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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Produção e caracterização de biocarvão de bagaço de laranja para utilização no pós-tratamento de água residuária

Carvalho, Roseanne Santos de 27 February 2018 (has links)
Due to the growing problem of water scarcity, as well as the need to preserve the environment, studies have been conducted aiming at the reuse of agroindustrial waste so that biofuels can be produced to promote the reuse of wastewater in crop irrigation as well as used in the removal of emerging micropollutants in wastewater. The bioadsorption arouses great interest in the research of new materials that can be used as adsorbents, because it presents a promising, efficient, economically viable and ecologically sustainable proposal when compared to other decontamination methods. In this context, the present study was based on the production of a biochar from the orange bagasse at 550oC to compose a tertiary treatment in the tetracycline retention as well as the use of the effluent in the irrigation of the radish culture. Samples of in natura orange pomace, biochar and activated commercial charcoal were characterized. The samples were characterized by thermogravimetry, surface area and porosity measurements, scanning electron microscopy and X-ray diffraction. Irrigation with the filtered effluent with activated charcoal and biocarbon did not influence representatively the agronomic variables of the culture, the physical- chemical properties of water and effluents were met by the aforementioned resolution and / or work on the subject. He observed the risk of salinization and sodification of the soil by the practice. The Langmuir model was the one that best adapted to the biochar, configuring adsorption of physical nature, beneficial to the desorption process. The kinetic model that fitted the most was the pseudo-second order and the estimated equilibrium time for the biochar was eight minutes. The spectrophotometric method was safe, economical and feasible in all the analyzes used. The biocarbon had a capacity of 100% tetracycline adsorption in domestic wastewater and the efficiency of the filtration with biochar was on average 25% higher than with the commercial coal. In view of the above, the possibility of converting a waste from the low-value agro-industry and without appropriate destination to a value-added product, orange marc bagasse, to be used as a tertiary treatment for reuse of effluent in irrigation and as adsorbent for the removal of tetracycline in domestic wastewater. / Devido ao crescente problema de escassez de água, bem como pela necessidade da preservação do meio ambiente, estudos têm sido conduzidos visando o reaproveitamento de resíduos da agroindústria para que possam ser produzidos biocarvões para a promoção do reuso de águas residuárias na irrigação de culturas, bem como utilizados na remoção de micropoluentes emergentes em águas residuárias. A bioadsorção desperta elevado interesse em relação à pesquisa de novos materiais que possam ser utilizados como adsorventes, por apresentar uma proposta promissora, eficiente, economicamente viável e ecologicamente sustentável quando comparado aos demais métodos de descontaminação. Neste contexto, o estudo do presente trabalho se baseou na produção de um biocarvão a partir do bagaço da laranja a 550oC para compor um tratamento terciário na retenção da tetraciclina bem como a utilização do efluente na irrigação da cultura do rabanete. Foram caracterizadas amostras do bagaço de laranja in natura, o biocarvão e o carvão comercial ativado. As amostras foram caracterizadas por termogravimetria, medidas de área superficial e porosidade, microscopia eletrônica de varredura e difração de raios X. A irrigação com o efluente filtrado com o biocarvão e carvão comercial ativado não influenciaram representativamente nas variáveis agronômicas da cultura, nas análises físico-químicas da água e efluentes foram atendidos pela referida Resolução e/ou trabalhos sobre a temática. Observou o risco de salinização e sodificação do solo pela prática. O modelo de Langmuir foi o que melhor se adaptou ao biocarvão, configurando adsorção de natureza física, benéficas para a processo de dessorção. O modelo cinético que mais se ajustou foi o de pseudo-segunda ordem e o tempo de equilíbrio estimado para o biocarvão foi de oito minutos. O método espectofotométrico apresentou-se seguro, econômico e viável em todas as análises utilizadas. O biocarvão teve capacidade de adsorção da tetraciclina de 100% em águas residuárias domésticas e a eficiência da filtração com biocarvão foi em média 25% maior do que com o carvão comercial. Diante do exposto conclui-se a possibilidade de conversão de um resíduo da agroindústria de baixo valor e sem destinação apropriada, a um produto de valor agregado, o biocarvão do bagaço da laranja, a ser utilizado como tratamento terciário para o reuso de efluentes na irrigação de culturas e como adsorvente para remoção da tetraciclina em águas residuárias domésticas. / São Cristóvão, SE
2

DeterminaÃÃo de Micropoluentes Emergentes em Esgoto SanitÃrio, Hospitalar e Ãguas Superficiais / Determination of Emerging Micropollutants in Sewage, and Surface Water Hospital

Neyliane Costa de Souza 18 November 2011 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / No Brasil, estudos de avaliaÃÃo de micropoluentes emergentes em matrizes ambientais como esgotos sanitÃrios e hospitalares, e corpos de Ãgua, ainda sÃo bastante incipientes, assim como a remoÃÃo desses compostos em EstaÃÃes de Tratamento de Esgotos (ETEs) de baixo custo como lagoas de estabilizaÃÃo, assim como em sistemas de lodos ativados e sistemas anaerÃbio-aerÃbio compactos. O presente trabalho teve como objetivo geral investigar a presenÃa de micropoluentes em matrizes ambientais como esgotos sanitÃrios e hospitalares, e Ãgua superficial, avaliar a remoÃÃo destes compostos em ETEs de baixo custo e aplicar o processo de oxidaÃÃo avanÃada (POA) UV/H2O2 como opÃÃo de pÃs-tratamento. Os principais micropoluentes emergentes estudados foram: 2,4,6-triclorofenol, pentaclorofenol, cafeÃna (CAF), dipirona (DIP), diclofenaco de sÃdio (DCF), bis (2-etil-hexil) ftalato (DEHP), estrona (E1), 17β-estradiol (E2), β-estradiol 17-acetato (EA2), 17α-etinilestradiol (EE2) e colesterol (COL). As amostras foram coletadas em ETEs localizadas em Fortaleza e em sua regiÃo metropolitana. Os corpos receptores investigados foram o Rio Maranguapinho e o Riacho Paupina. Para a prÃ-concentraÃÃo dos micropoluentes utilizou-se extraÃÃo em fase sÃlida (SPE) com cartuchos C-18 e extraÃÃo lÃquido-lÃquido (ELL). A SPE foi a tÃcnica mais eficiente na concentraÃÃo da maioria dos micropoluentes emergentes, e a ELL se mostrou a melhor tÃcnica para compostos organoclorados. Foram realizados estudos de otimizaÃÃo das condiÃÃes de detecÃÃo dos compostos pelo uso de tÃcnicas de cromatografia gasosa acoplada à espectrometria de massas (GC/MS). Foram identificados compostos farmacÃuticos e desreguladores endÃcrinos em todas as amostras de esgotos com as seguintes faixas de concentraÃÃes efluentes: CAF (3,0-15,8 μg/L), DIP (0,3 μg/L), DCF (1,9 μg/L), DEHP (0,01-8,5μg/L), E1 (0,04-1,7 μg/L), E2 (0,03-4,0 μg/L), EA2 (0,14-9,3 μg/L), EE2 (1,0 μg/L) e COL (0,01-6,2 μg/L). Nos dois corpos receptores estudados (Rio Maranguapinho e Riacho Paupina) foram identificados desreguladores endÃcrinos. Os tratamentos realizados pelas ETEs nÃo foram suficientes para remoÃÃo total de todos os micropoluentes estudados, no entanto, a eficiÃncia para a maioria dos compostos foi acima de 50%. Em se tratando da avaliaÃÃo em sistemas de lagoas de estabilizaÃÃo, o estudo revelou boas eficiÃncias de remoÃÃo em sistemas constituÃdos de lagoa anaerÃbia seguida de facultativa e de maturaÃÃo, sendo os menores valores de remoÃÃo alcanÃados quando uma Ãnica lagoa facultativa primÃria estava presente. A avaliaÃÃo do uso do POA por meio do planejamento fatorial multivariado revelou que as melhores condiÃÃes para remoÃÃo de micropoluentes emergentes foram pH Ãcido (pH 3), concentraÃÃo de perÃxido de hidrogÃnio acima de 400 mg/L e tempos de detenÃÃo hidrÃulica no reator acima de 50min. / In Brazil, studies evaluating emerging micropollutants in environmental matrices such as sewage and hospital wastewater, as well as surface waters, are still quite incipient as well as the removal of these compounds in low cost Wastewater Treatment Plants (WWTPs) such as stabilization ponds, as well as in activated sludge systems or anaerobic/aerobic compact systems. This work aimed to investigate the presence of micropollutants in environmental matrices such as sewage and hospital wastewaters, and in surface waters. Additionally, this study evaluated the removal of these compounds in low-cost WWTPs and studied the advanced oxidation process (AOP) â UV/H2O2 â as a post-treatment option. The main emerging micropollutants studied were: 2,4,6-trichlorophenol, pentachlorophenol, caffeine (CAF), dipyrone (DIP), sodium diclofenac (DCF), bis (2-ethylhexyl) phthalate (DEHP), estrone (E1), 17β-estradiol (E2), estradiol acetate (EA2), 17α-ethinyl estradiol (EE2) and cholesterol (CHO). The samples were collected from WWTPs located in Fortaleza and its metropolitan region. The receiving surface waters investigated were: Maranguapinho River and Paupina Creek. For the pre-concentration studies of micropollutants, solid phase extraction (SPE) with C-18 cartridges was used, as well as the liquid-liquid extraction (LLE) method. The SPE technique was the most efficient method in concentrating the majority of emerging micropollutants, and the LLE proved to be the best technique for organochlorine compounds. Optimization studies were performed to detect the ideal conditions to determine the compounds by using gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) techniques. In all wastewater samples pharmaceuticals and endocrine disrupting compounds were identified, and the range of effluent concentrations were: CAF (3.0-15.8 μg/L), DIP (0.3 μg/L), DCF (1.9 μg/L), DEHP (0.01-8.5μg/L), E1 (0.04-1.7 μg/L), E2 (0.03-4.0 μg/L), EA2 (0.14-9.3 μg/L), EE2 (1.0 μg/L) and CHO (0.01-6.2 μg/L). Endocrine disrupting compounds were identified in the Maranguapinho River and Paupina Creek. The wastewater treatment in the WWTPs was not enough for the complete removal of all micropollutants studied; however, the efficiency level for most of compounds was above 50%. Regarding the evaluation in stabilization ponds systems, the study revealed good removal of micropollutants in systems composed of anaerobic pond followed by facultative and maturation ponds, in which the lowest efficiency levels were verified when a single facultative pond was present. The evaluation of the AOP as a post-treatment option by multivariate factorial design showed that the optimal conditions for the removal of emerging micropollutants were acidic pH (pH 3), hydrogen peroxide concentration above 400 mg/L and hydraulic retention times in the reactor above 50 minutes.
3

Développements d’échantillonneurs passifs pour l’étude de la contamination des eaux par les micropolluants organiques / Development of passive sampling tools to monitor organic micropollutants in water

Wund, Perrine 09 December 2013 (has links)
Préserver les ressources en eau est l’une des problématiques environnementales majeures du 21è siècle. Pour faire face à cette nécessité, il est essentiel de mettre en place une surveillance réglementée de la qualité des eaux et des rejets se déversant dans le milieu aquatique et de développer de nouveaux outils d’échantillonnage. L’échantillonnage ponctuel est la technique la plus facile à mettre en œuvre. Toutefois, elle n’est pas toujours représentative d’un milieu hétérogène parfois soumis à des variabilités spatiales et temporelles importantes. L’échantillonnage passif, notamment avec l’outil POCIS (Polar Organic Chemical Integrative Sampler), est une approche complémentaire aux techniques traditionnelles, qui permet de concentrer des molécules organiques semi-polaires directement sur site. La pertinence du résultat obtenu (la concentration moyennée sur la durée d’exposition), couplée à la simplicité de sa mise en œuvre en font a priori un outil de choix pour suivre des hydrosystèmes complexes.Dans ce contexte, des familles des composés diversifiées ont été sélectionnées : pesticides, composés pharmaceutiques, hormones stéroïdiennes et composés perfluorés. Au sein de chaque famille, plusieurs composés traceurs, présents dans l’environnement, comportant des propriétés physico-chimiques variées et aux statuts règlementaires différents (Directive Cadre sur l’Eau notamment), ont été choisis.Des essais d’optimisation de design du POCIS (quantité et nature de phase réceptrice, nature de la membrane) ont été conduits, menant à la validation de la configuration classique dans le cas général. L’influence de différents paramètres environnementaux pertinents : débit, température, matrice, présence de biofilm et dispositif de déploiement a été évaluée lors de calibrations de l’outil réalisées dans des systèmes de complexité croissante : au laboratoire, sur pilote et sur site.Les différents déploiements sur site (effluent de STEP et rivière) ont permis de valider l’utilisation de cet outil de prélèvement passif dans le cadre d’un suivi environnemental. Le potentiel du POCIS a été pleinement confirmé, tant en termes de logistique que de résultats (justesse par rapport aux concentrations mesurées par des techniques classiques, intégration d’événements ponctuels, limite de quantification…). / The protection of water resources is one of the major environmental stakes of 21st century. Regulation concerning water quality and effluents is therefore definitely needed, as well as new approaches regarding water sampling. Spot sampling is the easiest strategy. However, it may not be representative of a heterogeneous matrix, with sometimes important spatial and temporal variability. Passive sampling, including POCIS (Polar Organic Chemical Integrative Sampler) is a complementary approach, which enables an on-site pre-concentration of semi-polar organic compounds. The relevance of the result (time-weighted average concentrations) and the ease to implement POCIS make it an appropriate tool to monitor complex hydrosystems.Within this work, various compound classes were selected: pesticides, pharmaceuticals, steroid hormones and perfluorinated compounds. Among each family, several tracer molecules, widely encountered in the environment, with different physic-chemical properties and regulatory status (particularly in the Water Framework Directive), were chosen.POCIS design optimization (amount and nature of sorbent, nature of membrane) was carried out, leading to the validation of the standard configuration for general purposes. The impact of different relevant environmental parameters (flow-rate, temperature, matrix, biofouling and deployment device), was assessed during calibrations of POCIS conducted in systems of increasing complexity: in the laboratory, at pilot-scale and on-site.All on-site deployments (WWTP effluent and river) enabled to validate the use of this passive sampling tool in the framework of an environmental monitoring. The potential of this tool was fully confirmed, both logistically and in terms of results (trueness compared to concentrations measured with traditional techniques, integration of punctual events, quantification limit…).

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