Because of the increasing trends in energy consumption and increased environmental awareness, greater focus has been placed on improvement and development of renewable energy sources. An already proven and accepted method is biogas production from anaerobic digestion at municipal wastewater treatment plants. In the waste water treatment process solid material and dissolved pollutants are separated from the water, forming a sludge. The sludge is separated from the process and stabilized during anaerobic digestion or aerobic aeration. Most often, mesophilic anaerobic digestion is used. Because of degradation by microorganisms, biogas with a high content of methane is formed during the digestion. To optimize the process different studies with co-digestion with sludge and other substrate have been made. It has been showed, in earlier research studies, that co-digestion with microalgae and sewage sludge results in a synergistic effect with increased biogas production. As the microalgae are microorganisms which use photosynthesis they contain stored energy from sun light. The stored energy will be available when the microalgae are digested in mesophilic conditions. In contrast to other biomass suitable for co-digestion microalgae have the advantage of being able to grow in waste water and reduce the pollutants in the water phase. Cultivation of microalgae will therefore not compete with the cultivation of food production and at the same time has the possibility to decrease the electricity- and heat consumption at the wastewater treatment plants. The aim of this study was to investigate how a possible synergetic effect between microalgae and sewage sludge effects the biogas production and the process stability. The microalgae was cultivated in municipal waste water from the WWTP in Umeå (Sweden) and the sludge was collected from the WWTP in Västerås (Sweden). The fermenters used was of the type DOLLY© and the active volume was 5 dm3. The temperature in the fermenters was kept at 37 °C and the study was divided into two periods. During the first period the hydraulic retention time was 15 days and the organic loading rate 2.4 g VS dm-3 d-1. During the second period the hydraulicretention time was kept at 10 days and the organic loading rate was 3.5 g VS dm-3 d-1. The result showed an increase with 54.6 % in methane production per reduced VS in the fermenter with co-digestion compared to the fermenter where only sludge was digested. Period one showed the highest increase. The result also showed a good process stability for both fermenters during the whole experiment. This study shows that there are reasons for continued investigations about co-digestion with microalgae and sewage sludge for an increased biogas production. / På grund av ökande el- och värmeförbrukning och ökat miljöengagemang har större fokus lagts på förbättring och utveckling av förnyelsebara källor för el- och värmeproduktion. En redan beprövad och accepterad metod för framställning av förnyelsebar energi är från biogasproduktion vid kommunala reningsverk. Vid rening av avloppsvatten avskiljs fasta partiklar och lösta föroreningar och bildar ett slam som separeras från vattnet. Slammet kan sedan stabiliseras anaerobt genom rötning eller aerobt genom luftning. En ofta använd metod vid konventionella reningsverk är mesofil anaerob rötning. Vid rötningen bryts material ner av mikroorganismer och genererar biogas som framförallt innehåller metan och koldioxid. För att optimera en sådan process och därmed kunna utvinna mer gas har det tidigare undersökts hur samrötning med olika material påverkar biogasproduktionen. Det har visat sig i forskningsförsök att samrötning med mikroalger och orötat blandslam ger en synergieffekt och mer biogas produceras. Mikroalgerna innehåller lagrad energi från solljus, då de är fotosyntesiserande organismer. Den lagrade energin har visat sig bli tillgänglig vid mesofil anaerob nedbrytning. Till skillnad från annan biomassa som undersökts för samrötning kan mikroalgerna odlas på avloppsreningsverken och fungera som en del av reningsprocessen då mikroalgerna tar upp näringsämnen ur vattnet de växer i. På det sättet undviks konkurrens om odlingsmark för livsmedel och så blir reningsprocessen på avloppsreningsverken mer el- och värmeeffektiv. Syftet med studien var att undersöka om eventuell synergieffekt mellan mikroalgerna och slammet påverkar biogasproduktionen och processtabiliteten vid mesofil anaerob rötning. Mikroalgerna som användes var odlade på mekaniskt renat spillvatten från Umeås reningsverk och slammet som användes hämtades ifrån Västerås reningsverk. Rötkamrarna som användes var av modellen DOLLY© med en aktiv volym på 5 dm3. Temperaturen i rötkamrarna hölls kring 37°C och studien var uppdelad i två perioder. Under period ett var den hydrauliska uppehållstiden 15 dygn och den organiska belastningen 2,4 g VS dm-3 d-1, medan period två hade en hydraulisk uppehållstid på 10 dygn och en organisk belastning på 3,5 g VS dm-3 d-1. Resultaten visade att metangasproduktionen per tillförd mängd organiskt material var lägre vid samrötning jämfört med rötning av enbart slam. Metangasproduktionen per reducerad mängd organiskt material ökade med upp till 54,6 % vid samrötningen jämfört med rötning av enbart slam. Period ett gav upphov till den största ökningen. Processen hölls stabil även vid inblandning av mikroalger, under både period ett och två. Studien visar att det finns ett underlag för fortsatta studier kring samrötning av mikroalger och slam för en ökad biogasproduktion.

La digestion anaérobie est un moyen de traitement des déchets solides produisant de l'énergie sous forme de biogaz (méthane et dioxyde de carbone). L'optimisation de la production de méthane passe par une sélection des déchets à fort potentiel méthane. Actuellement, la mesure du potentiel méthane est réalisée par le test BMP (Biochemical Methane Potential), qui repose sur une fermentation pouvant durer plus de 30 jours, ce qui est trop long pour une installation industrielle. Une méthode rapide de détermination du potentiel méthane est donc nécessaire. Le BMP est lié uniquement à la quantité et à la qualité de la matière organique. Cette méthode doit donc réaliser une analyse globale et rapide de la matière organique. L'objectif de la thèse a été d'identifier et d'étudier une méthode rapide d'analyse de la matière organique de déchets solides permettent de prédire le potentiel méthane. Suite au travail bibliographique, la spectroscopie proche infrarouge s'est révélée la méthode la plus appropriée: analyse globale et rapide, non destructive, préparation d'échantillon réduite, possibilité d'utiliser des fibres optiques pour déporter la mesure. Nous avons ensuite étudié des étalonnages pour prédire le potentiel méthane d'un ensemble homogène de 74 déchets. Un coefficient de corrélation de 0,76 et un écart standard de prédiction (RMSEP) de 28 ml CH4.g-1 MV ont été obtenus. Ensuite, les coefficients du modèle ont été analysés par rapport aux molécules présentes et rapprochés des variables sélectionnées par algorithme génétique afin de valider ce modèle d'un point de vue chimique. Enfin, la robustesse de ce modèle vis à vis de l'origine des échantillons et de l'humidité a été testée. Les résultats montrent clairement le fort potentiel de la spectroscopie proche infrarouge pour la prédiction du potentiel méthane. Pour une utilisation industrielle, il ressort qu'une attention particulière doit être portée sur l'ensemble d'étalonnage, qui doit être le plus exhaustif possible. / Anaerobic digestion is a solution to process solid waste, while producing energy by biogas production (methane and carbon dioxide). Methane production could be optimized by selecting only wastes with high methane potential. Currently, the BMP (Biochemical Methane Potential) test is conducted to predict the methane potential. This test is based on a fermentation process. It is time consuming, sometimes, lasting over 30 days, which is too long from an industrial point of view. A rapid method for determining the methane potential is therefore urgently needed. The BMP value depends only on the quantity and the quality of the organic matter, so a method capable of determining the quality and quantity of organic matter is searched for. The objective of this thesis was to identify and study such a method. First, a bibliographic study led us to chose the near infrared (NIR) spectroscopy method: fast and global analysis of the organic matter, non-destructive method, few or no sample preparation, and remote monitoring by use of fiber optics. Second, a calibration for predicting the BMP of and homogenous sample set has been built based on a 74-waste sample set. A correlation coefficient of R² = 0,76 and a standard error of prediction (RMSEP = 28 ml CH4.g-1 VS). Then, the regression coefficients (called b coefficients) were analysed with regard to the molecules in the waste and were compared to the variables selected from the spectrum, in order to validate the model from a chemical point of view. Finally, the robustness of the model, regarding the waste origins and the moisture was tested with heterogeneous samples set. Results show the potential of the near infrared spectroscopy to predict the methane potential quickly, but attention must be paid on the calibration data set when an industrial implementation is dealt with..

A digestão nos insetos ocorre no intestino médio de forma compartimentada. A digestão inicial dos polímeros ocorre no interior da membrana peritrófica. Os oligômeros resultantes difundem-se para o espaço luminal exterior à membrana peritrófica onde são atacados por outras enzimas. Na digestão final os dímeros resultantes são hidrolisados por enzimas imobilizadas na superfície do epitélio do intestino médio. Após o processo de digestão final os monômeros são absorvidos pelas células do epitélio intestinal. Os Díptera ditos superiores, incluindo a mosca doméstica, apresentam peculiaridades digestivas que aparentemente resultam de adaptações para digerir uma dieta que consiste principalmente de bactérias. No ventrículo anterior ocorre uma diminuição no conteúdo de amido do bolo alimentar. Na porção seguinte, o bolo alimentar passa para o ventrículo médio onde as bactérias são mortas pela ação combinada de baixo pH, uma lisozima digestiva e uma proteinase tipo catepsina D. O material liberado das bactérias é digerido no ventrículo posterior, como ocorre no ventrículo inteiro da maioria dos insetos de outros grupos taxonômicos. Com o objetivo de compreender a peculiar digestão em Musca domestica, foram utilizadas suas larvas para identificar funcionalmente as regiões absortivas de nutrientes, identificar as moléculas envolvidas na absorção de nutrientes, identificar as moléculas envolvidas com tamponamento e fluxos de fluidos intestinais, sequenciar as enzimas digestivas principais e identificar os seus sítios de secreção. Experimentos fisiológicos de absorção de glicose e análises de atividade enzimática permitiram acessar de maneira direta os aspectos da digestão. Contudo, experimentos de sequenciamento de bibliotecas de cDNA, análise de sequências transcritas e verificação de expressão de genes em diferentes tecidos foram abordagens fundamentais na identificação das moléculas subjacentes aos processos fisiológicos intestinas de Musca domestica. Os indícios de que absorção de glicose no intestino de Musca domestica se dê por transportadores do tipo SGLT, com a possível participação de facilitadores do tipo GLUT, permitem estabelecer um foco para futuros estudos. A descrição de sequências relacionadas ao tamponamento intestinal permitiu ampliar a discussão sobre tal processo. Ao detalhar os sítios de expressão da subunidade a da V-ATPase, do canal de cloreto e do transportador de amônia foi possível testar o modelo de tamponamento proposto anteriormente e propor a participação de outras moléculas no processo. Sequências correspondentes as atividades de carboxipeptidase, maltase e aminopeptidase descritas na literatura foram pesquisadas, gerando sequências candidatas a codificarem as referidas enzimas. Com isso, é possível descrever a digestão de oligômeros e dímeros com base nos genes transcritos e nas sequências de aminoácidos que formam as enzimas digestivas. A descoberta da sequência que transcreve uma metaloproteinase, por sua vez, abre caminhos para a descrição e caracterização de sua atividade proteolítica nos tecidos digestivos da larva de Musca domestica. Essa análise permitiu também elucidar a localização dos sítios de expressão e, portanto, as zonas de secreção de enzimas. De maneira geral, este estudo contribuiu para a compreensão de diversos aspectos da digestão de Musca domestica, elucidando questões da particular fisiologia digestiva desse inseto. / Digestion in insects occurs in the midgut in a compartmentalized way. Initial digestion takes place inside the peritrophic membrane. The resulting oligomers diffuse into the luminal space outside the peritrophic membrane where they are hydrolyzed by other enzymes. In the final digestion, the resulting dimers are hydrolyzed by enzymes immobilized on the midgut epithelium. After the final digestion, the monomers are absorbed by intestinal epithelial cells. The so-called higher Diptera, including the house fly, have digestive peculiarities apparently resulting of adaptations to digest a diet consisting mainly of bacteria. In the anterior midgut there is a decrease in the starch content of the food bolus. The bolus now passes into the middle midgut, where bacteria are killed by the combined action of low pH, a special lysozyme and a cathepsin D-like proteinase. Finally, the material released by bacteria is digested in the posterior midgut, as is observed in the whole midgut of insects of other taxa. In order to understand the peculiar digestion in Musca domestica, the larvae were used to identify (a) the functionally the nutrient absorptive regions, (b) the molecules involved in the absorption of nutrients, (c) the molecules involved in buffering and fluid flows, (d) the cDNA sequences corresponding to intestinal digestive enzymes, (e) the main sites of secretion. Physiological experiments of glucose absorption and enzyme activity analysis allowed a direct access to aspects of digestion. Otherwise, cDNA library sequencing followed by sequence annotation and tissue-specific expression analysis were fundamental approaches in the understanding of intestinal physiology of Musca domestica. Evidence that glucose absorption in the gut of Musca domestica occurs through SGLT-like transporters, with the possible participation of facilitators GLUT-like, allowed us to establish a focus for future studies. The description of cDNA sequences corresponding to proteins putatively responsible for intestinal buffering widened the discussion of this process. The finding of the expression sites of V-ATPase subunits, chloride channel, and ammonia transporter led to revising the present buffering model and the inclusion of other molecules in the process. The cDNA sequences corresponding to the activities of carboxypeptidase, aminopeptidase and maltase described in the literature were searched for as candidate sequences to encode those enzymes. This made it possible to describe the digestion of oligomers and dimers based on transcribed genes and enzyme amino acid sequences. The discovery of the metalloproteinase transcribing sequence opened a new research line: the description and characterization of its proteolytic activity in the midgut of the Musca domestica larvae. This study also allowed elucidating the location of digestive enzyme expression sites and, therefore, the putative zones of enzyme secretion. Overall, this study contributed to understanding many aspects of digestion of Musca domestica, clarifying aspects of the peculiar digestive physiology of this insect.

Biomass and biomass-derived waste are important renewable energy sources which plays a vital role in greenhouse gas reduction from fossil fuel.  Biomass can be degraded in a process known as anaerobic digestion (AD) to produce biogas. Biogas is a mixture of methane and carbon dioxide which is utilized as a renewable source of energy. This project was based on the investigation of AD process in Nordvästra Skånes Renhållnings AB (NSR) a biogas facility in Helsingborg Sweden. A lab simulation of NSR digesters was conducted to evaluate the effects of swine manure on AD using two continuously stirred tank reactors (CSTR) R1 (control) and R2 with a working volume of 4L for 21 weeks. The study was divided into 4 periods and the investigation was carried out by increasing the organic loading rate (OLR) step wise from 2.5 to 3.6 gVSL-1day-1. To assess the effects of swine manure, the performance and stability of the reactors were monitored by collecting data from process parameters. These process parameters included biogas production, pH, volatile fatty acids, methane yield, methane content and organic solids (total and volatile solids). Increase in OLR resulted in increase biogas production in both reactors, however R2 with additional swine manure (15%) produced more biogas than R1. Methane yield was fairly stable during the experiment and had a similar trend in both reactors, but however R2 had a slightly higher average yield (730±60 mLCH4 gVS-1) than R1 (690±60 mLCH4 gVS-1) during the entire experiment. Increase OLR resulted in increase VFA in period 2; R2 with additional swine manure had a lower peak VFA concentration of 25 mM as compared to 33mM in R1.  The characteristics of NSR substrate mix and swine manure provided a good buffering system (stable pH), and reactors were still running stably at 3.6 gVSL-1day-1. Furthermore swine manure was investigated to contain macro-nutrients and trace metals which might have enhanced the AD process in R2 containing more Co, Zn, Ni and Mo than R1. Since this investigation was a simulation, the waste mix used at NSR contained 7% swine manure, this made it difficult to give clearer conclusions about the effects of co-digestion of swine manure on the biogas process since the control (R1) had 7% swine manure. Keywords: Anaerobic digestion, co-digestion, swine manure, substrate mix, organic loading rate, biogas production, methane yield, VFA, process parameters, CSTR.

Cette thèse porte sur l'analyse et le contrôle optimal d'un digesteur anaérobie. L'objectif est de proposer une stratégie de commande optimale pour maximiser la quantité de biogaz produit dans un bioréacteur anaérobie sur une période de temps donnée. Plus particulièrement, à partir d'un modèle simple de bioprocédé et en considérant une classe importante de cinétiques de croissance, nous résolvons un problème de maximisation de biogaz produit par le système pendant un temps fixé, en utilisant le taux de dilution D(.) comme variable de contrôle. Dépendant des conditions initiales du système, l'analyse du problème de contrôle optimal fait apparaître des degrés de difficulté très divers. Dans une première partie, nous résolvons le problème dans le cas où le taux de dilution permettant de maximiser le débit de gaz à l'équilibre est à l'intérieur des bornes minimales et maximales du débit d'alimentation pouvant être appliqué au système : il s'agit du cas WDAC (Well Dimensioned Actuator Case). La synthèse du contrôle optimal est obtenue par une approche de comparaison de trajectoires d'un système dynamique. Une étude comparative des solutions exactes avec celle obtenues avec une approche numérique directe en utilisant le logiciel "BOCOP" est faite. Une comparaison des performances du contrôleur optimal avec celles obtenues en appliquant une loi heuristique est discutée. On montre en particulier que les deux lois de commande amènent le système vers le même point optimal. Dans une deuxième partie, dans le cas où l'actionneur est sous- (ou sur-) dimensionné, c'est-à-dire si la valeur du taux de dilution à appliquer pour obtenir le maximum de biogaz à l'équilibre est en dehors de la valeur minimale ou maximale de l'actionneur, alors nous définissons les cas UDAC (Uder dimensioned Actuator Case) et ODAC (Over Dimensioned Actuator Case) que nous résolvons en appliquant le principe du maximum de Pontryagin. / This thesis focuses on the optimal control of an anaerobic digestor for maximizing its biogas production. In particular, using a simple model of the anaerobic digestion process, we derive a control law to maximize the biogas production over a period of time using the dilution rate D(.) as the control variable. Depending on initial conditions and constraints on the actuator, the search for a solution to the optimal control problem reveals very different levels of difficulty. In the first part, we consider that there are no severe constraints on the actuator. In particular, the interval in which the input flow rate lives includes the value which allows the biogas to be maximized at equilibrium. For this case, named WDAC (Well Dimensioned Actuator Case) we solve the optimal control problem using classical tools of differential equations analysis.Numerical simulations illustrate the robustness of the control law with respect to several parameters, notably with respect to initial conditions. We use these results to show that an heuristic control law proposed in the literature is optimal in a certain sense. The optimal trajectories are then compared with those given by a purely numerical optimal control solver (i.e. the "BOCOP" toolkit) which is an open-source toolbox for solving optimal control problems. When the exact analytical solution to the optimal control problem cannot be found, we suggest that such numerical tool can be used to intuiter optimal solutions.In the second part, the problem of maximizing the biogas production is treated when the actuator is under (-over) dimensioned. These are the cases UDAC (Under Dimensioned Actuator Cases) and ODAC (Over Dimensioned Actuator Cases). Then we solve these optimal problems using the Maximum Principle of Pontryagin.

Cette thèse porte sur l’analyse mathématique de différents modèles de la digestion anaérobie. Dans la première partie, nous étudions un modèle à quatre étapes avec dégradation enzymatique du substrat (matière organique) qui peut être sous forme solide. Nous étudions l’effet de l’hydrolyse sur le comportement du processus de la digestion anaérobie et de la production du biogaz (méthane et hydrogène). Nous considèrons, dans un premier modèle, que l’hydrolyse se fait d’une manière enzymatique, alors que dans un second, nous supposons qu’elle est réalisée par un compartiment microbien. Les modèles considérés incluent l’inhibition de croissance des bactéries acétogènes, méthanogènes hydrogénétrophes et acétoclastes par plu- sieurs substrats. Pour étudier l’effet de ces inhibitions en présence de l’étape de l’hydrolyse, nous étudions dans un premier temps un modèle sans inhibition. Nous déterminons les équilibres et nous donnons des conditions nécessaires et suffisantes pour leur stabilité. L’existence et la stabilité des équilibres sont illustrées avec des diagrammes opératoires. Nous montrons que le modèle avec hydrolyse enzymatique change la production du méthane et d’hydrogène. En outre, l’introduction du com- partiment hydrolytique microbien donne de nouveaux équilibres et affecte les régions de stabilité. Nous prouvons que la production de biogaz est maximale en un seul point d’équilibre selon les paramètres opératoires et nous déterminons le taux maxi- mal de biogaz produit, dans chaque cas. Dans la deuxième partie, nous nous sommes intéressés à un modèle à deux étapes décrivant les phases de l’acétogénèse et de la méthanogénèse hydrogénotrophe. Le modèle représente une relation de syntrophie entre deux espèces microbiennes (les bactéries acétogènes et méthanogènes hydro- génotrophes), avec deux substrats à l’entrée (l’acide gras volatile et l’hydrogène), incluant les termes de mortalité et l’inhibition de croissance des bactéries acéto- gènes par un excès d’hydrogène dans le système. L’analyse de l’existence et de la stabilité des équilibres du modèle donne naissance à un nouvel équilibre qui peut être stable selon les paramètres opératoires du système. En utilisant les diagrammes opératoires, on remarque que, quelle que soit la région de l’espace considérée, il existe un seul équilibre localement exponentiellement stable. Cette étude est géné- ralisée dans le cas où la croissance des bactéries méthanogènes hydrogénotrophes est inhibée. Ce modèle donne naissance à deux équilibres strictement positifs et une bistabilité. Nous illustrons, en utilisant les diagrammes opératoires l’effet de cette inhibition sur la réduction des régions de coexistence et l’émergence de régions de bistabilité. / This PhD thesis focuses on the mathematical analysis of different anaerobic digestion (AD) models. In a first part, we study a 4-step model with enzymatic degradation of the substrate (organic matter) that can partly be under a solid form. We investigate the effects of hydrolysis on the behavior of the AD process and the production of biogas (namely, the methane and the hydrogen). We consider, in a first model, that the microbial enzymatic activity is constant, then we take into consideration an explicit hydrolytic microbial compartment for the substrate biodegradation. The considered models include the inhibition of acetogens, hydroge- notrophic methanogens and acetoclastic methanogens growth bacteria. To examine the effects of these inhibitions in presence of a hydrolysis step, we first study an inhibition-free model. We determine the steady states and give sufficient and neces- sary conditions for their stability. The existence and stability of the steady states are illustrated by operating diagrams. We prove that modeling the hydrolysis phase by a constant enzymatic activity affects the production of methane and hydrogen. Furthermore, introducing the hydrolytic microbial compartment yields new steady states and affects the stability regions. We prove that the biogas production occurs at only one of the steady states according to the operating parameters and state variables and we determine the maximal rate of biogas produced, in each case. In the second part, we are interested in a reduced and simplified model of the AD pro- cess. We focus on the acetogenesis and hydrogenetrophic methanogenesis phases. The model describes a syntrophic relationship between two microbial species (the acetogenic bacteria and the hydrogenetrophic methanogenic bacteria) with two in- put substrates (the fatty acids and the hydrogen) including both decay terms and inhibition of the acetogenic bacteria growth by an excess of hydrogen in the sys- tem. The existence and stability analysis of the steady states of the model points out the existence of a new equilibrium point which can be stable according to the operating parameters of the system. By means of operating diagrams, we show that, whatever the region of space considered, there exists only one locally exponentially stable steady state. This study is generalized to the case where the growth of the hydrogenetrophic methanogens bacteria is inhibited. This model exhibits a rich be- havior with the existence of two positive steady states and bistability. We illustrate by means of operating diagrams the effect of this inhibition on the reduction of the coexistence region and the emergence of a bistability region.

Lors du vieillissement, les capacités sensorielles et l’efficacité masticatoire diminuent, affectant négativement l'alimentation des séniors. Ainsi, la formulation d’aliments adaptés aux besoins nutritionnels et sensoriels des seniors est un enjeu pour les années à venir. L'objectif principal de cette thèse, intégrée au projet AlimaSSenS, est d’étudier l’impact de la texture de produits fromagers sur le confort en bouche et la biodisponibilité des acides aminés et du calcium. Les fromages modèles développés ont la même composition mais des textures variables. Des analyses sensorielles réalisées sur un panel de séniors, ainsi que des études de digestion in vitro et in vivo (sur modèle porcin) ont été réalisées. Les résultats des digestions soulignent la pertinence d’intégrer les protéines sériques en tant que source protéique majeure dans les produits fromagers, afin de maximiser l’apport plasmatique en acides aminés essentiels. Cependant, la texture des fromages modèles n’a pas influencé la bioaccessibilité des acides aminés et du calcium. De plus, la bioaccessibilité du calcium est majoritairement liée aux pH intra-gastrique et -intestinal, plutôt qu’à sa forme chimique initiale. Enfin, l’étude sensorielle a mis en évidence que seules les textures perçues comme « sèches » étaient liées à une baisse importante du confort en bouche des séniors. Ce travail souligne l'opportunité de développer des produits fromagers destinés aux séniors. Il serait intéressant de poursuivre ces travaux avec des études cliniques pour connaître l'impact physiologique de ces produits / During aging, the sensory capacities and the mastication efficacy decrease negatively affecting the diet of the elderly. Yet, protein and calcium requirements increase with age. In this context, the formulation of foods adapted to the nutritional and sensory needs of the elderly is a challenge for the next years. The main objective of this thesis, integrated into the project AlimaSSenS, is to study the impact of the texture of model cheeses, based on whey proteins and calcium fortified, on the oral comfort and on the bioavailability of amino acids and calcium.The model cheeses developed have the same composition and variable textures. Sensory analysis were performed on a panel of people over 65, and in vitro and in vivo digestion studies (on porcine model) were conducted.The results of the digestion studies highlighted the relevance of integrating whey proteins as a major protein source in dairy products, in order to maximize the bioavailability of essential amino acids. However, the texture of model cheeses did not significantly influence the bioaccessibility of amino acids and calcium. In addition, the bioaccessibility of calcium was mainly related to intra-gastric and intra-intestinal pH, rather than to the initial chemical form of its source of enrichment. Finally, the sensory study has shown that only the textures perceived as “dry” was linked to a significant decrease in the oral comfort.This work highlights the opportunity to develop dairy products adapted for the elderly. Based on this work, it would be interesting to carry out clinical studies to know t

Orientador: Joaquim Eugênio Abel Seabra / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-24T03:08:04Z (GMT). No. of bitstreams: 1 Mamede_MauricioCubadosSantos_M.pdf: 2829646 bytes, checksum: d25947395cd77eda7c39cdaf8fe0b8b6 (MD5) Previous issue date: 2013 / Resumo: Considerando-se a necessidade de aprofundar o conhecimento da gestão de resíduo sólido municipal (RSM) e seus efeitos no ambiente natural e sobre a viabilidade econômica, este trabalho procurou contribuir analisando diferentes rotas de aproveitamento energético de RSM no contexto brasileiro. Foram utilizadas as características de geração de RSM de 81 municípios brasileiros, com vistas à comparação de dois cenários distintos: cenário Combustível, com a combinação das tecnologias de digestão anaeróbia (D.A.) - com foco na produção de combustível veicular - e combustível derivado de resíduo (CDR), para utilização industrial; e cenário Eletricidade, com a aplicação das tecnologias de D.A. - com foco no uso do biogás em motor estacionário - e incineração, com geração elétrica em ciclo Rankine. Na avaliação econômica, realizou-se fluxo de caixa com entradas e saídas financeiras para a obtenção dos indicadores valor presente líquido (VPL) e taxa interna de retorno (TIR). Ao final realizou-se uma análise de sensibilidade, variando custos e receitas considerados, composição do RSM, além de analisar a tarifa de tratamento necessária para zerar o VPL de cada tecnologia. Na análise ambiental foi utilizada a avaliação do ciclo de vida (ACV) para consolidar os inventários dos cenários, considerando-se uso de materiais, energia, além das emissões durante a construção e operação das unidades, com posterior avaliação do impacto do ciclo de vida (AICV) pelo software SIMAPRO, no método CML 2, para sete categorias de impacto (acidificação, aquecimento global, eutrofização, depleção abiótica, depleção da camada de ozônio, toxicidade, e oxidação fotoquímica). Os resultados majoritariamente indicaram melhores desempenhos econômico e ambiental do cenário Combustível. Há vantagens econômicas e ambientais na comercialização do biogás veicular para frota automotiva à produção de eletricidade a partir do mesmo, apesar de maior necessidade de investimento e maior complexidade tecnológica. As emissões do composto orgânico e do uso de combustíveis auxiliares perfazem as maiores cargas ambientais desta tecnologia. A incineração permite diminuir significativamente o volume do RSM, entretanto é a tecnologia mais cara das analisadas e colabora significativamente com a toxicidade humana pela emissão de metais pesados. Os investimentos na planta de CDR são muito menores, entretanto há a produção significativa de rejeitos que necessitam ser gerenciados, implicando em maiores custos e emissões de transporte e disposição destes. Ainda, incertezas de comercialização do CDR podem comprometer a viabilidade do cenário. Ademais, a análise indicou significativa sensibilidade em relação às variações na composição do RSM, principalmente com relação à fração reciclável, a qual influencia diretamente o poder calorífico inferior (PCI) do CDR e incineração, e portanto as receitas obtidas. Menores taxas de adesão da população ao programa de coleta seletiva implicam em maior fluxo de materiais incinerados e de CDR, sendo a última beneficiada economicamente, devido ao maior PCI. Com exceção do CDR, as demais tecnologias necessitam de maiores tarifas de tratamento para sua viabilidade econômica comparado à atividade de aterro sanitário, que é relativamente baixa comparada à praticada em países europeus. O deslocamento de combustíveis traz maior benefício comparado ao deslocamento da matriz elétrica nacional, que é majoritariamente hidrelétrica / Abstract: Considering the necessity to deepen the knowledge about municipal solid waste (MSW) management and its effects on the natural environmental and economic performance, this work assessed different alternatives of energy recovery from MSW in Brazil. The characteristics of MSW generated in 81 Brazilian municipalities were used for the comparison of two different scenarios: Fuel scenario, with combined use of anaerobic digestion (A.D.) - focused on the production of biomethane - and refuse derived fuel (RDF), for industrial utilization; and Electricity scenario, with the employment of A.D. - focused on biogas use in stationary engines - and incineration, with electricity generation through the Rankine cycle. For the economic assessment, a cash flow analysis was carried out to evaluate the feasibility indicators net present value (NPV) and internal rate of return (IRR). Sensitivity analyses were performed varying costs and revenues, MSW composition, besides the analysis of the break even gate fee for achieving a zero NPV for each technology. For the environmental analysis, the life cycle assessment (LCA) technique was employed to consolidate the inventory of each scenario, accounting for the use of materials, energy, and the emissions during the construction and operation of the plants. The life cycle impact assessment, modeled in SIMAPRO, was based on the CML 2 method considering seven impact categories (acidification, global warming, eutrophication, abiotic depletion, ozone layer depletion, toxicity, and photochemical oxidation). For the majority of the municipalities, the Fuel scenario showed better economic and environmental performance. The commercialization of biogas as vehicle fuel has economic and environmental advantages over the production of electricity, despite the higher investments and technology complexity. The emissions from the organic compost and the use of auxiliary fuels are the main environmental burdens related to this technology. The incineration has the advantage of significantly reduce the volume of MSW, but it is the most expensive technology analyzed and contributes to human toxicity through the emissions of heavy metals. The required investments in the RDF plant are much smaller, although it produces significant amounts of rejects that need to be managed, implying in higher costs and emissions due to transportation and final disposal. Moreover, the uncertainty in commercializing RDF could affect the economic performance of the scenario. Furthermore, the analysis indicated significant sensitivity with respect to waste composition, mainly recyclables fraction, which has direct effects on the low calorific value (LCV) of RDF and incineration fuel, therefore affecting the revenues. Lower participation rates in the source separation program imply in grater fluxes of materials to be incinerated and production of RDF, with better economic performance for the RDF plant, because of the higher LCV. With the exception of RDF, the others technologies require higher gate fees, compared to landfill, in order to reach economic viability because of the lower fees for disposal in Brazil compared with European countries. Regarding the environmental analysis, the displacement of fuels leads to greater benefits when compared with the displacement of electricity, which is basically hydroelectricity / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Planejamento de Sistemas Energéticos

Dans les systèmes anaérobies de traitement d'eaux usées, la biomasse microbienne complexe incluant archées et bactéries peut être maintenue au sein du procédé par l'adhésion aux supports solides sous forme de biofilm. Le but de ce travail est d'évaluer l'impact des propriétés des matériaux supports sur l'adhésion et la colonisation du consortium méthanogène. Différents matériaux (le polyéthylène, le polypropylène, le chlorure de polyvinyle, l'acrylonitrile butadiène styrène, le polycarbonate, le verre borosilicaté, l'acier inoxydable 304L et Bioflow 30 ®) sont décrits en termes de topographie par la détermination de rugosité et en termes d'énergie de surface par la mesure d'angle de contact. Le biofilm est évalué quantitativement et les structures communautaires bactériennes et archéennes sont observées grâce à l'analyse moléculaire à différents stades de sa mise en place. L'adhésion d'un consortium méthanogène sur les matériaux après deux heures de contact dans un réacteur annulaire rotatif révèle que les communautés adhérées diffèrent de l'inoculum, y compris en termes de proportion archées/bactéries. Ce résultat a un impact significatif sur le démarrage de digesteurs anaérobie car les tendances observées sont confirmées pendant l'établissement du biofilm actif. La mise en oeuvre de différents matériaux dans des réacteurs à lit fixe a permis de montrer que les populations d'archées des biofilms sont spécifiques au matériau et indépendantes de l'inoculum. / In anaerobic wastewater treatment systems, the complex microbial biomass including Archeae and Bacteria may be retained as a biofilm by attachment to solid supports. The aim of this study is to evaluate the impact of support material properties on adhesion and colonization. Various substrata (polyethylene, polypropylene, polyvinyl chloride, acrylonitrile butadiene styrene, polycarbonate, borosilicate glass, stainless steel 304L and Bioflow 30®) are described in terms of topography by determinating of roughness and in terms of surface energy by contact angle measurement. Adhesion is quantified and the bacterial and archaeal community structure are assessed by molecular analysis in various stages of the biofilm development. Adhesion of a methanogenic consortium on these substrata Is measured after two hours of contact in a rotating annular reactor. The result reveals that the adhered communities were different from the parent inocula, including the Archeae/Bacteria ratio. This result has a significant impact on the start-up of anaerobic digesters because the observed tendencies are confirmed during the establishment of the active biofilm. Start-up of anaerobic fixed-bed reactors using different substrata showed that Archeae populations in the biofilms are specific to each of the material and independent of the inoculum.

La digestion anaérobie est un des piliers de l'économie circulaire européenne, produisant du méthane et des engrais organiques à partir de déchets. Le développement de ce secteur passe par la co-digestion et l’optimisation de l'alimentation des procédés. Cela nécessite l'estimation de l'état biologique du digesteur, la caractérisation du substrat ainsi que l’utilisation de modèles prédictifs simulant les performances du digesteur, pour lesquels les solutions actuelles ne sont pas adaptées. Dans cette thèse, un capteur titrimétrique couplant pH et conductivité électrique pour l'estimation des concentrations en acides gras volatils, carbone inorganique et azote ammoniacale a été conçu, améliorant la précision d'estimation des acides gras volatils de 14,5 par rapport aux capteurs actuels. Couplé à l’analyse du biogaz, il permet d'estimer l'état biologique du procédé. En parallèle, une analyse spectroscopique proche-infrarouge, estimant les teneurs en glucides, protéines, lipides, demande chimique en oxygène, rendement et cinétique de production de méthane a été développée réduisant le temps de caractérisation des substrats à quelques minutes. La caractérisation rapide des substrats est utilisée pour implémenter le modèle de digestion anaérobie ADM1 de l’IWA qui prédit les performances d'un digesteur dans des conditions de digestion optimales. Le couplage de l’estimation de l'état biologique à cette approche permet de corriger la prédiction en prenant en compte l'état actuel du digesteur. Cette approche fournit un outil prédictif puissant pour le contrôle avancé des unités de digestion anaérobie ainsi que l'optimisation de la recette d'alimentation. / Anaerobic digestion is an important pillar of the European circular economy, producing methane and organic fertilizers from waste. The development of the anaerobic digestion sector goes through co-digestion and feeding strategy optimization. Its development requires the biological state estimation of the plant, substrate characterization and predictive models simulating the plant performances, for which current solutions are not suitable. In this thesis, a titration sensor coupling pH and electrical conductivity for the estimation of volatile fatty acids, inorganic carbon and ammonia has been designed, improving the accuracy on volatile fatty acids estimation by 14.5 compared to current sensors. Along with biogas analyses, it allows estimating the biological state of the unit. Besides, fast near infrared spectroscopic analysis, estimating in a matter of minute carbohydrate, protein and lipid contents, chemical oxygen demand, methane production yield and kinetics, has been developed. Thus fast substrate characterization is then used to implement a modified Anaerobic Digestion Model n°1 which predicts the performances of a plant under optimal condition. Coupling biological state estimation to this approach enables to correct the prediction with the current state of the plant. This approach provides a powerful predictive tool for advanced control of anaerobic digestion plants and feeding strategy optimization.