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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Modélisation et observation des bioprocédés à membranes : application à la digestion anaérobie / Modeling and observation of membrane bioprocesses : Application to the anaerobic digestion

Benyahia, Boumediène 18 October 2012 (has links)
Cette thèse porte sur la modélisation des réacteurs membranaires anaérobies. Dans une première partie, nous proposons une analyse mathématique générique d'un modèle de digestion anaérobie en deux étapes appelé AM2. La principale limitation du développement des réacteurs membranaires étant le risque de colmatage, nous proposons, dans une seconde partie, d'étendre le modèle AM2 en incorporant une nouvelle variable d'état modélisant la dynamique des Produits Microbiens Solubles (SMP) dont le rôle dans le colmatage des membranes a été démontré. Une étude mathématique exhaustive de ce nouveau modèle appelé AM2b est réalisée pour comprendre et comparer les comportements qualitatifs des deux modèles. Dépendant des conditions de fonctionnement et des valeurs des paramètres biologiques utilisées, nous montrons que ce nouveau modèle peut se comporter comme le modèle initial AM2, ou, au contraire, présenter un comportement qualitatif très différent. L'étape suivante sera d'utiliser ce modèle pour la synthèse de régulateurs. Toutefois, le manque de capteurs en-ligne nous a amené, dans une troisième partie, à procéder à la synthèse d'un certain nombre d'observateurs d'état classiques. Au regard des caractéristiques spécifiques des bioprocédés, cette dernière partie se termine par la proposition de nouvelles pistes pour l'estimation d'état et de paramètres par des méthodes stochastiques, notamment les filtres particulaires dont nous présentons brièvement le principe. / This thesis focuses on the modeling of anaerobic membrane reactors. In the first part, we propose a generic mathematical analysis of a two-step model of the anaerobic digestion called AM2. The main limitation in the development of membrane reactors being the risk of clogging, we propose in a second part, to extend the AM2 model by incorporating a new state variable modeling the dynamics of the so-called Soluble Microbial Products (SMP) whose role in the clogging of the membranes has been demonstrated. A complete mathematical study of this new model called AM2b is realized to understand and compare the behavior of both models. Depending on operating conditions and on the model parameters values, we show that this new model can behave as the initial model AM2, or, conversely, have a completely different qualitative behavior. The next step is to use this model for the synthesis of controllers. However, the lack of online sensors led us to a third part where we carry out the synthesis of several state observers. In view of the specific characteristics of bioprocesses, this last part ends by proposing new ways to estimate both state and parameters using stochastic methods, including particulate filters which the concepts are briefly reviewed.
322

Lien entre paramètres opératoires, micro-organismes et performances de la digestion anaérobie par voie sèche / Link between process parameters, micro-organisms and performance of dry anaerobic digestion

Abbassi-Guendouz, Amel 06 April 2012 (has links)
La digestion anaérobie est un processus de transformation de la matière organique en biogaz riche en méthane. Les déchets solides sont le plus souvent traités par une technologie par voie sèche qui est caractérisée par des teneurs en matières sèches supérieures à 20%. Du fait de la faible teneur en eau, la digestion sèche présente de nombreuses inconnus scientifiques, tant au niveau microbiologique et physico-chimique. Le but de cette thèse est de comprendre l'influence des parametres opératoires spécifiques à la digestion anaérobie par voie sèche sur les performances et le comportement des communautés microbiennes de ce processus. Les résultats obtenus montrent que l'augmentation de la teneur en matières sèches au-delà de 30% et la diminution de la surface spécifique d'échange ont un effet négatif sur le processus de digestion anaérobie. En effet lorsque la teneur en matière sèche est supérieure à 30%, le transfert des gaz dissous du milieu réactionnel vers le ciel gazeux peut limiter la méthanisation. L'analyse des populations microbiennes montre la présence de bio-indicateurs bactériens liés au non fonctionnement de la digestion anaérobie. Ces bio-indicateurs sont des clostridium et sont présents quel que soit l'inoculum utilisé. L'étude des populations méthanogènes montre une sensibilité de ces microorganismes à leur environnement : des shifts de populations méthanogènes ont été observés en fonction de la concentration en matières sèches. Ce travail a permis d'accroître les connaissances dans le domaine de la digestion anaérobie sèche, ces connaissances pouvant contribuer à améliorer les performances des procédés. / Anaerobic digestion is the transformation of organic matter into biogas rich in methane. Solid waste is treated by dry anaerobic digestion process with a total solid content higher than 20%. The high solids content make the process difficult to control. The aim of this work is to study the influence of operating parameters specific to dry anaerobic digestion on performances and behavior of microbial communities. The results show that increasing the solids content higher than 30% and decreasing the specific surface area of change have a negative effect on the anaerobic digestion process. Indeed, when the solids content exceeds 30%, the transfer of dissolved gas from the reaction mixture to the headspace can limit anaerobic digestion. The analysis of microbial populations demonstrates the presence of bacterial bio-indicators related to no-functioning anaerobic digestion. These bio-indicators correspond to the clostridium genus and are present regardless of the inoculum source. The study of methanogenic Archaea shows a sensitivity of these microorganisms. Shifts in the methanogenic populations related to the concentration of total solids were observed. This work has improved the fundamental knowledge of dry anaerobic digestion which can help improve the performance of this process.
323

Small-scale biogas production from organic waste and application in mid-income countries – a case study of a Lebanese community

Huber, Sebastian January 2019 (has links)
The controlled anaerobic digestion of organic waste in a biogas facility aggregates advantages of waste treatment, energy recovery and nutrient recycling and is a promising technology to deal with contemporary issues of waste management and energy recovery. Small-scale biogas production units can be simply designed and successfully operated even in settings where means for advanced technology equipment are low and institutional capacities limited. In the country of Lebanon, landfilling and open dumping of solid waste is common practice and anaerobic treatment of waste is applied only sporadically and hence, not well-established. The aim of this study was to assess the feasibility of small-scale biogas production using organic waste, explore options for its application and propose a business model on how feedstock sourcing, facility operation and end product utilization could be realized in the research area. Research area was Ghazir village, a community within the urbanized coastal area in Lebanon. Methods were of both quantitative and qualitative nature.A techno-economic assessment served to quantify biogas and liquid digestate production rates, based on available resources of organic waste in the research area. Costs associated with installation, operation and maintenance of the proposed facility have been projected based on present examples of similar facilities in the country. Interviews with local stakeholders and a questionnaire survey among residents in the area of research allowed to identify suitable end use options for the produced biogas and served to explore communal acceptance of local biogas production. Results show that the produced biogas can be used for thermal feedstock treatment to supply local farmers with a fertilizer alternative, i.e. the liquid digestate. Organic waste that is subject to the anaerobic treatment in a digester can be provided by multiple point sources, i.e. households and a local food market in the form of source-sorted kitchen waste and unsold fruits and vegetables, respectively. Due to the current unfamiliarity with anaerobic treatment of organic waste in the research area, tests on the effects on crop yields are advised to take place before implementation of the proposed business model, as its communal benefits hinge on the suitability of the liquid digestate as a fertilizer. Economic calculations show low investment costs for the proposed facility as well as acceptable annual revenues in case the liquid digestate proves to be of interest for commercial acquisition by local farmers. The used methods and strategies in this feasibility assessment, i.e. waste quantification, yield and cost calculations, stakeholder interviews and questionnaire survey allow for replication of the taken investigation to eventually initiate small-scale biogas production using organic waste in other settings with similar conditions.
324

Étude de la matière organique de boues de station d'épuration. Influence de différents procédés de traitement des boues / Impact of different treatment processes on the organic matter of sewage sludge

Collard, marie 26 October 2015 (has links)
Cette étude porte sur l’influence de différents traitements sur les caractéristiques et l’évolution de la matière organique de boues de stations d’épuration (Step). Les échantillons étudiés proviennent de 3 stations municipales de la Vienne. Le premier volet développé au cours de l’étude a pour but la mise au point d’une méthode d’analyse qualitative et quantitative des constituants des boues de Step. Les résultats obtenus démontrent le potentiel de la thermochimiolyse-GCMS à caractériser, sans extraction préalable, la matière organique d’un échantillon brut. Le deuxième volet de cette thèse s’est intéressé à l’influence de différents traitements (séchages, accélérateur d’électrons et méthanisation) sur l’évolution de la matière organique. Ainsi, le séchage thermique provoque une fragilisation de la matière organique, le séchage solaire une complexification et les lits plantés de roseaux n’ont pas d’influence significative à court terme. L’application du procédé d’oxydation avancé sur une boue flottée a provoqué une acidification et des changements structuraux de la matière organique. Ainsi une faible dose (1,25 kGy) a conduit à une complexification de la matière organique alors qu’une plus forte dose (50 kGy) semble la fragiliser. La modification de la matière organique à l’issue du procédé de méthanisation concerne uniquement la fraction lipidique et notamment des acides gras. / This study investigated the influence of different treatments on the characteristics and evolution of organic matter of municipal wastewater sludge. For this, three municipal wastewater treatment plants of Vienne department were sampled.The first phase developed during the study focused on the improvement of a method for qualitative and quantitative analysis of the sewage sludge’s constituents. The presented results demonstrate the strong potential of the thermochemolysis-GCMS to characterize, without extraction, the organic matter of a raw sample.The second part of this Ph.D has focused on the influence of various treatments (drying, electron beam and methanation) on the evolution of organic matter. Thus, the thermal drying causes weakening of the organic matter while the solar drying induces its complexification and reed beds induce no significant change. The application of an advanced oxidation process on a floated sludge caused acidification and structural changes of the organic matter. A low dose (1.25 kGy) led to more complex organic matter, while a higher dose (50 kGy) seems to weaken it. The changes in organic matter induced by anaerobic digestion mainly concerned the lipid fraction, in particular fatty acids.
325

TRATAMENTO DE RESÍDUOS SÓLIDOS URBANOS COM APROVEITAMENTO ENERGÉTICO: AVALIAÇÃO ECONÔMICA ENTRE AS TECNOLOGIAS DE DIGESTÃO ANAERÓBIA E INCINERAÇÃO / Municipal Solid Waste as a Source of Energy: Economic Assessment Comparing Anaerobic Digestion and Incineration Technologies

Leite, Clauber Barão 12 December 2016 (has links)
Duas questões da sociedade do século XXI podem ser destacadas: a grande geração de resíduos; a carência por sistemas de tratamento adequado desses resíduos; e a crescente demanda por energia. A busca por alternativas para lidar com essas questões vem mobilizando os setores público e privado no sentido de explorar soluções ainda não praticadas na maior parte do mundo em desenvolvimento. A Política Nacional de Resíduos Sólidos (PNRS), instituída pela Lei nº 12.305/2010, estabeleceu um novo paradigma na gestão de resíduos sólidos no Brasil. Entre as mudanças apresentadas, uma das mais relevantes é a exclusividade de destinação de apenas rejeitos aos aterros sanitários, sendo os rejeitos entendidos como os resíduos que não mais apresentam possibilidade de tratamento. O cumprimento dessa lei irá requerer o estudo de alternativas de tratamento de resíduos gerados na fase anterior à sua disposição final. Entre as soluções possíveis está o seu aproveitamento energético, também previsto na PNRS. Nesse contexto, esta dissertação busca analisar duas tecnologias de tratamento de resíduos digestão anaeróbia e incineração e verificar suas respectivas viabilidades econômicas, tendo como objeto o cenário brasileiro, com foco especial no estado de São Paulo. Os resultados obtidos indicam que, respeitando-se as diretrizes da PNRS, entre os métodos de tratamento de resíduos sólidos urbanos analisadas, a digestão anaeróbia se mostrou mais viável do que a incineração para as regiões estudadas. Tais resultados tomaram como pressuposto que a PNRS é uma lei que deverá ser cumprida e exigida tal como se apresenta, e seu cumprimento implicará numa mudança significativa do modo como é feita a gestão de resíduos sólidos no país. Adicionalmente, as análises realizadas apontaram que, além dos aspectos econômicos, aspectos ambientais, sociais e culturais também são de fundamental importância na tomada de decisão por uma opção tecnológica adequada dos RSU. / Three issues of the XXI century society can be pointed out: The increasing volume of waste generation, the lack of adequate waste treatment systems and the increasing demand of energy. The search for alternatives to deal with these issues is calling the attention of both public and private agents who are engaged in exploring solutions not yet in place in most part of developing countries. The National Policy on Solid Waste (PNRS), established by the Law # 12,305/2010, set a new paradigm for the solid waste management in Brazil. Amongst the proposed changes, one of the most relevance is the destination of the so-called \"rejects\" to landfill, in which \"rejects\" stands for the residues that can no longer be processed. To abide by this law will require the analysis of alternatives for treating the residues prior to their final disposal. Amongst the possible solutions, there is the utilization of residues to generate electric energy. In this context, this master\'s thesis examines the two of the most used technologies in the developed world anaerobic digestion and incineration and evaluation their economic feasibility in the Brazilian scenario, particularly in the State of São Paulo. The analysis took as an assumption that the PNRS is a law that shall be enforced as it was stated, and that its compliance will require in a significant change in the way the solid waste management is done within the country. For the regions analyzed, our results showed that, under the PNRS requirements, the anaerobic digestion appeared to be more feasible than the incineration technology. Additionally, our work also indicates that, beyond the economic aspects, other issues such as environmental, social and cultural ones are fundamental for the decision making regarding the best technology applied in urban solid waste process.
326

Influência da origem e do pré-tratamento do inóculo na produção de hidrogênio a partir de águas residuárias em biorreatores anaeróbios / Influence of source and pre-treatments method of seed sludge on the hydrogen production from wastewater in anaerobic bioreactor

Penteado, Eduardo Dellosso 30 March 2012 (has links)
Esse trabalho investigou a influência de diferentes origens e pré-tratamentos do inóculo na produção de biohidrogênio em reatores anaeróbios de leito fixo e fluxo ascendente. Aparas de polietileno de baixa densidade foram usadas como material suporte para fixação da biomassa e os reatores foram operados com 2 h de tempo de detenção hidráulica (TDH) e a 25ºC, alimentados com efluente sintético a base de sacarose. Duas fontes de inóculo foram estudadas: lodo anaeróbio de reator UASB aplicado ao tratamento de água residuária de abatedouro de aves (D) e lodo anaeróbio de reator UASB aplicado ao tratamento de água residuária de suinocultura (S); além da autofermentação (A), quando não há nenhum inóculo no reator. Além disso, dois tipos de pré-tratamento térmico (T) e ácido (A) foram avaliados. Os rendimentos de hidrogênio foram de 2,1, 2,0, 2,0,1,0, 1,0, 0,7, 0,7 mol \'H IND.2\' mol-1 sacarose quando os reatores foram inoculados com A, DT, DA, D, SA, ST e S, respectivamente. Nessa nomenclatura, a primeira letra se refere à origem do inóculo e a segunda, ao pré-tratamento. Embora hidrogênio (20-78%) e dióxido de carbono (21-55%) tenham sido os principais produtos no biogás, metano foi detectado nos reatores inoculados com D, DA, S, ST e SA no início e no final da operação. A produção volumétrica máxima de hidrogênio (61,6 mL \'H IND.2\' h-1.L-1) foi obtida quando DA foi usado com inóculo. Porém, o menor valor (15,1 mL \'H IND.2\' h-1.L-1) foi observado usando o inóculo S. Quando o reator não foi inoculado (A), a produção volumétrica de hidrogênio foi 47,3 mL \'H IND.2\' h-1.L-1. Etanol, ácido butírico e acético foram os principais produtos \'metabólicos detectados na fase líquida. Em resumo, os resultados demonstraram que há influência da origem e do pré-tratamento do inóculo em todos os parâmetros analisados. Inóculos sem pré-tratamento resultaram em menor rendimento de hidrogênio do que os observados nos experimentos com inóculos pré-tratados devido a seleção das bactérias produtoras de hidrogênio (BPH). Ademais, embora o pré-tratamento térmico tenha gerado os maiores valores de rendimento, o pré-tratamento ácido resultou em uma operação mais estável com os maiores valores médios. A autofermentação teve desempenho semelhante aos DT e DA e pode ser uma alternativa para a produção biológica de hidrogênio, pois seleciona as BPH naturalmente. / This paper investigated the influence of different inoculums and pretreatment of seed sludge on the biohydrogen production in up-flow anaerobic fixed-bed reactors. Particles of low-density polyethylene were used as support for biomass attachment and the reactor was operated with hydraulic retention time (HRT) of 2 h at 25ºC, fed with a sucrose-based synthetic wastewater. Two sources of inoculums were studied: anaerobic sludge from an UASB (up-flow anaerobic sludge blanket) reactor applied to treat poultry slaughterhouse wastewater (Sl) and anaerobic sludge from an UASB reactor treating swine wastewater (Sw), besides the autofermentation (A), with no inoculation of the reactor. In addition, two kinds of pretreatment heat (He) and acid (Ac) shock were evaluated. Hydrogen yields were 2.1, 2.0, 2.0,1.0, 1.0, 0.7, 0.7, mol \'H IND.2\' mol-1 sucrose when the reactors were inoculated with A, SlHe, SlAc, SwAc, Sl, Sw, and SwHe, respectively. In this nomenclature, the first two letters refer to source and the others refer to pretreatment. Although hydrogen (20-78%) and carbon dioxide (21-55%) have been the main gaseous products in the biogas, methane was detected in Sl, SlAc, Sw, SwHe and SwAc at the beginning and in the last days of the operation. Optimal \'H IND.2\' production rate (61.6 mL \'H IND.2\' h-1 L-1) was obtained when SlAc was used as seed sludge. On the other hand, the smallest value (15.1 mL \'H IND.2\' h-1 L-1) were observed using Sw inoculums. When the reactor was not inoculated (A), \'H IND.2\' production rate was 47.3 mL \'H IND.2\' h-1 L-1. Ethanol, butyric acid and acetic acid were the main soluble products detected in the liquid phase. In summary, the results have demonstrated that there are influences of the source and the pretreatment of the seed sludge in all parameters analyzed. Inoculums without pretreatment resulted in hydrogen productivity lower than those observed for experiments with pretreated inoculums due the selection of hydrogen producing bacteria (HPB). Furthermore, although the heat shock has generated the highest values of hydrogen yield, the acid-shock provided more stable operation with the highest average values. Besides, the autofermentation had almost the same performance than SlAc and SlHe and could be an alternative for biological hydrogen production due to natural selection of HPB.
327

Observation et commande des procédés de digestion anaérobie pour l'amélioration de la production de biogaz / Observation and Control of Anaerobic Digestion Processes for Improved Biogas Production

Chaib Draa, Khadidja 07 July 2017 (has links)
La digestion anaérobie est un procédé permettant de transformer les déchets organiques en énergie utile, telle que le biogaz. Ce procédé fait intervenir des organismes vivants dont le comportement spécifique est fortement non linéaire. Par ailleurs, il est connu pour être sensible aux perturbations et naturellement instable. Ainsi, le développement de méthodologies efficaces pour sa commande et sa supervision est essentiel afin d’obtenir des résultats satisfaisants. Par conséquent, l’objet de cette thèse porte sur la modélisation de ce système complexe, la synthèse d’observateurs et de lois de commande afin d’améliorer le fonctionnement du procédé dans les stations de biogaz. Une modélisation formelle du procédé est alors proposée où des degrés de liberté additionnels ont été introduits dans la commande de production de biogaz. En effet, deux entrées de commande supplémentaires viennent compléter le modèle standard AM2 (Acidogenèse Methanogenesis, 2 étapes), reflétant l’ajout de substrats stimulants (acides et alcalinité) qui améliorent la qualité et la quantité du biogaz. Par la suite, l’identification des paramètres du modèle non linéaire résultant est traitée, ainsi que l’analyse de la positivité et la bornitude des variables d’état. Sur la base du modèle mathématique dérivé et des résultats de l’analyse, différents observateurs sont alors étudiés afin de surmonter le manque de capteurs fiables, autonomes et bons marché. En effet, deux observateurs sont alors développés, le premier dit invariant et le second non linéaire de la même forme que l’observateur généralisé d’Arcak. En outre, dans le but de rendre la conception d’observateurs plus robuste aux perturbations, le critère H∞ est introduit dans la synthèse. Une extension de la méthodologie est proposée pour les systèmes discrets ainsi qu’aux systèmes non linéaires avec sorties non linéaires. Pour la synthèse des différents observateurs, le théorème des accroissements finis est appliqué, ce qui permet de transformer la dynamique non linéaire de l’erreur d’estimation en un système linéaire à paramètres variants. La condition de Lipschitz est alors conjointement utilisée avec la fonction classique de Lyapunov pour la synthèse des conditions de stabilité sous forme d’Inégalités Matricielles Linéaires (LMIs). Enfin, afin d’améliorer la faisabilité de ces dernières conditions, une reformulation judicieuse de l’inégalité de Young est alors introduite. Concernant la commande du procédé, une commande par retour d’état pour le suivi d’une trajectoire de référence est choisie. Prenant en compte la disponibilité partielle des mesures du vecteur d’état, un observateur exponentiel non linéaire est introduit dans la synthèse de la loi de commande. Ainsi, une commande par retour d’état basée observateur est obtenue. Pour effectuer l’analyse de stabilité du système en boucle fermée composée du procédé, de l’observateur et du contrôleur, le lemme de Barbalat est alors utilisé conjointement avec les techniques déjà mentionnées pour la synthèse d’observateurs. Enfin, deux différentes méthodes pour le calcul des paramètres du contrôleur et de l’observateur sont proposées. Séparément, dans un premier temps. Puis simultanément dans un second temps / In this thesis, we propose a formal modelling framework for the anaerobic digestion process, where we add more degrees of freedom in the control of biogas production. Indeed, we add two additional control inputs to the standardized AM2 (Acidogenesis Methanogenesis, 2 steps) model, reflecting addition of stimulating substrates which enhance the biogas quality and quantity. Then, we describe how the parameters of the resulted nonlinear model can be identified, and we analyse the positiveness and boundedness of its state variables. Based on the derived mathematical model and the analysis results, we design different software sensors to overcome the lack of reliable and cheap sensors. Indeed, we present a general class of systems to which the considered process model belongs. Then, we design an LMI-based invariant like observer as well as an LMI-based nonlinear observer of the same form as the generalized Arcak’s observer. Furthermore, with the aim to render the observer design more robust to disturbances, we include the H∞ criterion in its synthesis. Also, to promote the use of the proposed observers in real applications, we extend the methodology to the discrete time case and to the case of nonlinear systems with nonlinear outputs. For the different observers design, we use the differential mean value theorem which allows the transformation of the nonlinear estimation error to a linear parameter varying system. Then, we use the Lipschitz conditions and the Lyapunov standard function to synthesize the stability conditions in the form of linear matrix inequalities. Finally, we enhance the feasibility of the later conditions by using a judicious reformulation of the Young’s inequality. In the thesis, we also deal with the process control where we propose a control strategy to track an admissible reference trajectory planned by the plant operator. Moreover, to account for the partial availability of the state vector measurements, we include an exponential nonlinear observer in the control synthesis. Thus, we design an observer based tracking control scheme. To perform the stability analysis of the closed loop system, composed of the system, the observer and the controller, we use the Barbalat’s lemma conjointly with the techniques already mentioned for the observers design. Finally, we propose two different methods to compute the controller and the observer parameters. In the first one, we propose to compute them separately. While, in the second one we compute the parameters simultaneously
328

PRODUÇÃO DE ÁCIDO PROPIÔNICO A PARTIR DE EFLUENTES AGROINDUSTRIAIS

Moreira, Debora Christina 08 July 2013 (has links)
Made available in DSpace on 2017-07-21T18:53:21Z (GMT). No. of bitstreams: 1 Debora C Moreira.pdf: 799615 bytes, checksum: bf5390535b39bc8ca4f452bde2fd297b (MD5) Previous issue date: 2013-07-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The search for renewable energy and food production with the minimum threat to the environment are themes that have been studied for all over the world. Several processes have been developed for the use of agroindustrial wastes, transforming them into chemical compounds and products with high added value. The use of agroindustrial wastes in bioprocesses helps the search for sustainable processes. The increasing in the agricultural productivity in Brazil, open a new market to the development of researches that study this issue. The statistical modeling of mixtures, allied with the design of experiments, has application in a several industrial systems. The aim of this work was to study the possibility of use agroindustrial wastewater mixtures to produce propionic acid. Four types of wastewater were studied: corn steep liquor, pet food wastewater, meat processing wastewater and dairy wastewater. Assays were performed to obtain the best composition of the mixtures and the best substrate ratio. Within the conditions employed, the mixture containing 75% of corn steep liquor and 25% of another substrate, were most suitable for the process. Studying the tests in which the fermentations conditions varied (boiling the substrate, agitation and pH correction to 6,5) the best concentrations of propionic acid, 229,57 mg.L-1, were produced by mixing 75% of corn steep liquor and 25% of pet food wastewater, after 72h of fermentation, with initial correcting of pH to 6,5, followed by the mixture containing 75% of corn steep liquor and 25% of meat processing wastewater, that enabled the production of 154,27 mg.L-1 of propionic acid. The mixture with 75% of corn steep liquor and 25% of dairy wastewater with daily pH correction enabled the production of 220,96 mg.L-1 of propionic acid after 72 hours of fermentation. The other essay conditions were not significant for propionic acid biosynthesis. The statistical analysis confirms that it is possible to use codigestion agroindustrial waste for propionic acid production. / A busca por fontes de energia renovável e a produção de alimentos com a mínima ameaça ao ecossistema têm sido temas bastante pesquisados em todo o mundo. Diversos processos têm sido desenvolvidos para a utilização de resíduos agroindustriais, transformando-os em compostos químicos e produtos com alto valor agregado. A utilização de resíduos agroindustriais em bioprocessos favorece a busca por processos sustentáveis. O aumento da produtividade agrícola no Brasil abre um novo mercado para o desenvolvimento de pesquisas que abordem este tema. O planejamento estatístico de misturas, aliado à otimização de experimentos, tem aplicação em diversos sistemas industriais. O objetivo deste trabalho foi avaliar a possibilidade da utilização de misturas de efluentes agroindustriais para a produção de ácido propiônico. Foram utilizados quatro tipos de efluentes: efluente do processamento de milho, efluente do processamento de ração animal, efluente de processamento de carnes e de laticínio. Foram realizados ensaios para a obtenção da melhor composição das misturas, definindo-se a melhor proporção dos substratos. Dentro das condições empregadas, as composições contendo 75% do efluente do processamento de milho e 25% de outro substrato foram as mais adequadas ao processo. Nos ensaios onde as condições de fermentação foram variadas (fervura prévia do substrato, agitação e correção do pH para 6,5), os melhores resultados de produção de ácido propiônico, 229,57 mg.L-1, foram obtidos com substrato composto por 75% de efluente do processamento de milho mais 25% de efluente de fábrica de ração, com 72h de fermentação, correção de pH inicial para 6,5 e sem agitação, seguido de substrato com 75% de efluente do processamento de milho mais 25% de efluente de processamento de carnes, nas mesmas condições, obtendo-se produção de 154,27 mg.L-1 de ácido propiônico. O substrato contendo 75% de efluente do processamento de milho mais 25% de efluente de laticínio, possibilitou produção de 220,96 mg.L-1 de ácido propiônico, após 72 horas de fermentação e com correção de pH a cada 24 horas. As outras condições testadas não foram significativas na biossíntese de ácido propiônico. A análise estatística dos dados confirmou que é possível a utilização de codigestão de efluentes agroindustriais para a produção de ácido propiônico.
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Avaliação da operação de biodigestor no processo de digestão anaeróbia de resíduos sólidos orgânicos

Schmeier, Nara Paula 20 November 2017 (has links)
Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-01-31T12:54:08Z No. of bitstreams: 1 Nara Paula Schmeier_.pdf: 877010 bytes, checksum: f002cde3446d9c5552d9a747ff097801 (MD5) / Made available in DSpace on 2018-01-31T12:54:08Z (GMT). No. of bitstreams: 1 Nara Paula Schmeier_.pdf: 877010 bytes, checksum: f002cde3446d9c5552d9a747ff097801 (MD5) Previous issue date: 2017-11-20 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Petrobras - Petróleo Brasileiro S. A. / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / O processo de digestão anaeróbia tem sido empregado com destaque no tratamento de resíduos sólidos orgânicos, por tratar-se de uma alternativa para amenizar problemas ambientais e também por uma questão energética, visto que possibilita a produção de energia para auxiliar a suprir a alta demanda, em consequência do elevado crescimento populacional e industrial. No entanto, questões relativas a escalas de trabalho, formas de operação, carga orgânica e influência de parâmetros como AGV, alcalinidade e nitrogênio amoniacal (NA) perduram. Desta forma o presente trabalho objetivou avaliar a operação de biodigestor, ao longo de 340 dias, mediante variação de frequências de adição de RSO e cargas orgânicas volumétricas (COV) de 7,98, 7,80, 9,64, 3,28, 4,10 e 5,00 kg STV/m3.d., com média de ST: 339,6 mg/g e umidade: 64%, frente a produção de biogás e CH4. Ademais, também buscou avaliar a influência de parâmetros como AGV, alcalinidade e nitrogênio amoniacal sobre o processo de DA. O sistema experimental foi composto por um biodigestor de câmara única, com volume de 0,28 m³, alimentado com RSO do restaurante universitário e inoculo ambientado a digestão de RSO. O monitoramento do processo experimental foi realizado por meio de caracterização físico-química (pH, DQO, DBO, alcalinidade, AGV, ST, STF, STV, NT, NA, PT e COT) das frações sólidas e líquidas, além da quantificação do biogás (volume e percentual de CH4). O processo de digestão revelou que aplicações de COVs de 3,28, 4,10 e 5,00 kg STV/m3.d. possibilitaram maiores rendimentos de biogás e CH4, em relação a COVs de 7,98, 7,80 e 9,64 kg STV/m3.d. A aplicação continua da COV de 4,10 kg STV/m3.d. apresentou o maior rendimento de biogás e CH4 em função dos STV aplicados, sendo 94,63 NL/kg STV e 45,42 NL/kg STV, respectivamente. No decorrer do processo de digestão, elevadas razões de AGV/Alcalinidade, baixas razões de C/NT e elevadas concentrações de AGV e NA levaram a uma condição de digestão que representou rendimentos reduzidos de biogás e metano. / The anaerobic digestion (AD) process has been used in the treatment of organic solid waste, for being an alternative to ease environmental problems and also an energy issue, since it allows the production of energy to help supplying the high demand, as a result of high population and industrial growth. However, issues concerning work scales, operation forms, organic loads and influence of parameters such as VFA, alkalinity and ammonia nitrogen (AN) to linger. In this way, the objective of this work was to evaluate the biodigester operation, during 340 days, by varying the frequencies of organic solid waste (OSW) and organic loading rate (OLR), of 7,98, 7,80, 9,64, 3,28, 4,10 e 5,00 kg STV/m3.d., with mean de TS: 339,6 mg/g and humidity: 64%, against production of biogas and CH4. In addition, it also sought to evaluate the influence of parameters such as VFA, alkalinity and AN on the DA process. The experimental system consisted of a single chamber biodigester with a volume of 0.28 m³, fed with OSW from a university restaurant and inoculum set to the digestion of OSW. The monitoring of the experimental process was carried out through physicochemical characterization (pH, COD, BOD, alkalinity, VFA, TS, TFS, TVS, TN, AN, PT and TOC) solid and liquid fractions, in addition to the quantification of biogas (volume and percentage of CH4). The digestion process revealed that OLRs applications of 3,28, 4,10 e 5,00 kg TVS/m3.d. allowed higher yields of biogas and CH4, in relation to OLRs of 7,98, 7,80 e 9,64 kg TVS/m3.d. The continuous application of OLR of 4,10 kg TVS/m3.d. showed the highest biogas yield and CH4 as a function of the VTS applied, being 94,63 NL/kg TVS and 45,42 NL/kg TVS, respectively. During the digestion process, high AGV/Alkalinity ratios, low C/N ratios and high concentrations of VFA and AN led to an digestion condition which represented reduced yields of biogas and methane.
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Tratamento combinado de lixiviado de aterro sanitário e esgoto doméstico por processo anaeróbio em reator UASB

Miorim, Mirela 23 February 2018 (has links)
Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-04-03T16:15:47Z No. of bitstreams: 1 Mirela Miorim_.pdf: 846687 bytes, checksum: 14941a4020bedba06eadbccc896dd4d1 (MD5) / Made available in DSpace on 2018-04-03T16:15:47Z (GMT). No. of bitstreams: 1 Mirela Miorim_.pdf: 846687 bytes, checksum: 14941a4020bedba06eadbccc896dd4d1 (MD5) Previous issue date: 2018-02-23 / Nenhuma / O tratamento combinado de lixiviado de aterro sanitário (LAS) e esgoto sanitário (ES) é uma solução promissora, uma vez que com a diluição do lixiviado ocorre a redução de elevadas concentrações de nitrogênio amoniacal e matéria orgânica. No entanto, é necessário que sejam determinadas as proporções de LAS:ES adequadas para este tipo de tratamento. A presente pesquisa objetiva estudar o tratamento combinado por processo anaeróbio através de um reator anaeróbio de manta de lodo e fluxo ascendente (UASB), utilizando como substratos o esgoto sanitário e o lixiviado de aterro sanitário. A primeira etapa da pesquisa abordou os ensaios de bancada realizados, afim de caracterizar os substratos adotados e assim determinar o acréscimo de cargas orgânicas e de nutrientes, e alterações nos parâmetros físico-químicos (pH, alcalinidade e AGV) com a adição de 3 e 6% de lixiviado ao esgoto sanitário. A segunda etapa da pesquisa compreende ensaios em escala piloto, utilizando o reator UASB em regime contínuo, com 830L, operando com um TDH de 12 h,e temperatura ambiente a qual foi monitorada por um termômetro no corpo do reator. O reator UASB foi inoculado com lodo anaeróbio proveniente do reator UASB em escala plena da UNISINOS. Este lodo apresentou uma concentração de 515 mg ST/L, 265,4 mg SV/L e 250,2 mg SF/L. O reator UASB operou inicialmente apenas com esgoto sanitário por um período de 127 dias (Fase 1), em seguida operou por 49 dias com a adição de 3% de LAS (Fase 2) e a última fase por um período de 28 dias com a adição de 6% de LAS (Fase 3). Verificou-se que houve um equilíbrio no pH, alcalinidade e AGV na Fase 1, enquanto que nas Fases 2 e 3 estes parâmetros sofreram uma elevação no afluente, e um decréscimo na alcalinidade efluente devido a necessidade de se neutralizar os AGV. Foi verificada uma concentração média de alcalinidade afluente e efluente de 114,7 e 129,3 mgCaCO3/L (Fase 1), de 373,0 e 345,0 mgCaCO3/L (Fase 2) e 665,8 e 581,3 mgCaCO3/L (Fase 3), nesta ordem. O pH inicial do afluente operando somente com ES foi de 6,9, chegando a 8,8 na Fase 3 na mistura com 6% de LAS. Foi observado que o nitrogênio amoniacal afetou diretamente o processo anaeróbio, uma vez que o aumento da alcalinidade do afluente ao partir da entrada do LAS ao processo, este aumento foi atribuído a formação de hidróxido de amônia a partir do nitrogênio amoniacal presente no LAS. A concentração de nitrogênio amoniacal correspondeu a mais de 80% do nitrogênio total da mistura LAS:ES, e manteve-se nestes patamares durante todo o período experimental. As concentrações de nitrogênio amoniacal afluente e efluente, foram, respectivamente, 31,4 e 42,7 mg/L (Fase 1), 60,8 e 60,8 mg/L (Fase 2) e 91,9 e 89,4 mg/L (Fase 3). A remoção de DQO na Fase 1 variou entre 27,1 - 63,6%, de 33,7 - 54,7% na Fase 2 e de 22,9 - 32,3% na Fase 3. Para as condições estudas não verificou-se uma elevada eficiência de remoção de matéria orgânica no reator operando com a mistura LAS:ES. Quantitativamente observou-se teores de metano entre 63,2 e 74%. / The combined treatment of landfill leachate (LAS) and sanitary sewage (ES) is a promising solution, since with the dilution of the leachate the reduction of high concentrations of ammoniacal nitrogen and organic matter occurs. However, it is necessary to determine the proportions of LAS: ES suitable for this type of treatment. The present research aims to study the combined treatment by anaerobic process through an anaerobic sludge blanket and UASB reactor, using wastewater and landfill leachate as substrates. The first stage of the research was carried out in order to characterize the substrates and to determine the increase of organic loads and nutrients, as well as changes in physical and chemical parameters (pH, alkalinity and VFA) with the addition of 3 and 6% of leachate to wastewater. The second stage of the research involves pilot scale tests using the continuous UASB reactor with 830 L, operating with a HRT of 12 h, and ambient temperature which was monitored by a thermometer in the reactor. UASB reactor was inoculated with anaerobic sludge from the UASB reactor at full scale from UNISINOS, this sludge presented a concentration of 515 mg ST/L, 265.4 mg VS/L and 250.2 mg FS/L. UASB reactor initially operated only with wastewater for a period of 127 days (Phase 1), then operated for 49 days with the addition of 3% leachate (Phase 2) and the last phase for a period of 28 days with addition of 6% leachate (Stage 3). It was verified that there was a balance in pH, alkalinity and VFA in Phase 1, whereas in Phases 2 and 3 these parameters suffered an increase in the affluent, and a decrease in the alkalinity effluent due to the necessity to neutralize the VFA. A mean affluent alkalinity affluent and effluent concentration of 114.7 and 129.3 mgCaCO3/L (Phase 1), 373.0 and 345.0 mgCaCO3/L (Phase 2) and 665.8 and 581.3 mgCaCO3/L (Phase 3), in that order. The initial pH effluent operating with wastewater alone was 6.9, reaching 8.8 in Phase 3 in the mixture with 6% of leachate. It was observed that the ammonia nitrogen directly affected the anaerobic process, since the increase of the alkalinity of the affluent from the addition of the leachate to the process, this increase was attributed to the formation of ammonia hydroxide from the ammonia nitrogen present in the leachate. The concentration of ammonia nitrogen corresponded to more than 80% of the total nitrogen of the leachate/wastewater mixture, and remained at these levels throughout the experimental period. The concentrations of ammonia nitrogen affluent and effluent were respectively 31.4 and 42.7 mg/L (Phase 1), 60.8 and 60.8 mg/L (Phase 2) and 91.9 and 89.4 mg/L (Phase 3). Removal of COD in Phase 1 ranged from 27.1 - 63.6%, from 33.7 - 54.7% in Phase 2 and from 22.9 - 32.3% in Phase 3. In the conditions under study, a high removal efficiency of organic matter was not verified in the reactor operating with the leachate/wastewater mixture. Methane levels between 63.2 and 74% were quantitatively observed.

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