Les procédés d'osmose inverse (OI) permettent la production d'eau recyclée de très haute qualité grâce à l'élimination de contaminants organiques et inorganiques et de micro-organismes. Le suivi du bon fonctionnement de ce procédé est nécessaire pour valider la rétention des virus pathogènes afin de protéger la santé des usagers. La présence de minéraux et matières organiques dans les effluents rend inévitable le colmatage des membranes lors de leur fonctionnement et diminue ainsi leur performance. Afin d'éviter et d'éliminer ces colmatages, les stations de traitements des eaux utilisent des produits chimiques. Ces derniers vont modifier les performances globales des membranes en polyamide comme par exemple la diminution de la perméabilité à l'eau, et plus particulièrement les performances de rétention des virus, or l'ensemble de ces perturbations n'est que très peu compris et donc peu maitrisé. L'abattement des virus par l'OI sur des membranes intègres ou modifiées (ex : colmatage) ont donc été déterminés en mesurant la rétention d'un virus modèle de type phage MS2 et de substituts comme les sels (mesurés par conductivité), la rhodamine-WT (R-WT) ou les sulfates. La conductivité est, en effet, la technique de contrôle standard dans les stations de traitement des eaux (échelle industrielle).Le premier objectif de ce travail est d'évaluer l'utilisation d'un autre paramètre, les matières organiques dissoutes (DOM) comme nouveau substitut de virus et de déterminer l'impact du dysfonctionnement des procédés d'OI sur l'abattement des DOM et des sels à l'échelle industrielle. Les DOM peuvent en effet également être utilisées comme indicateur de qualité des eaux en fonction de leurs compositions et de leurs concentrations. L'abattement des DOM est donc testé comme nouvelle technique de surveillance afin de distinguer les fuites des changements de performance des membranes. Il est conclu que les DOM peuvent être utilisées comme nouvelle technique de contrôle. De plus, une variation de l'abattement des DOM peut aider à identifier des fuites de manière plus robuste que par l'abattement des sels. Le deuxième objectif est de déterminer l'effet des défauts membranaires sur les abattements d'un virus modèle (phage MS2) et de quatre substituts (R-WT, DOM, sulfate et sels) à l'échelle de systèmes de laboratoire. Deux systèmes à flux longitudinal est utilisés : une membrane plane et un module à spirale. Dans un premier temps, l'effet du colmatage sur les abattements de ces différents virus et substituts est étudié. Le colmatage organique, créé en utilisant un mélange de matières organiques, a pour effet d'augmenter de plus de 0,1 log les abattements de la R-WT, des sels et des DOM. Cette augmentation générale peut être due au blocage des cavités de la membrane et/ou par la sorption des substituts sur les matières organiques.Le colmatage inorganique, créé en utilisant un mélange de sels, n'a pas d'effet sur le rejet des substituts sauf pour les sels qui montre un comportement différent entre les deux systèmes. Dans le système à membrane plane, la couche inorganique permet d'augmenter le passage des sels à travers la membrane. Par opposition, il n'y a pas d'effet sur leur abattement avec le module à spirale. Cette variation entre les deux systèmes peut être causée par la différence de configuration (module à spirale contre membrane plane). Dans un deuxième temps, l'effet du chlore (modes passif et actif) sur la rétention de ces cinq composés est mesuré. Après un contact de 9000 ppm.h de NaOCl à pH 7, la surface membranaire change chimiquement. La formation de liaison Cl dans la couche en polyamide et la rupture des liaisons NH provoquent l'augmentation de la perméabilité à l'eau et diminuent l'abattement de l'ensemble des substituts. Malgré une forte diminution de 1,2 log de l'abattement en sel, l'abattement minimum du phage MS2 reste de 3 log. / One of the major applications of reverse osmosis (RO) process is the production of high quality recycled water by providing a barrier to remove organic and inorganic contaminants as well as pathogens including viruses. In order to protect public health, validation and monitoring of the RO process integrity are necessary to ensure its correct operation. During operation a certain degree of fouling is inevitable and can reduce RO membrane performance. Thus, chemicals are often used in water treatment plants to prevent or remove the membrane fouling. However, these chemicals can modify the integrity of the polyamide layer on RO membrane overtime. Up-to-date, the impact of membrane's physical change on its virus removal efficiency cause by the chemical use during operation is still not well understood.A minimum virus removal efficiency of intact and impaired (e.g. by fouling) RO membranes can be ascertained by measuring the rejection of MS2 phage and virus surrogates such as salt as measured by conductivity, rhodamine-WT (R-WT) or sulphate. However, conductivity measurement is the only full-scale standard monitoring technique. The removal of dissolved organic matter (DOM), which has been used as an indicator of water quality, can possibly be used for this purpose.The first objective of this work was to assess the suitability of DOM as a virus surrogate and to determine the impact of process failure on salt and DOM rejection in full-scale plants. A change of the conductivity does not necessarily mean that the membrane integrity has been breached. Thus, DOM monitoring has been tested and combined with the conductivity monitoring in order to distinguish between leaks and changes in membrane performances. It was concluded that DOM could be used as new monitoring technique. Moreover, a variation of DOM rejection can help identifying leaks better than just conductivity profiling alone.The second objective was to determine the effect of membrane impairments on the rejection of one model virus (MS2 phage) and four virus surrogates (R-WT, DOM, sulphate and salt) using lab-scale RO set-ups. To this aim, two different cross-flow set-ups were used: a flat-sheet and a single 2.5” spiral-wound module.Firstly, the effects of organic fouling and scaling on the rejection of model virus and virus surrogates were studied separately. Organic fouling was created using a mix of organic foulants. The result of this study showed an increase of the rejection by more than 0.1 log for R-WT, salt and DOM. The general increase of the surrogates' rejection might be due to the blocking of cavities of the polyamide membrane and/or to the sorption of surrogates to the fouling layer, which was observed by different autopsy techniques.Scaling was created using a mix of inorganic salts in order to reconstitute the composition of a RO feed water and avoiding the presence of organic foulants. Scaling was found to have no impact on the rejection of all tested virus surrogates except for salt. Salt rejection showed a change of behaviour between different set-ups: with the 2.5” module set-up the inorganic layer led to a stabilisation of the salt rejection, whereas the salt rejection increased with the flat-sheet set-up. This could be explained by the variations of the systems configuration (i.e. spiral module versus flat-sheet, feed spacer height, etc.).Secondly, the long-term impact of membrane ageing by exposure to chlorine, either active under filtration or passive by soaking, on the rejection of the model virus and four surrogates was studied. After a contact time of 9000 ppm∙h NaOCl at pH 7, the membrane surface chemistry changed. The introduction of chlorine in the membrane chemistry and the breakage of amide bonds caused an increase of the water permeability and a decrease of the model virus and virus surrogates rejection.

Les déchets liés à l'élevage intensif ont un impact environnemental reconnu du fait de leur composition riche en en matière organique et minérale. Il apparait opportun de promouvoir des procédés de traitement permettant de maitriser l'impact environnemental de ce retour au sol, voire d'ouvrir de nouvelles valorisations au travers de la récupération d'énergie ou de l'exportation de co-produits (azotés et phosphatés notamment). Ce travail entre dans cette démarche en proposant de compléter les étapes de digestion anaérobie de ces déchets par des étapes de séparation sur membranes perm-sélectives. Les essais ont été réalisés sur unités pilotes de laboratoire en utilisant des digestats réels de diverses origines prélevés sur sites. Pour l'étape de clarification par ultrafiltration, la conduite d'une séparation en mode tangentiel est obligatoire au regard de la concentration des suspensions à traiter. La viscosité des suspensions, d'autant plus importante que la suspension est concentrée, apparait comme un paramètre déterminant pour le choix du protocole opératoire. Dans tous les cas, l'opération d'ultra-filtration (UF) permet une rétention conséquente (de 80 à 90%) de la fraction organique encore présente dans les digestats, à l'inverse, la rétention de la fraction minérale soluble est restée négligeable comme attendu. Le seuil de coupure de la membrane d'UF n'est pas apparu déterminant sur cette rétention. Malgré le mode tangentiel de séparation, l'opération de filtration induit une accumulation de composés au voisinage de la membrane qui diminue significativement la perméabilité du milieu filtrant. Cette chute de perméabilité apparaît d'autant plus importante que la suspension présente une concentration en demande chimique en oxygène (DCO) élevée. Ce critère apparaît alors comme le facteur limitant pour atteindre un facteur de concentration volumique (FCV) élevé (réduction des volumes). La surface membranaire à développer est directement liée à la perméabilité membranaire, elle-même dépendante de la concentration de la suspension à traiter donc de la nature du digestat et du FCV à atteindre. Le coût opérationnel de l'opération apparaît directement lié à l'énergie nécessaire pour assurer le mode tangentiel de filtration. Pour l'étape de concentration des sels d'intérêts, la rétention des composés minéraux solubles par osmose inverse haute pression dépasse 90% quels que soient les ions ciblés ou l'origine du digestat. A l'inverse, cette rétention est dépendante de l'ion ciblé et de l'origine du digestat pour les opérations de nano-filtration et d'osmose inverse basse pression. Dans tous les cas, la rétention de la fraction organique résiduelle est importante (>90%) permettant une décoloration du perméat très poussée (elle dépend toutefois du seuil de coupure de la membrane et du FCV choisi). La perméabilité membranaire diminue d'autant plus que la conductivité électrique (CE) de la solution à traiter est importante du fait de la pression osmotique et de l'accumulation de composés solubles au voisinage de la barrière membranaire. Cette conductivité, dépendante du digestat initial et du FCV choisi, apparaît alors comme le paramètre déterminant pour le dimensionnement de l'unité. Sur le plan énergétique, l'énergie liée à la mise sous pression des unités NF/OI est dominante par rapport à la circulation tangentielle du rétentat. Ce travail a permis de confirmer l'intérêt des séparations membranaires pour le traitement des digestats, afin d'une part, d'obtenir une eau de qualité permettant sa réutilisation ou son rejet dans le milieu naturel et d'autre part de récupérer et de concentrer des composés d'intérêt dans les différents rétentats. Ce travail a fait l'objet d'un soutien financier de l'ANR dans le cadre du programme BIOENERGIE 2010 (projet DIVA). / Intense spreading of livestock wastes are recognized to be detrimental to the environment due to their content of organic matter and mineral fraction. Then, it would appear to be necessary to promote greens treatments processes. In fact, anaerobic digestion allows the production of biogas (extremely useful source of renewable energy), whilst digestate should be a highly valuable biofertilizer This work enters in this approach by proposing to complete anaerobic digestion steps by the use of perm-selective membrane separation process. The first step is a clarification step by ultrafiltration, following by a soluble mineral concentration step by nanofiltration, low pressure and/or high pressure reverse osmosis (LPRO, HPRO). The tests were performed in a laboratory-scale pilot unit using real digestates. For clarification step, a cross-flow mode separation is obligate in view of suspended solid concentrations and viscosity which appeared as a determining factor for the choice of operative protocol. In any case, the ultra-filtration operation allows a high organic retention rate (of 80 to 90%). Conversely, soluble mineral retention remained at negligible as expected. The cut-off of ultrafiltration membrane is not a determining factor for this retention. Despite the cross-flow mode separation filtration induces a compound accumulation on the membrane which decreases significantly the permeability of filtering media. This permeability drop appears greater when suspension presents a high COD concentration. This criterion appears as a limiting factor to achieve a high volumic concentration factor (VCF). Membrane surface to develop is then directly related to the membrane permeability which depends on the digestate origin and VCF. The operational cost is linked directly to the energy required to ensure cross-flow mode. The retention of soluble mineral compounds by HPRO exceeds 90% whatever the target ions or the origine of digestate are. However, for NF and LPRO steps, this rejection depends on the target ions or the origine of digestate. In any case, organic retention is important (more than 90%) which allows significant discoloration of permeate. The, the more the electronic conductivity (EC) is, the more permeability decreases of suspension is important, due to an osmotic pressure and soluble compound accumulation on the membrane that increases with EC. This conductivity depends on initial digestate and, of course, of the chosen VCF target, which appears as decisive parameter for unit dimensioning. On the efficient energy, energy linked to separation step chosen is dominant in the absence of cross-flow mode of retentate. This work has allowed to confirm the potential interest of membrane separation to (i) obtain a final effluent: named fresh or new water and (ii) and (ii) to allow the production of liquid fertilizers.This work is financially supported by the National French Agency (Bio-Energy Program 2010, DIVA Project) and by TRIMATEC competitiveness cluster.

Este trabalho apresenta uma configuração alternativa para a dessalinização de água e geração de energia elétrica com recurso à energia eólica. Trata-se de um modelo físico que permite armazenar água do mar ou água salobra sob a forma de energia potencial gravitacional, através do seu bombeamento até um reservatório a uma determinada altura. O bombeamento é feito com o recurso à energia do vento. Uma vez, tendo a água sida acumulada no reservatório, sua energia potencial gravitacional EPG é usada para a sua dessalinização ou/e para a geração de eletricidade. O referido modelo é semelhante a um grupo de bombas de pistões. Os pistões possuem formato especial de modo que se consiga obter pressões elevadas suficientes quer para a dessalinização de água por osmose reversa, quer para a geração de eletricidade através de turbinas Pelton. Consegue-se o movimento alternado dos pistões a partir da transferência da energia da água acumulada (EPG) através dum sistema de roldanas e contrapesos. Assim sendo, provar que o modelo é capaz de transformar a EPG de baixa pressão (inferior a 2 bar) em energia cinética de um fluxo com alta pressão (superior a 55 bar) se apresenta como o foco principal deste trabalho. Com esse foco em mira, construiu-se um protótipo com o objetivo de demonstrar a viabilidade técnica da proposta. Imagens do protótipo são apresentadas neste trabalho. Em relação à osmose reversa, a referida configuração difere do que é convencional em plantas de dessalinização que usam esse processo, pelo fato de contemplar o uso de EPG. Com o modelo proposto, consegue-se um fluxo à entrada dos módulos de membrana (ou à saída do injetor da turbina Pelton) com pressão suficiente para a osmose reversa (ou para geração de eletricidade). Em relação à captação da energia eólica para o bombeamento de água, o modelo é divido em dois sistemas.O primeiro (sistema 1) usa cataventos tradicionais e o segundo (sistema 2) aerogeradores. É feita a comparação qualitativa entre os dois sistemas com base em alguns parâmetros tais como área ocupada, versatilidade etc. / This work presents an alternative configuration for sea, and brackish water desalination by reverse osmosis and electricity generation, resorting to wind energy. It is a physical model that allows the storage of sea or brackish water as gravitational potential energy, through its pumping to a reservoir located at a certain height. The water pumping is done resorting to wind energy. Once the water is stored in the reservoir, its gravitational potential energy GPE is used for its desalination or/and for electricity generation. The referred model is similar to a group of piston pumps. The pistons have a special shape so that it is possible to achieve the high pressures that are enough, either for water desalination by reverse osmosis or for electricity generation with Pelton turbines. The alternated movement of the pistons is achieved with the energy transfer from the stored water (GPE), through a system of pulleys and counterweights. Thus, to prove that the model is capable of transforming the GPE at low pressure (below 2 bar) into kinetic energy of a flux with high pressure (over 55 bar) is the main focus of this work. Targeting that focus, a prototype was constructed with the objective of demonstrating the technical viability of the proposal. Images of the prototype will be shown in this work. In respect of reverse osmosis, the referred configuration differs from the conventional in desalination plants that use the method, in that it incorporates the use of GPE. With the proposed model, one achieves a flux at the inlet of the membranes (or at the exit of the injector of the Pelton turbine) with enough pressure for reverse osmosis (or for electricity generation). In respect of the harvesting of wind energy for water pumping, the model is divided into two systems. The first system (system 1), uses the traditional windmills and the second one (system 2), uses wind generators.In respect of the harvesting of wind energy for water pumping, the model is divided into two systems. The first system (system 1), uses the traditional windmills and the second one (system 2), uses wind generators. It is carried out a comparison between the two systems based on some parameters such as occupied area, versatility and so on.

Grande parte da população rural do Semiárido brasileiro sofre com problemas de acesso à água de qualidade. A exploração da água subterrânea representa uma das principais alternativas para o abastecimento dessa parcela da população, mas muitas vezes os poços perfurados encontram-se longe da rede elétrica. A região apresenta abundante recurso solar e, assim, essa dificuldade poderia ser contornada com a utilização de sistemas fotovoltaicos de bombeamento. Mas, além da questão da energia para o funcionamento dos sistemas de bombeamento, pelo fato da maior parte do Semiárido estar localizada sobre escudo cristalino, muitos poços apresentam água com altos níveis de salinidade, o que inviabiliza a utilização desses mananciais para o fornecimento de água potável ou faz com que a população rejeite seu consumo, por conta do gosto. O presente trabalho tem como objetivo verificar se a adaptação de sistemas de dessalinização de pequeno porte disponíveis comercialmente a sistemas fotovoltaicos domiciliares pode potencializar a difusão dos sistemas fotovoltaicos de bombeamento em poços de água com alto teor de sais dissolvidos e se essa opção pode representar uma alternativa de fornecimento de água para a população rural de áreas com problemas de salinização dos mananciais de abastecimento. A opção analisada consiste em um sistema duplo de fornecimento de água, com tratamento do tipo ponto de uso da água para consumo humano. Foi verificado que os sistemas de dessalinização atualmente disponíveis no mercado podem funcionar acoplados a geradores fotovoltaicos e utilizados para fornecimento de água potável a partir de água salobra. / Much of the rural population of the Brazilian Semiarid region suffers from problems related to access of improved water quality. The exploitation of ground water is the main alternative for water supply solutions regarding this population, but often the boreholes are away from power lines. The region has abundant solar source and therefore this problem could be overcome with the use of photovoltaic pumping systems. Beyond the issue of energy for operation of the borehole systems, considering that most of the semiarid region is located on crystalline shield, many boreholes have water with high level of salinity, which hinder their use for drinking water supply solutions, as the population rejects the water because of its taste. This study aims to determine whether the adaptation of commercially available small household desalinization systems adapted to photovoltaic systems can enhance the diffusion of photovoltaic pumping systems of boreholes with high concentrations of dissolved salt, by proposing this water supply solution as an alternative for water supply systems in rural areas with problems of salinization of the main water sources. The proposed technical solution consists of a dual water supply system with the use a point of use water treatment for human consumption. It was found that desalination systems available on the market can operate coupled to photovoltaic generators and used to supply drinking water from brackish water.

Sistemas de membranas filtrantes, principalmente os de osmose reversa, estão sendo cada vez mais utilizados em diversos seguimentos de empresas (farmacêutica, tratamento de água, alimentícia e química), devido à diminuição do preço dos elementos filtrantes e da alta qualidade do produto obtido. O biofouling corresponde a um tipo de fouling inevitável, caracterizado pelo crescimento de microrganismos na superfície das membranas e liberação de EPS pelos mesmos; por isso, um melhor conhecimento sobre estas estruturas é necessário. O presente trabalho teve como objetivo caracterizar o biofouling em diferentes membranas de osmose reversa colmatadas de diferentes indústrias pela técnica da autópsia e comparar com resultados obtidos com biofilmes de cultura pura formados em membranas de osmose reversa; além de verificar a influência de biofilmes na deposição de sais e ação de compostos químicos utilizados na limpeza química de membranas nos mesmos. A autópsia dos elementos colmatados mostrou uma grande quantidade de células viáveis porém, com concentrações de carboidratos muito baixas; diferentemente do que ocorreu quando biofilmes de cultura pura isolados destas membranas foram analisados, apresentando correlações fortes entre quantidade de células viáveis e macromoléculas como proteínas e, principalmente, carboidratos. Com relação à influência dos biofilmes na deposição de sais, dois dos quatro biofilmes de cultura pura apresentaram incorporação de bário em sua estrutura (revelado por análises de fluorescência de raios X), esta incorporação, provavelmente, ocorreu por troca iônica e não pela deposição de sulfato de bário. Compostos como hidróxido de sódio (pH = 12) e ácido clorídrico (pH = 2) apresentaram bons resultados na diminuição de células viáveis porém, a recuperação dos microrganismos foi menor com a utilização do ácido. Os compostos EDTA e SDS não foram eficazes na diminuição de viáveis. / Systems of filter membranes, especially reverse osmosis, are being increasingly used in various segments of companies (pharmaceutical, water treatment, food and chemical industries) due to the decrease in the price of the filter elements and high quality of the product. The biofouling corresponds to a type of inevitable fouling characterized by growth of microorganisms on the surface of the membrane and release of EPS by them; so a better understanding of these structures is necessary. This study aimed to characterize the biofouling in different reverse osmosis membranes addressed from different industries by the technique of autopsy and compared with results obtained with pure culture biofilms in reverse osmosis membranes; and to verify the influence of biofilms in the deposition of salts and action of chemical compounds used in chemical cleaning of membranes in them. The autopsy of clogged elements showed a lot of viable cells but with very low carbohydrate concentrations; unlike what occurred when biofilms isolated pure culture of these membranes were analyzed, showing strong correlation between number of viable cells and macromolecules such as proteins and especially carbohydrates. Regarding the influence of biofilms in the deposition of salts, two of the four pure culture biofilms showed barium incorporation in its structure (revealed by fluorescence analysis X-ray), this merger probably occurred by ion exchange and not by deposition barium sulfate. Compounds such as sodium hydroxide (pH = 12) and hydrochloric acid (pH = 2) showed good results in the decrease of viable cells however, the recovery of microorganisms was lower with use of the acid. EDTA and SDS compounds were not effective in reducing viable.

O presente trabalho avaliou o desempenho de um sistema de pré-tratamento para água do mar constituído por um filtro lento de areia, com uma etapa prévia de filtração por um filtro de discos. O sistema demonstrou eficiência na remoção de fatores causadores de fouling em membranas de osmose reversa, removendo aproximadamente 97% dos sólidos suspensos totais presentes na água bruta, e gerando um filtrado com turbidez entre 0.1 e 0.2 UNT. As concentrações de microrganismos e AOC, principais fatores causadores da formação de biofouling, foram ambas reduzidas em cerca de 90%. Em sistemas de dessalinização de água do mar por osmose reversa, o pré-tratamento da água de alimentação constitui a principal estratégia no controle da formação do biofouling, que é gerado pelo estabelecimento de biofilmes sobre a superfície da membrana. A formação de biofouling gera impacto no desempenho do processo de osmose reversa e nos custos de operação. / This study evaluated the performance of a pretreatment system for seawater comprising of a slow sand filter, with a preliminary stage of filtration by disc filtration system. The system proved to be efficient in removing factors causing fouling in reverse osmosis membranes removing around 97% of the total suspended solids present in the raw water, and yielding a filtrate with turbidity between 0.1 and 0.2 NTU. The bacterial concentrations and AOC, main factors causing biofouling formation, were both reduced by about 90%. In seawater reverse osmosis systems, pretreatment of the feeded water is the main strategy to control biofouling, which is formed by the establishment of biofilms on a membrane surface. The biofouling formation produces an impact in the performance of the reverse osmosis process and operating costs.

O consumo de cervejas não alcoólicas tem aumentado nos últimos anos devido, principalmente, às novas e restritivas leis de trânsito, às preocupações com a saúde ou por razões religiosas. Entre as estratégias de produção das cervejas não alcoólicas ou com baixo teor de álcool estão os processos de separação por membranas, alternativas de grande interesse na remoção do etanol de cervejas tradicionais, pois não promovem impacto térmico no produto. A osmose direta é uma técnica de membranas que tem passado por avanços significativos na última década, apresentando potencial de aplicação na remoção de etanol de soluções aquosas e, consequentemente, na obtenção de cervejas não alcoólicas. No entanto, até o momento, nenhum estudo relacionado à sua utilização na remoção de compostos orgânicos voláteis, como o etanol de soluções aquosas ou bebidas, é encontrado na literatura. Neste contexto, o objetivo deste trabalho é avaliar a viabilidade da utilização da técnica de osmose direta para a esse fim. Em um primeiro momento, membranas comerciais de osmose direta foram caracterizadas de acordo com suas propriedades morfológicas, químicas e de desempenho hidráulico para que pudessem ser comparadas no restante do trabalho, que foi dividido em diversos estudos. Estes estudos avaliaram os efeitos de variáveis de operação sobre o desempenho do processo de remoção de etanol de soluções aquosas: a velocidade de escoamento, a temperatura, a concentração e o tipo do agente osmótico, o pH da solução osmótica e o tipo de membrana. Finalmente, um estudo efetivo sobre a desalcoolização completa de cerveja comercial foi realizado para suportar a aplicabilidade da técnica de OD. Os resultados mostraram que os parâmetros estudados possuem influência sobre as variáveis de resposta do processo, como fluxo permeado total, fluxo inverso de soluto e fluxo de etanol e que estes podem ser otimizados para aumentar o desempenho na desalcoolização. As características da cerveja sem álcool obtida no último estudo foram diferentes daquelas da cerveja tradicional com álcool e alguns motivos como elevado tempo de operação, baixa seletividade da membrana para compostos de aroma e alto fluxo inverso do agente osmótico foram responsáveis pelas alterações. O trabalho demonstrou que é possível utilizar a osmose direta para a remoção de etanol de soluções aquosas e, consequentemente, para a desalcoolização de cervejas. / The consumption of non-alcoholic beer has increased in the last years mainly due to the stricter traffic laws, to personal health concerns or even due to religious reasons. Among the strategies for production of non-alcoholic or low alcohol beers are the membrane separation processes. Membrane-based processes are alternatives of great interest for removing the ethanol from beer because low operating temperatures can be used, avoiding the thermal impact caused on the product by traditional thermal technologies. Forward osmosis (FO) is a membrane technology that has been significantly improved in the last decade, presenting a potential of application to ethanol removal from aqueous solutions and, consequently, for producing non-alcoholic beers. However, until now, no study related to the removal of ethanol from aqueous solutions or beverages using FO is found in the literature. In this context, the main objective of this doctorate thesis is to evaluate the possibility of using the forward osmosis technology for ethanol removal from beer and other aqueous solutions. Initially, commercial forward osmosis membranes were characterized according to morphological and chemical properties and to their hydraulic performance in order to be compared in the following work, which was divided in several studies. These studies evaluated the effects of operating parameters, such as the crossflow velocity, the osmotic solution temperature, concentration and pH, the osmotic agent characteristics, and the membrane characteristics on the performance of ethanol removal from aqueous solutions process. Finally, an effective study about beer dealcoholization was performed to support the applicability of the forward osmosis. Results showed that the studied parameters have influence on response variables such as total permeate flux, reverse solute flux and ethanol flux, and that these parameters can be optimized to enhance the dealcoholization performance. The characteristics of the dealcoholized beer obtained in the last study were different from that of traditional beer in the beginning of dealcoholization process and some reasons such as the prolonged experiment time, the low selectivity of the membrane to flavor compounds and high reverse osmotic agent flux were responsible for these significant changes. This thesis demonstrated that it is possible to take advantage of the forward osmosis technology to remove ethanol from aqueous solutions and consequently dealcoholize beer.

Une étude a été menée sur la faisabilité technique du traitement de potabilisation des eaux de forage contaminées à l’arsenic par procédé membranaire. Pour ce faire, l’efficacité de deux membranes commerciales (NF270 et TW30) vis-à-vis de la rétention des espèces d’arsenic, arsénite [As (III)] et arséniate [As (V)], a été d’abord comparée sous différentes conditions expérimentales. Ensuite, la contribution des différents mécanismes intervenant dans l’élimination des espèces d’arsenic a été identifiée. Enfin, la membrane la plus performante a été utilisée pour le traitement d’une eau souterraine naturellement riche en arsenic. Il ressort de cette étude que la pression opératoire et le pH sont les paramètres importants sur lesquels il faut agir pour améliorer l’efficacité du système membranaire pour le traitement de l’arsenic. L’As(V) est facilement éliminé par rapport à l’As (III) aussi bien avec la membrane de nanofiltration que d’osmose inverse. Toutefois, la membrane d’osmose inverse (TW30) permet une meilleure élimination des différentes espèces d’arsenic que la membrane NF270. Cela est dû au fait que la membrane TW30 est une membrane dense. L’application de cette membrane pour la production d’eau potable à partir d’une eau de forage contenant 413,74µg/L d’arsenic total dont 405,63µg/L d’As (V) et 8,11 µg/L d’As (III) a donné une concentration d’arsenic total dans l’eau traitée de 9,99 µg/L soit un taux de rétention de 97,6% et un volume d’eau traité correspondant à 70% du volume d’eau brute. Il est donc possible de mettre en place un procédé de traitement de ces eaux de forage à partir de la membrane TW30 afin de produire de l’eau potable pour les populations du nord du Burkina Faso. La performance de ce procédé peut être encore améliorée en oxydant l’As (III) en As (V) avant filtration. / In order to produce potable water for human consumption, a study was carried out on the technical feasibility of arsenic-rich borehole water treatment by membrane process. Firstly the efficiency of two commercial membranes (NF2Une étude a été menée sur la faisabilité technique du traitement de potabilisation des eaux de forage contaminées à l’arsenic par procédé membranaire. Pour ce faire, l’efficacité de deux membranes commerciales (NF270 et TW30) vis-à-vis de la rétention des espèces d’arsenic, arsénite [As (III)] et arséniate [As (V)], a été d’abord comparée sous différentes conditions expérimentales. Ensuite, la contribution des différents mécanismes intervenant dans l’élimination des espèces d’arsenic a été identifiée. Enfin, la membrane la plus performante a été utilisée pour le traitement d’une eau souterraine naturellement riche en arsenic. Il ressort de cette étude que la pression opératoire et le pH sont les paramètres importants sur lesquels il faut agir pour améliorer l’efficacité du système membranaire pour le traitement de l’arsenic. L’As(V) est facilement éliminé par rapport à l’As (III) aussi bien avec la membrane de nanofiltration que d’osmose inverse. Toutefois, la membrane d’osmose inverse (TW30) permet une meilleure élimination des différentes espèces d’arsenic que la membrane NF270. Cela est dû au fait que la membrane TW30 est une membrane dense. L’application de cette membrane pour la production d’eau potable à partir d’une eau de forage contenant 413,74µg/L d’arsenic total dont 405,63µg/L d’As (V) et 8,11 µg/L d’As (III) a donné une concentration d’arsenic total dans l’eau traitée de 9,99 µg/L soit un taux de rétention de 97,6% et un volume d’eau traité correspondant à 70% du volume d’eau brute. Il est donc possible de mettre en place un procédé de traitement de ces eaux de forage à partir de la membrane TW30 afin de produire de l’eau potable pour les populations du nord du Burkina Faso. La performance de ce procédé peut être encore améliorée en oxydant l’As (III) en As (V) avant filtration.70 and TW30) for different arsenic species removal, arsenite [As (III)] and arsenate [As (V)], was compared under various experimental conditions. Afterward, the contribution of mechanisms in As species removal was determined. Finally, the most efficient membrane was used for As-rich groundwater treatment. Results show that, applied pressure and feed pH are the important parameters which must be considered if As removal wants to be improved. As (V) is much easily removed than As (III) both NF270 and TW30 membranes. Nevertheless, TW30 membrane has a better removal of As species than NF270 membrane. It is due to the fact that TW30 membrane is a compact membrane. The application of this membrane for potable water production from naturally contaminated groundwater containing 413.74 µg/L of total arsenic (405.63 µg/L of As (V) and 8.11 µg/L of As (III)) gave a treated water of 9.99 µg/L (97.6% of rejection) of total As concentration and water produced volume equivalent to 70% of raw water volume. Therefore, it is possible to implement a treatment process with TW30 membrane to remove arsenic from naturally contaminated groundwater coming from the northern part of Burkina Faso. The efficiency of this process can be improved again by oxidizing As (III) in As (V) before filtration.

Sistemas de membranas filtrantes, principalmente os de osmose reversa, estão sendo cada vez mais utilizados em diversos seguimentos de empresas (farmacêutica, tratamento de água, alimentícia e química), devido à diminuição do preço dos elementos filtrantes e da alta qualidade do produto obtido. O biofouling corresponde a um tipo de fouling inevitável, caracterizado pelo crescimento de microrganismos na superfície das membranas e liberação de EPS pelos mesmos; por isso, um melhor conhecimento sobre estas estruturas é necessário. O presente trabalho teve como objetivo caracterizar o biofouling em diferentes membranas de osmose reversa colmatadas de diferentes indústrias pela técnica da autópsia e comparar com resultados obtidos com biofilmes de cultura pura formados em membranas de osmose reversa; além de verificar a influência de biofilmes na deposição de sais e ação de compostos químicos utilizados na limpeza química de membranas nos mesmos. A autópsia dos elementos colmatados mostrou uma grande quantidade de células viáveis porém, com concentrações de carboidratos muito baixas; diferentemente do que ocorreu quando biofilmes de cultura pura isolados destas membranas foram analisados, apresentando correlações fortes entre quantidade de células viáveis e macromoléculas como proteínas e, principalmente, carboidratos. Com relação à influência dos biofilmes na deposição de sais, dois dos quatro biofilmes de cultura pura apresentaram incorporação de bário em sua estrutura (revelado por análises de fluorescência de raios X), esta incorporação, provavelmente, ocorreu por troca iônica e não pela deposição de sulfato de bário. Compostos como hidróxido de sódio (pH = 12) e ácido clorídrico (pH = 2) apresentaram bons resultados na diminuição de células viáveis porém, a recuperação dos microrganismos foi menor com a utilização do ácido. Os compostos EDTA e SDS não foram eficazes na diminuição de viáveis. / Systems of filter membranes, especially reverse osmosis, are being increasingly used in various segments of companies (pharmaceutical, water treatment, food and chemical industries) due to the decrease in the price of the filter elements and high quality of the product. The biofouling corresponds to a type of inevitable fouling characterized by growth of microorganisms on the surface of the membrane and release of EPS by them; so a better understanding of these structures is necessary. This study aimed to characterize the biofouling in different reverse osmosis membranes addressed from different industries by the technique of autopsy and compared with results obtained with pure culture biofilms in reverse osmosis membranes; and to verify the influence of biofilms in the deposition of salts and action of chemical compounds used in chemical cleaning of membranes in them. The autopsy of clogged elements showed a lot of viable cells but with very low carbohydrate concentrations; unlike what occurred when biofilms isolated pure culture of these membranes were analyzed, showing strong correlation between number of viable cells and macromolecules such as proteins and especially carbohydrates. Regarding the influence of biofilms in the deposition of salts, two of the four pure culture biofilms showed barium incorporation in its structure (revealed by fluorescence analysis X-ray), this merger probably occurred by ion exchange and not by deposition barium sulfate. Compounds such as sodium hydroxide (pH = 12) and hydrochloric acid (pH = 2) showed good results in the decrease of viable cells however, the recovery of microorganisms was lower with use of the acid. EDTA and SDS compounds were not effective in reducing viable.

O objetivo deste trabalho foi investigar o desempenho de uma membrana comercial na remoção de um metal pesado (níquel) de efluentes sintéticos, por osmose inversa. Na primeira etapa foi realizada uma comparação com os resultados obtidos com soluções de alimentação contendo sais, como NaCl, NaNO3 e Ni(NO3)2.6 H2O, nas concentrações de 50, 100 e 200 ppm, e nas pressões de 10, 20 e 26 bar. Os resultados mostraram que a influência da concentração e da pressão aplicada ao sistema não afetaram as rejeições de forma significativa. Na segunda etapa, como os parâmetros não influíram significativamente na rejeição dos sais, optou-se, pela aplicação de uma pressão de operação de 10 bar, para avaliar a eficiência de remoção de níquel. A membrana utilizada, constituída de poliamida, modelo HR98PP e fornecida pela DOW/Filmtec, apresentou uma boa permeabilidade hidráulica. Os resultados mostraram que para todas as concentrações testadas, as rejeições de níquel ultrapassaram 96%, comprovando a boa seletividade deste tipo de membrana na rejeição do referido metal, com fluxos de permeado variando entre 4,78 e 5,55 L/h.m2 , sob pressão de operação de 10 bar. Para estudar o efeito do tamanho iônico na rejeição da membrana, o níquel foi complexado pela adição de um agente quelante na solução de alimentação. O agente escolhido foi o Na2EDTA, devido à formação de um complexo estável com o níquel e por ser um agente não prejudicial à saúde humana. Os resultados com adição de EDTA indicaram um aumento na rejeição de níquel, atingindo o índice máximo de 98,22 %, partindo-se de uma solução com 40,39 ppm de Ni2+, e confirmam que o processo de osmose inversa com a membrana HR98PP é altamente adequado para o tratamento de efluentes contendo níquel / The present work aim to investigate the performance of commercial membrane (HR98PP) at reverse osmosis process for nickel removal from synthetic effluents. The results was obtained by using salt solution of NaCl, NaNO3 and Ni(NO3)2.6 H2O at different feed concentration (50, 100 and 200 mg/L) and pressure (10, 20 and 26 bar), as drive-force of process. The membrane performance showed a good hydraulic permeability (Lp) and nickel removal at 10 bar. This condition was used to investigate the influence of EDTA, as chelate agent, on nickel rejection when a feed solution with lower Ni2+ concentration (≈ 40 mg/L) was prepared. The EDTA was chosen due to the stable complex formations and because this agent in not a prejucial element to human health and to environment. In this case, the HR98PP membrane was showed a high nickel rejection (≈ 98%), using feed solution containing 40,39 mg/L Ni2+. However, it is suitable for the wastewater nickel treatment