Coal-fired electricity production is the major emitter of CO2 and other greenhouse gases including NOx and SOx. Microalgae-based CO2 mitigation systems have been proposed to reduce the net CO2 emission from coal-fired power plants. This study focused on developing an optimum culture media and exploring the possibilities for recycling nutrients, which were added as commercial mineralized chemicals at the beginning of cultivation. In order to release the nutrients embedded in the cells so that they can be used as a nutrient source for new cells, Scenedesmus biomass was digested by anaerobic bacteria. Results showed that thermal pretreatment enhanced the methane production rate for the first 7 days of digestion. Three operational factors were tested: heating temperature, heating duration and NaOH dosage. The combination of 10 min heating with 3~6% NaOH at 50 °C gave the highest cell wall destruction for all samples except oven-dried algae. The anaerobic digestate, rich in mineralized nutrients including ammonium and phosphate, potassium and magnesium ions, was tested as a possible nutrient source for the algae cultivation. To cope with the high solid content of the digestates, the dosage of the digestates was reduced or the solid particles were removed prior to addition to the microalgae. Both approaches worked well in terms of providing nutrients with minimal effect on light penetration. Using digestates without any sterilization did not cause contamination or other deleterious effects on the Scenedesmus growth rate. Harvesting microalgae cells was critical to ensure a continuous and robust growth rate. The used media could be recycled at least four times without altering the algae growth. Nutrient replenishment was the key for a healthy culture when used media was incorporated. The combination of used media and digestates can sustain a normal algae growth. Life cycle assessment was conducted on the system including the photobioreactor, the anaerobic digester, the biomass settling and dewatering and used media and nutrient recycling. Considering methane as the energy source, the overall energy return of the system was 2.4. CO2 mitigation rate was about 39% under current mitigation system.

Made available in DSpace on 2014-06-11T19:23:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-19Bitstream added on 2014-06-13T20:30:25Z : No. of bitstreams: 1 silveira_cb_me_arafcf.pdf: 664642 bytes, checksum: 583d75a34cda4c32a0f77e29304fc61d (MD5) / Universidade Estadual Paulista (UNESP) / Recentemente, os constituintes do leite têm sido reconhecidos como substâncias funcionais, sugerindo que seu uso tenha efeitos diretos e mensuráveis na saúde. Dentre esses constituintes, merece especial importância o soro do leite, um co-produto obtido durante a fabricação de queijos, sendo de grande importância na indústria de laticínios, pelo seu volume de produção e composição nutricional. O presente trabalho tem o objetivo de verificar, in vitro, a digestibilidade das proteínas do soro do leite, padronizando as características de bioacessibilidade, permitindo que esta fração possa ser utilizada em formulações de maneira funcional. Para isso, o soro lácteo foi preparado a partir de leite B e enzima renina, dialisado e filtrado, após adição de caulim. A amostra obtida foi caracterizada através de dosagens protéicas, de açúcar redutor e de gordura. O método de digestão in vitro foi realizado em duas etapas: digestão gástrica (realizada com a utilização da enzima pepsina em pH 2,0) e intestinal (aonde foi utilizada uma mistura enzimática de pancreatina-extrato biliar em pH 7,5, seguida de diálise para separação dos peptídeos e aminoácidos absorvíveis)... / Recently, the constituents of milk have been recognized as functional substances, suggesting that its use has direct and measurable effects on health. Among these constituents, special importance is given to the milk whey, a byproduct obtained during the cheese-making process, and which shows great importance in the dairy industry, regarding its production volume and nutrient composition. This study aims to determine the in vitro digestibility of milk whey proteins, standardizing the characteristics of its bioaccessibility, allowing this fraction to be used in formulations at a functional way. For this, the whey was prepared from milk B and enzyme renin, dialyzed and filtered after the addition of kaolin. The sample obtained was characterized by measurements of protein, reducing sugar and fat. The method of in vitro digestion was performed in two steps: gastric digestion (performed using the enzyme pepsin at pH 2,0) and intestinal (where we used an enzyme mixture of pancreatin-bile extract at pH 7.5, followed by dialysis for separation of peptides and absorbable amino acids). Aiming to confirm the in vitro gastrointestinal digestion and standardize the assay for the study samples, it were used methodologies for measuring the peptides and amino acids, SDS-PAGE ...(Complete abstract click electronic access below)

The present study was developed having as aims to investigate the effect of storage at low temperatures on level changes of resistant starch of foods usually consumed by the Brazilian population, the acceptability of these foods after the freezing process, and the influence of increasing levels of resistant starch obtained through this process on glycemy. Three kinds of foods were tested, i.e. rice, beans and pasta in order to verify the resistant starch behavior; the same kinds of foods, but with higher levels of this starch, were employed to test the acceptability on the part of forty-two non-trained food testers as well as the glycemic response of thirty-four healthy adults. It was observed that several factors acting together define starch digestion and absorption, and not just one factor. It was noticed that, regardless of samples, all of them increased their level of resistant starch throughout storage time at low temperatures and that the changes in the increase of this starch among the samples was in a decreasing order: beans, pasta and rice. Noodles with a screw form, cooked and stored for sixty days, presented low acceptability on most requisites; on the other hand, the other tested foods received approval regarding practically all the attribute, therefore demonstrating that it is possible to increase the resistant starch level without interfering with tasting quality of products. Even though storage at low temperature of samples increased the levels of resistant starch, this increase was not enough to provoke changes in individuals glycemic levels since that various other factors can be involved in starch hydrolysis and absorption. Therefore, it was demonstrated through the present study that food storage at low temperatures serves as an efficient and cheap tool to increase resistant starch levels and it can be used to improve population s life and nutritional qualities. / O presente estudo foi conduzido com os objetivos de investigar o efeito do armazenamento a baixa temperatura sobre a variação nos teores de amido resistente de alimentos usualmente consumidos pela população brasileira; a aceitabilidade desses alimentos após congelamento; e, a influência da elevação dos níveis de amido resistente obtidos pelo processamento, sobre a glicemia. Para isso, foram testados três alimentos: arroz, feijão e massa, para verificação do comportamento do amido resistente, e os mesmos alimentos, porém com teores aumentados desse amido, para testar a aceitabilidade de quarenta e dois provadores não treinados, assim como a resposta glicêmica de trinta e quatro indivíduos adultos sadios. Concluiu-se que vários fatores atuando em conjunto irão definir a digestibilidade e absorção do amido, e não um único fator isoladamente. Percebeuse que, independentemente da amostra, todas aumentaram seu teor de amido resistente no decorrer do tempo de armazenamento a baixa temperatura e que a variação na elevação desse amido entre as amostras foi em ordem decrescente: feijão, massa e arroz. A massa parafuso cozida e armazenada por sessenta dias apresentou menor aceitabilidade na maioria dos requisitos; já os outros alimentos foram aprovados em praticamente todos os atributos sensoriais, mostrando portanto, que é possível aumentar o teor de amido resistente sem interferir na qualidade sensorial dos produtos. Embora o congelamento das amostras tenha elevado os teores de amido resistente, esse acréscimo não foi suficiente para interferir na glicemia dos indivíduos, visto que inúmeros outros fatores podem estar envolvidos na hidrólise e absorção desse. Assim, demonstrou-se através do estudo que o armazenamento de alimentos a baixa temperatura, serve como ferramenta eficiente e econômica na elevação dos teores de amido resistente e pode ser usado para melhorias na qualidade nutricional e de vida da população.

Made available in DSpace on 2014-06-11T19:32:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-02-17Bitstream added on 2014-06-13T20:27:53Z : No. of bitstreams: 1 goncalves_jc_dr_botfmvz.pdf: 385502 bytes, checksum: f252f5f8c1f09237dda0f395ffd9cb72 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / O objetivo deste trabalho foi avaliar os níveis de inclusão de silagem de grãos úmidos de sorgo (SGUS) em substituição ao milho seco da ração sobre o desempenho, rendimento de carcaça, cortes e gordura abdominal, além de avaliação econômica da criação alternativa, no período de 1 a 49 dias de idade. Também foi avaliada a digestibilidade das rações aos 21 dias de idade. O trabalho foi conduzido no Laboratório de Nutrição de Aves da FMVZ, UNESP - Campus de Botucatu e para as análises de desempenho e rendimento de carcaça foram distribuídos no galpão, 600 pintos machos (Cobb), com um dia de idade, vacinados no incubatório contra Gumboro, Marek e Bouba aviária em um delineamento em blocos casualizados, com seis tratamentos (0, 10, 20, 30, 40 e 50% de inclusão SGUS em substituição ao milho seco da ração), com quatro repetições de 25 aves cada, totalizando 100 aves por tratamento. Em relação a digestibilidade, foram alojados na câmara climatizada termoneutra, 72 pintainhos em 24 gaiolas, sendo 3 aves/gaiola, totalizando 12 aves/tratamento. Os tratamentos experimentais e manejo foram os mesmos adotados para o galpão. A inclusão de silagem nas rações foi feita considerando-se o teor de umidade do milho e da silagem, mantendo a mesma proporção de matéria seca de milho nas mesmas, com o fator de correção 1,220. A SGUS pode substituir em até 50% o milho seco das rações de frangos de corte alternativos criados até 49 dias de idade, sem alterar desempenho, rendimento de carcaça, cortes e gordura abdominal, bem como a digestibilidade de nutrientes aos 21 dias de idade. Entretanto, o maior retorno econômico e melhor fator de produção foi obtido com 10% de substituição. / The objective of this study was to evaluate levels of inclusion of high moisture sorghum grains silage (HMSS) in substitution of dry corn in diet on performance, carcass yield, cuts and abdominal fat, and also economic analysis of alternative system at 1 to 49 d of age. The digestibility of diets was determined at 21 d of age. The experiment was carried out at the Poultry Nutrition Laboratory of the Faculty of Veterinary Medicine and Animal Science, UNESP, Botucatu, Brazil and to performance and carcass yield analysis were used 600 one-day-old male broiler chicks (Cobb), installed in a broiler house, vaccinated against Gumboro, Marekis and Bouba Aviária disease in a randomized blocks, with six treatments based on the inclusion of 0, 10, 20, 30, 40 and 50% of HMSS in substitution of dry corn, four replicates/treatment of 25 chicks each, totalizing 100 chickens per treatment. With regard to digestibility were housed to the termoneutral acclimatized chamber 72 one-day-old male chicks (Cobb) in 24 cages, 3 chicks/cage, 12 chicks/treatment. The experimental treatments and management had been the same adopted for the broiler house. The inclusion of silage in the rations was performed considering the corn and silage humidity amount, keeping the same proportion of dry matter of corn with the correction factor 1,220. HMSS can be included up to 50% in substitution of dry corn in the diet of alternative broiler chickens with 49 d of age, without modifying performance, carcass yield, cuts and abdominal fat, as well as the digestibility at the age of 21 d. However, better economic return and production factor had gotten with 10% of substitution.

Made available in DSpace on 2015-03-03T11:52:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-01-27Bitstream added on 2015-03-03T12:07:08Z : No. of bitstreams: 1 000811629.pdf: 518619 bytes, checksum: acbdc9f19f75db221690f6f0f805b15a (MD5) / Objetivou-se com este trabalho estudar os efeitos de diferentes aditivos alimentares administrados sozinhos ou associados na dieta de tourinhos Nelore confinados por 109 dias. Os tratamentos foram constituídos por dieta controle, dieta com monensina sódica (27,0 mg.kg MS-1), dieta com levedura viva Yea-Sacc8417 (2,0 g.animal-1) e dieta com associação dos dois aditivos. As dietas (10,00% bagaço de cana; 73,60% milho triturado; 6,40% caroço de algodão; 6,40% farelo de soja; 0,26% glúten de milho; 0,79% ureia e 2,55% núcleo mineral) variaram somente na inclusão dos aditivos. Para a avaliação do desempenho produtivo, utilizou-se 66 bovinos Nelore, não castrados (387,24±21,17 kg), sendo 22 abatidos durante o experimento (6 ao início e 16 logo após a adaptação - 25 dias) para mensuração do peso em corpo vazio (PCVz) e serviram como animais referência (Experimento 1). Para a avaliação dos parâmetros ruminais, utilizou-se 16 bovinos Nelore, não castrados (422,00 ± 80,26 kg), canulados no rúmen (Experimento 2). Os experimentos foram delineado em blocos casualizados em função do peso corporal inicial. Os animais foram mantidos em confinamento individual e considerados como unidade experimental. Experimento 1 - Nos tratamentos contendo monensina sódica, o consumo de matéria seca (CMS) foi menor (P=0,0798) (8,47 kg MS.dia-1) em relação a dieta controle (10,20 kg MS.dia-1). A levedura fornecida sem a associação não interferiu (P>0,10) no CMS. O fornecimento de energia líquida (EL) pela dieta foi maior (P=0,0055) nos 2 tratamentos contendo monensina sódica (1,98 e 1,33 Mcal.kg MS-1 para mantença e ganho, respectivamente) quando comparado com a dieta controle e com levedura sem a associação (1,79 e 1,17 Mcal.kg MS-1, mantença e ganho, respectivamente). O ganho em peso médio diário avaliado em peso corporal (1,47 kg.dia-1) e PCVz (1,58 kg.dia-1) não diferiram (P>0,10) entre dietas, porém, quando avaliado em ... / The objective of this study was to analyze the effects of different food additives administered solely or combined in diets for young Nellore bulls in a feedlot for 109 days. The treatments consisted of a control diet with monensin sodium (27.0 mg kg DM-1), a diet with Yea-Sacc8417 live yeast (2.0 g animal-1) and a diet with the two additives combined. Diets (10.00% sugarcane bagasse, 73.60% ground corn, 6.40% cottonseed, 6.40% soybean meal, 0.26% corn gluten, 0.79% urea and 2.55% mineral mix) varied only in the inclusion of additives. For evaluation of performance, we used 66 non-castrated Nellore bulls (387.24±21.17 kg), 22 of which were slaughtered in the course of the experiment (6 at the beginning and 16 right after the adaptation period [25 days]) to measure the empty body weight (EBW) and served as reference animals (Trial 1). For evaluation of ruminal parameters, we used 16 non-castrated Nellore bulls (422.00 ± 80.26 kg) cannulated in the rumen (Trial 2). The trials were arranged in a completely randomized blocks design as a function of the initial body weight. The animals were kept in individual pens and were considered the experimental unit. Trial 1 - The dry matter intake (DMI) was lower (P=0.0798) (8.47 kg DM day-1) in the treatments containing monensin in relation to control diet (10.20 kg DM day-1). The yeast supplied alone did not interfere (P>0.10) on DMI. The supply of net energy (NE) by the diet was greater (P=0.0055) in the two treatments containing monensin (1.98 and 1.33 Mcal kg DM-1 for maintenance and gain, respectively) as compared with the control diet and with yeast alone (1.90 and 1.17 Mcal kg DM-1 for maintenance and gain, respectively). The average daily gain evaluated as body weight (BW) (1.47 kg day-1) and as EBW (1.58 kg day-1) did not differ (P>0.10) among diets, but when evaluated as carcass, the diets with monensin reduced (P<0.10) the values (0.89 kg day-1) as compared with the others ...

Submitted in fulfillment of the requirements of the degree of Masters of Engineering: Chemical Engineering, Durban University of Technology, Durban, South Africa, 2018. / The anaerobic process is increasingly becoming a subject for many as it reduces greenhouse gas emissions and recovers carbon dioxide energy as methane. Even though these benefits are attainable, proper control and design of the process variables has to be done in order to optimize the system productivity and improve stability. The aim of this research was to optimize methane and biogas yields on the anaerobic co-digestion of sewage sludge using bio-chemical substrates as co-substrates. The first objective was to find the bio-chemical substrate that will generate the highest biogas and methane yields. The anaerobic digestion of these substrates was operated using 6 L digesters at 37.5℃. The substrate which generated the highest biogas and methane yield in the first batch experiment was then used for the second batch test. The objective was to optimize the anaerobic conditions (substrate to inoculum ratio, co-substrate concentration and temperature) in-order to optimize the biogas and methane yields. The second batch test was achieved using the conventional One-Factor-At-A-Time (OFAT) and the Design of Experiment (DOE) methods. Final analysis showed that the bio-chemical substrates could be substrates of interest to biogas generators. Amongst the substrates tested in the first batch experiment glycerol (Oleo-Chemical Product waste) generated the highest methane and biogas yields of 0.71 and 0.93 L. (g volatile solids added)-1, respectively. It was believed that glycerol contains significant amount of other organic substances such as lipids that have higher energy content than the other bio-chemical substrates, thus generating larger biogas and methane yields. Moreover, digestion of sewage sludge alone produced biogas yields of 0.19 L /g VS and 0.33 L/g COD, and methane yields of 0.16 L/g VS and 0.28 L/g COD. Generally, co-digestion yields were higher than digestion yields of sewage alone. Using the OFAT method the results of the second batch test on glycerol demonstrated highest amounts of volatile solids (VS) reduction, chemical oxygen demand (COD) reduction, biogas yield and methane yield of 99.7%, 100%, 0.94 L (g VS added)-1 and 0.75 L (g VS added)-1 at a temperature, substrate to inoculum ratio and glycerol volume of 50℃, 1 (on VS basis) and 10 mL, respectively. Above 22 mL and substrate to inoculum ratio of 1, the process was inhibited. The DOE results suggested that the highest methane and biogas yields were 0.75 and 0.94 L (g VS added)-1, respectively. These results were similar to the OFAT results, thus the DOE software may be used to define the biogas and methane yields equations for glycerol. In conclusion, anaerobic co-digestion of bio-chemical substrates as co-substrates on sewage sludge was successfully applied to optimize methane and biogas yields. / M

abstract: To address sustainability issues in wastewater treatment (WWT), Siemens Water Technologies (SWT) has designed a "hybrid" process that couples common activated sludge (AS) and anaerobic digestion (AD) technologies with the novel concepts of AD sludge recycle and biosorption. At least 85% of the hybrid's AD sludge is recycled to the AS process, providing additional sorbent for influent particulate chemical oxygen demand (PCOD) biosorption in contact tanks. Biosorbed PCOD is transported to the AD, where it is converted to methane. The aim of this study is to provide mass balance and microbial community analysis (MCA) of SWT's two hybrid and one conventional pilot plant trains and mathematical modeling of the hybrid process including a novel model of biosorption. A detailed mass balance was performed on each tank and the overall system. The mass balance data supports the hybrid process is more sustainable: It produces 1.5 to 5.5x more methane and 50 to 83% less sludge than the conventional train. The hybrid's superior performance is driven by 4 to 8 times longer solid retention times (SRTs) as compared to conventional trains. However, the conversion of influent COD to methane was low at 15 to 22%, and neither train exhibited significant nitrification or denitrification. Data were inconclusive as to the role of biosorption in the processes. MCA indicated the presence of Archaea and nitrifiers throughout both systems. However, it is inconclusive as to how active Archaea and nitrifiers are under anoxic, aerobic, and anaerobic conditions. Mathematical modeling confirms the hybrid process produces 4 to 20 times more methane and 20 to 83% less sludge than the conventional train under various operating conditions. Neither process removes more than 25% of the influent nitrogen or converts more that 13% to nitrogen gas due to biomass washout in the contact tank and short SRTs in the stabilization tank. In addition, a mathematical relationship was developed to describe PCOD biosorption through adsorption to biomass and floc entrapment. Ultimately, process performance is more heavily influenced by the higher AD SRTs attained when sludge is recycled through the system and less influenced by the inclusion of biosorption kinetics. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2011

In this thesis, the anaerobic co-digestion of thickened waste activated sludge (TWAS) and, fat, oil and grease (FOG) was investigated as a method for TWAS:FOG treatment, stabilization, reduction and conversion to bio-methane gas as a valuable source of renewable energy. In the first phase, thermophilic and hyper-thermophilic anaerobic co-digestion of TWAS and FOG were investigated and compared. 20 – 80%FOG (based on total volatile solids) were tested using two sets of biochemical methane potential assays (BMP). Hyper-thermophilic co-digestion of TWAS with up to 60%FOG was shown to significantly increase the methane production and VS reduction as compared to the thermophilic co-digestion of the same TWAS:FOG mixture and as compared to the control (TWAS thermophilic mono-digestion). Both linear and non-linear regression models were used to represent the co-digestion results. In the second phase, the feasibility of the thermophilic and hyper-thermophilic co-digestion of TWAS and FOG were more investigated using lab scale semi-continuous reactors. The dual stage hyper-thermophilic reactor was introduced for the first time in this work for co-digesting TWAS and FOG. The dual stage co-digestion reactor was shown to significantly outperform the single-stage thermophilic mono-digestion reactor (the control) and the single-stage thermophilic co-digestion reactor at all three hydraulic retention times (HRTs) considered in the study namely, 15, 12 and 9 days. The dual-stage hyper-thermophilic co-digester digested up to 70%FOG at 15 days HRT without any stressing signs and produced a methane yield that was 148.2% higher compared to the control methane yield at the same HRT. It also produced a class A effluent at all three tested HRTs and positive net energy for 15 and 12 days HRT. The effects of microwave (MW) pretreatment, and combined alkaline-MW pretreatment on the co-digestion of TWAS:FOG mixtures with 20, 40 and 60% FOG were investigated in the third phase of this study. MW pretreatment at a high temperature of 175ᵒC was shown to be the most effective MW pretreatment option in solubilizing TWAS:FOG mixtures and in boosting the methane yield. It resulted in maximum solubilization for the 20%FOG samples and maximum methane yield for samples with 60%FOG. The combined alkaline-MW (NaOH-MW) pretreatment at a pH 10 showed to be an ineffective option for TWAS:FOG pretreatment before the anaerobic co-digestion process. In the fourth phase, the effects of the three selected pretreatments on the solubilization of TWAS and 20%FOG mixture on the molecular scale were investigated. The pretreatments used included: (i) MW pretreatment at 175ᵒC (since this was the best MW pretreatment condition according to the results of phase 3), (ii) hyper-thermophilic stage @ 70ᵒC and 2days HRT (effectively used in phases 1 and 2), and (iii) conventional heat at 70ᵒC. The analysis involved separation of the solubilized substrates after pretreatment using ultrafiltration (UF) at four different sizes (1, 10, 100 and 300 kDa). The results showed that each pretreatment method uniquely changed the particle size distribution. These changes showed to affect the biodegradability of substrates with different class size. Finally, two brief studies were performed using BMP tests to investigate the feasibility of FOG addition as a biogas booster in TWAS anaerobic digestion. First, the effect of FOG addition on TWAS and organic fraction of municipal solid waste (OFMSW) co-digestion was tested using hyper-thermophilic BMP tests. The addition of 30% FOG (based on total volatile solids) was shown very effective in improving the methane yield. The 30% FOG addition to TWAS:OFMSW mixture resulted in 59.9 and 84.4% higher methane yield compared to the methane yields of TWAS:OFMSW and TWAS samples, respectively. Second, the feasibility of using the soluble part of FOG (L-FOG) as a co-digestion substrate to increase the biogas production from the thermophilic digestion of TWAS was investigated. The results showed that co-digestion of TWAS and 20 to 80% (based on total VS) of L-FOG using a substrate to inoculum ratio (S/I) of 1 improved the biogas yield by 13.5 to 83.0%, respectively. No inhibition was reported at high L-FOG %.

Orientador: Wanderley José de Melo / Resumo: O lodo de esgoto (LE) tem sido usado em muitos países em substituição parcial aos fertilizantes minerais. Em regiões de clima tropical a falta de estudos quanto ao comportamento dos metais pesados no solo ao longo do tempo tem limitado seu uso. O objetivo do trabalho foi avaliar os métodos de extração: Mehlich-1, USEPA 3050b e método de Jackson, quanto sua disponibilidade em função da aplicação de lodo e acúmulo dos teores de Cromo (Cr) e Chumbo (Pb) no solo. Verificou-se que, mesmo com aplicação de altas doses de Cr via LE a disponibilidade do Cr é baixa, e tem mais influência do tempo que do acréscimo do metal. O método de digestão da USEPA 3050b não apresentou sensibilidade para diferenciar o balanço do Cr em função dos tratamentos. Para extração do Cr em Latossolos de regiões de clima tropical a digestão fluorídrica juntamente com o extrator Mehlich-1 são os mais recomendados para a extração. Para o Pb o método de extração da USEPA 3050b, demonstrou de forma eficiente a diferença nos teores e no acúmulo de Pb nos diferentes tratamentos. O acréscimo de Cr e Pb via LE não influenciaram as culturas, não sendo identificados valores fitotóxicos nas plantas, nem acúmulo de Cr e Pb no grão. / Abstract: Sewage sludge (LE) has been used in many countries as a partial replacement for mineral fertilizers. In regions of tropical climate the lack of studies on the behavior of heavy metals in the soil over time has limited its use. The objective of this work was to evaluate the extraction methods: Mehlich-1, USEPA 3050b and Jackson method, as well as its availability as a function of sludge application and accumulation of Chromium (Cr) and Lead (Pb) levels in the soil. It has been found that even with high doses of Cr via LE the availability of Cr is low, and has more time influence than the addition of the metal. The USEPA 3050b digestion method showed no sensitivity to differentiate the Cr balance depending on the treatments. For extraction of Cr in Latosols of regions of tropical climate the fluoride digestion together with Mehlich-1 extractor are the most recommended for the extraction. For Pb, the USEPA 3050b extraction method efficiently demonstrated the difference in Pb levels and accumulation in the different treatments. The addition of Cr and Pb via LE did not influence the cultures, neither phytotoxic values were identified in the plants nor Cr and Pb accumulation in the grain. / Mestre

This study investigated the fate of lignocellulosic biomass (wheat-feed and perennial rye grass) in different anaerobic digestion systems, evaluating the role of substrate specificity on the pattern of degradation. The two-stage (biohydrogen-biomethane) anaerobic system was found to be more effective in the degradation of lignocellulose, when compared to the conventional single-stage system. The perennial rye grass substrate possessed about 21% higher holocellulose concentration when compared to the wheat-feed; its exploitation in the acidogenic digestion was however poor, resulting in a 2.9% lower biogas yield in a equivalent two-stage system. The study therefore developed a treatment technique involving the use of cellulase and ferulic acid esterase enzyme combinations for the treatment of perennial rye grass. The enzyme cocktail at 0.202 ml enzyme/g VS added resulted in efficient bioconversion of the complex polymers to soluble carbohydrates, evident in the yield increase of soluble COD, to 321.0±10.9 mg/gVS, a 393.2% yield increase, when compared to the no enzyme added control. The yield of bio-hydrogen after enzymatic addition was 48ml/gVS, 335% higher when compared to the alkaline treatment; and more than seven fold higher than the yield obtained from the fermentation with no pre-treatment. The acetate to butyrate ratio varied from 4:1, when no pre-treatment was used, to 2:1when alkaline pre-treatment was used, then to 1:1 after the enzymatic treatment. The downstream effect of the prior hydrolysis on the subsequent processes to acidogenic fermentation like biomethane and PHA production and lignin recovery were also investigated. The hydrogenic/acidogenic fermentation resulted in methane yield improvement of 45.7%. The study shows that the more effective a hydrolysis procedure is in the depolymerisation of complex polymers, the greater the accumulation of PHA in the PHA biosynthesis operations. The enhanced hydrogenic /acidogenic fermentation having effectively degraded the holocellulose component of the perennial rye grass substrate ensured that relatively high quality lignin was obtained in an Organosolv lignin-extraction procedure. FT-IR profile show less contamination of polysaccharides and proteins in the lignin extracted from the enzymatically enhanced acidogenic fermentation. An evaluation of the economic viability of the investigated secondary processes showed that direct integrations of those processes to the biohydrogen process may not be as economically advantageous, when compared to a 2nd -stage biomethanation system.