photocatalysts synthesized with N-SiZnO irradiated by the high-pressure mercury lamp: 37% of organic matter removal (60 minutes) and inactivation of microorganisms higher than 4.0 log for total coliforms and E. coli (after 30 minutes of treatment), besides to result in the smallest phytotoxicity of the three radiation sources. The use of mercury vapor lamp showed the best results for 60 minutes of treatment time. No fall in the nitrite concentration was obtained during 60 minutes of treatment although a rise in the nitrite concentration has been observed in 15 minutes, which may indicate probable oxidation to nitrate. The proposed photocatalysts could be applied for treating inlet water's at MWTP; however, due to necessity of separation of solution water-photocatalyst and due to small increase of values observed in the toxicity tests, a detailed cost-benefit analysis is recommended / Mestrado / Tecnologia e Inovação / Mestra em Tecnologia

L’objectif principal de ce travail est d’étudier les mécanismes d’oxydation lors de la photocatalyse (TiO2 irradié sous UV-A) appliquée à la dégradation des microorganismes et leurs effets sur les composants cellulaires. L'étude de l'efficacité antimicrobienne de TiO2 sur un panel de microorganismes (bactéries, spores, champignons) réalisée dans différents milieux (TiO2 en milieu riche, 'sec', en phase liquide) montre l’influence des méthodes d’évaluation, de test et de comptage sur les efficacités d’inactivation. Des études menées en présence de molécules scavengers d’anions superoxydes (O2°-) mettent en évidence l’implication des O2°- dans l’effet antibactérien et dans la peroxydation lipidique. Au niveau protéomique, diverses cibles d’action potentielles du TiO2 sont aussi proposées. Enfin, une partie applicative détermine l’efficacité antimicrobienne de dispositifs photocatalytiques équipés de mousses alvéolaires de β-SiC et de diodes électroluminescentes, et met en avant les propriétés auto-désinfectantes sous lumière solaire de textiles photocatalytiques fonctionnalisés par la technique layer-by-layer. / The main objective of this work is to study the oxidation mechanisms of UV-A photocatalysis on TiO2 applied to the degradation of microorganisms and their effects on cellular components. The study of the antimicrobial efficiency of TiO2 towards a panel of microorganisms (bacteria, spores, fungi) in different media (TiO2 in rich or 'dry' environment, in liquid phase) shows the influence of the evaluation methods, test and counting on the inactivation efficiency. Studies carried out in the presence of scavenger molecule of superoxide anions (O2°-) highlight the involvement of O2°- in the antibacterial effect and lipid peroxidation. Proteomics analysis leads to propose various potential targets of the TiO2 action. Finally, an application part deals with the design of photocatalytic devices based on LEDs and β-SiC alveolar foams for air disinfection, and of sunlight active self-disinfecting layer-by-layer functionalized photocatalytic textiles.

Diese Arbeit untersucht den Einsatz von keramischen Materialien in der Trinkwasseraufbereitung mittels Filtration und fokussiert dabei die Entfernung von Viren. Herkömmliche, auf Kieselgur basierende Tiefenfilter (Filterkerzen) mit Porengrößen im unteren Mikrometerbereich, werden hinsichtlich ihres Rückhaltevermögens gegenüber Kolloiden (Viren sowie Polystyrolpartikel) untersucht, um deren Einsatzfähigkeit in der Entfernung von Mikroorganismen im Allgemeinen abschätzen zu können. Ferner wird gezeigt, wie durch ein einfaches Verfahren solche Filter modifiziert werden können, um auch kleinste Viren mit ca. 30 nm Durchmessern aus dem Rohwasser zu entfernen. Die Zugabe von MgO während der Granulierungsstufe im Herstellungsprozess der Filterkerzen bewirkt eine erhebliche Verbesserung des Virenrückhalts bis zu über 99.9999%. Die experimentellen Ergebnisse wurden dabei mit theoretischen Modellen verglichen, um Aussagen über die Mechanismen der Virenentfernung treffen zu können.

Diese Arbeit untersucht den Einsatz von keramischen Materialien in der Trinkwasseraufbereitung mittels Filtration und fokussiert dabei die Entfernung von Viren. Herkömmliche, auf Kieselgur basierende Tiefenfilter (Filterkerzen) mit Porengrößen im unteren Mikrometerbereich, werden hinsichtlich ihres Rückhaltevermögens gegenüber Kolloiden (Viren sowie Polystyrolpartikel) untersucht, um deren Einsatzfähigkeit in der Entfernung von Mikroorganismen im Allgemeinen abschätzen zu können. Ferner wird gezeigt, wie durch ein einfaches Verfahren solche Filter modifiziert werden können, um auch kleinste Viren mit ca. 30 nm Durchmessern aus dem Rohwasser zu entfernen. Die Zugabe von MgO während der Granulierungsstufe im Herstellungsprozess der Filterkerzen bewirkt eine erhebliche Verbesserung des Virenrückhalts bis zu über 99.9999%. Die experimentellen Ergebnisse wurden dabei mit theoretischen Modellen verglichen, um Aussagen über die Mechanismen der Virenentfernung treffen zu können.:Contents Chapter I Introduction 1 Chapter II Removal or inactivation of microorganisms, in particular viruses, for drinking water purposes with focus on small-scale, decentralised systems: A literature review 7 II. I Physical and chemical treatments 8 II. II Filtration processes 10 II. III Conclusions 15 Chapter III Mechanisms of adsorption in depth filtration 17 III.I Surface charge and the electrical double layer 18 III.II van der Waals interactions 22 III.III DLVO theory 23 III.IV Non-DLVO forces 25 III.V Extended DLVO Theory 27 Chapter IV Virus adsorption studies 29 IV.I A literature review 30 IV.I.I Virus concentration by adsorption-elution 33 IV.I.II Improved virus adsorption in filtration 35 IV.II The electrostatic enhanced adsorption approach 37 Chapter V Viruses 39 V.I Literature review 40 V.I.I Structure and morphology 40 V.I.II The viral life cycle 41 V.I.III Human pathogenic viruses in the aquatic environment 42 V.II Experimental 46 V.II.I The choice of viruses for adsorption studies 46 V.II.II Propagation and enumeration of the bacteriophages 48 V.II.III Characterisation of bacteriophages 51 V.III Results and discussion 54 V.III.I Production of high-titre and high-purity phage stocks 54 V.III.II Characteristics of bacteriophages 59 V.III.III Detection of a viral contaminant - the ‘Siphophage’ 64 Chapter VI The diatomaceous earth-based depth filter 69 VI.I Literature review 70 VI.I.I Diatomaceous earth 70 VI.I.II Retention of microorganisms in the DE-based depth filter 71 VI.II Experimental 73 VI.II.I Manufacturing the depth filter 73 VI.II.II Physical characterisation 74 VI.II.III Performing filter retention tests 75 VI.II.IV Latex retention test 76 VI.II.V Studying adsorption kinetics in a batch experiment 79 VI.II.VI Applying (X-)DLVO theory 80 VI.III Results and discussion 83 VI.III.I Characterisation of the depth filter 83 VI.III.II Latex removal in the depth filter 86 VI.III.III Filter performance on virus removal 94 VI.III.IV Batch-sorption experiments 99 VI.IV Summary and conclusions 102 Chapter VII The magnesium oxide modified depth filter 103 VII.I Experimental 104 VII.I.I Choice of the adsorbent material 104 VII.I.II Manufacturing the MgO-modified filter and characterisation methods 105 VII.II Results and discussion 106 VII.II.I The adsorbent: Magnesium oxide powder 106 VII.II.II Physical characterisation of modified depth filters 108 VII.II.III Virus removal in depth filters containing MgO 113 VII.II.IV Ageing behaviour of MgO modified filters 118 VII.II.V Discussion on the removal mechanisms 130 VII.III Summary and conclusions 134 Chapter VIII Summary, conclusions and outlook 135 VIII.I Summary and conclusions 136 VIII.II Outlook 137 Abbreviations, symbols and physical constants 139 Reference list 142