[pt] Este trabalho apresenta o planejamento e gestão integrados de resíduos sólidos urbanos e tratamento mecânico-biológico, como alternativa para reduzir as Pegadas Ecológicas dos pequenos municípios com a emissão de gases de aterro na disposição de lixo doméstico residual e contribuir para uma política microrregional de sustentabilidade ambiental. O caso estudado é de um grupo de pequenos municípios no sul do estado de Minas Gerais, que, em face da proximidade de seus centros urbanos e interdependência entre suas atividades sociais, econômicas e ambientais, apresentam condições favoráveis aos objetivos do trabalho. Este grupo, constituído pelos municípios de Caxambu, Baependi, Conceição do Rio Verde, Cambuquira, Campanha, Lambari e Jesuânia, encontra-se em uma região de reservas naturais, produção agropecuária, turismo histórico e ecológico prescindindo de políticas públicas, ambientalmente adequadas, para a gestão de resíduos sólidos urbanos. Importa destacar a opção metodológica do trabalho em abordar aspectos das dimensões social e econômica da sustentabilidade, limitando-se à verificação de indicadores apenas da sua dimensão ambiental. A pesquisa está baseada na avaliação de Indicadores de Sustentabilidade Ambiental relacionados à coleta, transporte e disposição do lixo doméstico residual dos pequenos municípios em estudo, e permite uma análise comparativa para medir o impacto ambiental entre a prática usual de vazamentos desses resíduos em lixões e o seu processamento em uma estação comunitária de tratamento mecânico-biológico. Para a análise comparativa de impacto ambiental é adotado, parcialmente, o Método para Avaliação de Sustentabilidade Ambiental de Pequenos Municípios desenvolvido por Carolina Herrmann Coelho-de-Souza (2009), adaptado do método de avaliação da Pegada Ecológica de Wackernagel e Rees (1996). O resultado da pesquisa revelou uma expressiva redução nas Pegadas Ecológicas dos pequenos municípios com a emissão de CO2 equivalente, provenientes da disposição de lixo doméstico residual após o tratamento mecânico-biológico, confirmando a hipótese do trabalho. / [en] This work presents the integrated planning and management of urban solid waste and mechanical-biological treatment, as an alternative to reduce the Ecological Footprints of small municipalities with the landfill gas emissions from residual household waste disposing and thus contributing to a micro-regional policy of environmental sustainability. The studied case is a group of small municipalities in the South of the State of Minas Gerais, which, given the proximity of their urban centres and interdependence among its social, economic and environmental activities, shows suitable conditions for the purposes of this work. This group is formed by the municipalities of Caxambu, Baependi, Conceição do Rio Verde, Cambuquira, Lambari, Campanha and Jesuânia, and is located in a region of natural reserves, agricultural production, historic and ecological tourism, and lacks appropriate environmental public policies for the management of municipal solid waste. It is noteworthy the work s methodology option of approaching the social and economic aspects of Sustainability, focusing on verifying those Indicators only at their environmental aspect. The research is based on the assessment of Environmental Sustainability Indicators related to the collection, transportation and disposal of residual household waste of the small municipalities studied, and allows for a comparative analysis to measure the environmental impact between the regular practice of using open-air uncontrolled landfill (non-treated garbage depository or dumping) and the processing on a community mechanical-biological treatment station.

Récemment, la pyro-gazéification de déchets ménagers solides (DMS) a suscité une plus grande attention, en raison de ses bénéfices potentiels en matière d’émissions polluantes et d’efficacité énergique. Afin de développer un système de traitement de ces déchets, durable et intégré, ce manuscrit s’intéresse plus spécifiquement au développement de la technique de pyro-gazéification des DMS, à la fois sur l’aspect technologique (expérimentations) et sur son évaluation globale (modélisation). Pour cette étude, quatre composants principaux représentatifs des DMS (déchet alimentaire, papier, bois et plastique) ont été pyro-gazéifiés dans un lit fluidisé sous atmosphère N2, CO2 ou vapeur d’eau. Les expériences ont été menées avec les composés seuls ou en mélanges afin de comprendre les interactions mises en jeu et leurs impacts sur la qualité du syngas produit. La présence de plastique améliore significativement la quantité et la qualité du syngas (concentration de H2). La qualité du syngas est améliorée plus particulièrement en présence de vapeur d’eau, ou, dans une moindre mesure, en présence de CO2. Les résultats obtenus ont été ensuite intégrés dans un modèle prédictif de pyro-gazéification basé sur un réseau de neurones artificiels (ANN). Ce modèle prédictif s’avère efficace pour prédire les performances de pyro-gazéification des DMS, quelle que soit leur composition (provenance géographique). Pour améliorer la qualité du syngas et abaisser la température du traitement, la gazéification catalytique in-situ, en présence de CaO, a été menée. L’impact du débit de vapeur d’eau, du ratio massique d’oxyde de calcium, ainsi que de la température de réaction a été étudié en regard de la production (quantité et pourcentage molaire dans le gaz) d’hydrogène. La présence de CaO a permis d’abaisser de 100 oC la température de gazéification, à qualité de syngas équivalente. Pour envisager une application industrielle, l’activité du catalyseur a aussi été évaluée du point de vue de sa désactivation et régénération. Ainsi, les températures de carbonatation et de calcination de 650 oC et 800 oC permettent de prévenir la désactivation du catalyseur, tandis que l’hydratation sous vapeur d’eau permet la régénération. Ensuite, une étude a été dédiée à l’évaluation et à l’optimisation de la technologie de pyro-gazéification par la méthode d’analyse de cycle de vie (ACV). Le système de gazéification permet d’améliorer les indicateurs de performances environnementales comparativement à l’incinération conventionnelle. De plus, des systèmes combinant à la fois la transformation des déchets en vecteur énergétique et la mise en œuvre de ce vecteur ont été modélisés. La pyro-gazéification combinée à une turbine à gaz permettrait de maximiser l’efficacité énergétique et de diminuer l’impact environnemental du traitement. Ainsi, les résultats permettent d’optimiser les voies actuelles de valorisation énergétique, et de d’optimiser les techniques de pyro-gazéification. / Due to the potential benefits in achieving lower environmental emissions and higher energy efficiency, municipal solid waste (MSW) pyro-gasification has gained increasing attentions in the last years. To develop such an integrated and sustainable MSW treatment system, this dissertation mainly focuses on developing MSW pyro-gasification technique, including both experimental-based technological investigation and assessment modeling. Four of the most typical MSW components (wood, paper, food waste and plastic) are pyro-gasified in a fluidized bed reactor under N2, steam or CO2 atmosphere. Single-component and multi-components mixture have been investigated to characterize interactions regarding the high-quality syngas production. The presence of plastic in MSW positively impacts the volume of gas produced as well as its H2 content. Steam clearly increased the syngas quality rather than the CO2 atmosphere. The data acquired have been further applied to establish an artificial neural network (ANN)-based pyro-gasification prediction model. Although MSW composition varies significantly due to geographic differences, the model is robust enough to predict MSW pyro-gasification performance with different waste sources. To further enhance syngas properties and reduce gasification temperature as optimization of pyro-gasification process, MSW steam catalytic gasification is studied using calcium oxide (CaO) as an in-situ catalyst. The influence of CaO addition, steam flowrate and reaction temperature on H2-rich gas production is also investigated. The catalytic gasification using CaO allows a decrease of more than 100 oC in the reaction operating temperature in order to reach the same syngas properties, as compared with non-catalyst high-temperature gasification. Besides, the catalyst activity (de-activation and re-generation mechanisms) is also evaluated in order to facilitate an industrial application. 650 oC and 800 oC are proven to be the most suitable temperature for carbonation and calcination respectively, while steam hydration is shown to be an effective CaO re-generation method. Afterwards, a systematic and comprehensive life cycle assessment (LCA) study is conducted. Environmental benefits have been achieved by MSW gasification compared with conventional incineration technology. Besides, pyrolysis and gasification processes coupled with various energy utilization cycles are also modeled, with a gasification-gas turbine cycle system exhibits the highest energy conversion efficiency and lowest environmental burden. The results are applied to optimize the current waste-to-energy route, and to develop better pyro-gasification techniques.