La Digestion Anaérobie (DA), ou méthanisation, est un procédé qui permet le traitement de déchets organiques et la production d’énergie renouvelable sous forme de biogaz. La DA par voie sèche permet en particulier la valorisation de substrats solides, offrant plusieurs possibilités aux traitements de résidus d’origine agricole tels les fumiers, des substrats constitués d’un mélange de paille, fèces et urine accumulés dans les litières des étables. Parmi les technologies disponibles en méthanisation, les « leach-bed reactors » (LBRs), constituent une option valide mais toutefois peu connue et peu développée soit au niveau scientifique qu’industriel.Dans le but d’optimiser ce procédé, plusieurs problématiques ont été affrontées : (i) la caractérisation bio-physico-chimique du fumier et du potentiel énergétique exprimé dans un LBR; (ii) l’optimisation de l’inoculation des réacteurs et de la température de digestion ; (iii) la co-digestion du fumier avec un substrat facilement biodégradable et la problématique reliées à la gestion des acides gras volatiles (AGVs) ainsi produits.Les résultats montrent que le fumier est un substrat lentement biodégradable qui nécessite un long temps de digestion. Cependant, il s’agit d’un déchet agricole adapté à la valorisation par méthanisation et dont les rendements de dégradation et de production de méthane en LBRs sont intéressants industriellement. Ce substrat est par conséquent une ressource organique précieuse dans le contexte agricole.Il a été montré que le fumier bovin contient une population méthanogène active capable de démarrer un procédé de digestion anaérobie efficacement sans l’ajout d’un inoculum externe spécifique, autant en mode mésophile que thermophile. Une analyse économique a démontré que cette propriété peut être exploitée afin de diminuer les coûts d’investissement initiaux d’un projet à l’échelle industrielle, en favorisant de cette manière le développement de la filière. De plus, les résultats montrent que pour la digestion du fumier en LBRs le mode thermophile ne comporte aucun intérêt par rapport à la production finale de méthane (qui est similaire pour les deux régimes) et que, au contraire, la valorisation par cogénération du méthane produit en thermophile diminue le rendement de production électrique surtout à cause d’une production de méthane très importante en début de digestion. Le régime mésophile parait donc être le mode de fonctionnement le plus adapté dans ce contexte.Enfin, le rôle joué par la percolation du lixiviat sur la mobilisation des AGV accumulés dans la fraction solide a été mis en lumière dans un réacteur de co-digestion traitant une fraction de lentement biodégradable (le fumier) et une fraction facilement biodégradable. Une stratégie a été développée afin d’étudier le problème de l’extraction et de la consommation des AGV dans le but d’améliorer le rendement global du procédé.Pour conclure, ce travail a permis d’optimiser certains paramètres fondamentaux dans la gestion d’un LBR. Cette technologie s’est révélée efficace dans le traitement du fumier, autant en mono-digestion qu’en co-digestion avec un substrat facilement biodégradable. Ces recherches montrent que l’utilisation des LBR est appropriée au contexte agricole et que la modification des paramètres de contrôle permet à ce procédé de répondre efficacement aux problématiques du terrain. Ce travail représente une avancée significative vers la compréhension et le développement des LBRs pour le traitement des résidus agricole et, plus globalement, des énergies renouvelables mobilisant des biomasses agricoles / Anaerobic Digestion (AD) is a process which allows the treatment of organic waste and the production of renewable energy. In particular, dry AD allows the treatment of solid organic substrates, offering several possibilities to the enhancement of agricultural waste such as spent livestock bedding (a mixture of straw, faeces and urine). Among the available biotechnologies in AD, leach-bed reactor (LBRs) is a promising but yet poorly known process both at scientific and industrial level.In order to develop this process, several issues have been studied: (i) the bio-physico-chemical characterization of spent animal bedding and its digestion potential in LBRs; (ii) the optimization of the start-up and the operating temperature of the digesters; (iii) the co-digestion of spent animal bedding with an easily-degradable substrate and the issues connected to the management of the volatile fatty acids (VFAs) produced.The results showed that spent animal bedding is a slowly-degradable substrate which needs a long digestion time. However, it is a substrate suitable to be treated through AD displaying high degradation and methane production rates when processed in LBRs. This substrate is, therefore, a valuable organic resource in the agricultural context.Spent animal bedding was shown to contain an active methanogenic population able to start the process efficiently, both in thermophilic and mesophilic temperature, without requiring a specific external inoculation. An economic study at industrial scale proved that this peculiarity can be used to diminish the investment costs and then promote the development of this process. Moreover, thermophilic temperature was proved to be less advantageous over mesophilic condition. In fact, despite the very close methane yield reached in both temperature range, the different biogas production rates in thermophilic conditions would lead to a reduction of the final electric energy production in this condition. Mesophilic temperature was then shown to be the best operating condition for this process.Finally, the role played by the leachate recirculation in the mobilization of the VFAs accumulating in the solid bulk was highlighted in the case of a reactor co-digesting slowly- (spent livestock bedding) and easily-degradable substrates. A strategy was even proposed to efficiently face such a problem by optimizing both the VFA extraction and consumption with the objectives of increasing the overall process efficiency.In the end, this work allowed to optimize some important parameters for the correct management of the LBRs. This technology was proved to be efficient in the treatment of spent livestock bedding, both as a sole substrate or in co-digestion with an easily-degradable substrate. This research study demonstrates that LBRs is an adapted process for the agricultural context and this technology can easily answer to the full scale issues usually encountered. This work represents a significant advance towards the comprehension and development of LBRs to treat agricultural waste and, more generally, to the development of renewable energies based on biomass

Anaerobic digestion (AD) of corn thin stillage (CTS) offers the potential to reduce corn grain ethanol production energy consumption. This thesis focuses on results collected from AD of CTS at mesophilic temperatures in batch and by down-flow fixed film reactor. Experiments conducted include a series of biochemical methane potential (BMP) assays that investigated the digestion of CTS as the sole carbon source at a variety of food-to- microorganism ratios with and without acclimated biomass, under co-digestion conditions and also with the addition of supplemental nutrients. Additional BMP assays were conducted which investigated the potential to reduce fresh water consumption by using of digested effluent for substrate dilution. Continuous studies employed two 28L down-flow stationary fixed film reactors to examine. Chemical oxygen demand and volatile solids removal efficiencies greater than 85% were achieved up to an organic loading rate of 7.4 g TCOD/L/d and hydraulic retention time of 5 days.

The Ontario biogas industry is relatively young and the overall objective of this research was to help support the growth of the industry with investigating the use of co-substrates and reactor design to enhance biogas production, recommend guidelines on the operation of full scale systems to optimize performance and characterize digestate quality. Laboratory studies evaluated the use of various substrates in the co-digestion with liquid dairy manure. These studies were used to establish ultimate biogas yields, % volatile solids (VS) reduction and minimum hydraulic retention times (HRTs). Box-Wilson Central Composite design models for corn thin stillage and waste grease (as co-substrates with dairy manure) suggest methane yields optimize with increasing proportion of the feed VS from co-substrates (constant total VS in all assays) and increasing temperatures; however, temperature had a great effect. Bench scale studies were conducted to determine a change in digester design to optimize biogas yields and increase digestate stability. A two-phase digestion system was implemented for co-digestion systems using thin stillage and waste grease with dairy manure, and methane yields showed to increase by over 22% when compared with single-phase systems. Based on current FIT contracts of 18 to 20¢/kWhe, the increased electricity and heat production could make the two-phase system economically attractive for producers. Organic loading rates (OLRs) over 4.4 g VS/L led to digester upset and OLRs of over 4.2 g VS/L·day are not recommended. On-farm anaerobic digester systems were studied for digester performance and digestate quality. Residual biogas potential (RBP) yields were effective at evaluating the stability of digestate and the U.K. PAS 110:2014 limit of 0.45 L biogas/g VS (28 days incubation) was assessed too lenient for the Ontario systems studied. A limit of 0.25 L biogas/g VS after 28 days of incubation or 0.45 L biogas/g VS after 60 days of incubation are recommended. VS reductions ranged from 56 to 76% and easily achieved the O. Reg. 267/03 regulated 50% VS reduction. E.coli and Salmonella were typically 1 to 3 logs CFU/100 mL lower than raw manure and increased HRT did not demonstrate a significant impact on the bacterial log reductions. Intermediate alkalinity (IA)/partial alkalinity (PA) proved to be a valuable tool in determining potential digester upset and has been recommended as a standard performance parameter for on-farm systems.

Dans un contexte de développement durable, trouver des moyens de réduire l’impact environnemental de la production avicole est d’une grande importance. L’estimation des paramètres génétiques de nombreux caractères de rejets chez les lignées divergentes D+ et D- nous a permis de définir plusieurs critères pertinents à prendre en compte dans les schémas de sélection pour maîtriser l’excrétion des poulets. Nous avons également montré que l’utilisation de ces critères n’aurait pas de conséquences négatives sur les caractéristiques d’importance économique pour l’industrie avicole. Enfin, nous avons pu montrer que la morphologie du tractus gastro-intestinal était très fortement impliquée dans les variations d’excrétion des poulets. En effet, un important développement du proventricule et du gésier et une réduction du développement de l’intestin grêle sont associés aux animaux produisant moins de rejets et présentant une meilleure efficacité digestive. / The reduction of the environmental impact of poultry production is crucial to ensure its sustainability. The estimation of genetic parameters of several excretion characteristics in D+ and D- divergent lines allowed us to define pertinent criteria that could be included in selection schemes in view to reduce chicken excretion. We also showed that using these criteria would not have negative consequences on the traits of economic importance for poultry industry. Finally, we showed that the gastro-intestinal tract morphology is highly implied in the variations of excretion between chickens. Indeed, an important development of the proventriculus and gizzard and a reduction of the small intestine development were associated with birds producing less excreta and showing a higher digestive efficiency.

The relationship between beetles and flowers is often mutually beneficial. Flowers provide not only edible rewards and favourable micro-environments, but may also be sites for mating and egg-laying activities. Even though beetles consume various parts of flowers, including pollen, and can sometimes cause considerable damage, they are in fact important pollinators of many flowers. Pollen was once considered indigestible but is actually a highly nutritious food source for many animals (including insects, birds and mammals) which use a variety of methods to digest it. Six basic methods are discussed in detail: mechanical damage, piercing and sucking, external digestion, enzymatic action, osmotic shock and pseudogermination. In this study I investigated the mechanism and efficiency of pollen digestion of two different kinds of pollen, that of maize Zea mays and sunflower Helianthus annuus, by the spotted maize beetle Astylus atromaculatus (Melyridae) an economically important pest in South Africa Histological observations were made of the gut contents and faeces of spotted maize beetles that fed on maize and sunflower. A high percentage of maize pollen grains (88%) was found to be empty and ruptured in the anterior midgut of these beetles, while sunflower pollen, although the contents were removed from most of the grains (84%), remained intact. Osmotic shock was apparently involved in digestion of maize pollen while another method, such as enzymatic action, may be used for the digestion of sunflower pollen by this beetle. Digestion efficiency of pollen, which corrects for the number of initially empty grains, was determined for the spotted maize beetle (67% for sorghum, 72% for sunflower and 74% for maize) and was found to be high in comparison to values for various mammals, birds and insects consuming pollen of other plant species. Kroon et al. (1974) proposed osmotic shock as a prerequisite for pollen digestion in honeybees and this hypothesis was accepted into the literature without question. I investigated the effect of osmotic shock on maize pollen by looking at behaviour of pollen grains under varying osmotic concentrations. Given that rainwater can sometimes cause irreversible damage to pollen grains, distilled water was used to simulate rain and sucrose solutions the stigmatic exudates of flowers. A small number of studies have focused on differences between cultivars, therefore in vitro studies were carried out subjecting maize pollen of different cultivars to different sucrose and glucose:fructose concentrations, using distilled water as a control. Results of this study indicated that maize pollen might burst in distilled water and sugar solutions of various concentrations did not decrease the amount of rupturing compared to that in water. Few studies have looked at pollen of a single plant species being digested by different animals. I compared the efficiency and mechanism of maize pollen digestion by honeybees (Apis mellifera) and spotted maize beetles. Digestive efficiency was high (80%) in beetles compared to that of bees (21 %). Maize pollen bursts early in the midgut of maize beetles but remained intact in honeybees: this suggests that osmotic shock is not as important for bees as previously suggested. / Dissertation (MSc (Entomology))--University of Pretoria, 2006. / Zoology and Entomology / unrestricted

No description available.

Anaerobic digestion can be used to decrease the mass of organic wastes to be disposed of while producing useful biogas (CH4 and CO2) for heat or power production, but in air basins with strict emissions limits, biogas combustion is difficult to implement due to the high costs of controlling NOx emissions. NOx production can be minimized by blending H2 gas with CH4 at a volume ratio of 15:85 H2:CH4, which allows burning at ultra-lean air-to-fuel ratios. For biogas systems, a potential low-cost NOx control strategy is to produce H2-CH4 mixtures through two-phase anaerobic digestion, where two digester tanks are operated in series, with the first one producing a majority H2 and the second CH4. The resulting mixture of H2, CH4, and CO2 should combust with low NOx emissions. Furthermore, in theory, if the biogas from the second-phase is sparged through the first-phase, H2 would be stripped from the first-phase liquid medium, and H2 production would be more thermodynamically favored, possibly increasing H2 production. Laboratory experiments were used to determine the optimal conditions to generate biogas with a 15:85 H2:CH4 ratio using two phase digestion with glucose as the substrate. Specifically, the objectives of this thesis were to (1) determine the optimal conditions for operating the first-phase to produce H2, (2) determine the sparging rate required to achieve 15:85 H2:CH4 in the biogas, and (3) operate the first and second-phases together with second-phase biogas being sparged through first-phase medium to achieve 15:85 H2:CH4. The results from each of these objectives are described below. (1) The optimal conditions for H2 production in the first-phase were an organic loading rate of 22.9 g COD/L-day (chemical oxygen demand) and a hydraulic residence time of 12 hours. The resulting pH in the first-phase was 6.11 when operated under these conditions. Optimized hydrogen production in the first phase resulted in the generation of 1.02 ± 0.13 L H2/Ldigester-day, which can also be expressed as 0.61 ± 0.10 mol H2/mol glucoseconsumed, 0.42 ± 0.06 mol H2/mol glucoseintroduced, 1.06 ± 0.16 mol H2/mol CODdestroyed, and 0.06 ± 0.01 mol H2/mol CODintroduced. (2) Initial sparging experiments were conducted using nitrogen (N2) to represent second-phase biogas. The rates tested ranged from 1- 30 L N2/Lfirst-phase digester-hr. A 1.1 L gas/L-hr sparging rate was projected to result in a 15:85 H2:CH4 ratio. The projection was made using a power regression model (R2 = 0.99) of sparging rate vs. hydrogen content results, assuming the sparged N2 was replaced with typical biogas (60% CH4 and 40% CO2). (3) When both phases were integrated, the second-phase produced enough gas to sparge at only 0.28 L gas/Lfirst-phase digester-hr, which was far less than the optimal 1.1 L gas/Lfirst-phase digester-hr sparging rate. A non-optimal H2:CH4 ratio of 15:12 was obtained at the 0.28 L gas/L-hr sparging rate. Insufficient CH4 was generated due to the low organic loading provided to the second-phase. Although the 1.1 L gas/L-hr sparging rate was not tested in an integrated system, the results obtained from the 0.28 L gas/L-hr sparging rate differed from what was predicted by the nitrogen sparging model by only 14%. Therefore, the model was fairly accurate (at least at a low flow rate of 0.28 L gas/L-hr) and could still be valid for the predicted optimal flow rate of 1.1 L gas/L-hr. For future two-phase digestion studies, biogas production from the second-phase can be increased by adding more substrate to the second-phase or by using fixed-film digesters to possibly increase the number density of methanogens. It is also recommended to digest practical waste feedstocks, and possibly digest different feedstocks in the first and second-phases. Also, the effects of carbon dioxide on the combustion characteristics and NOx emissions of hydrogen-methane mixtures in biogas need to be researched.

The presented diploma thesis is focused on complex characterization of chosen superfoods and subsequent composition of supplement suitable for children´s nutrition. Different kinds of superfoods were chosen for analyses, such as: barley grass (Hordeum vulgare), wheat grass (Triticum aestivum), moringa (Moringa oleifera), matcha tea (Camellia sinensis), microalgae chlorella (Chlorella pyrenoidosa), spirulina (Arthrospira platensis), flax seeds (Linum usitatissimum) and sesame seeds (Sesamum indicum). The theoretical part is focused on children´s nutrition issue and the most common food allergies and intolerances. Also, children food products legislation and characterization of chosen samples are included in theoretical part. Main macronutrients, such as saccharides, lipids and proteins, were analysed in the very beginning of experimental part. Fibre, fructan and -glucan, which have a high impact on intestinal microbiome and whole process of digestion, were analysed as well. However, barley grass was the best evaluated sample by containing 205,5 mg/g of insoluble fibre; 152,57 mg/g of fructans and 18,76 mg/g of -glucans. Finally, for complex nutritional profile, also samples pigments were analysed. Spectrophotometry, HPLC chromatography, gas chromatography and other analytical techniques were performed for experiments.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23184号 / 工博第4828号 / 新制||工||1754(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 高岡 昌輝, 教授 田中 宏明, 准教授 大下 和徹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The substance choline, one of the quaternary nitrogen bases, has been the subject of a number of reviews and investigations. It has been described as a cholinergic agent, an inotropic agent, a vitamin, and perhaps in other ways. In spite of the interest shown in its action and uses, there is as yet very little information available as to the mechanism by which it is absorbed by the intestinal mucosa. The studies referred to thus far leave the field open for additional investigation. No mention was found in the literature of studies on selective areas of absorption of choline in the small intestine, or whether enzyme inhibitors might produce an effect on rate of absorption. In view of the possibility that active transport, and thus enzyme activity, might be involved in choline absorption, it is conceivable that rate of choline absorption might be altered by such enzyme inhibitors as phlorizin and 2, 4-dinitrophenol. Selective areas of choline absorption, and the effects of several enzyme inhibitors were, then, selected as the areas for investigation in the study described here.