Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-03-17T12:09:57Z No. of bitstreams: 1 PDF - Thales Lacerda Querino de Albuquerque.pdf: 9461957 bytes, checksum: fdb6c4eaac7cffec8adb8d1366435b61 (MD5) / Made available in DSpace on 2017-03-17T12:09:58Z (GMT). No. of bitstreams: 1 PDF - Thales Lacerda Querino de Albuquerque.pdf: 9461957 bytes, checksum: fdb6c4eaac7cffec8adb8d1366435b61 (MD5) Previous issue date: 2017-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / With the growth of sewage collection networks, sludge production in Sewage Treatment Plants (ETEs) has been growing steadily as these networks are expanded and new treatment plants are deployed. The sludge generated in the ETEs presents a composition of constituents that can pose risks to the health of the population and the environment, and it is necessary to make adequate final disposal of this residue or to reuse the nutrients that can be obtained in membrane filtration processes. Recent studies have shown that nutrient recovery from sewage sludge can be performed in Anaerobic Membrane - AnMBR systems, which include a feed reservoir, an anaerobic digester, a membrane filtration module and a permeate storage reservoir. Some factors contribute to the performance of the bioreactor process, making constant monitoring of some parameters necessary. The constant monitoring was performed through the automation of the system, using the micro controller Arduino board, connected to pressure and temperature sensors, where values are displayed through reports generated by the software. The software shows information in real time, but also provides a tool where you can query data from the bioreactor according to the desired date. At the end of the research it was possible to verify that the software facilitates the storage and processing of data, offering a better management of information of extreme importance in the aid of decision making in the management of membrane bioreactors. / Com o crescimento das redes de coleta de esgotos, a produção de lodos em Estações de Tratamento de Esgotos (ETEs) vêm crescendo continuamente à medida que estas redes são ampliadas e novas estações de tratamento são implantadas. O lodo gerado nas ETEs apresenta uma composição de constituintes que podem trazer riscos para a saúde da população e ao meio ambiente, sendo necessário realizar disposição final adequada a este resíduo ou reaproveitar os nutrientes que podem ser obtidos em processos de filtração por membranas. Estudos recentes demonstram que a recuperação de nutrientes do lodo de esgoto pode ser realizada em sistemas de Biorreatores Anaeróbios de Membrana - AnMBR, que incluem um reservatório de alimentação, um digestor anaeróbio, um módulo de filtração de membrana e um reservatório de armazenamento de permeado. Alguns fatores contribuem no desempenho do processo do biorreator, tornando necessário o acompanhamento constante de alguns parâmetros. O acompanhamento constante foi realizado através da automação do sistema, utilizando a placa micro controladora Arduino, conectada a sensores de pressão e temperatura, onde os valores são exibidos através de relatórios gerados pelo software. O software mostra informações em tempo real, como também disponibiliza uma ferramenta onde é possível consultar dados do biorreator de acordo com a data desejada. Ao término da pesquisa foi possível constatar que o software facilita a armazenagem e tratamento de dados, oferecendo um melhor gerenciamento das informações de extrema importância no auxílio à tomada de decisão na gestão de biorreatores de membrana.

Cette recherche porte sur l’élimination des micropolluants pharmaceutiques des effluents hospitaliers par des procédés biologiques classiques (boue activée) et membranaire. Il est montré que les systèmes à membrane, externe ou immergée, permettent un meilleur traitement, ou une meilleure rétention, de plus de 50% des molécules pharmaceutiques mesurés. Afin d’améliorer l’efficacité des procédés membranaires, des supports bactériens ont été ajoutés dans le bassin biologique permettant de diminuer considérablement le colmatage. Il est montré qu’une des conséquences de la présence de ce garnissage est une diminution globale des EPS produits, donc du colmatage membranaire, et de la rétention des molécules pharmaceutiques,. Afin d’augmenter encore l’efficacité du procédé, du charbon actif en poudre ou en grain a été ajouté avant la filtration (CAP) ou en sortie de filtration (CAG), permettant une élimination quasi complète des molécules mesurées. La qualité des biomasses épuratrices a été suivie par microscopie confocale avec marquage fluorescent des exopolymères et de la viabilité cellulaire. Il est montré que les effluents hospitaliers modifient la structure des flocs et des biofilms, leur composition biochimique, avec une augmentation des concentrations en protéines extracellulaires, et la répartition des populations caractérisées par métagénomique. / This research investigates the removal of pharmaceutics present in hospital wastewaters by conventional activated sludge and MBR systems of treatment and under various operating conditions to elucidate the removal mechanism and increasing the efficiency of removal. In this study, laboratory scales was composed to four types of reactors used: Bach reactors, conventional activated sludge, submerged membrane bioreactor and extern membrane bioreactor and all these reactors were feed in reel hospital wastewaters. Different Technical studies and many experiments were affected to develop the MBR systems: the beginning was with biofilm supports media and the attached growth of biofilms in the reactor and the finish by using the powder activated carbon. En general, the reported results show high performance for the MBR with compared to CAS system in treating the basic organic pollutants. Presence the biofilm supports media was very important for high removal of pharmaceuticals compounds from the hospital wastewaters. The presence of the pharmaceutical compounds stimulated the mechanisms of survival higher production of EPS. Fouling potential seems to be linked more closely to polysaccharides than other EPS. In this study, for the first time, was employed the confocal microscopy for qualities and quantities analyses for the EPS in the biologic reactors. Microscopic observations were confirmed the chemical analyses of EPS compounds. In final experiment 21 pharmaceuticals were eliminated from the hospital effluents during the treatment in extern membrane (UF) with modified granular activated carbon. In addition to many biomolucles analyses which study the principals impact of hospital effluents on the microorganism’s especially the bacteria in using different, recent techniques. This study demonstrates by reel conditions the role the developed MBR systems in treating the hospital effluents and its impact direct on the environment.

No description available.

The exploitation of lignocellulosic materials with the aim of producing high value-added products will potentially counteract concerns related to the depletion of fossil resources or exponential population growth. Bioethanol produced from lignocellulosic agriculture residue exhibits promising alternative to the petroleum-based fossil fuel which reduces net emission of greenhouse gases (GHG). But, due to certain technological barriers, the large scale production of lignocellulosic bioethanol has not been successfully commercialized. In this thesis, membrane filtration as an energy efficient separation process with low environmental impact was chosen with a possibility of improvement. Interconnected multi-staged microfiltration submerged membrane bioreactors (MBRs) set-up has been applied in order to separate suspended solids, obtain high concentration of yeast inside the bioreactor, and recover particle-free ethanol stream in a continuous high productivity process. The MBRs were effectively optimized comparing to different constant permeate fluxes of 21.9 LMH, 36.4 LMH, and 51 LMH. Moreover, membrane bioreactor performed effectively at low flux 21.9 LMH up to 262 h comparing to other applied fluxes. During continuous hydrolysis, membrane showed the capability of lignin recovery nearly 70% of medium SS content in all applied flux. Although the conversion rate of total sugars by concentrated cells were similar, yeast cells proved the capability of inhibitor tolerance, and to co-utilize 100% of glucose and up to 89% of xylose, resulted in bioethanol volumetric productivity of 0.78 g ethanol/l per hour 1.3 g ethanol/l per hour and 1.8 g ethanol/l per hour for 21.9 LMH, 36.4 LMH, and 51 LMH respectively. Moreover, the effect of different factors such as filtration flux, medium quality and backwashing on fouling and cake-layer formation in submerged MBRs during continuous filtration was thoroughly studied.

Les eaux usées peuvent possiblement être traitées par un système membrane intégré et combinant les procédés de bioréacteur à membrane (BAM) et d’osmose inverse (OI) pour une élimination efficace des micropolluants en vue de la réutilisation des eaux. Cependant, le rejet des concentrats d’OI dans l’environnement pourraient représenter un danger en raison de la toxicité de certains de leurs composés (micropolluants, sels, matières organiques). Une des solutions possibles peut être de recycler le concentrat d’OI vers le BAM. Néanmoins, une étude approfondie s’impose pour une telle configuration car le recyclage mettrait en jeu la recirculation de matière organique non biodégradable, ou de fortes concentrations en sels ou micropolluants, qui pourraient finalement engendrer, directement ou indirectement, un colmatage de la membrane ainsi qu’une modification de l’activité bactérienne dans le BAM. Les effets du recyclage de concentrat d’OI sur les performances de BAM ont été étudiés de deux différentes manières, en distinguant les effets à court-terme (ou court temps de contact) et les effets à long-terme (ou long temps de contact). Les résultats montrent qu’après un temps de contact de 3 heures entre le concentrat et les boues, les concentrations en protéines et polysaccharides dans le surnageant restent inchangées par rapport au début de l’opération. Une analyse HPLC-SEC a permis d’étudier les effets du concentrat d’OI sur la production de matières microbiennes solubles de types protéique. Un pic de concentration en substances protéiques ayant une masse moléculaire de 10 à 100 kDa a été observé dans le surnageant juste après l’addition du concentrat d’OI. Le pouvoir colmatant des boues n’a lui pas été modifié après l’injection du concentrat d’OI. Cette observation ouvre sur la possibilité de développer une opération d’OI comme traitement tertiaire en aval du BAM. La combinaison BAM-OI pourrait donc être une solution envisageable pour traiter le concentrat d’OI. Pour les longs temps de contact, les résultats ont montré que l’impact de l’effluent toxique (concentrat d’OI) sur les boues dépendait du rendement de l’opération d’OI et des caractéristiques du concentrat. Les mêmes tendances ont été observées quelle que soit la composition du concentrat en sels et en matière organique, puisqu’une augmentation de la concentration en protéine a été mise en évidence. L’effet du recyclage du concentrat d’OI a aussi été étudié à différents débits et avec différentes caractéristiques. Les effets sur les performances globales du BAM ainsi que sur son colmatage ont plus particulièrement été investigués. Le taux d’abattement en termes de Demande Chimique en Oxygène (DCO) est, dans tous les cas, supérieur à 93 %, quel que soit le débit de recyclage. Des résultats similaires ont été obtenus en termes de Carbone Organique Dissous. De plus, l’efficacité de la nitrification n’a pas été affectée en présence de concentrat d’OI dans le BAM. L’analyse HPLC-SEC a révélé un pic important de concentration en composés protéiques dans le surnageant, avec des masses moléculaires comprises entre 10 et 100 kDa et entre 100 et 1000 kDa. Par conséquent, une augmentation significative du pouvoir colmatant des boues a été observée et attribuée à la présence de protéines. Par ailleurs, le recyclage du concentrait d’OI n’a pas eu d’effet sur l’élimination de la carbamazépine et du diclofenac dans le BAM. Au contraire, l’élimination du ketoprofene a légèrement baissé, en passant de 94 à 72 %. Enfin, l’effet du recyclage de concentrat d’OI sur la biodégradation a été révélé comme insignifiant, ce qui indique que le recyclage du concentrat d’OI pourrait être une bonne alternative pour réduire les concentrats d’OI et limiter leur rejet dans l’environnement. / Wastewater effluents can be treated by an integrated membrane system combining membrane bioreactors (MBR) and reverse osmosis (RO) for effective removal of micropollutants in the field of high-quality water reuse. However, discharging the RO concentrate waste stream directly into the natural environment could lead to serious problems due to the toxic components contained in the concentrates (micropollutants, salts, organic matter). A possible solution could be the recirculation of RO concentrate waste to the MBR. However, such an operation should be studied in detail since the recirculation of non-biodegradable organic matter or high concentrations of salts and micropollutants could directly or indirectly contribute to MBR membrane fouling and modification of the biodegradation activity. The effects of RO concentrate recirculation on the MBR performances were investigated in two different ways of contact, i.e. short term peak contact and long-term continuous contact at various operating conditions. The results demonstrated that after 3 hours of contact time between the sludge and concentrate, the same values of both protein and polysaccharide concentrations were found in the supernatant, compared to that at the beginning of the reactor. HPLC-SEC analysis was employed to study the effects of RO concentrate on the production of protein-like SMPs. A significant peak of protein-like substances with a molecular size of 10-100 kDa was observed immediately in the supernatant after the addition of RO concentrate. Besides, no significant change was found of the sludge fouling propensity after the injection of RO concentrate into the activated sludge. This finding proposes the opportunities to develop RO process as a tertiary treatment of the membrane bioreactor (MBR), hence, the integrated MBR - RO concept with the RO concentrate recirculation to the MBR might be a solution to treat the concentrate waste stream produced by RO. During the long-term continuous contact, the results demonstrated that the impact of the toxic flow on activated sludge depends on the recovery of the RO step and the characteristics of the concentrate but the same trends were observed whatever the organic matter and salt contents of the concentrates: the concentration of proteins increased. The effects of the reverse osmosis concentrate recirculation, at different flow rates and with different characteristics, to the MBR were investigated. Their impacts on MBR global performances, especially the MBR fouling were evaluated. The removal efficiencies of chemical oxygen demand (COD) at the different flow rates of concentrate were greater than 93%. Similar results for the dissolved organic carbon removal efficiency were found in the MBR. Additionally, the presence of RO concentrate in the MBR did not inhibit the nitrification process. HPLC-SEC analysis employed to study the effects of RO concentrate on the production of protein-like SMPs demonstrated a significant peak of protein-like substances corresponding to 10-100 kDa and 100-1000 kDa molecules in the supernatant. Thus a significant increase of sludge fouling propensity was observed, which could be attributed to the increased quantity of protein-like substances. Furthermore, the recirculation of RO concentrate to the MBR did not significantly affect the removal of carbamazepine and diclofenac in the MBR. Meanwhile, the removal rate of ketoprofen was impacted slightly by the RO concentrate recycling to the MBR (from 94 to 72%). Finally, the effect of the concentrate on sludge activity was studied and no significant effect was observed on biodegradation, indicating that the return of the concentrate to the MBR could be a good alternative for the reduction of concentrate quantities before disposal to the environment.

Securing water in the right quantities at the right quality for the right price is a major issue around the world. Membranes are making an increasingly important contribution to meeting this need; however their performance is limited by fouling. This thesis reports on an investigation into the fouling of systems related to water treatment using the Direct Observation Through the Membrane (DOTM). The investigation focused on the measurement of critical flux and observation of particle behaviour under a variety of conditions and for a number of different particles. The range of meanings attributed to critical flux in the literature was analysed and several proposals made for the improved use of the concept. In particular, critical flux determination techniques were classified by whether they measure resistance changes or particle deposition; leading to the definition of Critical Resistance and Critical Deposition Fluxes. In this thesis the deposition definition is used exclusively. The effect of Reynolds number and spacer orientation on critical flux was correlated for spacer-filled channels. The heterogeneous deposition patterns observed with regions of heavy deposition next to areas of little or no deposition. This pattern was related to the local hydrodynamics of spacer cells (a few mm2 in size). The correlations developed for critical flux in spacer-filled channels were adjusted for submicron particle size and incorporated into a SpiralWound Module (SWM) leaf model and then used to simulate the fouling of SWM leaves under a range of operating conditions and operating policies. The Mass Balance technique of critical flux determination was also briefly assessed. The applicability of critical flux criteria to SWM arrays was discussed. Fouling, particle behaviour and critical flux were also investigated in air-sparged systems. The post-cleaning water flux was found to be enhanced when the membrane is fouled in the presence of bubbles. The rate of flux decline was reduced by bubbles. Critical flux increased with air flowrate, and decreased with increased liquid flowrate and concentration. Bubbles caused particles to periodically deposit on the membrane. Particles were observed to stream past the membrane under the influence of back-diffusive forces. Video clips of particulate fouling are provided.

Os produtos de cuidado pessoal (PCP) são substâncias utilizadas para fins de saúde, beleza e higiene, enquadrando-se como contaminantes de caráter emergente. Dentre os PCP estão os parabenos (alquil-p-hidroxibenzoatos), considerados desreguladores endócrinos, encontrados em águas fluviais e efluentes de estações de tratamento em concentrações na faixa de ng L-1 a ?g L-1. A presença destes compostos nessas matrizes reforça a importância de processos alternativos de tratamento de efluentes, como o processo de biorreator com membranas (MBR) e o processo oxidativo avançado (POA) baseado em persulfato (PS) ativado. Aliando um reator biológico e membranas de separação, o MBR destaca-se como alternativa para obtenção de efluentes de boa qualidade, com remoção de contaminantes por sorção, biodegradação e/ou retenção física. Em contrapartida, o POA com persulfato ativado utiliza radicais sulfato como espécie oxidante para degradação de poluentes. Este trabalho objetivou avaliar a remoção de metilparabeno (MeP) e propilparabeno (PrP) pelo processo MBR, bem como estudar a degradação de tais compostos por persulfato ativado com radiação UVA (UVA/PS) ou ferro de valência zero (Fe0/PS). Objetivou-se, outrossim, avaliar a remoção dos parabenos do permeado do MBR por esses POA. Os resultados mostraram que o processo MBR apresentou eficiência média de 95,9% na remoção de MeP e PrP ([parabenos]0 = 0,5 mg L-1) e eficiência média de 85% na remoção de PrP ([PrP]0 = 10 mg L-1). A degradação de MeP e PrP em mistura (50-500 ?g L-1, cada) por UVA/PS exibiu interferência de um parabeno sobre o outro. Assim, optou-se por investigar a degradação apenas de PrP (1 mg L-1) via UVA/PS e Fe0/PS. Para UVA/PS (120 min), quanto maior a irradiância e a concentração inicial de PS, menor o tempo de meia-vida, sendo possível atingir t1/2 mínimo de 37,9 min, com remoção máxima de 77,3%. Para Fe0/PS (15 min), obteve-se um mínimo de t1/2 igual a 0,65 min, para [PS]0 = 5,38 mmol L-1 e [Fe0]0 = 51,6 mg L-1, com porcentagens de degradação superiores a 97% para todos os ensaios realizados. Nesses casos, a identificação de intermediários de degradação do PrP para os processos UVA/PS e Fe0/PS permitiu comprovar a formação de benzoato de propila, benzoato de metila, ácido 4-hidroxibenzoico e MeP. Finalmente, no tratamento do permeado do MBR, obtiveram-se remoções de PrP de 24,5% para UVA/PS (120 min) e de 61,2% para Fe0/PS (90 min), o que se deve ao efeito da matriz complexa. / Personal care products (PCP) are substances used for health, beauty and hygiene purposes, and are classified as emerging contaminants. Parabens (alkyl-p-hydroxybenzoates), included among the PCPs, are considered endocrine disrupters and found in river waters and effluents from wastewater treatment plants, at concentrations ranging from ng L-1 to ?g L-1. The presence of these compounds in environmental matrices reinforces the importance of alternative effluent treatments, such as membrane bioreactors (MBR) and advanced oxidation processes (AOP) based on activated persulfate (PS). The MBR combines a biological reactor and membrane separation membranes, standing out as an alternative to obtain good quality effluents, with contaminants removed by sorption, biodegradation and/or physical retention. In contrast, the AOP based on activated persulfate uses sulfate radicals as oxidizing species for the degradation of pollutants. This work aimed to evaluate the removal of methylparaben (MeP) and propylparaben (PrP) by the MBR process, as well as to investigate the degradation of these compounds by using persulfate activated with UVA radiation (UVA/PS) or zero valence iron (Fe0/PS). The results showed that the MBR process achieved 95.9% MeP and PrP removals ([parabens]0 = 0.5 mg L-1), and 85% PrP removal ([PrP]0 = 10 mg L-1). However, the degradation of MeP and PrP in the mixture (50-500 ?g L-1, each) by the UVA/PS process exhibited the interference of one paraben over the other. It was therefore decided to investigate the degradation of only PrP (1 mg L-1) via UVA/PS and Fe0/PS. For the UVA/PS process (120 min), the higher the irradiance and the initial PS concentration, the shorter the PrP half-life time, with a minimum t1/2 of 37.9 min and maximum removal of 77.3%. For Fe0/PS (15 min), a minimum t1/2 equal to 0.65 min was achieved for [PS]0 = 5.38 mmol L-1 and [Fe0]0 = 51.6 mg L-1, with percent removals higher than 97% for all the experiments performed. In these cases, the identification of PrP degradation intermediates for the UVA/PS and Fe0/PS processes allowed to prove the formation of propyl benzoate, methyl benzoate, 4-hydroxybenzoic acid, and MeP. Finally, regarding the post-treatment of the MBR permeate, lower PrP removals of 24.5% for the UVA/PS process (120 min), and 61.2% for Fe0/PS (90 min) were obtained, which are due to the effect of the complex aqueous matrix.

Dans cette thèse ont été développés des modèles mathématiques pour les procédés de distillation membranaire à contact direct (DCMD) et avec balayage gazeux (SGMD) ainsi qu’un modèle sur l’hydrodynamique des bioréacteurs membranaires anaérobiques (AnMBRs) équipés d’un système de vibration membranaire induite (MMV). Les modèles pour la DCMD et la SGMD permettent de simuler le comportement des modules plats ou à fibres creuses sous différentes conditions opératoires, sans avoir recours aux données expérimentales ou à des équations empiriques pour les transferts de masse et de chaleur. Les modèles ont été validés avec des résultats expérimentaux et de la littérature et ont permis de déterminer l'influence de différents paramètres opérationnels et de la géométrie des modules sur les performances des procédés. Le modèle développé pour les AnMBRs équipés du système MMV permet d’étudier l’effet de la vibration membranaire sur l’hydrodynamique du réservoir. L’analyse paramétrique a permis d’étudier l’effet de la fréquence et de l’amplitude des vibrations sur la vitesse du fluide et la fraction volumique des solides dans le réservoir. Dans ce travail il a été démontré que les modèles proposés pourront être potentiellement appliqués à des études expérimentales préliminaires, l’optimisation des conditions opératoires, la conception des modules membranaires ainsi que pour l’estimation des coûts des procédés. / In this work have been developed general predictive models for direct contact membrane distillation (DCMD) and sweeping gas membrane distillation (SGMD) as well as a hydrodynamic model for anaerobic membrane bioreactors (AnMBRs) equipped with the induced membrane vibration (MMV) system. The DCMD and SGMD models allow simulating hollow fibre and flat sheet configurations under wide range of process conditions without empirical mass and heat transfer coefficients or laboratory experiments. The models have been validated with experimental and literature data. Indeed, the influence of operating conditions and membrane geometric characteristics on the process performance has been investigated. The model for AnMBRs with MMV studies the effect of the membrane vibration on the hydrodynamics of the AnMBR tank. The parametric study allows knowing, the effects of the vibration frequency and amplitude on the fluid velocity and volume fraction of solids. The conducted studies prove that all the proposed models would be potentially applied for the pre-experimental study, optimization of process conditions, design of membrane modules as well as for the further cost estimation of the processes.

La thèse est consacrée à l’étude de l’influence de l’aération sur le colmatage demembranes fibres creuses, en application aux bioréacteurs à membranes (BAMs)traitant les eaux usées. Un pilote expérimental permet des expériences de filtrationpar plusieurs faisceaux de fibres creuses immergées, en filtration externe-interne, lacompacité des fibres est proche de la configuration de modules membranairesindustriels. Les fibres ont une surface totale de 1,2 m. Les filtrations sont menéessur une suspension synthétique complexe dont les caractéristiques rhéologiquessont comparables à celles des boues activées de BAM. Les différents paramètresde l’aération testés sont le débit d’air, le lieu d’injection des bulles, et le type debulles injectées (grosses ou fines), pour un flux de filtration constant égalementparamètre d’étude. Pour des conditions d’aération montrant des performances defiltration contrastées, il est effectué la caractérisation locale de la phase gaz parbisonde optique, à l’intérieur des faisceaux de fibres. La rétention gazeuse et lesprofils de vitesse (tant la vitesse moyenne des bulles, que les fluctuations de vitesse)sont mesurés et analysés en fonction des paramètres d’aération. La synthèse des résultats met en évidence deux mécanismes hydrodynamiqueslocaux liés à l’aération, et permettant d’expliquer les performances de filtrationconsidérées. Les perspectives de l’étude proposent des emplacements pour lesaérateurs ce qui pourrait mener à une meilleure utilisation de l’air pour la réductiondu colmatage dans les bioréacteurs à membranes. / This thesis is dedicated to better understand the role of aeration to limit fouling onsubmerged hollow fibers membrane fouling, for wastewater treatment industry. Thisstudy uses an innovative experimental setup to perform outside-in filtrationexperiments thanks to several submerged loose hollow fibers organized in confinedbundles. The total membrane area is about 1.2 m2; the configuration of the bundlesis close to the one found in Membrane Bioreactors (MBRs). A complex synthetic fluidwith rheological characteristics close to MBRs sludge is used. Different aerationconditions such as the air flowrate, the location of the air injection, the type ofbubbles injected (whether they are coarse or fine bubbles injected in the reactor)were tested and membrane performances were analysed under a low or a ratherhigh flux of filtration. In specific aeration conditions showing a different behaviour interm of fouling, local characterization of the dispersed phase in an air and watersystem was undertaken by optical probes. Gas hold up and both mean and rootmean square bubble velocity profiles were determined and analysed regarding thelocation of air injection, the air flowrate and the type of bubbles. This study helps understanding the link between local hydrodynamics and foulingmechanisms and could lead to input for aeration device design and location in orderto decrease operating costs due to aeration in Membrane Bioreactors technology.

Orientadora: Prof.ª Dra Luisa Helena dos Santos Oliveira / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, 2016. / Biorreatores com Membranas Submersas (BRMS) são, atualmente, reconhecidos como opção viável para o tratamento de esgotos sanitários e o reúso de águas. Apesar disso, a tecnologia é geralmente vista como de alto investimento quando comparado a sistemas convencionais de tratamento de esgoto, sobretudo pelo maior gasto energético com aeração do sistema. Porém, BRMS quando operados sob condições específicas para nitrificação e desnitrificação simultâneas (NDS), é possível obter um efluente de elevada qualidade com menor custo, devido a menor necessidade de aeração. Nesse sentido, a operação do sistema de BRMS com o processo de NDS pode aumentar a utilização desta tecnologia no tratamento de esgoto sanitário. Neste contexto, este trabalho teve por objetivo principal avaliar a remoção de nitrogênio via NDS em diferentes concentrações de oxigênio dissolvido (OD) em uma unidade piloto de um Biorreator de Membranas Submersas tratando esgoto sanitário. Para isso, o experimento foi dividido em três Fases de acordo com a concentração de oxigênio dissolvido no licor misto: Fase I (2,3 mgO2/L), Fase II (0,8 mgO2/L e Fase III (0,3 mgO2/L). Foram alcançadas elevadas eficiências de remoção de material orgânico, independente das variações na concentração de OD, DBO5 com valores médios de 98%, 97% e 98% e DQO de 95%, 96% e 95% para as Fases I, II e III, respectivamente. A remoção média de nitrogênio total obtida foi 33% na Fase I, 60% na Fase II e 50% na Fase III. Onde a remoção via NDS foi responsável por 60%, 78% e 74% do total removido para as Fases I, II e III, respectivamente. A remoção de nitrogênio amoniacal não foi limitada devido as baixas concentrações de OD e houve acúmulo de NO2-. O sistema operou sob baixos valores de pressão transmembrana durante todo o período, porém foi encontrada diferença significativa nos valores da Fase III em relação às Fases I e II. Houve uma redução significativa na permeabilidade da membrana quando a concentração de OD no licor misto foi reduzida para 0,3 mg/L, porém sem efeito significativo quando a concentração de OD foi de 0,8 mg/L. Foram observados maiores valores de SPE ligado na Fase III em relação às demais, principalmente na fração de carboidratos que pode estar diretamente ligada a taxa de fouling. Foi possível alcançar remoção de NT em OD de 0,8 mg/L (Fase II) sem causar um impacto negativo no desempenho das membranas, sendo esta fase a mais adequada para a ocorrência do processo de NDS em BRMS. / Submerged Membrane Bioreactors (SMBR) are actually, recognized as viable option for wastewater treatment and reuse. Nevertheless, this technology is generally viewed as a high investment compared to conventional sewage treatment systems, especially for greater energy requirement for aeration system. However, SMBR when operated under specific conditions for simultaneous nitrification and denitrification (SND) it is possible to obtain a high quality effluent with lower compared to the conventional configuration because of less need for aeration. Therefore, the operation of the system SMBR with the NDS process can increase the utilization of this technology in the wastewater treatment. In this context, this study aimed to evaluate the removal of nitrogen via SND under different dissolved oxygen concentrations (DO) in a pilot of a SMBR treating wastewater. For this, the experiment was divided into three phases according to the concentration of dissolved oxygen in the mixed liquor: Phase I (2,3 mgO2/L), Phase II (0,8 mgO2/L and Phase III (0,3 mgO2/L). Were achieved high organic matter removal efficiencies regardless of fluctuations in DO concentration in terms of BOD5 average values of 98%, 97% and 98% and COD average values of 95%, 96% and 95% for Phases I, II and III respectively. The average total nitrogen removal was 33% in Phase I, 60% in Phase II and Phase III 50%. Where the removal means SND is responsible for 60%, 78% and 74% of the total removed for Phases I, II and III respectively. The removal of ammoniacal nitrogen is not limited by the low DO concentrations and there was accumulation of NO2- in Phase III. The system operated under low transmembrane pressure values throughout the period, but significant difference was found in the values of Phase III in relation to phases I and II. There was a significant reduction in membrane permeability when the DO concentration in the mixed liquor was reduced to 0.3 mg/L, but without significant effect when the DO concentration was 0.8 mg/L. It was observed highest bound EPS values in Phase III in relation to the others, mainly in the fraction of carbohydrates that can be directly linked to fouling rate. Satisfactory NT removal was achieved when concentration DO was 0.8 mg/L (Phase II) without causing a negative impact on the performance of membranes, being this phase the most suitable for the occurrence of the SND process in SMBR.