O presente trabalho se propôs a avaliar o efeito de uma etapa de tratamento alcalino no bagaço de malte visando à extração de acetato e de compostos fenólicos, e como consequência diminuir a concentração destes no hidrolisado hemicelulósico. Foi ainda objetivo deste trabalho, estudar o efeito do tratamento alcalino na bioconversão das frações celulósica e hemicelulósica do bagaço de malte, por meio de fermentação com as leveduras Kluyveromyces marxianus e Pichia stipitis, respectivamente. Os resultados mostraram que para todas as condições de tratamento alcalino avaliadas, ocorreu solubilização de acetato, compostos fenólicos e furanos, não sendo observada solubilização de açúcares. A capacidade de solubilização destes compostos aumentou com o aumento da concentração de hidróxido de sódio empregada até o tempo de 40 min, sendo observada uma concentração máxima de 0,86 g/L, 13,0 g/L e 0,58 g/L empregando 1%%, 2% e 2% de NaOH, respectivamente. Para todas as condições avaliadas, o tratamento alcalino do bagaço de malte reduziu a concentração de ácido acético no hidrolisado hemicelulósico. A menor concentração (0,026 g/L) foi obtida após 20 minutos de tratamento com 2% de NaOH. Com relação à concentração xilose, o menor teor desta pentose (8,3 g/L) foi obtido após o tratamento do bagaço com 0,25 % de NaOH por 2 minutos e o maior (22,0 g/L) com 0,5% de NaOH por 60 minutos. Visando estabelecer as condições de tratamento alcalino que permitissem uma redução na concentração de ácido acético, concomitantemente ao favorecimento da solubilização de xilose no hidrolisado hemicelulósico e de glicose no hidrolisado celulósico, as condições de temperatura e concentração de NaOH do tratamento alcalino do bagaço de malte foram otimizadas através de um planejamento estatístico. Nas condições otimizadas (concentração de NaOH de 0,63%, temperatura de 67,6°C e tempo de 20 min), o tratamento alcalino do bagaço de malte promoveu uma redução de 90% na concentração de ácido acético, concomitante ao aumento de 4,5% e 15% na concentração de xilose no hidrolisado hemicelulósico e concentração de glicose no hidrolisado celulósico, respectivamente. Os resultados referentes à bioconversão da fração celulósica demonstraram que para ambas as configurações de processo avaliadas (SHF e SSF) a fermentação da celulignina do material tratado (CLT) forneceu maior concentração de etanol, e essa diferença foi mais pronunciada na SSF. Além disso, na SSF, a produtividade volumétrica total em etanol, a qual considera o tempo de sacarificação e fermentação no processo foi aumentada em 2,2 vezes em relação à SHF. Com relação a bioconversão da hemicelulose, os resultados mostraram que tanto para o hidrolisado do bagaço referência não tratado (HHR) quanto para o previamente tratado com álcali (HHT), a concentração máxima de etanol foi obtida após 89 horas de fermentação, porém na fermentação do (HHT) a produção de etanol foi cerca de 3 vezes superior a obtida no (HHR), passando de 5,8 para 17,4 g/L. Com base nos resultados obtidos, pode-se concluir que a etapa de tratamento alcalino do bagaço de malte, provavelmente promoveu mudanças estruturais na celulignina aumentando a liberação de glicose no hidrolisado e ainda foi capaz de remover substâncias inibidoras do metabolismo microbiano, especialmente o ácido acético, favorecendo o processo fermentativo da fração hemicelulósica. / This study aimed to evaluate the effect of alkaline treatment in brewer\'s spent grain on extraction of acetate and phenolic compounds, and consequently to decrease their levels on hemicellulosic hydrolyzate. In addition, the effect of the alkali treatment on the bioconversion of cellulose and hemicellulose hydrolyzates employing Kluyveromyces marxianus and Pichia stipitis, respectively, was also evaluated. The results showed that for all conditions of treatment studied occurred solubilization of acetate, phenolics and furans, but not sugars. The solubilizing capacity of these compounds increased with increasing concentration of sodium hydroxide employed until the time of 40 min, and the maximum concentration observed was 0.86 g / L 13.0 g / L and 0.58 g / L from 1%, 2% NaOH and 2%, respectively. For all conditions evaluated, alkali treatment of brewer\'s spent grain reduced the acetic acid concentration in hemicellulosic hydrolyzate. The lowest concentration (0.026 g / L) was obtained after 20 minutes with 2% NaOH. With respect to xylose concentration, the lower content of this pentose (8.3 g / L) was obtained after the treatment with 0.25% NaOH for 2 minutes and the highest (22.0 g / L) with 0.5 % NaOH for 60 minutes. To establish optimal conditions of temperature and NaOH concentration in the alkaline treatment aiming to decrease the concentration of acetic acid and, at the same time, increase the solubilization of xylose in the hemicellulose hydrolyzate and glucose in the cellulosic hydrolyzed, a statistical design was used. Under optimized conditions (NaOH concentration of 0.63%, a temperature of 67.6 °C and time of 20 min) alkaline treatment of the brewer\'s spent grain promoted a decrease of 90% in acetic acid concentration, concomitant to an increase of 4.5% and 15% on xylose concentration in the hemicellulose hydrolyzate and on glucose concentration in the cellulosic hydrolyzate, respectively. The results concerning the bioconversion of cellulosic fraction showed that for both configurations of the process evaluated (SHF and SSF) the treated material cellulignin (CLT) provided higher ethanol concentration, and this difference was more pronounced in SSF. In addition, in SSF, the total ethanol volumetric productivity, which considers time saccharification and fermentation process was increased by 2.2 times compared to SHF. In relation to the hemicellulose bioconversion, the results showed that for both hydrolyzate employed, i.e untreated (HHR) and previously treated with alkali (HHT), the maximum ethanol concentration was achieved after 89 hours of fermentation, however the ethanol production in HHT was about 3 times higher obtained in HHR (from 5.8 to 17.4 g/L). Based on these results, we conclude that the alkali treatment, probably induced structural changes in the fraction of cellulignin regarding glucose released in the hydrolyzate and still was able to remove substances inhibitory to microbial metabolism, especially acetic acid, favoring the fermentation of hemicellulose fraction.

Barley spent grain, the main residue of the brewing industry, is a lignocellulosic material, which could be considered a potential raw material for ethanol production. In this work, spent grains generated in a microbrewery were fractionated by acid hydrolysis and delignification. The investigated sort of barley spent grains had high carbohydrate content, accounting for 60% of the dry matter, while its lignin content was lower than that reported for other sorts of spent grains. Since the used spent grains contained residual starch different treatment approaches were used for separating their main components without affecting the sugars generated by starch hydrolysis. Two kinds of acid hydrolysis processes, namely single-step and two-step hydrolysis, were used for solubilising the carbohydrate fraction. Single-step hydrolysis was performed either at 100oC or at 121oC. In the two-step approach, a second hydrolysis, at 121oC, was performed after the first hydrolysis step. The dilute-acid hydrolysis at 100oC removed all the starch, whereas the hydrolysis at 121oC removed also a part of the hemicelluloses in addition to starch. During the second hydrolysis step, the content of easily hydrolysable polysaccharides decreased from 32.5 to 7.6% in the material pre-hydrolyzed at 100oC and from 20.3 to 10.6% in the material pre-hydrolyzed at 121oC. The amount of easily hydrolysable polysaccharides removed in the second step corresponded to 83% and 81.5% of the total removed matter in the materials pre-hydrolyzed at 100 and 121oC, respectively. In the next step, acetosolv and alkaline delignification, either alone or combined with acid hydrolysis, were used for dissolving the lignin fraction. A higher solubilisation occurred after alkaline delignification, where 83% of the initial material was removed. Only 34% of the initial lignin was removed by direct acetosolv, while the combined acid hydrolysis/acetosolv approach resulted in lignin removal between 70 and 75%. However, the resulted pulp still contained important amount of lignin. The acid prehydrolysis was also beneficial for alkaline delignification, but the effect was less noticeable than for acetosolv. Lignin removal increased from 95% in direct alkaline delignification to nearly 100% in the acid hydrolysis-assisted alkaline treatment. Two different methods were carried out for lignin precipitation. In the liquid fraction obtained by acetosolv, lignin was precipitated by water addition after concentration of the liquors to 75% of the initial volume. Although the visual inspection of the liquors after water addition revealed a relatively good lignin precipitation, the separation by filtration of the precipitated material was difficult, apparently due to the small particle size of precipitated lignin molecules. Some improvement was observed for the combined treatments, especially for those including two-step acid hydrolysis. The best recovery, 54% of the precipitated lignin, occurred for the process including consecutive acid hydrolyses at 100 and then at 121oC before acetosolv. In the alkaline liquors, lignin was precipitated by pH adjustment to 2.0 by HCl. Around 40.5% of the solubilised lignin was precipitated, and it increased to 85-100% when combined treatments were applied. The best results were achieved upon the treatment including acid prehydrolysis at 121oC before alkaline process.

Quando um país se torna auto-suficiente em uma parte do ciclo nuclear, quanto à produção de combustível que será usado em suas centrais nucleares para a geração de energia, precisa voltar sua atenção para a melhor forma de armazenar este combustível após a sua utilização. A armazenagem do combustível nuclear queimado é uma prática necessária e utilizada nos dias atuais em todo o mundo como temporária, tanto por países que não têm definido o plano de destinação final, isto é, o repositório definitivo, como também por aqueles que já o possuem. Existem dois aspectos principais que envolvem os combustíveis queimados: um referente à armazenagem do combustível nuclear queimado destinado ao reprocessamento e o outro ao que será enviado para deposição final quando o sítio de deposição definitiva estiver definido, corretamente localizado, adequadamente caracterizado quanto aos diversos aspectos técnicos, e licenciado. Este último aspecto pode envolver décadas de estudos por causa das definições técnicas e normativas em um dado país. No Brasil, o interesse está voltado para a armazenagem dos combustíveis queimados que não serão reprocessados. Este trabalho analisa os tipos possíveis de armazenagem, o panorama internacional e a possível proposta para a futura construção de um sítio de armazenagem temporária no país. / When a country becomes self-sufficient in part of the nuclear cycle, as production of fuel that will be used in nuclear power plants for energy generation, it is necessary to pay attention for the best method of storing the spent fuel. Temporary storage of spent nuclear fuel is a necessary practice and is applied nowadays all over the world, so much in countries that have not been defined their plan for a definitive repository, as well for those that already put in practice such storage form. There are two main aspects that involve the spent fuels: one regarding the spent nuclear fuel storage intended to reprocessing and the other in which the spent fuel will be sent for final deposition when the definitive place is defined, correctly located, appropriately characterized as to several technical aspects, and licentiate. This last aspect can involve decades of studies because of the technical and normative definitions at a given country. In Brazil, the interest is linked with the storage of spent fuels that won't be reprocessed. This work analyses possible types of storage, the international panorama and a proposal for future construction of a spent nuclear fuel temporary storage place in the country.

Fast-paced lifestyles result in consumers replacing traditional meals with on-the-go snack foods. In general, snacks are higher in saturated fats and simple sugars, and pose health concerns for consumers, which prompts the need for healthy nutritious alternatives to common snacks. Proso millet is a nutritious, and fast growing gluten free cereal. Spent grain (SG), the main by-product of brewing and distilling, contains high amount of protein and insoluble fibers. This study utilized proso millet and spent grain in the production of an extruded expanded snack, demonstrating their appropriateness as an ingredient in food production. The first objective of this study was to determine the effect of extrusion processing conditions (moisture, barrel temperature, screw speed) on the physical, chemical, and functional properties of proso millet based extruded snack. The second objective of this research was to determine the effect of distiller’s spent grain (DSG) addition level and particle size on physicochemical and functional properties of extruded snacks. The third objective of this research was to evaluate the effect of spent grain type and particle size on the physicochemical and functional properties of extruded snacks. Samples were produced using a co-rotating twin-screw 25:1 L/D laboratory scale extruder.

<p>Nuclear energy is currently one of the world’s main sources of electricity. Closely connected to the use of nuclear energy are important issues such as the nonproliferation of fissile material that may potentially used in nuclear weapons (safeguards), and the management of the highly radioactive nuclear waste. This thesis addresses both these issues by contributing to the development of new experimental methods for ensuring safe and secure handling of the waste, with focus on methods to be used prior to encapsulation and final storage.</p><p>The methods rely on high resolution gamma ray spectroscopy (HRGS), involving the measurement and analysis of emitted gamma radiation from the fission products ¹³⁷Cs, ¹³⁴Cs and ¹⁵⁴Eu. This technique is nondestructive, making it relatively nonintrusive with respect to the normal operation of the nuclear facilities.</p><p>For the safeguards issue, it is important to experimentally verify the presence and identity of nuclear fuel assemblies and also that the fuel has experienced normal, civilian reactor operation. It has been shown in this thesis that the HRGS method may be used for verifying operator declared fuel parameters such as burnup, cooling time and irradiation history. In the experimental part of the work, the burnup and the cooling time has been determined with an accuracy of 1.6% and 1.5%, respectively (1 σ).</p><p>A technique has also been demonstrated, utilizing the ratio ¹³⁴Cs/¹⁵⁴Eu, with which it is possible to determine whether a fuel assembly is of MOX or LEU type. This is of interest for safeguards as well as for the safe operation of a final storage facility.</p><p>As an improvement to the HRGS technique, measuring a part of the fuel assembly length in order to reduce measurement time has been suggested and investigated. A theoretical case for partial defect verification has also been studied as an extension of the HRGS technique. </p><p>Finally, HRGS has been used for determining the decay heat in spent nuclear fuel assemblies, which is of importance for the safe operation of a final storage facility. This application is based on the radiation from ¹³⁷Cs, and the accuracy demonstrated was within 3% (1 σ).</p>

Nuclear energy is currently one of the world’s main sources of electricity. Closely connected to the use of nuclear energy are important issues such as the nonproliferation of fissile material that may potentially used in nuclear weapons (safeguards), and the management of the highly radioactive nuclear waste. This thesis addresses both these issues by contributing to the development of new experimental methods for ensuring safe and secure handling of the waste, with focus on methods to be used prior to encapsulation and final storage. The methods rely on high resolution gamma ray spectroscopy (HRGS), involving the measurement and analysis of emitted gamma radiation from the fission products 137Cs, 134Cs and 154Eu. This technique is nondestructive, making it relatively nonintrusive with respect to the normal operation of the nuclear facilities. For the safeguards issue, it is important to experimentally verify the presence and identity of nuclear fuel assemblies and also that the fuel has experienced normal, civilian reactor operation. It has been shown in this thesis that the HRGS method may be used for verifying operator declared fuel parameters such as burnup, cooling time and irradiation history. In the experimental part of the work, the burnup and the cooling time has been determined with an accuracy of 1.6% and 1.5%, respectively (1 σ). A technique has also been demonstrated, utilizing the ratio 134Cs/154Eu, with which it is possible to determine whether a fuel assembly is of MOX or LEU type. This is of interest for safeguards as well as for the safe operation of a final storage facility. As an improvement to the HRGS technique, measuring a part of the fuel assembly length in order to reduce measurement time has been suggested and investigated. A theoretical case for partial defect verification has also been studied as an extension of the HRGS technique. Finally, HRGS has been used for determining the decay heat in spent nuclear fuel assemblies, which is of importance for the safe operation of a final storage facility. This application is based on the radiation from 137Cs, and the accuracy demonstrated was within 3% (1 σ).

The topic of this doctoral thesis is the potential near field immobilization of the radionuclide 79Se after intrusion of groundwater into a spent nuclear fuel canister in a repository. 79Se is a non naturally occurring long lived selenium isotope formed as a result of fission in nuclear fuel. Given the long half life (~3 x 105 y) and that the oxyanions of selenium are expected to be highly mobile and potentially difficult toimmobilize the isotope is of interest for the long term safety assessment of high level waste repositories. In this work the near field has been limited to the study of processes at or near the UO2 surface of (simulated) spent nuclear fuel and to processes occurring at or near the surface of iron (canister material) corroding under anoxic conditions. Selenite (HSeO32-) was found to adsorb onto palladium (simulated noble metal inclusion in spent nuclear fuel). Under hydrogen atmosphere selenite was reduced to elemental selenium with a rate constant of ~2 x 10-9 m s-1 (with respect to the Pd surface, 24 bar H2) forming colloidal particles. The rate constant of selenite reduction was increased by about two orders of magnitude to ~2.5 x 10-7 m s-1 (with respect to the Pd surface, 10 bar H2) for a UO2 surface doped with Pd particles, indicating that UO2 is an efficient co-catalyst to Pd. Selenate (SeO42-) was neither adsorbed nor reduced in the presence of Pd, UO2 and hydrogen. In the iron corrosion studies selenate was found to become reduced to predominantly elemental Se in the presence of a pristine iron surface. Iron covered by a corrosion layer of magnetite did however appear inert with respect to selenate whereas selenite was reduced. The reduction of dissolved uranyl into UO2 by the corroding iron surfaces was found to significantly increase the removal rate of selenite as well as selenate. The uranyl was found to transiently transform the outer iron oxide layers on the iron, forming a reactive mixed Fe(II)/Fe(III) oxyhydroxide (Green rust). Exchanging the solution and increasing the carbonate content (from 2 mM to 20 mM NaHCO3) only resulted in a minor, transient remobilization of uranium. Addition of H2O2 did however result in a significant release of uranium as well as selenium from the iron oxide surfaces. An irradiation experiment was also performed confirming the one electron reduction barrier of selenate as an important factor in systems where selenate reduction would be thermodynamically favorable. / QC 20101208

Sustainable development is a growing concern for inhabitants of the planet earth. Consumption of fossil sources keeps up the depletion of nature’s capital and causes environmental impacts. One solution to have a sustainable society is to reduce the dependency on fossil fuels and substitute them by renewable energy sources. Among different types of renewable energy, biofuels have great potential for development and improvement. Though, the production of biofuels is criticized by many experts from the energy efficiency, environmental and economical points of view. Biogas as one type of first generation biofuels is achieved from the wastes and by-products of other industries, and can be used as a transportation fuel in the form of biomethane. The use of by-products may give added value as inputs to the biogas production process, a process which may be called "upcycling." The aim of upcycling is to convert wastes into new materials with higher quality or higher environmental value in order to reduce the consumption of raw materials which results in decreasing of energy usage and environmental impacts The aim of this thesis is to study the possibility of a biogas plant to act as an upcycler of wastes and by-products through anaerobic digestion process by the use of exergy analysis and economic evaluation. An imaginary biogas plant which uses a major by-product of brewing industry, i.e. Brewer’s Spent Grain (BSG), is considered to quantify the added value by biogas production process. The results of the exergy analysis show that the exergy of the input BSG (78,320 MJ) is upgraded into two main products as biomethane (47,430 MJ) and biofertilizer (37,026 MJ) with a total exergy amount of 84,456 MJ. On the other hand, the economic analysis of the studied biogas production process indicates that the biogas plant has the added value for the input material. In the economic analysis, the annual costs and benefits of the biogas production is calculated. The results show that the production of biomethane and biofertilizer from the by-product of brewing industry is profitable. However, the price of input BSG and also the variation price of the biofertilizer in different seasons, have great impact on the economy of a biogas plant. The outcomes from exergy and economic analysis are indicated that the biogas production process is an "upcycling" process which has the added value for the inputs, from both economic and quality points of view. The exergy and economic evaluation may be used as indicators of the sustainable development, but only increasing the exergy and the economic value of a production process alone should not be considered as the sustainability of a system.

This study aimed at seeking for the solution to recover the energy from agriculture waste in the Mekong Delta, Vietnam. The spent mushroom compost - a residue from the mushroom growing - was chosen for co-digestion with pig manure in anaerobic batch and semi-continuous experiments. The results showed that in case of spent mushroom compost made up 75% of the mixed substrate, the gained biogas volume was not significantly different compared to the treatment fed solely with 100% pig manure. The average produced biogas was 4.1 L×day-1 in the experimental conditions. The semi-continuous experiments remained in good operation up to the 90th day of the fermentation without any special agitating method application. The methane contents in both experiments were around 60%, which was significantly suitable for energy purposes. These results confirm that spent mushroom compost is possibly an acceptable material for energy recovery in the anaerobic fermentation process. / Nghiên cứu này nhằm tìm kiếm giải pháp thu hồi năng lượng từ chất thải nông nghiệp tại ĐBSCL, Việt Nam. Rơm sau ủ nấm - phế phẩm sau khi trồng nấm rơm - được chọn để ủ kết hợp với phân heo trong các bộ ủ yếm khí theo mẻ và bán liên tục. Kết quả cho thấy nếu phối trộn đến 75% rơm sau ủ nấm trong nguyên liệu ủ, tổng lượng khí thu được không khác biệt đáng kể so với thí nghiệm ủ 100% phân heo. Trong điều kiện thí nghiệm, lượng khí thu được trung bình là 4.1 L.ngày-1. Thí nghiệm ủ bán liên tục vẫn vận hành tốt ở ngày thứ 90 mặc dù mẻ ủ không được khuấy đảo. Hàm lượng khí mê-tan đo được chiếm khoảng 60% hoàn toàn có thể sử dụng cho các nhu cầu về năng lượng. Những kết quả thí nghiệm khẳng định có thể sử dụng rơm sau ủ nấm để thu hồi năng lượng thông qua quá trình ủ yếm khí kết hợp.

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