Les règlements plus stricts pour les rejets d'eaux usées présentent de nouveaux défis technologiques pour le traitement d'eaux usées urbaines et industrielles. Le besoin notamment d‘améliorer la qualité hygiénique de l'eau traitée se fait ressentir en cas de sites sensibles ou de réutilisation. Le bioréacteur à membranes (BRMs) représente une des approches les plus innovatrices pour éviter la présence d'agents pathogènes dans l‘eau en sortie de station. En utilisant des membranes avec un seuil de coupure dans la gamme 0.04~0.2 μm, les bactéries mais aussi les virus sont pratiquement complètement retenus. Si l'encrassement membranaire reste un problème déterminant pour le développement des BRMs, le manque d‘outils de caractérisation en ligne de la qualité et la quantité de biomasse active dans les réacteurs reste un point important pour favoriser le contrôle et l‘optimisation des BRMs. Dans cette étude une méthode originale a été développée pour évaluer la viabilité des boues activées présentes dans un réacteur biologique d‘épuration en complémentarité des informations données par la mesure d'activité respirométrique. Cette méthode permet la distinction entre cellule morte et vivante, la respirométrie pouvant alors distinguée la part active de la biomasse vivante. Le travail expérimental a été conduit dans deux réacteurs biologiques de type chenal d‘oxydation équipés de membranes immergées "airlift oxidation ditch membrane bioreactor" (AOXMBR). Les modules membranaires sont immergés dans un zone aérée où l‘apport d‘air permet à la fois la circulation d‘eau par air-lift, l‘aération du milieu et le nettoyage des membranes par aération. Les essais ont été conduits en mode fermé (batch reactor), alterné (fed batch reactor) et continu. La première partie de l‘étude concerne la caractérisation hydrodynamique du réacteur déterminante en terme de conformité du système pour la circulation des fluides, l‘intensité des transferts et des réactions d‘épuration. Les résultats mettent en avant le rôle de la géométrie de l‘airlift sur la circulation des fluides mais aussi la rétention gazeuse déterminante en terme de transfert d‘oxygène et capacité de nettoyage des membranes. La viabilité et l'activité respirométrique de boues activée ont alors été étudiées sous différentes conditions opératoires. Les résultats ont montré une évolution semblable des deux paramètres en fonction des conditions imposées. Ceci confirme l‘intérêt de la mesure de viabilité qui peut être conduite en ligne sur le système, à la différence de la mesure par respirométrie qui nécessite une procédure spécifique plus ou moins complexe. Toutefois, les essais ont montré aussi qu‘une concentration en biomasse importante était nécessaire dans le bioréacteur pour que la viabilité soit mesurable. Les résultats ont aussi montré que la viabilité et l'activité augmentent avec la charge organique (Cv). Cette variation était conforme à l'augmentation des matières volatiles en suspension MVS et de la vitesse de consommation d‘oxygène OUR. Lors de diminution de charge organique, la concentration de protéine dans le milieu a changé inversement avec la viabilité de la biomasse. De possibles améliorations de l'instrument de mesure en ligne de la viabilité et de l'activité de boues activées dans les bioréacteurs sont également discutées. Les performances épuratives mesurées ont confirmé la grande capacité épuratoire d‘un BRM, toutefois, travailler à très forte charge engendre une dynamique de colmatage intense qu‘il faut maîtriser. / In this study a novel method was developed to assess the viability of activated sludge present in a biological treatment process and signify its complementarity from respirometric activity. This method allows the distinction between viable vs. dead and inactive vs. active microbial cells in biomass population and can be used for a better and more efficient control of the biological activity especially in MBR systems.For this purposed two airlift oxidation ditch membrane bioreactors (AOXMBR), were designed and constructed. They were equipped with flat sheet, membranes directly immersed in the airlift section where the air injection induced sludge aeration, water circulation and continuous membrane cleaning.To evaluate the relevance of the batch, fed-batch and AOXMBR) were carried out in order to obtain a better understanding of biomass characteristic for MBR performance.Firstly, for determining the treatment capacity of the proposed AOXMBR is important to understanding of the hydrodynamic characteristics of the system. And impact of design parameter on hydrodynamic characterization of the system was investigated. The results showed the gas holdup and liquid velocity increased with increase in superficial gas velocity and decrease in distance from aeration zone. Furthermore, gas holdup and liquid velocity in downcomer section did not show any significant variations with change in the top to bottom clearance ratio. The riser gas holdup data was related to the superficial gas velocity and the top to bottom clearance ratio data. Also, the downcomer gas holdup was related to superficial gas velocity and distance from airlift section.Secondly, viability and respirometric activity of activated sludge under different activated sludge conditions (batch, fed-batch) at high cell density as the model of membrane bioreactors were investigated. The results showed the same downward trend for both these parameters (viability and respirometric activity) which was due to quantitative and qualitative changes in the microbial culture in the activated sludge. Based on different fed of substrate for each experimental run (batch, fed-batch), operational variables showed significant influence in viability and activity of activated sludge. Also, the effect of changing physicochemical condition.on viability and respirometric activity was investigated. The results showed that respirometric activity was affected more strongly by temperature than viability.Thirdly, biological performance of AOXMBR was carried out.Finally, base on data obtained in the last experiment, in this part the capacitance sensor used as the on-line monitoring of viability of activated sludge in AOXMBR. Results showed that viability and activity were increased with organic loading rate (OLR) increasing until 5 kg COD m-3 d-1. This variation was in accordance with increasing of MLSS, MLVSS and OUR. The results also showed that the viability of biomass decreased when reducing the organic loading rate from 5 to 4 kg COD m-3 d-1. Also, protein concentration in system changed inversely with activated sludge viability.The possible reasons are discussed for future improvements online instrument for measuring viability and activity of activated sludge in biological wastewater. Summary of the principal results and novelty of this thesis obtained in this study: The porposed system would reward improved efficiency across the oxidation ditch, airlift and membrane bioreactor. The AXOMBR is a suitable system for operating at high organic laoding rate. However, the suddenly reduction of OLR affects on viability of activated sludge. The specific characterization of the system is capable of working at three different zone: aerobic, anoxic and anaerobic zone. Also, the time of operating at each zone can be changed with superficial gas velocity top to bottom clearance.

The overall objective of this thesis was to examine mitochondrial bioenergetics in muscle biopsies from humans with type 1 diabetes (T1D) to gain a deeper understanding of the cellular mechanism(s) underlying changes to skeletal muscle health reported in T1D, a phenotype we have referred to as ‘diabetic myopathy’. It was hypothesized that humans with T1D, compared to their matched counterparts without diabetes (control), would demonstrate significant deficiencies in muscle mitochondrial function and ultrastructure/content as determined by the gold-standard in vitro methodology: high-resolution respirometry and transmission electron microscopy, respectively. It was further hypothesized that sex differences would not exist in mitochondrial function with T1D, and mitochondrial deficiencies would be more dramatic at an earlier age with T1D. Adults with uncomplicated T1D and strictly matched controls (age, sex, BMI, self-reported physical activity levels) were recruited from surrounding university-dwelling communities. Site-specific deficiencies in mitochondrial respiration, H2O2 emission, and calcium retention capacity were found in young, physically active adults with T1D despite normal mitochondrial content. Further experiments revealed that muscle mitochondrial respiration in women and men differentially adapt to the T1D environment where men with T1D have lower complex II but higher complex I respiration compared to women with T1D, while women (irrespective of T1D) have lower ADP sensitivity. Women with T1D also demonstrated lower H2O2 emission compared to men with T1D. In contrast, despite a lower mitochondrial content in middle- to older-aged adults with T1D, mitochondrial respiration (normalized to content) was either normal or increased in adults with T1D compared to control, with observable differences between sexes. Overall, this research has demonstrated that despite being recreationally to physically active, adults with uncomplicated T1D with moderately well-managed glycemia demonstrate alterations in skeletal muscle mitochondrial function and ultrastructure, including differences between sexes. / Dissertation / Doctor of Science (PhD) / Type 1 diabetes (T1D) is a complex disease that still has no known cure. Current treatment focuses on managing blood sugar levels with exogenous insulin injections and frequent blood sugar checks. However, over time, people with T1D still develop serious complications that inevitably impact their quality of life and lifespan. A potential adjuvant therapy to prevent complications in T1D is improving the health of skeletal muscle through exercise given its role in stabilizing blood sugar/lipid levels and whole-body insulin sensitivity. However, this area continues to be severely understudied in the T1D population. Thus, this thesis examined skeletal muscle metabolic ‘health’ from adults with T1D who do not have major diabetes complications and manage their blood glucose moderately-well. Through a series of novel experiments, we found that young and middle- to older-aged adults with T1D have alterations in the metabolic engines of their muscles, and depending on biological sex, the alterations manifest as either heightened or degraded cellular function. These findings are the first to provide a comprehensive cellular investigation of the impact of T1D on the metabolic health of skeletal muscle in people with T1D and provide the foundation for future research examining skeletal muscle as an essential and early adjuvant therapy in this population.

Les facteurs de stress biotiques, tels que les parasites, peuvent affecter le fitness d’un animal en modifiant le comportement et la physiologie de l’hôte. Puisque les parasites sont omniprésents et ont des impacts importants sur les communautés écologiques, il importe de comprendre comment et dans quelle mesure ils modifient la vie de leurs hôtes. Ainsi, l’étude de la capacité de performance d’un hôte parasité par le biais de la physiologie et du comportement pourrait fournir une compréhension plus mécanistique des changements phénotypiques de l'hôte pendant l'infection. Nous avons utilisé des crapets-soleil (Lepomis gibbosus) infectés par des trématodes et cestodes comme système modèle pour étudier les effets des endoparasites sur les traits métaboliques et le comportement de fuite de l'hôte. Les traits de performance métaboliques aérobiques (taux métabolique standard et maximal, capacité aérobique) et de performance de fuite (réactivité et temps de réponse à une attaque aérienne simulée) ont été mesurés chez les poissons à travers un gradient d'infection visible (c.-à-d. la prévalence de points noirs sur les poissons) et d’infection non-visible (c.-à-d. causée par des endoparasites, cestodes et trématodes, non-apparents mais quantifiés post-mortem) à l'aide de respiromètres et d'arènes comportementales. Nous avons démontré que la charge parasitaire influence les performances physiologiques et comportementales des crapets-soleil. Nous avons observé une diminution significative des taux métaboliques standard et maximal le long d’un gradient d'infection par des endoparasites non-visibles, mais pas pour une infection visible de type point noir. L'intensité de l'infection par les endoparasites non-visibles était également liée à une diminution de la réponse à une attaque aérienne simulée. Nos résultats suggèrent que l'incorporation de l'infection parasitaire dans les études écologiques, physiologiques et comportementales s’avère essentielle pour identifier et comprendre les causes de la variation des caractères intraspécifiques au sein des populations sauvages. / Biotic stressors, such as parasites, can affect an animal’s fitness through changes to their host’s behaviour and physiology. Since parasites are ubiquitous and have significant impacts on ecological communities, it is important to understand how and to what extent they alter the lives of their hosts. Thus, studying how host performance capacity is affected by parasites through physiology and behaviour could provide a more mechanistic understanding of host phenotypic changes during infection. We used pumpkinseed sunfish, Lepomis gibbosus, infected with endoparasites, including trematodes (the causal agent of black spot disease), as a model system to study the effects of infection on host aerobic metabolic performance and escape behaviour. Aerobic metabolic performance traits (standard and maximum metabolic rate, aerobic scope) and escape response performance traits (responsiveness and response latency to a simulated aerial attack) were measured in fish from across a gradient of visible endoparasite infection (i.e. trematodes causing black spot disease) and non-visible infection (i.e. internal cestodes and trematodes quantified post-mortem) using custom-built respirometers and behavioural arenas. Here, we demonstrate that parasite load is related to the physiological and behavioral performances of wild caught pumpkinseed sunfish. We find a significant decrease in standard metabolic rate and maximal metabolic rate along the gradient of non-visible endoparasite infection but not for visible infection with black spot. Non-visible endoparasite infection intensity was also related to decreased responsiveness to a simulated aerial attack. Our results provide further confirmation that incorporating parasite infection in ecological, physiological and behavioural studies is critical for understanding the causes of intraspecific trait variation in wild animal populations.

For many scientific applications, inverse problems have played a key role in solving important problems by enabling researchers to estimate desired parameters of a system from observed measurements. For example, large-scale inverse problems arise in many global problems and medical imaging problems such as greenhouse gas tracking and computational tomography reconstruction. This dissertation describes advancements in computational tools for solving large-scale inverse problems and for uncertainty quantification. Oftentimes, inverse problems are ill-posed and large-scale. Iterative projection methods have dramatically reduced the computational costs of solving large-scale inverse problems, and regularization methods have been critical in obtaining stable estimations by applying prior information of unknowns via Bayesian inference. However, by combining iterative projection methods and variational regularization methods, hybrid projection approaches, in particular generalized hybrid methods, create a powerful framework that can maximize the benefits of each method. In this dissertation, we describe various advancements and extensions of hybrid projection methods that we developed to address three recent open problems. First, we develop hybrid projection methods that incorporate mixed Gaussian priors, where we seek more sophisticated estimations where the unknowns can be treated as random variables from a mixture of distributions. Second, we describe hybrid projection methods for mean estimation in a hierarchical Bayesian approach. By including more than one prior covariance matrix (e.g., mixed Gaussian priors) or estimating unknowns and hyper-parameters simultaneously (e.g., hierarchical Gaussian priors), we show that better estimations can be obtained. Third, we develop computational tools for a respirometry system that incorporate various regularization methods for both linear and nonlinear respirometry inversions. For the nonlinear systems, blind deconvolution methods are developed and prior knowledge of nonlinear parameters are used to reduce the dimension of the nonlinear systems. Simulated and real-data experiments of the respirometry problems are provided. This dissertation provides advanced tools for computational inversion and uncertainty quantification. / Doctor of Philosophy / For many scientific applications, inverse problems have played a key role in solving important problems by enabling researchers to estimate desired parameters of a system from observed measurements. For example, large-scale inverse problems arise in many global problems such as greenhouse gas tracking where the problem of estimating the amount of added or removed greenhouse gas at the atmosphere gets more difficult. The number of observations has been increased with improvements in measurement technologies (e.g., satellite). Therefore, the inverse problems become large-scale and they are computationally hard to solve. Another example of an inverse problem arises in tomography, where the goal is to examine materials deep underground (e.g., to look for gas or oil) or reconstruct an image of the interior of the human body from exterior measurements (e.g., to look for tumors). For tomography applications, there are typically fewer measurements than unknowns, which results in non-unique solutions. In this dissertation, we treat unknowns as random variables with prior probability distributions in order to compensate for a deficiency in measurements. We consider various additional assumptions on the prior distribution and develop efficient and robust numerical methods for solving inverse problems and for performing uncertainty quantification. We apply our developed methods to many numerical applications such as greenhouse gas tracking, seismic tomography, spherical tomography problems, and the estimation of CO2 of living organisms.

Les poissons vivant au sein d’une rivière sont soumis à des variations circadiennes de température pouvant influencer la croissance, la digestion et le métabolisme standard. Les modèles bioénergétiques utilisant les fonctions métaboliques pour déterminer la croissance d’un poisson ont souvent été élaborés avec des poissons acclimatés à des températures constantes. Ces modèles pourraient sous-estimer l’énergie dépensée par un poisson soumis à des températures fluctuantes. En utilisant la respirométrie par débit intermittent, les objectifs de ce travail étaient : (1) de quantifier les différences entre les taux métaboliques standards de poissons acclimatés à une température constante (20.2 oC ± 0.5 oC) et à des fluctuations circadiennes de température (19.8 oC ± 2.0 oC; 19.5 oC ± 3.0 oC) et (2) comparer deux méthodologies pour calculer les taux métaboliques standards de poissons sujets aux fluctuations circadiennes de températures : respirométrie (a) en température constante ou (b) en température fluctuante. Les poissons acclimatés à des fluctuations circadiennes de température ont des taux métaboliques standards plus élevés que des poissons acclimatés à une température constante. À 20.2 oC ± 0.5 oC, les taux métabolique standards ont été de 25% à 32% plus bas pour des poissons maintenus à une température constante que pour des poissons gardés sous des fluctuations circadiennes de température. Les méthodologies utilisées pour estimer les taux métaboliques standards de poissons sujets aux fluctuations de température offrent des résultats similaires. / Fish that inhabits river are subjected to circadian fluctuations in water temperature. These fluctuations can influence growth, digestion and metabolic processes. Bioenergetic models are traditionally modeled using data recorded from fish kept at constant water temperatures. These models could underestimate the energy spent by fish subjected to fluctuating temperatures. Thus, with intermittent-flow respirometry, the objectives of this study were to: (1) quantify the differences between standard metabolic rates of fish acclimatized to a constant temperature (20.2 oC ± 0.5 oC) and two circadian fluctuating temperatures (19.8 oC ± 2.0 oC; 19.5 oC ± 3.0 oC) and (2) compare two methodology for calculate standard metabolic rates of fish subjected to circadian fluctuating temperatures: intermittent-flow respirometry with (a) constant temperature or (b) fluctuating temperatures. Fish held at circadian fluctuating temperatures have higher standard metabolic rates than fish acclimatized to a constant temperature. At 20.2 oC ± 0.5 oC, standard metabolic rates was 25% to 32% lower for fish held at constant temperature than for fish held under circadian fluctuations. However, results of the two different strategies used to calculate standard metabolic rates of fish subjected to circadian fluctuating temperatures did not differ.

Les poissons vivant au sein d’une rivière sont soumis à des variations circadiennes de température pouvant influencer la croissance, la digestion et le métabolisme standard. Les modèles bioénergétiques utilisant les fonctions métaboliques pour déterminer la croissance d’un poisson ont souvent été élaborés avec des poissons acclimatés à des températures constantes. Ces modèles pourraient sous-estimer l’énergie dépensée par un poisson soumis à des températures fluctuantes. En utilisant la respirométrie par débit intermittent, les objectifs de ce travail étaient : (1) de quantifier les différences entre les taux métaboliques standards de poissons acclimatés à une température constante (20.2 oC ± 0.5 oC) et à des fluctuations circadiennes de température (19.8 oC ± 2.0 oC; 19.5 oC ± 3.0 oC) et (2) comparer deux méthodologies pour calculer les taux métaboliques standards de poissons sujets aux fluctuations circadiennes de températures : respirométrie (a) en température constante ou (b) en température fluctuante. Les poissons acclimatés à des fluctuations circadiennes de température ont des taux métaboliques standards plus élevés que des poissons acclimatés à une température constante. À 20.2 oC ± 0.5 oC, les taux métabolique standards ont été de 25% à 32% plus bas pour des poissons maintenus à une température constante que pour des poissons gardés sous des fluctuations circadiennes de température. Les méthodologies utilisées pour estimer les taux métaboliques standards de poissons sujets aux fluctuations de température offrent des résultats similaires. / Fish that inhabits river are subjected to circadian fluctuations in water temperature. These fluctuations can influence growth, digestion and metabolic processes. Bioenergetic models are traditionally modeled using data recorded from fish kept at constant water temperatures. These models could underestimate the energy spent by fish subjected to fluctuating temperatures. Thus, with intermittent-flow respirometry, the objectives of this study were to: (1) quantify the differences between standard metabolic rates of fish acclimatized to a constant temperature (20.2 oC ± 0.5 oC) and two circadian fluctuating temperatures (19.8 oC ± 2.0 oC; 19.5 oC ± 3.0 oC) and (2) compare two methodology for calculate standard metabolic rates of fish subjected to circadian fluctuating temperatures: intermittent-flow respirometry with (a) constant temperature or (b) fluctuating temperatures. Fish held at circadian fluctuating temperatures have higher standard metabolic rates than fish acclimatized to a constant temperature. At 20.2 oC ± 0.5 oC, standard metabolic rates was 25% to 32% lower for fish held at constant temperature than for fish held under circadian fluctuations. However, results of the two different strategies used to calculate standard metabolic rates of fish subjected to circadian fluctuating temperatures did not differ.

The current understanding of lactate metabolism in fish is based almost entirely on interpretation of concentration measurements that cannot be used to infer changes in flux. Moreover, the transporters regulating these fluxes have never been characterized in rainbow trout. My goals were: (1) to quantify lactate fluxes in rainbow trout under normoxic resting conditions, during acute hypoxia, and exercise by continuous infusion of [U-14C] lactate; (2) to determine lactate uptake capacity of trout tissues by infusing exogenous lactate in fish rest and during graded exercise, and (3) to clone monocarboxylate transporters (MCTs) and determine the effects of exhausting exercise on their expression. Such information could prove important to understand the mechanisms underlying the classic “lactate retention” seen in trout white muscle after intense exercise. In normoxic resting fish, the rates of appearance (Ra) and disappearance (Rd) of lactate were always matched (~18 to 13 µmol kg-1 min-1), thereby maintaining a low baseline blood lactate concentration (~0.8 mM). In hypoxic fish, Ra lactate increased from baseline to 36.5 µmol kg-1 min-1, and was accompanied by an unexpected 52% increase in Rd reaching 30.3 µmol kg-1 min-1, accounting for a rise in blood lactate to 8.9 mM. In exercising fish, lactate flux was stimulated > 2.4 body lengths per second (BL s-1). As the fish reached critical swimming speed (Ucrit), Ra lactate was more stimulated (+67% to 40.4 μmol kg-1 min-1) than Rd (+41% to 34.7 μmol kg-1 min-1), causing an increase in blood lactate to 5.1mM. Fish infused with exogenous lactate stimulated Rd lactate by 300% (14 to 56 μmol kg-1 min-1) during graded exercise, whereas the Rd in resting fish increased by only 90% (21 to 40 µmol kg-1 min-1). Four MCT isoforms were partially cloned and characterized in rainbow trout: MCT1b was the most abundant in heart, and red muscle, but poorly expressed in gill and brain where MCT1a and MCT2 were prevalent. MCT4 was more expressed in the heart. Transcript levels of MCT2 (+260%; brain), MCT1a (+90%; heart) and MCT1b (+50%; heart) were stimulated by exhausting exercise. This study shows that: (i) the increase in Rd lactate plays a strategic role in reducing the lactate load imposed on the circulation. Without this response, blood lactate accumulation would double; (ii) a high capacity for lactate disposal in rainbow trout tissues is elicited by the increased blood-to-tissue lactate gradient when extra lactate is administered; and (iii) rainbow trout may be unable to release large lactate loads rapidly from white muscle after exhausting exercise (lactate retention) because they poorly express MCT4 in white muscle and fail to upregulate its expression during exercise.

Made available in DSpace on 2014-12-17T14:08:42Z (GMT). No. of bitstreams: 1 CintiaCC_DISSERT.pdf: 1504056 bytes, checksum: 13440ae86adf05b61136b7a79d592863 (MD5) Previous issue date: 2010-08-16 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The oil activity in the Rio Grande do Norte State (RN) is a permanent threat to coastal ecosystems, particularly mangroves, with the possibility of oil spills. In this context, the objective of this study was to evaluate the potential resistance of the mangrove environment of a possible spill. Were selected and isolated microorganisms degrading oil by the technique of enrichment cultures and formation of a bacterial consortium. The kinetic study of the consortium was held in rotary incubator shaken at 150 rpm and 30? C. Samples were taken at intervals of 4 hours for analysis of cell concentration and surface tension. The biodegradation was monitored using two methods of respirometry: manometric (OxiTop-C ?) and conductivimetry, where the biodegradation of oil was estimated indirectly by oxygen consumption and CO2 production, respectively. Furthermore, it was used a full 2? factorial design with triplicate at central point to the runs that used the conductivimetric methodology.. The technique of enrichment cultures allowed to obtain thirteen bacterial strains. Kinetic study of the consortium, we can showed the absence of the lag phase, reaching a maximum cell concentration of 2.55 g / L at 16 h of cultivation and a reduction on surface tension. When we adopted the methodology of OxiTop-C was detected a band indicating biodegradability (1% oil v/v), however when we used the conductivimetry methodology did not observe any band that would indicate effective biodegradation. By monitoring a process of biodegradation is necessary to observe the methodology will be adopted to evaluate the biodegradation process, since for the same conditions adopted different methodologies can produce different results. The oil-degrading isolates from soils of the mangrove estuary Potengi / RN are largely to be used in bioremediation strategies of these places, in the case of a possible oil spill, or it can be used in the treatment of waste oil generated in saline environments, since they are optimized the conditions of the tests so that the efficiency of biodegradation reach the minimum level suggested by the standarts / A atividade petrol?fera do RN constitui uma amea?a permanente aos ecossistemas costeiros, principalmente os manguezais, com a possibilidade de derramamentos de ?leo. Neste contexto, o objetivo desse estudo foi avaliar o potencial de resist?ncia do ambiente de manguezal a um poss?vel derramamento. Foram selecionados e isolados microrganismos degradadores de petr?leo pela t?cnica de enriquecimento de culturas e forma??o de um cons?rcio bacteriano. O estudo cin?tico do cons?rcio foi realizado em incubador rotativo sob agita??o de 150 rpm e temperatura de 30?C. As amostras foram retiradas em intervalos de 4h para an?lise da concentra??o celular e tens?o superficial. A biodegrada??o foi monitorada atrav?s de dois m?todos de respirometria: manom?trico (OxiTop-C?) e condutivimetria, nos quais a biodegradabilidade de petr?leo foi estimada indiretamente pelo consumo de oxig?nio e produ??o de CO2, respectivamente. Al?m disso, nos ensaios de condutivimetria foi realizado um planejamento fatorial completo 2? com triplicata no ponto central. Pela t?cnica de enriquecimento de culturas foram obtidas treze linhagens bacterianas. No estudo cin?tico do cons?rcio, pode-se observar aus?ncia da fase lag atingindo-se uma concentra??o celular m?xima de 2,55 g/L em 16 h de cultivo e queda da tens?o superficial. Quando adotou-se a metodologia do OxiTop-C foi detectado uma faixa que indica biodegradabilidade (1% de petr?leo v/v), no entanto quando utilizou-se a metodologia de condutivimetria n?o foi observado nenhuma faixa que indicasse biodegradabilidade efetiva. Ao monitorar um processo de biodegradabilidade ? necess?rio avaliar qual a metodologia ser? adotada para avaliar o processo de biodegrada??o, pois para as mesmas condi??es adotadas diferentes metodologias podem apresentar resultados divergentes. Os degradadores de petr?leo isolados do solo de mangue do estu?rio do Rio Potengi/RN podem vir a ser utilizados em estrat?gias de biorremedia??o desses lugares, no caso de um eventual derramamento de ?leo, ou ainda, podem ser empregados no tratamento de res?duos petrol?feros gerados em ambientes salinos, desde que sejam otimizadas as condi??es dos ensaios de modo que as efici?ncias de biodegrada??o atinjam o patamar m?nimo sugerido pelas normas

La bio-augmentation des stations d’épuration est parfois envisagée pour faire face à des situations transitoires au cours desquelles la capacité nitrifiante des boues activées est insuffisante pour traiter efficacement la charge reçue par l’installation. Le succès de cettestratégie repose sur l’activité nitrifiante de la biomasse ajoutée ainsi que sur sa capacitéd’adaptation et de maintien dans les boues activées en place.L’objectif de ce travail était d’évaluer la possibilité d’adaptation des micro-organismes d’une solution commerciale nitrifiante dans une station d’épuration municipale à très faible charge.Les populations nitrifiantes composant la solution étudiée ont été comparées à celles des boues activées de treize stations d’épurations, échantillonnées en été et en hiver. Une démarche couplant des outils de la biologie moléculaire et du génie des procédés a été mise en oeuvre afin d’analyser et de comparer ces populations selon trois axes : diversité, abondance et activité. Cette comparaison a été complétée par une expérience de bio-augmentation en réacteur fermé. D’après les profils obtenus en DGGE, les communautés nitrosantes des stations d’épuration à très faible charge sont généralement dominées par une même espèce appartenant au groupe Nitrosomonas oligotropha.Les biomasses nitrosantes et nitratantes ont été chacune estimées entre 0,5 et 3,5 % de la biomasse totale des boues activées par marquage FISH. La solution commerciale comporteune seule espèce nitrosante, du groupe N. europaea, qui représente 45 % de sa biomasse.Les analyses cinétiques, réalisées par suivi direct des vitesses de réaction (analyses chimiques) et/ou par respirométrie, indiquent que N. europaea adopte une stratégie de type –r contrairement aux bactéries autochtones des boues activées (stratégie de type –K). Ces résultats expérimentaux laissent supposer une faible capacité d’adaptation de la biomasse nitrifiante de cette solution commerciale aux conditions environnementales des stationsd’épuration à très faible charge. En revanche, l’expérience de bio-augmentation a montré sa capacité d’intégration aux flocs, et le maintien de son activité lors de son mélange à des boues activées. / Bio-augmentation is sometimes proposed to cope with transient situations in wastewatertreatment plants, when the nitrifying capacity of the autochthonous biomass is insufficient totreat the nitrogen load.The success of such a strategy is conditioned by the nitrifying activity of the added biomass,its adaptation to local conditions and its residence time in the system.This work aimed at evaluating the adaptation of nitrifying microorganisms from a commercialsolution in very low loaded municipal wastewater treatment plant. Nitrifying populations ofthe studied solution were compared to those of thirteen wastewater treatment plants (activatedsludge), observed in summer and in winter. The analysis and the comparison of the biomasseswere performed using tools from two disciplines: molecular biology and processengineering. Three points were especially characterised: the diversity, abundance and activityof the biomasses. A bio-augmentation experiment performed in a batch reactor completed thecomparison. DGGE profiles showed that Ammonia Oxidising Bacteria (AOB) communities from lowloaded wastewater treatment plants are mostly dominated by the same species related to theNitrosomonas oligotropha.The abundance of ammonia oxidising bacteria and of nitrite oxidising bacteria, estimatedusing the FISH technique, was almost similar, ranging from 0.5 to 3.5 % of the total biomass.The AOB species present in the commercial solution is identified as Nitrosomonas europaea,and represents 45 % of the solution’s total biomass.Kinetic analyses carried out by chemical analysis and/or by respirometry indicate that N.europaea behave as –r strategist, whereas activated sludge’s bacteria are –K strategist. These results suggest a slight adaptation capacity of the commercial solution’s nitrifyingbiomass to environmental conditions prevailing in low loaded municipal wastewater treatmentplants. On the other hand, bio-augmentation experiment showed the capacity of the addedmicroorganisms to integrate the activated sludge flocs and to maintain its activity when addedto activated sludge.

O processo de tratamento de efluentes por lodos ativados é um dos processos de tratamento mais difundido em todo o mundo, devido principalmente a qualidade do efluente obtido. Entretanto, trata-se de um processo biológico dependente da atividade bacteriana para a estabilização da matéria orgânica proveniente dos esgotos e com isso, se faz necessária a manutenção das condições ideais para a sobrevivência e proliferação das bactérias e dos outros microrganismos envolvidos neste processo. Efluentes salinos causam um grande distúrbio na atividade celular dos microrganismos presentes neste processo. A análise biológica do lodo e a taxa de consumo de oxigênio são testes rápidos, práticos, baratos e sem geração de resíduos químicos e que foram adotados neste trabalho para acompanhar a eficiência do processo. Esses dois parâmetros são amplamente utilizados em pesquisas, porém ainda é sub-utilizado para efetivo monitoramento de Estações de Tratamento de Esgotos. Este presente trabalho investigou a influência da salinidade nos processos de lodos ativados através de parâmetros que levam em consideração a atividade metabólica dos organismos aeróbios e através do monitoramento da comunidade de protozoários indicadores biológicos do lodo ativado, os testes de respirometria e os testes da análise biológica do lodo, respectivamente. Os resultados da atividade metabólica são apresentados em forma de gráficos, em termos de taxa de consumo de oxigênio específico e porcentagem de inibição. Os resultados da qualidade biológica são apresentados em números de 0 a 10 de acordo com o Índice de Madoni (1994). Os resultados demonstraram a imediata intoxicação dos lodos ativados em concentrações de sal a partir da concentração mínima utilizada neste trabalho, que foi de 5 gL de NaCl. Para entender melhor o processo de intoxicação foi realizado experimentos de 96 horas de monitoramento após o choque de cloreto de sódio nos reatores com lodos ativados, os resultados não demonstraram melhoria no processo. Os resultados sugerem que os testes de taxa de consumo de oxigênio em consonância com os testes da qualidade biológica são eficientes e complementares para a avaliação da influência da salinidade no processo de lodos ativados. / Effluent treatment process by sludge activated is one of the most used processes of treatment all over the world, mainly because of the quality of the final effluent. However, this process is a biological one, and so, it depends on the bacterial activity to the stabilization of the organic matter of the sewage. Considering this, it is necessary to maintain the ideal conditions to the survival and proliferation of the bacteria responsible for the process. This work considered two parameters to evaluate the influence of the salinity in the sludge activated processes; these parameters are widely used in research, however, little used for the monitoring of the Wastewater Treatment Plants. The objectives of this work are to investigate the influence of the salinity through the respirometry test and the biological quality of the sludge. The results of the metabolic activity are presented in graphics, in terms of Oxygen Uptake Rate and percentage of inhibition. The results of the biological quality are presented in numbers by 0 to 10 according to the Mandonis Index (1994). The results show the intoxication of the sludge activated in saline concentrations higher than 5 g/L of NaCl in the saline shock, and it seems that efficiency do not get better even after 96 hours. The results suggests that the respirometry test and the biological quality test are efficient and complementary to the evaluation of salinity in the sludge activated processes.