Produced water is formed in underground formations and brought up to the surface along with crude oil during production. It is by far the largest volume byproduct or waste stream. The most popular preference to deal with produced water is to re-inject it back into the formation. Produced water re-injection (PWRI) needs a treatment before injection to prevent formation blockage. Due to the increase of produced water during oil production in the west of Kuwait, an effluent treatment and water injection plants were established and commissioned in 2004 so that produced water could be used for re-injection purposes. It is estimated that oil wells in the west of Kuwait produce 15 to 40 % of produced water. The main aim of this treatment train is to reduce not only the oil-in-water amount to less than 10 ppm, but also total suspended solids to 5 ppm which is the maximum allowable concentration for re-injection and disposal. Furthermore, with respect to the upper limit for injection, the maximum number of particles between 5 and 8 microns is 200 in 0.1 ml. In practice the number is found to exceed this limit by 10 times...

Quelque soit la zone de culture, l'anacardier (Anacardium occidentale L.) est essentiellement cultivé pour la production de noix de cajou, filière d'une grande importance socio-économique notamment au Brésil. Le jus de cajou est un produit secondaire qui résulte du pressage du pédoncule hypertrophié de la noix appelé pomme de cajou (pseudo-fruit). Le traitement des pommes engendre de grands volumes de déchets solides qui sont soit mis en décharge, soit utilisés pour l'alimentation animale. Dans ce contexte, le travail a pour objectif de proposer et d'évaluer un nouveau procédé permettant d'accroître la valeur ajoutée de ce sous-produit en extrayant les caroténoïdes qu'il contient. Le procédé comporte 3 opérations successives : une extraction par pressage associée à une macération enzymatique, une concentration à froid de l'extrait par microfiltration tangentielle et une purification par diafiltration. La première opération a été optimisée à l'aide de 2 plans d'expériences : un plan de criblage de facteurs de Plackett-Burmam (matrice de Hadamard) pour sélectionner les paramètres opératoires les plus influents suivi d'un plan central composite pour les optimiser. La dose de pectinase utilisée durant la macération et la force appliquée lors du pressage sont les paramètres les plus influents sur le profil caroténoïdique de l'extrait. De fortes doses de pectinase associées à une force de pressage élevée permettent d'obtenir à la fois un extrait plus riche en caroténoïdes et une meilleure densité de flux de perméat en microfiltration. L'utilisation de plusieurs cycles successifs de pressage permet d'augmenter les teneurs en caroténoïdes de l'extrait mais augmente également son pouvoir colmatant en microfiltration. L'étude de la concentration de l'extrait par microfiltration tangentielle a montré qu'il est possible d'atteindre un facteur de réduction volumique (FRV) de 20 en maintenant des densité de flux de perméat supérieures à 100 L.h-1.m-2. Les caroténoïdes sont concentrés à hauteur du FRV choisi (jusqu'à 20 fois). La diafiltration a permis de purifier 5 fois les caroténoïdes par rapport à la matière sèche. Un modèle simple basé sur des bilans matières pour prévoir l'impact du FRV et du diavolume sur la composition de l'extrait a été développé et validé. L'extrait final obtenu présente une teneur en caroténoïdes de 70 mg.kg-1. Parmi les 11 molécules identifiées par HPLC-DAD, les caroténoïdes majoritaires sont les isomères cis et trans de l'auroxanthine, la β-cryptoxanthine et le β-carotène. Les extraits finaux obtenus se présentent sous forme de liquides visqueux de couleur jaune intense, faciles à disperser dans l'eau. Ils possèdent un fort potentiel d'utilisation dans la formulation des aliments comme colorant naturel. / Whatever is the area of plantation, cashew (Anacardium occidentale L.) is grown primarily for the production of nuts, a supply chain that has great socioeconomic importance, especially in Brazil. The cashew juice is a by-product that results from pressing the nut hypertrophied peduncle, known as cashew apple, a juicy pseudo fruit. Peduncle processing generates large volumes of industrial solid waste that are usually discarded or sometimes used as animal feed. In this context, this work aimed to propose and evaluate a new process that provides an added value to this industrial byproduct, extracting carotenoids that were contained therein. The process comprised three successive operations: an extraction by pressing associated to an enzymatic maceration, a cold concentration of the extract by crossflow microfiltration and a purification by diafiltration. The first operation was optimized with the use of two experimental designs: a Plackett-Burmam (Hadamard matrix) plan for factors screening to select the most influential operating parameters, followed by a central composite design for optimization. The dose of pectinase used during maceration and the applied force used during the pressing operation were the most influential parameters on the carotenoid extract profile. High doses of pectinase associated with a high pressing force led to a richer carotenoid extract and enhanced the permeate flux in microfiltration. The use of several successive cycles of compression increased the carotenoid content of the extract but also increased its fouling properties during microfiltration. The extract concentration by crossflow microfiltration study showed that it was possible to reach values of volumetric reduction ratio (VRR) of about 20, maintaining the permeate flux above 100 Lh-1.m-2. The carotenoids were concentrated in the same levels of FRV (up to 20 times). The diafiltration allowed purification of carotenoids 5 times in relation to the dry matter. A simple model, based on a mass balance to predict the impact of VRR and diavolume on the extract composition was developed and validated. The final extract obtained presented a carotenoid content of 70 mg.kg-1. Among the 11 compounds identified by HPLC-DAD, the main carotenoids were cis and trans isomers of auroxanthine, β-cryptoxanthin and β-carotene. The final extracts obtained were in the form of viscous liquids of a yellow intense color, and easily dispersed in water. These concentrates have a strong potential for use in the formulation of foods and beverages as a natural dye.

A constante exploração dos recursos hídricos para os mais diferentes usos sem um planejamento adequado, tem levado ao comprometimento desses recursos, verificando-se cada vez mais aumento no número de pesquisas e investimentos, visando o estudo de alternativas que viabilizem o tratamento avançado de águas residuárias e sua reutilização. Entre essas alternativas, estão as técnicas de separação dos materiais contaminantes por membranas. Neste trabalho estudou-se a viabilidade da utilização da microfiltração tangencial como alternativa de pós-tratamento de efluente de Reator Anaeróbio de Leito Expandido alimentado com esgoto sanitário, analisando-se a influência da utilização de cloreto férrico como coagulante, bem como, membranas com diferentes tamanhos de poro (0,2 e 1,0 &#956m), no desempenho da microfiltração tangencial. Os ensaios no sistema de microfiltração tangencial foram realizados em batelada, com amostras de efluente do reator anaeróbio de leito expandido (RALEX). Verificou-se que para os ensaios realizados com a membrana de 0,2 &#956m, o aumento das dosagens de cloreto férrico, contribuiu para diminuição nos valores de luxo de permeado. Esta relação não ocorreu de forma direta com a membrana de 1,0 &#956m. Os processos de coagulação e floculação foram essenciais para ambas membranas no aumento na eficiência de remoção da demanda química total de oxigênio (mg/l), fosfato total (mg P/l) e turbidez, no entanto, em relação aos valores de fluxo do permeado,foi prejudicial, pois nos ensaios em que as amostras de efluente do RALEX não foram previamente coaguladas e floculadas, a permeabilidade das membranas foi bem maios. O sistema de microfiltração tangencial operando com a membrana de 0,2 &#956m apresentou melhor desempenho, com valores de fluxo do permeado, em geral superiores a 100 L/m2.h, eficiência de 100% na remoção de coliformes totais e fecais, e a dosagem de 40 mg/l de cloreto férrico, já foi suficiente para uma eficiência média de remoção de DQOt de 95%; P.PO4-3 (89,5%) e Turbidez (96,4%). Portanto, a microfiltração tangencial pode ser considerada uma alternativa eficaz como unidade de pós-tratamento de efluente de reator anaeróbio de leito expandido, produzindo efluente que atende os padrões de reuso na agricultura, para coliforme totais e fecais. / The constant exploration of water resources for the most different uses, without an appropriate planning, has lead to the exhaustion of this resources. This scenery has showed the need of increasing researches and investments on alternative forms of wastewater treatment. This work studied the viability of using crossflow microfiltration as an alternative form of advanced treatment of effluents of Anaerobic Reactor Expanded Bed feed with sewage, examining the effect of the use of ferric chloride as coagulam, as well as of different pore size membranes (0,2 and 1,0 &#956m) on the performance of crossflow microfiltration. The experiments on crossflow microfiltration system were carried out in batch, using effluent samples of anaerobic reactor expanded bed. The results obtained with the 0,2 &#956m membrane showed that the increase of ferric chloride dosages contributed for the reduction on flux values. The 1,0 &#956m membrane did not presented this relation. The flocculation and coagulation processes were essentials for increasing the removal efficiency of Total Chemical Oxygen Demand, Total Phosphorus and Turbidity for both membranes, however, for the flux values the effect was harmful, because when the samples of the Anaerobic Reactor Expanded Bed were not previously coagulated and flocculated, the membranes penneability were higher. The Crossflow Microfiltration System, operating with the 0,2 &#956m membrane, presented better performance, with flux values generally superior than 100 L/m2.h, efficiency around 100% on the removal of Total and Fecal Coliforms. For this membrane (0,2 &#956m) the dosage of 40 mg/l of FeCl3 (first stage) was enough for an average of removal efficiency of Total Chemical Oxygen Demand (95%); Turbidity (96.4%); and P.PO4-3 (89,5%). Therefore, crossflow mocrofiltration can be considered an effective alternative for advanced treatment of effluents of Anaerobic Reactor Expanded Bed, producing a final effluent with large potentiality to be used in agriculture.

A proposta desta pesquisa consistiu na avaliação da microfiltração tangencial para o tratamento avançado de efluente gerado em sistema de tratamento de esgoto sanitário constituído de reator UASB (Upflow Anaerobic Sludge Blanket) seguido de tanque de aeração. Neste trabalho foram avaliados métodos de limpeza física (retrolavagem com ar comprimido) e química (ácida e básica) das membranas, bem como análise comparativa da colmatação e do desempenho de membranas de tamanhos de poro de 0,2 e 1,0 'mü'm, quando aplicadas ao pós-tratamento de efluentes do tanque de aeração em diferentes concentrações de SST. Foram contemplados ainda estudos de desinfecção de efluentes da microfiltração por radiação UV e aplicação do processo de coagulação antecedendo a microfiltração tangencial. Os experimentos foram realizados em unidade piloto com membranas tubulares de polipropileno com área efetiva de filtração de 0,036 'M POT.2'. Constatou-se que a limpeza física foi essencial para obtenção de maiores valores de fluxo de permeado na unidade de microfiltração. A limpeza química das membranas por solução básica foi mais eficiente quando comparada a limpeza ácida. Foram obtidos melhores resultados com a membrana de 0,2 'mü'm, quando comparada a membrana de 1 'mü'm, a qual apresentou intensa colmatação interna de seus poros. Para membrana de 0,2 'mü'm obteve-se permeado de excelente qualidade microbiológica (E.Coli < 1 UFC/100 mL e Colifagos < 16 UFP/100 mL), bem como valores de turbidez inferiores a 1,46 uT e remoção praticamente completa de SST. A prévia coagulação das amostras de licor misto do tanque de aeração contribuiu para obtenção de maiores taxas e melhor remoção de P-'PO IND.4'POT.3-' e DQOt na unidade de microfiltração. Para dosagem de 40 mg/L de cloreto férrico obteve-se a maior taxa média (139,7 L/'M POT.2'.h), concentrações residuais de P-'PO IND.4'POT.3-' inferiores a 1,4 mgP/L e DQOt menor que 33 mg/L. A radiação UV permitiu inativação completa de E.Coli e Colifagos das amostras de permeado. Concluiu-se que a microfiltração tangencial apresentou grande potencialidade para ser aplicada no tratamento avançado de efluente gerado em sistema de tratamento de esgoto sanitário constituído de reator UASB (Upflow Anerobic Sludge Blanket) seguido de tanque de aeração. / The proposal of this research was to evaluate the crossflow microfiltration as an alternative for an advanced treatment of effluent generated in a system of sewage treatment composed by a UASB (Upflow Anaerobic Sludge Blanket) reactor followed by an aeration tank. This work aimed to evaluate the membranes physical cleaning methods (backwashing with compressed air) and the chemical ones (acid and basic), as well as the comparative analysis between the fouling event and the 0,2 and 1,0 'mü'm pore size membranes performance, when applied to the aeration tank effluents in a post-treatment stage at TSS different concentrations. Studies for microfiltration effluents disinfection by UV radiation and the application of the coagulation process preceding the crossflow microfiltration were also developed. The experiments were performed in a pilot unit with polypropylene tubular membranes with 0.036 'M POT.2' of effective filtration area. It was verified that the physical cleaning was essential to the attainment of higher permeate flux values in the microfiltration unit. The chemical cleaning of the membranes through basic solution was more efficient when compared to their acid cleaning. Better results were attained when the 0,2 'mü'm membrane was employed in comparison with the 1 'mü'm membrane, which presented intense internal blocking of its pores. It was attained an excellent microbiological quality (E.Coli < 1 FCU/100 mL and Coliphages < 16 FPU/100 mL) for the 0,2 'mü'm membrane, as well as turbidity levels under 1,46 uT and almost total removal of TSS. The previous mixed liquor samples coagulation of the aeration tank contributed to the attainment of higher rates and better removal of P-'PO IND.4'POT.3-' and CODt in the microfiltration unit. It was attained, for the ferric chloride 40 mg/L dosage, the higher mean rate (139,7 L/'M POT.2'.h), P-'PO IND.4'POT.3-' remaining concentrations under 1,4 mgP/L and CODt lesser than 33 mg/L. The UV radiation allowed the complete inactivation of E.Coli and Coliphages from the permeate samples. It was concluded that the crossflow microfiltration presents great possibilities of application in the advanced treatment of effluent generated in a system of sewage treatment composed by a UASB (Upflow Anaerobic Sludge Blanket) reactor followed by an aeration tank.

A proposta desta pesquisa consistiu na avaliação da microfiltração tangencial para o tratamento avançado de efluente gerado em sistema de tratamento de esgoto sanitário constituído de reator UASB (Upflow Anaerobic Sludge Blanket) seguido de tanque de aeração. Neste trabalho foram avaliados métodos de limpeza física (retrolavagem com ar comprimido) e química (ácida e básica) das membranas, bem como análise comparativa da colmatação e do desempenho de membranas de tamanhos de poro de 0,2 e 1,0 'mü'm, quando aplicadas ao pós-tratamento de efluentes do tanque de aeração em diferentes concentrações de SST. Foram contemplados ainda estudos de desinfecção de efluentes da microfiltração por radiação UV e aplicação do processo de coagulação antecedendo a microfiltração tangencial. Os experimentos foram realizados em unidade piloto com membranas tubulares de polipropileno com área efetiva de filtração de 0,036 'M POT.2'. Constatou-se que a limpeza física foi essencial para obtenção de maiores valores de fluxo de permeado na unidade de microfiltração. A limpeza química das membranas por solução básica foi mais eficiente quando comparada a limpeza ácida. Foram obtidos melhores resultados com a membrana de 0,2 'mü'm, quando comparada a membrana de 1 'mü'm, a qual apresentou intensa colmatação interna de seus poros. Para membrana de 0,2 'mü'm obteve-se permeado de excelente qualidade microbiológica (E.Coli < 1 UFC/100 mL e Colifagos < 16 UFP/100 mL), bem como valores de turbidez inferiores a 1,46 uT e remoção praticamente completa de SST. A prévia coagulação das amostras de licor misto do tanque de aeração contribuiu para obtenção de maiores taxas e melhor remoção de P-'PO IND.4'POT.3-' e DQOt na unidade de microfiltração. Para dosagem de 40 mg/L de cloreto férrico obteve-se a maior taxa média (139,7 L/'M POT.2'.h), concentrações residuais de P-'PO IND.4'POT.3-' inferiores a 1,4 mgP/L e DQOt menor que 33 mg/L. A radiação UV permitiu inativação completa de E.Coli e Colifagos das amostras de permeado. Concluiu-se que a microfiltração tangencial apresentou grande potencialidade para ser aplicada no tratamento avançado de efluente gerado em sistema de tratamento de esgoto sanitário constituído de reator UASB (Upflow Anerobic Sludge Blanket) seguido de tanque de aeração. / The proposal of this research was to evaluate the crossflow microfiltration as an alternative for an advanced treatment of effluent generated in a system of sewage treatment composed by a UASB (Upflow Anaerobic Sludge Blanket) reactor followed by an aeration tank. This work aimed to evaluate the membranes physical cleaning methods (backwashing with compressed air) and the chemical ones (acid and basic), as well as the comparative analysis between the fouling event and the 0,2 and 1,0 'mü'm pore size membranes performance, when applied to the aeration tank effluents in a post-treatment stage at TSS different concentrations. Studies for microfiltration effluents disinfection by UV radiation and the application of the coagulation process preceding the crossflow microfiltration were also developed. The experiments were performed in a pilot unit with polypropylene tubular membranes with 0.036 'M POT.2' of effective filtration area. It was verified that the physical cleaning was essential to the attainment of higher permeate flux values in the microfiltration unit. The chemical cleaning of the membranes through basic solution was more efficient when compared to their acid cleaning. Better results were attained when the 0,2 'mü'm membrane was employed in comparison with the 1 'mü'm membrane, which presented intense internal blocking of its pores. It was attained an excellent microbiological quality (E.Coli < 1 FCU/100 mL and Coliphages < 16 FPU/100 mL) for the 0,2 'mü'm membrane, as well as turbidity levels under 1,46 uT and almost total removal of TSS. The previous mixed liquor samples coagulation of the aeration tank contributed to the attainment of higher rates and better removal of P-'PO IND.4'POT.3-' and CODt in the microfiltration unit. It was attained, for the ferric chloride 40 mg/L dosage, the higher mean rate (139,7 L/'M POT.2'.h), P-'PO IND.4'POT.3-' remaining concentrations under 1,4 mgP/L and CODt lesser than 33 mg/L. The UV radiation allowed the complete inactivation of E.Coli and Coliphages from the permeate samples. It was concluded that the crossflow microfiltration presents great possibilities of application in the advanced treatment of effluent generated in a system of sewage treatment composed by a UASB (Upflow Anaerobic Sludge Blanket) reactor followed by an aeration tank.

A constante exploração dos recursos hídricos para os mais diferentes usos sem um planejamento adequado, tem levado ao comprometimento desses recursos, verificando-se cada vez mais aumento no número de pesquisas e investimentos, visando o estudo de alternativas que viabilizem o tratamento avançado de águas residuárias e sua reutilização. Entre essas alternativas, estão as técnicas de separação dos materiais contaminantes por membranas. Neste trabalho estudou-se a viabilidade da utilização da microfiltração tangencial como alternativa de pós-tratamento de efluente de Reator Anaeróbio de Leito Expandido alimentado com esgoto sanitário, analisando-se a influência da utilização de cloreto férrico como coagulante, bem como, membranas com diferentes tamanhos de poro (0,2 e 1,0 &#956m), no desempenho da microfiltração tangencial. Os ensaios no sistema de microfiltração tangencial foram realizados em batelada, com amostras de efluente do reator anaeróbio de leito expandido (RALEX). Verificou-se que para os ensaios realizados com a membrana de 0,2 &#956m, o aumento das dosagens de cloreto férrico, contribuiu para diminuição nos valores de luxo de permeado. Esta relação não ocorreu de forma direta com a membrana de 1,0 &#956m. Os processos de coagulação e floculação foram essenciais para ambas membranas no aumento na eficiência de remoção da demanda química total de oxigênio (mg/l), fosfato total (mg P/l) e turbidez, no entanto, em relação aos valores de fluxo do permeado,foi prejudicial, pois nos ensaios em que as amostras de efluente do RALEX não foram previamente coaguladas e floculadas, a permeabilidade das membranas foi bem maios. O sistema de microfiltração tangencial operando com a membrana de 0,2 &#956m apresentou melhor desempenho, com valores de fluxo do permeado, em geral superiores a 100 L/m2.h, eficiência de 100% na remoção de coliformes totais e fecais, e a dosagem de 40 mg/l de cloreto férrico, já foi suficiente para uma eficiência média de remoção de DQOt de 95%; P.PO4-3 (89,5%) e Turbidez (96,4%). Portanto, a microfiltração tangencial pode ser considerada uma alternativa eficaz como unidade de pós-tratamento de efluente de reator anaeróbio de leito expandido, produzindo efluente que atende os padrões de reuso na agricultura, para coliforme totais e fecais. / The constant exploration of water resources for the most different uses, without an appropriate planning, has lead to the exhaustion of this resources. This scenery has showed the need of increasing researches and investments on alternative forms of wastewater treatment. This work studied the viability of using crossflow microfiltration as an alternative form of advanced treatment of effluents of Anaerobic Reactor Expanded Bed feed with sewage, examining the effect of the use of ferric chloride as coagulam, as well as of different pore size membranes (0,2 and 1,0 &#956m) on the performance of crossflow microfiltration. The experiments on crossflow microfiltration system were carried out in batch, using effluent samples of anaerobic reactor expanded bed. The results obtained with the 0,2 &#956m membrane showed that the increase of ferric chloride dosages contributed for the reduction on flux values. The 1,0 &#956m membrane did not presented this relation. The flocculation and coagulation processes were essentials for increasing the removal efficiency of Total Chemical Oxygen Demand, Total Phosphorus and Turbidity for both membranes, however, for the flux values the effect was harmful, because when the samples of the Anaerobic Reactor Expanded Bed were not previously coagulated and flocculated, the membranes penneability were higher. The Crossflow Microfiltration System, operating with the 0,2 &#956m membrane, presented better performance, with flux values generally superior than 100 L/m2.h, efficiency around 100% on the removal of Total and Fecal Coliforms. For this membrane (0,2 &#956m) the dosage of 40 mg/l of FeCl3 (first stage) was enough for an average of removal efficiency of Total Chemical Oxygen Demand (95%); Turbidity (96.4%); and P.PO4-3 (89,5%). Therefore, crossflow mocrofiltration can be considered an effective alternative for advanced treatment of effluents of Anaerobic Reactor Expanded Bed, producing a final effluent with large potentiality to be used in agriculture.

Hibiscus sabdariffa L. est une plante vivace herbacée localisée dans les zones tropicales et subtropicales des deux hémisphères. Au Sénégal, où elle a été introduite au 19ème siècle, H. sabdariffa, encore appelé bissap ou roselle, est cultivé sur l'ensemble du territoire et exploité principalement pour ses calices. Une boisson désaltérante est traditionnellement élaborée à partir des calices séchés par extraction à l'eau. La caractérisation physico-chimique et biochimique des calices nous a tout d'abord permis de mieux évaluer le potentiel de ce produit. Ainsi, les calices contiennent entre 767 et 1480 mg.100g -1 d'anthocyanes et entre 1347 et 3736 mg.100g-1 de polyphénols totaux. Ils présentent un pouvoir antioxydant voisin de 260 µmolTrolox.g-1. L'acide malique y est l'acide organique majoritaire avec une teneur pouvant atteindre 2,3 g.100g-1. De part ces caractéristiques, l'extrait aqueux de calices d'H. sabdariffa constitue une excellente source d'anthocyanes. Le travail s'est ensuite focalisé sur le procédé d'obtention de cet extrait. L'étude de l'extraction solide-liquide a été réalisée à partir de calices séchés et d'eau à des températures comprises entre 25 et 90 °C. Un rendement d'extraction en anthocyanes maximum de 88 % a été obtenu à 25 °C avec un ratio calice/eau de 1/25. La réduction de la taille des particules et l'augmentation de la température diminuent le temps d'extraction mais n'affectent pas le rendement d'extraction. Un modèle d'extraction solide-liquide incluant les cinétiques de dégradation thermique des anthocyanes a été proposé puis validé. La microfiltration tangentielle sur membrane céramique de diamètre moyen de pores 0,2 µm a permis de produire un extrait stérilisé à froid, stable pendant 90 j à 20 °C. Nous avons montré à ce niveau que la pression transmembranaire optimisée à un facteur de réduct ion volumique (FRV) égal à 1 n'est plus optimale lorsque le FRV augmente. Pour concentrer les anthocyanes présents dans l'extrait, l'ultrafiltration sur une membrane de seuil de coupure de 5 kDa peut être utilisée malgré une rétention incomplète (95-97 %). Par contre, la nanofiltration offre une rétention totale des anthocyanes. Le procédé, mis en uvre dans des conditions semi-industrielles, a permis d'augmenter la teneur en extrait sec soluble (ESS) de 40 à 250 g.kg-1 à 35 °C, à une pression transmembranaire comprise entre 20 et 30 bar avec un flux moyen de 15 kg.h-1.m-2. L'évaporation osmotique, testée sur un pilote équipé d'une membrane en polypropylène de 10 m2, a permis de concentrer l'extrait anthocyanique jusqu'à 620 g d'ESS.kg-1. Cet extrait concentré conserve toutes les qualités physico-chimiques, biochimiques, nutritionnelles et aromatiques de l'extrait initial. Le flux évaporatoire est directement corrélé à la teneur en extrait sec solub le du produit à concentrer. Enfin, divers couplages d'opérations unitaires ont été comparés pour obtenir un extrait concentré à partir de calices d'H. sabdariffa. Le procédé qui associe une extraction à froid, une pré-concentration par nanofiltration et une concentration par évaporation osmotique est la meilleure voie tant en terme de coûts d'investissement et de fonctionnement que de qualité de l'extrait. / Hibiscus sabdariffa L. is a herbaceous plant, cultivated largely in tropical and subtropical areas of both hemispheres. In Senegal, where it was introduced in the 19th century, H. sabdariffa L. also called bissap or roselle is grown throughout the territory and operated primarily for its calyx. A refreshing drink is traditionally made from dried calyx by water extraction. The physical-chemical and biochemical characterization of the calyx allowed us to assess better the potential of this product. Thus, the calyx contained between 767 and 1480 mg.100g-1 of anthocyanins and between 1347 and 3736 mg.100g-1 of total polyphenols. They have an antioxidant capacity closed to 260 μmolTrolox.g-1. Malic acid is the major organic acid with content up to 2.3 g.100g-1. Because of these characteristics, the aqueous extract of H. sabdariffa calyx is an excellent source of anthocyanins. The work was then focused on the process for obtaining this extract. The study of solid-liquid extraction was performed from dried calyx with water at temperature range from 25 and 90 ° C. A maximum extraction yield of anthocyanin of 88 % was obtained at 25 ° C with a solid-to-solvent ratio of 1/25. Reducing the particle size and increasing the temperature decreased the extraction time but do not affect the extraction efficiency. A model of solid-liquid extraction which included the thermal anthocyanins degradation kinetics has been proposed and validated. Crossflow microfiltration with tubular ceramic 0.2 pore size membrane has produced a cold sterilized extract, stable during 90 days at 20 °C. We have shown here that the transmembrane pressure optimized at a volume reduction ratio (VRR) equal to 1 is no longer optimum when the VRR is increasing. To concentrate the anthocyanins present in the extract, the ultrafiltration membrane with a cutoff of 5 kDa can be used despite incomplete retention (95-97%). By cons, nanofiltration offers a tot al retention of anthocyanins. The method, implemented in semi-industrial conditions, has increased the content of total soluble solids (TSS) from 40 to 250 g.kg-1 at 35 °C at a transmembrane pressure between 20 and 30 bar with an average flow of 15 kg.h-1.m-2. The osmotic evaporation, tested on a pilot equipped with a polypropylene membrane of 10 m2, has concentrated anthocyanin extract up to 620 g TSS. kg-1. This concentrated extract retains all the physical-chemical, biochemical, nutritional and aromatic quality of the original extract. The evaporation flux is directly correlated with the total soluble solids content of the product to concentrate. Finally, various couplings of unit operations were compared to obtain a concentrated extract from H. sabdariffa calyx. The process which combines a cold extraction, a pre-concentration by nanofiltration and concentration by osmotic evaporation is the best way both in terms of investment costs and operating and quality of the ext ract.