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

La méthanisation émerge comme une technique efficace pour la production énergétique ainsi que le traitement des résidus organiques. Une analyse de la méthanisation dans les différentes filières sélectionnées est menée par une démarche reposant sur la définition de filières-type, renseignées à partir d'enquêtes techniques auprès des installations existantes et des professionnels. Ces filières-type nous permettent d’étudier globalement les bilans énergétiques et environnementaux de la digestion anaérobie pour la comparer avec d’autres procédés en utilisant l’approche par analyse du cycle de vie. Énergétiquement, un potentiel important de plus de 11 Mtep/an est estimé à partir des ressources disponibles dans les filières retenues. Les ressources agricoles contribuent à une part importante de ce potentiel. Les déchets résiduaires des industries agroalimentaires complètent ce potentiel sachant que la quantité des déchets méthanisables est importante sur le territoire français. Environnementalement, le biogaz valorisé procure un avantage à la méthanisation devant la filière de comparaison. Les résultats des études comparatives d’ACV sont sensibles à la méthode d’analyse d’impact retenue par rapport à leur sensibilité à certains aspects. Les résultats d’ACV sont aussi sensibles à la définition des filières et alors définir d’autres filières lorsque des interrogations subsistent est une perspective importante à ne pas négliger. / Anaerobic digestion is emerging as an efficient technology for energy production as well as for of organic residues treatment. An analysis of the anaerobic digestion in different chosen procedures is led by an approach based on the standard procedures definition, filled from technical investigations with existing installations and professionals. These standard procedures allow us to study the overall energy and environmental balance sheets of anaerobic digestion in order to compare it with other processes by using the approach of life cycle assessment. Energetically, an important potential for more than 11 Mtoe/year is estimated from available resources in chosen procedures. Agricultural resources contribute to a significant portion of this potential. The residual waste from food industries completes this potential knowing that the amount of waste processed with anaerobic digestion is important on the french territory. Environmentally, the biogas recovered is advantageous to anaerobic digestion against comparison procedures. The results of comparative studies of LCA are sensitives to the impact assessment method adopted in relation to their sensitivity to certain aspects. The LCA results are also sensitives to the definition of procedures and define other procedures, when we have doubts, remains an important perspective not to be neglected.

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.

Dans un contexte d’augmentation des volumes de boues résiduaires produits, comprendre et optimiser les processus de déshydratation mécanique est crucial. Leurs performances conditionnent tant le fonctionnement global de la station que son bilan environnemental et économique. En effet, la siccité des boues déshydratées impacte fortement les procédés ou filières permettant leur valorisation à l’échelle des territoires (compostage, valorisation agronomique directe, incinération, …) ainsi que leur bilan environnemental direct et indirect (tonnages à transporter, ...). De plus, les filtrats devront être traités par la station, et leur composition influence significativement le fonctionnement de la filière de traitement des eaux. Les filtres-presses font partie des procédés de déshydratation mécanique les plus utilisés dans les filières boues des stations d’épuration des eaux usées. Leurs performances sont fonction à la fois de leurs paramètres de fonctionnement et des propriétés de la boue à déshydrater. Les connaissances actuelles sont cependant insuffisantes pour permettre (1) d’expliquer pourquoi certaines boues se déshydratent mieux que d’autres et (2) de relier ces phénomènes aux processus mis en oeuvre lors de la déshydratation mécanique. Le poste de déshydratation fonctionne ainsi comme une boîte noire à partir de laquelle il est difficile de prédire les performances d’un outil de déshydratation appliqué à une boue particulière et d’anticiper des dysfonctionnements. Dans ce contexte, l’objectif de ce travail de thèse était de comprendre quels sont les facteurs de contrôle des performances de la déshydratation mécanique des boues d’épuration en filtre-presse et comment ces derniers impactent le fonctionnement du procédé. Dans un premier temps, l’impact des paramètres de fonctionnement des filtres-presses sur leurs performances a été étudié en cellule de filtration tangentielle (cellule de laboratoire reproduisant les processus d’un filtre presse industriel). Ce travail a permis de hiérarchiser les paramètres opératoires selon leur impact sur les performances de déshydratation. Cette étude a permis de mettre en évidence que le paramètre le plus sensible est l’épaisseur de gâteau suivi de la pression. L’impact de ces paramètres est en partie lié à celui du gradient de pression sur les équations de la filtration même si ce dernier doit être considéré en 3D pour expliquer les résultats observés. Dans un second temps l’étude de l’impact des propriétés des boues sur les performances de déshydratation a été réalisée. Pour ce faire, ce travail s’est focalisé sur l’impact d’un des procédés qui modifie le plus les propriétés des boues : la digestion anaérobie. L’objectif de ce travail était d’identifier comment le temps de séjour hydraulique (TSH) appliqué dans le digesteur influence les propriétés physicochimiques des boues et les performances de déshydratation évaluées au travers d’essais de déshydratation en cellule de filtration tangentielle. Cette phase a permis de montrer que quand le TSH augmente de 0 à un TSHcritique, la déshydratabilité de la boue diminue. Au-delà de ce TSHcritique, cette dernière s’améliore sans pour autant atteindre celle de la boue brute. Ces phénomènes ont pu être reliés à une modification des équilibres osmotiques entre les flocs et le milieu interstitiel couplée à une modification de la matrice d’exopolymères solubles des flocs. Enfin, un modèle numérique permettant de simuler la déshydratation des boues résiduaires a été implémenté sous COMSOL multiphysics®. Au travers des processus modélisés, il prend en compte les principaux facteurs de contrôle des performances identifiés auparavant. Après ajustement des paramètres sur un unique essai de déshydratation à une pression donnée, le modèle permet de prédire la siccité du gâteau pour une pression comprise entre 3 et 15 bars. / As more and more sewage sludge are generated, understanding and optimization of mechanical dewatering processes is crucial. Their performances affect both plant management and its environmental and economic impacts. Indeed, dryness of dewatered sludge strongly impacts processes for agronomic and energetic recovery (composting, direct agricultural recycling, incineration ...) and their direct and indirect environmental impacts (volumes to transport...). In addition, the filtrates have to be treated by the wastewater treatment plant, and their composition significantly affects its operating. Filter presses are one of the most common mechanical dewatering processes operated for sludge treatment in wastewater treatment plant. Their performance depends on their operating parameters and sludge properties. However, current knowledge is insufficient (1) to explain why some sludges are easier or harder to dewater than others, and (2) to link these phenomena to processes that carry out during the mechanical dewatering. Hence, dewatering works like a black box from which it is difficult to predict the efficiency of a dewatering tool performed with a particular sludge and to anticipate operating problems. In this context, the objective of this thesis was to understand witch factors drive the efficiency of mechanical dewatering of sewage sludge in the filter press and how they impact the process. First, the impact of operating parameters of filter presses on their efficiency was investigated in cross-flow filtration cell (lab-scale cross-flow filtration cell reproducing processes that occur in an industrial filter press). This work allowed the classification of the operating parameters according to their impact on the dewatering performances. This study highlighted that the most sensitive parameter is the cake thickness followed by pressure. The impact of these parameters is partially linked with their influence on the pressure gradient even if it should be considered in 3D to explain the results. Secondly, the study of the impact of sludge properties on dewatering performances was carried out. In this thesis, this work focuses on the impact of one of the processes which modifies most significantly sludge properties: anaerobic digestion. The objective of this work was to identify how hydraulic retention time (HRT) in the digester affects physicochemical properties of sludge and dewatering performance. Results demonstrated that when the HRT increases from 0 to a critical HRT (HRTcritical), sludge dewaterability decreases. Beyond this HRTcritical, it increases without reaching cake dryness of the raw sludge. These phenomena could be linked to a change in osmotic balance between the flocs and the bulk solution, combined with a modification of the soluble exopolymer matrix of flocs. Finally, a numerical model, allowing the simulation of sludge dewatering was implemented with COMSOL multiphysics®. Equation system takes into account the main factors that affect performances previously identified. After parameter calibration on a single dewatering experiment at 8 bars, the model allows the prediction of cake dryness for any pressure between 3 and 15 bars.

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.

Anaerobic digestion is the process by which organic carbon is converted into biogas in the form of carbon dioxide (CO2) and methane (CH4). Both of these products are greenhouse gases that contribute to global warming. Therefore if anaerobic reactors are improperly maintained and biogas is leaked or intentionally released into the atmosphere because biogas production exceeds household demand, these reactors may become generators of greenhouse gas emissions instead of sustainable energy producers. The objective of this research was to develop a framework to assess if the demand for biogas by a rural adopter of an anaerobic digester matched with the associated local gas production. A literature review of the energy required to prepare commonly consumed food of rice and beans was conducted to establish required household biogas volumes. This review determined that 0.06 m3 of methane was required to prepare a half a kg of rice (on a dry weight basis) and 0.06 m3 of methane was required to prepare a half a kg of beans (on a dry weight basis). Furthermore an analysis of occupants of a rural Panamanian town was performed along with a design model for rural anaerobic reactor gas production to determine if an overproduction of biogas would occur if anaerobic reactors were built for families who owned swine. It was determined using this approach that all of the fifteen household would experience an overproduction of biogas based on household demand of methane and therefore would risk the release of greenhouse gases. Household size ranged from one to seven occupants and swine ownership ranged from one to fifteen per household. The differences of biogas supply with respect to demand from these fifteen situations ranged from 0.09 to 0.35 m3 of a biogas with 40% methane and 0.27 to 6.17 m3 of excess biogas with a methane content of 70% per household per day. An average of 0.45 m3 of a biogas with 40% methane per household per day was calculated and 0.87m3 for 70% methane for all fifteen households, excluding one outlier. However, because this research uses a model based on plug flow reactor mechanics, results may produce varied results from other studies concerning small scale anaerobic digestion.

This diploma paper deals with contemporary practice in dispose of biodegradable waste, especially biodegradable communal waste (biowaste) in the Czech Republic. It explains fundamental terms, points out relevant legal rules and describes methods of biowaste handling. It evaluates collection and utilization systems in two cities in the way of comparison method. It compares them from cost and benefits (economic, environmental) points of view. The main purpose of the diploma paper is general introduction into the issue, pointing out negative effect of biowaste landfilling and presentation of actual systems of utilization. Also the work points out contemporary trend consisting in raising separation and reducing biodegradable communal waste landfilling.

O papel representa cerca de 25% de todo resíduo sólido presente nos aterros sanitários. O papel jornal pode representar até 50% de todo papel descartado e encontra-se na sua maioria impresso. A tinta de impressão pode ser tóxica aos microrganismos responsáveis pela digestão anaeróbia. O presente trabalho teve como principal objetivo avaliar a influência dessa tinta na digestão anaeróbia do papel jornal. Este estudo buscou colaborar para uma melhor compreensão da caracterização dos resíduos sólidos, toxicidade, biodegradabilidade, e processos de tratamento dos resíduos sólidos. O trabalho foi desenvolvido em duas etapas. Na primeira etapa foi avaliada a eficiência de quatro inóculos: lodo de digestor anaeróbio de fluxo ascendente (UASB) tratando esgoto sanitário da cidade de Piracicaba - SP - (LU); lodo granulado de digestor anaeróbio de fluxo ascendente (UASB) proveniente do tratamento do esgoto da Avícola Dacar - Ltda, localizada na cidade de Tietê - SP - (LA); percolado do aterro sanitário da cidade de Jaboticabal - SP, operando há 11 meses - (PI) e percolado do aterro sanitário experimental de São Carlos - SP, em operação há 11 anos (PII). Essa etapa de trabalho permitiu escolher o inóculo proveniente do aterro sanitário de Jaboticabal por apresentar maior eficiência na digestão anaeróbia do papel jornal. Esse inóculo foi utilizado para os reatores na segunda etapa do trabalho, no qual o principal objetivo foi avaliar a influência da tinta de impressão na digestão anaeróbia do papel jornal em quatro reatores alimentados com papel jornal não impresso (JNI), papel jornal impresso com tinta preta (JIP), papel jornal impresso com tinta colorida (JIC) e reator de controle (B). A tinta de impressão não se apresentou como inibitória ao processo anaeróbio, pois a degradação observada foi praticamente semelhante nos reatores alimentados com papel jornal impresso e não impresso. / Paper represents about 25% of all solid waste presented in sanitary landfills. Newspaper can represent up to 50% of all the discarded paper and is found mostly printed. The printing ink can be toxic to the microorganisms that have anaerobic digestion. The main objective of the present dissertation was to evaluate the influence of this ink on the anaerobic digestion of newspaper. It also intends to collaborate for a better comprehension of characterization, toxicity, biodegradability and processes of treatment of solid wastes. The research was developed in two stages. First the efficiency of four inoculum was evaluated: they were sludge of upflow anaerobic sludge blanket (UASB) treating the sanitary sewage of Piracicaba city - SP (LU); granulated sludge of upflow anaerobic sludge blanket (UASB) originated form the sewage treatment of Avícola Dacar - Ltda, located in Tietê city - SP (LA); leachate from sanitary landfill of Jaboticabal city - SP, with 11 months of operation (PI) and leachate from experimental sanitary landfill in São Carlos city - SP, with 11 years of operation (PII). This stage of work allowed choosing the inoculum from the sanitary landfill of Jaboticabal as it showed greater efficiency in the anaerobic digestion of newspaper. This inoculum was used to inoculate the reactors in the second stage of the work, aiming to evaluate the influence of the printing ink on the anaerobic digestion of the newspaper, in four reactors fed with non-printed newspaper (JNI), printed newspaper with black ink (JIP), printed newspaper with colorful ink (JIC) and reactor of control (B). The printing ink did not show to be inhibitory to the anaerobic process, as the observed digestions were almost similar for the reactors fed with printed and non-printed newspaper.

Swedish state has been promoting alternative renewable fuels like biogas to reduce the dependency on fossil fuels and to curb related greenhouse gas emissions. Owing to many policies like subsidies and tax exemptions for using biogas, the country has seen a surge in demand for biogas. Meanwhile, the increase in production of biogas in Sweden has been modest in recent years, though many studies have estimated substantially higher potentials from many sources. Agricultural feedstock/biomass is one among these sources where production and use of biogas could address many challenges faced by farmers like agricultural waste management, soil nutrient management, methane emissions from manure etc. while closing the nutrient cycle and contributing to sustainability.This work is an investigation on how to stimulate the growth of biogas production based on agricultural feedstock/biomass production in Sweden. Since policies give different results in different states/countries depending on the local preconditions, locally developed policies, national policies and EU policies should integrate well in all the policy sectors in that particular region to give the intended result. The current production capacity is about 2 TWh worth of biogas/year but the theoretical potential is estimated to be up to 15 TWh that has been claimed by many researches and literature works like in (Westlund, et al., 2019). Much of the potential has not been explored especially in the field of agriculture. It is asserted in many articles that the true potential of biogas production from Swedish agriculture is far greater than what is produced today. Yet, all the regulations, financial and other financial instruments failed to stimulate local biogas production in Sweden to attain its full theoretical potential. The results presented in this study show where these policies failed and what else apart from the policies could be improved in order promote biogas production.Farmers are hesitant to invest in biogas production because of the complexity and unpredictability of the existing policies. There has been significant negative impact from lack technological training of anaerobic digestion (AD) technology. This is also reflected as difficulties in finding trained and dedicated staff for biogas plant operations. Low profitability of biogas business exists ever since the production started and the financial aids are insufficient. Strict digestate regulations along with worsening substrate competition also creates problems. Permits to run the biogas plants are perceived to be expensive alongside increasing investment costs and taxes, affecting already low profitability. There is also a lack of infrastructure in terms of electricity/gas grid connectivity. Feed in tariffs for electricity produced from renewable sources are not bringing enough profitability to the business. Technological improvements are needed in terms of agricultural machinery that can use upgraded biogas as fuel and treatment of digestate to eliminate heavy metal content. Producers need more long term, sure market for their biogas. / Biogasmarknadsutredningen of BRC

Orientador: Jorge de Lucas Júnior / Banca: Mario Benincasa / Banca: Roberto Alves de Oliveira / Banca: Edson Aparecido Abdul Nour / Banca: Simone Damasceno / Resumo: Com o objetivo de caracterizar quantitativa e qualitativamente os dejetos produzidos em um sistema de confinamento para criação de novilhos superprecoces e avaliar o desempenho de processos biológicos de reciclagem de nutrientes: compostagem, vermicompostagem e biodigestão anaeróbia, conduziu-se esta pesquisa. O trabalho foi dividido em quatro ensaios: caracterização dos dejetos, compostagem, vermicompostagem e biodigestão anaeróbia. O ensaio de caracterização dos dejetos teve como objetivo principal determinar o coeficiente de resíduo para o período de confinamento. Nos ensaios de compostagem e vermicompostagem objetivou-se avaliar o desempenho dos processos utilizando-se dejetos produzidos por animais que receberam três dietas (dieta 1: 65% concentrado + 35% volumoso; dieta 2: 70% concentrado + 30% volumoso e dieta 3:75% concentrado + 25% volumoso), oferecidas aos animais durante o período de engorda. No ensaio de biodigestão anaeróbia, foram avaliados os efeitos de duas dietas (dieta 1: 65% concentrado + 35% volumoso e dieta 2: 80% concentrado + 20% volumoso), uso de inóculo e três níveis de temperatura (40º C, 35º C e 25º C) sobre a produção de biogás. O coeficiente de resíduo encontrado, considerando todo o período de engorda, foi de 3,03, ou seja, para cada quilo de animal produzido, gerou-se 3,03 kg de dejeto (matéria seca). Considerando todo o período de confinamento, 154 dias, cada animal gerou 515,4 kg de dejeto (matéria seca) ou 2577 kg (fezes + urina), os quais em termos de nutrientes produzidos por animal representam 12,4 kg de N; 8,8 kg de P2O5; 6,7 kg de K2O; 397,0 kg de MO; 219,6 kg de C; 13,9 kg de Ca; 2,6 kg de Mg; 1,6 kg de S; 2,2 kg de Na; 0,05 kg de Cu; 1,0 kg de Fe; 0,06 kg de Mn; 0,11 kg de Zn. Os valores dos componentes da análise bromatológica dos dejetos foram 14% de PB; 20,7% de FB; 2,2% de EE; 51,9% de FDN; 33,3% de FDA; ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present study aimed to quantify wastes produced in a confined system for steers breeding and to evaluate the performance of biological process such as nutrient recycling, composting, vermicomposting and anaerobic biodigestion. Four trials were performed: wastes characterization, composting, vermicomposting and anaerobic biodigestion. The waste characterization trial aimed to determine the residual coefficient while animals were confined. The composting and vermicomposting trials were conducted in order to evaluate the process performance by using wastes products from animal fed three differents diets (diet 1: 65% concentrated + 35% voluminous ; diet 2: 70% concentrated + 30% voluminous; diet 3: 75% concentrated + 25% voluminous). The effect of two different diets (diet 1: 65% concentrated + 35% voluminous and diet 2: 80% concetrated + 20% voluminous), inoculum and three temperatures rates (40º C, 35º C e 25º C) influence all over biogas production were evaluated during the biodigestion trial. The residue coefficient found during all confined period was 3.03, whereas, to produce one kilogram body weight, 3.03 kg of waste (dry matter) was produced. During all confined period (154 days), each animal produced 515.4 kg of waste (dry matter) or 2577 kg (feces + urine), wich represents in terms of nutrients produced per animal a total of: 12.4 kg of N; 8.8 kg of P2O5 ; 6.7 kg of K2O ; 397.0 kg of OM ; 219.6 kg of C; 13.9 kg of Ca; 2.6 kg of Mg; 1.6 kg of S; 2.2 kg of Na; 0.05 kg of Cu; 1.0 kg of Fe; 0.06 kg of Mn; 0.11 kg of Zn. Bromatological analysis values of waste were: 14% of PB; 20,7% of FB; 2,2% of EE; 51,9% of FDN; 33,3% of FDA; 48,2% of ENN e 63,16% of NDT. Percentage of dry matter redution during composting trial were: 44.5%; 40.5% and 43.8% for waste produced by animals that received diets 1, 2 and 3, respectively...(Complete abstract click electronic access below) / Doutor