Dans le cadre des législations européennes relatives au traitement des déchets et aux énergies renouvelables, la méthanisation apparaît comme une alternative prometteuse pour la stabilisation et la valorisation des Ordures Ménagères Résiduelles (OMR). D'un point de vue opérationnel l'hétérogénéité et les difficultés de mise en mouvement d'une matrice aussi complexe que les OMR sont à l'origine de pertes de rendement voire de l'arrêt d'installations de méthanisation. Les performances de méthanisation sont en particulier limitées par l'étape d'hydrolyse des fractions lignocellulosiques qui représentent la majorité du potentiel méthanogène des OMR. Dans ce contexte, l'objectif principal du travail de thèse, était l'étude d'un procédé de percolation dans lequel le déchet n'est pas mis en mouvement. Au travers de ce travail nous avions également pour ambition de produire des connaissances à caractère plus générique sur l'hydrolyse afin d'en améliorer les performances. Des expériences préliminaires ont d'abord permis la définition d'un système expérimental adéquat pour l'étude à l'échelle laboratoire de l'hydrolyse des OMR. La représentativité d'un déchet reconstitué, reproductible et d'utilisation aisée, a notamment été vérifiée en termes de potentiel méthanogène, de profil hydrolytique et de flore microbienne. Suite à la définition de ce système expérimental, son comportement hydrolytique a été comparé à celui d'un test de lixiviation de référence (NF EN 12457-4) afin de valider l'intérêt opérationnel de la percolation pour l'hydrolyse des OMR. De façon inattendue, l'extraction de 38,90% de la matière carbonée initiale du déchet a ainsi été mise en évidence lors de l'hydrolyse par percolation contre 17,84% lors de l'hydrolyse par lixiviation, renforçant l'intérêt suscité par la percolation pour l'hydrolyse des OMR. L'optimisation des performances d'hydrolyse par percolation a ensuite été réalisée par le criblage de huit paramètres opérationnels afin de déterminer leur influence sur les performances d'hydrolyse des OMR, au travers de deux plans d'expérience. L'ajout d'alcalinité (12 gHCO3-.L-1) et la recirculation du percolat pendant 6 h par jour ont ainsi permis d'augmenter significativement les performances d'hydrolyse, passant de 17 à 43% d'extraction de la matière organique (DCO) initiale du déchet (autrement dit de 26 à 69% de la matière biodégradable initiale). L'étude des communautés microbiennes et de leur activité a également été réalisée. Le séquençage des pyrotags d'ADNr 16S a ainsi permis de mettre en évidence le caractère dominant des Classes Clostridia et Bacteroidia au sein des communautés hydrolytiques. Le couplage de cette démarche qualitative à une approche quantitative par qPCR sur une série de biomarqueurs taxonomiques et fonctionnels a permis de montrer qu'il existe une corrélation positive entre l'ajout de carbonates, la neutralisation du pH, la quantité de matière hydrolysée à 14 jours et soit l'abondance de la Classe Bacteroidia soit celle des gènes de la famille hydA, impliqués dans la fermentation. Finalement, l'analyse microbiologique a été approfondie au jour 4, c'est-à-dire durant la phase d'hydrolyse intense, grâce à une approche de métatranscriptomique. L'analyse des transcrits fonctionnels indique que l'alcalinité influence l'activité des microorganismes de la Classe Clostridia dès le jour 4 des essais d'hydrolyse. Plus spécifiquement, l'ajout de carbonates semble corrélé à une modification du métabolisme des sucres chez des microorganismes non cultivables apparentés à Clostridium cellulolyticum et à l'augmentation de l'expression de l'opéron nif, impliqué dans la fixation de l'azote, chez différents groupes de microorganismes. / In the framework of the European green policy, anaerobic digestion appears as a promising technology for stabilization and valorization of Municipal Solid Waste (MSW). In practice, mechanical mixing of a complex and heterogeneous matrix such as MSW induces major operational constraints. Anaerobic digestion performances are especially limited by hydrolysis of lignocellulosic fractions which represent the main part of MSW methanogenic potential. In this context, this PhD project was aiming to characterize and optimize of a percolation process in which MSW stands still. Preliminary experiments were conducted in order to define an experimental system suitable for lab-scale study of MSW hydrolysis. Therefore, the representativeness of an easy-to-use and reproducible reconstituted waste was verified in terms of methanogenic potential, hydrolytic profiles and associated microbial communities. Following system definition, hydrolysis behavior by percolation was compared to a reference lixiviation test (NF EN 12457-4). Surprisingly, hydrolysis by percolation permitted the extraction of 39% of carbonated matter initially contained in waste whereas 18% were extracted during hydrolysis by lixiviation, thus validating operational benefit of percolation for MSW hydrolysis. Optimization of hydrolysis performance was then conducted through the screening of eight operational parameters for their influence on MSW hydrolysis performances thanks to two Designs Of Experiment (DOE). Cumulative effect of alkalinity addition (12 gHCO3-.L-1) and percolate recirculation (6 hour.day-1) significantly improved hydrolysis yield, from 17 to 43% of extracted organic matter compared to the initial content of waste (corresponding to an extraction of 26 and 69% of biodegradable matter). Structure and activity of hydrolytic microbial communities were also studied. 16S rDNA-pyrotags sequencing brought out the dominance of classes Clostridia and Bacteroidia. Additionally, a quantitative approach led by qPCR revealed a correlation between carbonates addition, pH neutralization, amounts of hydrolyzed matter at day 14 and either class Bacteroidia or genes from hydA family, involved in fermentation. Finally, metatranscriptomic approach was conducted at day 4 in order to further study microbial activity during the intense hydrolysis phase. According to functional analysis, alkalinity seems have positive influence on class Clostridia activity. More specifically, carbonates addition seems correlated to a modification of carbohydrates metabolism of organisms affiliated to Clostridium cellulolyticum and to transcriptional up-regulation of nif operon, involved in nitrogen fixation, among various types of microorganisms.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第14561号 / 工博第3029号 / 新制||工||1451(附属図書館) / 26913 / UT51-2009-D273 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 松岡 譲, 教授 酒井 伸一, 准教授 倉田 学児 / 学位規則第4条第1項該当

The increasing volume of solid waste (SW), not only arising from household (Municipal SW, MSW) but also from industrial process (Industrial SW, ISW), has become a serious issue in Chinese metropolises with the economic growth, urbanization, industrialization, and increasing affluence. Growth of industry leads to the expansion of population, while the augment of demand by increasing population stimulates the industrial growth in turn, thereby increasing not only ISW generation, but also MSW generation. Therefore, in order to solve the waste problem for the construction of sustainable waste management system in a city, it is necessary to consider these two types of waste together, in which, the emphasis should be focused on waste reduction from the source. The starting point in adopting this should be a good understanding of the upstream flow of waste and accurate knowledge of the volume and composition of waste that will be generated in the future. However, due to deficient historical records and complex production process, the effective attempts at forecasting SW generation are far from enough, especially for ISW by waste category. A common approach which is based on the limited waste statistics and can be easily popularized into Chinese countries is thus urgent. This paper, therefore, attempts the construction of a systematic approach to make projections of SW generation by waste category from the following issues: (1) to develop household consumer behaviour model taking into account lifestyle of residents and project the demand of private consumption in the future; (2) to quantitatively investigate and project MSW generation fully considering the change in consumer behaviour and waste management policies; (3) to effectively evaluate the present and future industrial structure and their contributions to ISW generation among industries; (4) to carry out a scenario analysis of calculating CO2 emissions in different waste treatment options based on the projected waste quantity and composition in 2015. The approach is applied on a city level as the basic administrative unit of SW management in China. The entire framework comprises four modules-regional macro-economic module, MSW generation module, ISW generation module, and waste treatment module. Further, the study of consumption pattern conducted from the consumer behaviour model in MSW module is a prerequisite for industrial restructuring caused by change in consumption demand in ISW module. Moreover, the regional macro-economic module is to provide a means for economic structural analysis and economic forecasting, considering the influence of national GDP and socioeconomic indicators including world trade. It is found out that the regional model fits the historical records reasonably well and provides an acceptable reproduction. In the MSW generation module for estimating and projecting MSW generation, firstly the per capita total household consumption expenditure is estimated by using total consumption expenditure model; then, household consumption pattern is estimated using an extension of the linear expenditure system (LES); thereafter, MSW generation by composition is quantitatively expressed in terms of the expenditure for consumption category and waste management policies by using ordinary least squares (OLS). Then, five Chinese cities with distinct economic levels are presented by applying the module to determine the waste generation features in different regions. The research findings clearly indicate that 1) the number of variables affecting consumer behaviour in Chinese cities is not one but the integrations of a series of indicators. Aside from Shanghai, saving rate towards consumption (SAV) and natural growth rate (NAGR) are currently the two common factors. However, in Shanghai, consumer behaviour is strongly influenced by SAV and the average number of persons per household (ANPH). 2) The MSW generation model quantitatively demonstrates the linear conversion process from consumption to corresponding waste generation in all cities. For example, education and consumption of food-as the form of consumption expenditure in this research-is the source of generation of food, plastic and paper waste. Further, glass and metal waste is estimated by food expenditure in all cities. 3) Total MSW generation per unit consumption is 0.198~0.225 kg/RMB with an average value of 0.213 kg/RMB. 4) All the waste management policies analyzed in the research will provide feasible experiences or valuable lessons to other Chinese cities. 5) Volume of per capita MSW generated in 2020 will be 1.24-2.18 folds compared to that in 2008 in each city if there were no effective policies implemented advancing to diminishing waste generation. Then, for the forecasting of ISW generation of each waste category by industry, the ISW module is developed, linking three principal models-regional macro-economic model, regional input-output (IO) analysis, and ISW generation model. The approach investigates the influence of industrial restructuring on ISW generation, based on the study of consumption patterns, export composition figures and change in ISW generation coefficient. The principal priorities in the case study on Shanghai are as follows: 1) the approach provides an idea for a way to quantitatively analyze industrial restructuring by adjusting the converter that, in turn, helps assess the impact of these changes on sectoral output. 2) A sensitivity analysis describes that per yuan of increase in consumption on FOOD, CLSH, FUNI, EDUC, TRAN, HLTH and RESI induces to an average increase of 76.41, 76.16, 82.28, 106.54, 93.89, 148.30 and 292.58 g total ISW, respectively. 3) It is verified that ISW generation not only arises from economic growth but also from the onset of industrial restructuring. The unit ISW generation per gross output reduces from 0.16 to 0.14 tons/10 000 RMB as we move from 2002 to 2020. 4) It is investigated that the total volume of ISW generated in 2010, 2015 and 2020 will be 2.07, 2.83 and 4.12 times that of the 2002 levels. The total SW generation of Shanghai in 2020 will be 4.06 times of that in 2002. 5) However, if considering scenario analysis of adjusting ISW generation coefficient, the total SW generation is 1.93 times compared to 2002 and ISW is 2.18 times of MSW generation. 6) Based on our results, the industrial sectors making the biggest contribution to the production of each type of ISW can each be separately identified. Therefore, constraining specific industries or penetrating them with selective technological changes will be useful attempts on the way to meeting the objectives of overall waste reduction. Finally, in the waste treatment module, the greenhouse gas (GHG) emissions emitting from the treatment and disposal of waste, including landfill site, waste-to-energy incineration and composting are calculated, respectively. Further, based on the projection of waste quantity and composition of Shanghai in 2015, a scenario analysis is carried out as well concerning the GHG emissions from alternative treatment options. The results confirm that composting and recycling of waste before the treatment are effective attempts at reducing GHG emissions in Shanghai. Further, scenario designed as the integrated waste treatment system makes the biggest reduction of GHG emissions, as 34% as compared to current treatment options with energy recovery. In a word, this research develops the entire systematic approach investigating the upstream flow of waste generation from the viewpoint of economic growth, change in socioeconomic indicators and constitution of waste management policies, and makes a reasonable attempt at projecting SW generation of each type of waste category. Based on the results, it is suggested that for the waste reduction to promote sustainable society, government interventions including promoting green consumption, reducing extra consumption, et al. and waste policies such as increasing recycling and penetrating technological innovation in specific industries will be effective. Further, based on the forecasts of SW generation, the recycling and appropriate treatment of waste generating from municipal and industrial process can be examined from the long view. From the relationship between ISW and MSW generation, the development of industry will promote the growth of service industry and induce greater generation of recyclable items. While the recycling of these items before the waste treatment is essential for effectively reducing GHG emissions which contribute to global warming. In addition, the systematic model can be easily popularized into other Chinese cities even other Asian developing cities, thereby possibly promoting the sustainable waste management of China and Asian countries. / Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第14928号 / 工博第3155号 / 新制||工||1473(附属図書館) / 27366 / UT51-2009-M842 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 松岡 譲, 教授 森澤 眞輔, 准教授 倉田 学児 / 学位規則第4条第1項該当