Despite the importance of coalbed methane (CBM) as a natural gas resource, little is known about the microbial communities responsible for production of biogenic CBM (~20% of all CBM gas). It is thought that coal-associated microbial communities are limited by nutrients, such as nitrogen or phosphate and a of suite trace elements, but it's not clear whether these nutrients are sourced from in-situ biodegradation of the coal or transported in with groundwater recharge. To address this knowledge gap, we examined the nitrogen and phosphorous species and trace metal geochemistry of the solid coal and overlying siliciclastic sediment and associated groundwater from monitoring wells across the Powder River Basin (PRB). Four Groups were identified that represent the geochemical evolution of groundwater from shallow unconsolidated siliciclastic aquifers, to recharge-associated coal waters, to sulfate-reducing coal waters, and finally, methanogenic coal waters, along a hydrologic gradient within single coal seams. The highest nutrient concentrations were found in the first two water types, and the lowest in the last two, suggesting that essential nutrients are mobilized at the surface and transported downgradient into the coal and overlying unconsolidated siliciclastic sediment. However, by the time groundwater reaches sulfate-reducing or methanogenic conditions, the nutrients are either utilized in reactions or precipitated under changing redox conditions. Sequential chemical extraction experiments of coal and siliciclastic core materials revealed that all essential nutrients for microbial methanogenesis are present and easily leachable into groundwater. Therefore, under anoxic conditions, microbial communities are unlikely to be limited by the presence of essential elements; rather, they are likely limited by the slow rates of coal biodegradation and liberation of essential nutrients.

Energy demand, greenhouse gas emissions, and operational costs are continuing to rise year on year in the wastewater treatment sector, with traditional treatment options unable to provide sustainable solutions to increasing volumes and tightening quality standards. Current processes produce inherent fugitive greenhouse gas (GHG) emissions, whilst also generating large quantities of sludge for disposal. Anaerobic ponds (APs) are natural wastewater treatment processes that have traditionally been confined to a pre-treatment stage of larger stabilisation pond systems. Consequently, current standard guidelines are not suited for low temperature, weak strength wastewaters, or for the emerging usage of APs for energy recovery and enhanced organic breakdown. To establish effective guidelines for adapting AP design for this purpose, this thesis explores the fundamental mechanisms with APs, in order to provide design alterations to enhance AP performance for full flow domestic wastewater treatment with a focus on the UK water sector. Initially, a literature review of current AP design guidelines was conducted to determine the current state of the art and understand the fundamental design processes currently adopted. The review found that most APs are currently underloaded, largely to avoid malodour emissions, but this leads to unnecessarily large footprints and inhibits the digestion process through restricting biomass/substrate contact. It was concluded that the current design guidelines are not suitable for recent AP developments and application, such as covering to prevent odour escape, and the use of baffling to improve mixing and enhance organic degradation. A pilot scale study was conducted on UK domestic wastewater to gain insight into the limitations of current AP design for this application and identify areas for optimisation. The pilot trial demonstrated the efficacy of AP usage for low temperature, weak strength wastewaters, even with unoptimised design. Decoupling hydraulic and solids retention time lead to biomass retention and subsequent acclimatisation, and was able to compensate for the low temperatures and weak wastewater. It was concluded that APs can provide an attractive alternative to current primary treatment options, through reducing GHG emissions and providing less frequent desludging requirements. To optimise AP design, the effect of baffle configuration on AP hydrodynamics and the subsequent impact on treatment efficiency was investigated, in order to develop structural designs specifically targeting enhanced anaerobic degradation. Advantages found in baffling APs included improving mixing patterns between baffles, enhancing biomass/substrate contact, and creating an overall plug flow effect through the entire pond enabling the retention of biomass. Furthermore, the removal mechanism with the pond can be manipulated with use of baffles, with different orientations generating different flow patterns and therefore creating conditions preferential for greater solids settlement and capture, or mixing and contact. Following trials on single stage alternate baffling configurations, the development of a novel two stage AP design was trialled, applying knowledge gained from trials of differing baffle orientations to target separate stages of organic breakdown. Further trials were conducted on the staged AP to establish optimal loading rates to be applied to APs in order to maximise performance and reduce physical footprint. These trials led to recommended design improvements including shorter hydraulic retention times (HRTs) to enhance mixing and decrease physical footprint, and improvements to the staged AP design to greater separate the stages of anaerobic digestion and provide optimal conditions for the stages at different points in the AP. Finally, the knowledge gained from experimental work was used to present evidence for the inclusion of APs into decentralised WWT through flowsheet modelling of a proposed AP treatment works compared to a current base case. Advantages were found in decreasing sludge management requirements whilst providing suitable primary treatment, with additional potential benefits in renewable energy generation, which could increase both with improved biogas yields and the option of combining with other renewable technologies. In some circumstances, it may be possible for an AP flowsheet to operate entirely off-grid, eliminating the need for costly infrastructure such as permanent access roads and national electrical grid connection.

Significant discrepancies exist in global estimates of the atmospheric methane (CH4) budget. This is particularly true for tropical South America where bottom-up approaches, rooted in field observation, tend to under estimate atmospheric observations. As such, a better understanding of soil environments, which are capable of acting as both source and sink for atmospheric CH4, is required. Soil-atmosphere CH4 exchange is fundamentally determined by the balance between strictly anaerobic methanogenic and aerobic methanotrophic microbial processes. For this reason, CH4 emissions are typically associated with anoxic wetland soils, whilst, oxic upland soils are thought to uptake CH4 from the atmosphere. However, there is increasing evidence that upland soils may act as sources of CH4 through methanogenic activity within cryptic wetlands or anoxic microsites. This thesis aims to: document soil-atmosphere CH4 fluxes in poorly represented tropical upland and montane ecosystems, investigate controls on CH4 flux with a focus on soil oxygen (O2) concentration and investigate relationships between methanogenic and methanotrophic processes under oxic conditions. These aims are addressed in three chapters focusing on lowland terra firme, premontane and montane forests and montane humid puna grasslands and wetlands along an Amazonian to Andean transect spanning ~ 3300 m of elevation in southeastern Peru. In the lowland rainforest intensive seasonal field campaigns and laboratory incubations were conducted on higher porosity ultisol and lower porosity inceptisol soils. Mean (s.e.) net CH4 fluxes for dry and wet seasons were, respectively, -1.59 (0.06) and - 1.39 (0.07) mg CH4-C m−2 d−1 for the ultisol and -0.95 (0.06) and -0.41 (0.10) mg CH4-C m−2 d−1 for the inceptisol. Greater uptake rates in the ultisol than the inceptisol were best explained by lower water-filled pore space (WFPS). Similarly, WFPS best explained between season variation in net CH4 flux from the inceptisol, whilst, we were unable to explain the smaller variations observed for the ultisol. Methanogenic processes were active in both the ultisol and inceptisol soils despite oxic conditions. In the premontane and montane forests, long-term monthly field measurements were conducted over two and a half years in premontane, lower montane and upper montane settings. Mean (s.e.) net CH4 fluxes for aggregated dry and wet season months were, respectively, -0.20 (0.15) and -0.08 (0.13) mg CH4-C m−2 d−1 for the premontane forest, -1.12 (0.13) and -0.97 (0.11) mg CH4-C m−2 d−1 for the lower montane forest and -1.55 (0.13) and -1.04 (0.11) mg CH4-C m−2 d−1 for the upper montane forest. Increased uptake with elevation was best explained by decreases in WFPS. Significant variation in net CH4 flux between seasons, driven by variation in WFPS, was only identified for the upper montane forest.

The overarching theme of my thesis is understanding observed variations of northern hemisphere atmospheric carbon dioxide (CO2) and methane (CH4) concentrations. I focus my analysis on high-latitude observations of these gases, as there are large stores of carbon in boreal vegetation and tundra which are vulnerable to rapid warming in the Arctic. My thesis is split into two parts. First, I use the wavelet transform to spectrally decompose observed multi-decadal timeseries for CO2 and CH4. I perform a series of numerical experiments based on synthetic data in order to characterise the errors associated with the analysis. For CO2, I analyse the phase and amplitude of the detrended seasonal cycle of CO2 to infer changes about carbon uptake by northern vegetation. I do not find a long-term change in the length of the carbon uptake period despite significant changes in the spring and autumn phase. I do find an increase in the rate of peak uptake which coincides with the observed increase in seasonal amplitude. These results suggest that the carbon uptake period of boreal vegetation has become more intense but has not changed in length, which provides evidence for an increase in net uptake of CO2 in the high latitudes. For CH4, I test the hypothesis that an increase in Arctic wetland emissions could result in a decrease in the seasonal amplitude of CH4 in the high latitudes. This hypothesis is based on the fact that the seasonal minima of CH4 roughly coincides with the peak of high latitude wetland CH4 emissions. I find that the CH4 seasonal amplitude has significantly decreased at a number of high-latitude sites. However I also find that atmospheric transport appears to drive much of the variability in high-latitude CH4 and that transport could also be responsible for the observed changes in amplitude. I show that an increase in wetland emissions is likely to have a more pronounced effect on the high-latitude CH4 seasonal cycle in the future. In the second section of my thesis, I describe a series of experiments in collaboration with the UK Astronomy Technology Centre, in which I characterise a new instrument technology for satellite applications to observe changes in CO2 from low-Earth orbit. The proof of concepts experiments were performed with a bench top hyperspectral imager. I show that the instrument is able to capture clean spectra at the wavelengths required for CO2 with low levels of scattered light between spectra.

In this thesis, combustion processes in a laboratory-scale methane based low pressure rocket motor (LPRM) is studied experimentally and numerically. Experiments are conducted to measure flame temperatures and chamber temperature and pressure. Single reaction-four species reacting flow of gaseous methane and gaseous oxygen in the combustion chamber is also simulated numerically using a commercial CFD solver based on 2-D, steady-state, viscous, turbulent and compressible flow assumptions. LPRM geometry is simplified to several configurations, i.e. Channel and Combustion Chamber with Nozzle and FWD. Flow in a Bunsen burner is simulated inside Channel geometry in order to validate the reaction model. Grid independence study is also conducted for reacting as well as non-reacting flows. Numerical model is calibrated based on experimental results. Results of the computational model are found in a good agreement with the experimental data after calibrating specific heats of the products. Parametric study is conducted in order to investigate the effects of different mass flow rates and chamber pressures on flow and combustion characteristics of a LPRM to provide insight to future studies.

<p>Wetland ecosystems provide many valuable ecosystem services, including carbon (C) storage and improvement of water quality. Yet, restored and managed wetlands are not frequently evaluated for their capacity to function in order to deliver on these values. Specific restoration or management practices designed to meet one set of criteria may yield unrecognized biogeochemical costs or co-benefits. The goal of this dissertation is to improve scientific understanding of how wetland restoration practices and waterfowl habitat management affect critical wetland biogeochemical processes related to greenhouse gas emissions and nutrient cycling. I met this goal through field and laboratory research experiments in which I tested for relationships between management factors and the biogeochemical responses of wetland soil, water, plants and trace gas emissions. Specifically, I quantified: (1) the effect of organic matter amendments on the carbon balance of a restored wetland; (2) the effectiveness of two static chamber designs in measuring methane (CH4) emissions from wetlands; (3) the impact of waterfowl herbivory on the oxygen-sensitive processes of methane emission and coupled nitrification-denitrification; and (4) nitrogen (N) exports caused by prescribed draw down of a waterfowl impoundment.</p><p>The potency of CH4 emissions from wetlands raises the concern that widespread restoration and/or creation of freshwater wetlands may present a radiative forcing hazard. Yet data on greenhouse gas emissions from restored wetlands are sparse and there has been little investigation into the greenhouse gas effects of amending wetland soils with organic matter, a recent practice used to improve function of mitigation wetlands in the Eastern United States. I measured trace gas emissions across an organic matter gradient at a restored wetland in the coastal plain of Virginia to test the hypothesis that added C substrate would increase the emission of CH4. I found soils heavily loaded with organic matter emitted significantly more carbon dioxide than those that have received little or no organic matter. CH4 emissions from the wetland were low compared to reference wetlands and contrary to my hypothesis, showed no relationship with the loading rate of added organic matter or total soil C. The addition of moderate amounts of organic matter (< 11.2 kg m-2) to the wetland did not greatly increase greenhouse gas emissions, while the addition of high amounts produced additional carbon dioxide, but not CH4. </p><p>I found that the static chambers I used for sampling CH4 in wetlands were highly sensitive to soil disturbance. Temporary compression around chambers during sampling inflated the initial chamber CH4 headspace concentration and/or lead to generation of nonlinear, unreliable flux estimates that had to be discarded. I tested an often-used rubber-gasket sealed static chamber against a water-filled-gutter seal chamber I designed that could be set up and sampled from a distance of 2 m with a remote rod sampling system to reduce soil disturbance. Compared to the conventional design, the remotely-sampled static chambers reduced the chance of detecting inflated initial CH4 concentrations from 66 to 6%, and nearly doubled the proportion of robust linear regressions from 45 to 86%. The new system I developed allows for more accurate and reliable CH4 sampling without costly boardwalk construction. </p><p>I explored the relationship between CH4 emissions and aquatic herbivores, which are recognized for imposing top-down control on the structure of wetland ecosystems. The biogeochemical consequences of herbivore-driven disruption of plant growth, and in turn, mediated oxygen transport into wetland sediments, were not previously known. Two growing seasons of herbivore exclusion experiments in a major waterfowl overwintering wetland in the Southeastern U.S. demonstrate that waterfowl herbivory had a strong impact on the oxygen-sensitive processes of CH4 emission and nitrification. Denudation by herbivorous birds increased cumulative CH4 flux by 233% (a mean of 63 g CH4 m-2 y-1) and inhibited coupled nitrification-denitrification, as indicated by nitrate availability and emissions of nitrous oxide. The recognition that large populations of aquatic herbivores may influence the capacity for wetlands to emit greenhouse gases and cycle nitrogen is particularly salient in the context of climate change and nutrient pollution mitigation goals. For example, our results suggest that annual emissions of 23 Gg of CH4 y-1 from ~55,000 ha of publicly owned waterfowl impoundments in the Southeastern U.S. could be tripled by overgrazing. </p><p>Hydrologically controlled moist-soil impoundment wetlands provide critical habitat for high densities of migratory bird populations, thus their potential to export nitrogen (N) to downstream waters may contribute to the eutrophication of aquatic ecosystems. To investigate the relative importance of N export from these built and managed habitats, I conducted a field study at an impoundment wetland that drains into hypereutrophic Lake Mattamuskeet. I found that prescribed hydrologic drawdowns of the impoundment exported roughly the same amount of N (14 to 22 kg ha-1) as adjacent fertilized agricultural fields (16 to 31 kg ha-1), and contributed approximately one-fifth of total N load (~45 Mg N y-1) to Lake Mattamuskeet. Ironically, the prescribed drawdown regime, designed to maximize waterfowl production in impoundments, may be exacerbating the degradation of habitat quality in the downstream lake. Few studies of wetland N dynamics have targeted impoundments managed to provide wildlife habitat, but a similar phenomenon may occur in some of the 36,000 ha of similarly-managed moist-soil impoundments on National Wildlife Refuges in the southeastern U.S. I suggest early drawdown as a potential method to mitigate impoundment N pollution and estimate it could reduce N export from our study impoundment by more than 70%.</p><p>In this dissertation research I found direct relationships between wetland restoration and impoundment management practices, and biogeochemical responses of greenhouse gas emission and nutrient cycling. Elevated soil C at a restored wetland increased CO2 losses even ten years after the organic matter was originally added and intensive herbivory impact on emergent aquatic vegetation resulted in a ~230% increase in CH4 emissions and impaired N cycling and removal. These findings have important implications for the basic understanding of the biogeochemical functioning of wetlands and practical importance for wetland restoration and impoundment management in the face of pressure to mitigate the environmental challenges of global warming and aquatic eutrophication.</p> / Dissertation

Orientador: Lucia Galvão de Albuquerque / Coorientador: Renata Helena Branco / Coorientador: Ana Claudia Ruggieri / Banca: Juliana Duarte Messana / Banca: Maria Eugênia Zerlotti Mercadante / Banca: Alexandre Berndt / Banca: Roberta Canesin / Resumo: Este trabalho foi conduzido com o objetivo de desenvolver equações de predição da emissão metano entérico além de avaliar equações descritas na literatura quanto a sua acurácia, estimar a herdabilidade da emissão de metano e estabelecer relações entre esta emissão e eficiência alimentar de bovinos Nelore em crescimento sob condições de clima tropical. Quarenta e oito bovinos Nelore foram avaliados quanto ao consumo de matéria seca, consumo de nutrientes e emissão de metano e equações foram geradas com base nos dados de consumo e avaliadas pela raiz quadrada do quadrado médio do erro de predição (RQME) e por regressão residual. A partir dos dados de emissão de metano obtidos in vivo, foram validadas equações descritas na literatura, avaliadas de acordo com os mesmos critérios utilizados para as novas equações geradas. Para a estimativa da herdabilidade foram utilizados dados de consumo individual e peso corporal de 896 bovinos Nelore (541 machos e 355 fêmeas) com peso corporal inicial médio de 276 ± 53 kg, nascidos entre 2004 e 2012 (286 ± 39 dias de idade inicial) e avaliados quanto ao consumo alimentar residual (CAR). Uma equação gerada a partir do consumo de matéria seca dos 48 animais avaliados foi utilizada para estimar a emissão de metano dos demais 896 animais, sendo outras duas equações descritas por Ellis e colaboradores também utilizadas com a mesma finalidade. A herdabilidade da emissão de metano foi estimada para cada equação. Equações incluindo as variáveis consumo de matéria seca e consumo de hemicelulose, consumo de matéria seca e consumo de carboidratos totais, consumo de energia metabolizável e consumo de celulose e consumo de carboidratos não fibrosos apresentaram os menores valores de RQME, sendo consideradas as mais ajustadas para o conjunto de dados estudado. Cinco das 17 equações descritas na literatura puderam predizer a emissão de metano adequadamente apresentando ... / Abstract: This work was conducted with the objective of developing enteric methane (CH4) emission prediction equations and to evaluate equations described in the literature as to accuracy, estimate the heritability of methane emission and linking this issue and feed efficiency of Nellore in growth under tropical conditions. Forty-eight Nellore were evaluated for dry matter intake, nutrient intake and methane emission and equations were generated based on consumption data and evaluated by the square root of the mean square prediction error (RMSE) and residual regression. From the methane emission in vivo data, equations described in the literature were validated, assessed according to the same criteria used for the new generated equations. To estimate the heritability of individual consumption, data were used and body weight of 896 Nellore (541 males and 355 females) with an average initial body weight of 276±53 kg, born between 2004 and 2012 (286±39 days old) and assessed for residual feed intake (RFI). An equation generated from dry matter intake of 48 animals evaluated was used to estimate methane emissions from the other 896 animals, and two other equations described by Ellis et al also used for the same purpose. The heritability of methane emission was estimated for each equation. Equations including the variables dry matter intake and consumption of hemicellulose, dry matter intake and intake of total carbohydrates, metabolizable energy intake and consumption of pulp and consumption of non-fiber carbohydrates had the lowest RMSE values, are considered the most adjusted to the data set studied. Five of the 17 equations described in the literature could predict methane emissions properly to the lowest RMSE values among the evaluated equations. However, the equations developed in this study were more accurate in predicting the methane emission evaluating under the same parameter. The heritability estimate (h2) of CH4 showed high magnitude ... / Doutor

Orientador: Ricardo Andrade Reis / Banca: Gustavo Rezende Siqueira / Banca: Giovani Fiorentini / Banca: Renata Helena Branco Arnandes / Banca: Otávio Rodrigues Machado Neto / Resumo: O correto manejo do pastejo e o uso estratégico da suplementação são os principais caminhos quando se visa aumentar a produção animal e/ou o ganho de área no sistema a pasto. No entanto, dados divergentes sobre o correto manejo em forrageiras tropicais e o efeito da suplementação com soja diferente disponível no rúmen ainda são encontrados. Nesse sentido, três experimentos foram realizados para avaliar o efeito da suplementação de touros jovens da raça Nelore em pastagem de Brachiaria brizantha cv. Marandu manejado em diferentes alturas. No primeiro experimento os tratamentos consistiram de três alturas do dossel (15, 25 e 35 cm) do pasto e foram estudadas as características de forragem, consumo de matéria seca, digestibilidade, desempenho animal e ganho por área durante a estação chuvosa. Foram utilizados trinta e seis animais tourinhos Nelore. Aumentar a altura do dossel refletiu em aumento da massa de forragem, enquanto diminuiu a taxa de lotação. Não houve diferença na composição química de PB, FDN e concentração DIVMS entre os tratamentos. No segundo experimento, foi avaliado o efeito da suplementação (sal mineral; suplemento com gordura protegida; suplemento com soja grão) no desempenho e produção de metano de bovinos mantidos em pastos de Brachiaria brizantha cv. Marandu manejados a 25 cm. Animais suplementados apresentaram valores de consumo e digestibilidade superior para todos os nutrientes, exceto proteína quando comparado ao tratamento controle. No entanto, a suplementação não afetou a produção de CH4, expressos em g CH4 / dia. O aumento no ganho de peso vivo dos animais suplementados refletiu em diminuição na produção de CH4 / kg de produto e g CH4 / kg CMS. No terceiro experimento foi avaliado um fatorial 3x3 - três alturas do dossel (15, 25 e 35 cm) e três suplementos (sal mineral; suplemento com gordura protegida; suplemento com soja grão) no desempenho, consumo e ... / Abstract: Canopy height and supplementation is the mainly strategies to increase animal production or area gain in system on pasture. However, some reporter diverge about the correct management in tropical forages, furthermore, the effect of supplementation with soybean differently available in rumen in pasture still inconclusively. By this sense, two trials were conducted to evaluate the effect of supplementation for young Nellore bulls grazing Brachiaria brizantha cv. Marandu with different sward height on herbage characteristics, dry matter intake, digestibility, animal performance and gain per area during the rainy season. Hundred and eight animal young Nellore bulls were used. Treatments corresponded to three different canopy height (15, 25 and 35 cm) when years where analyzed and the combined with sward height and supplementation with mineral salt, supplement with soybean grain or supplement with protect fat. The level of supplementation was 0.5% of BW. Pastures were fertilizer according to local recommendations following soil analysis plus 135 and 90 kg of nitrogen by urea during first and second year, respectively. Increase the canopy height increased herbage mass whilst decreased stocking rate. There was no difference in hand-plucked herbage CP, NDF and IVDMD concentration among treatments. Supplemented animals had higher DM intake and digestibility values of all nutrients except protein when compared to the control treatment. However, the supplements did not affect the production of CH4 expressed as g CH4/day. The increase in liveweight gain using either supplement caused a decrease in the production CH4/ kg product and g CH4/kg DMI. Considering that relation between animal performance and stocking rate, marandu pastures should be not be grazed below 20-cm stubble or above 30-cm for greater productivity. By other hand, supplementation with lipid of low ruminal degradation can increase performance with higher effect of protect fat source ... / Doutor

Orientador: Roberto Alves de Oliveira / Coorientador: Rose Maria Duda / Banca: Valderi Duarte Leite / Banca: Marcelo Bruno / Resumo: Neste trabalho avaliou-se os efeitos da suplementação de ferro, níquel e cobalto na produção de metano da vinhaça proveniente da destilação do etanol de cana-de-açúcar, em reatores anaeróbios de fluxo ascendente com manta de lodo (UASB, R1 e R2) termofílicos, em série. Para determinar os efeitos da adição do Fe, Ni e Co, o experimento foi realizado em 3 diferentes fases. Na fase I foi realizada a partida dos reatores UASB, R1 e R2, com o aumento gradativo da carga orgânica volumétrica (COV) até valores de 9,4 g DQOtotal (L d)-1. Nas fases II e III a COV variou entre 9,9 a 14,9 g DQOtotal (L d)-1, e a fase III distinguiu-se da fase II pela suplementação com Fe, Ni e Co, na vinhaça afluente. Para o R1, a suplementação com elementos traço induziu ao decréscimo de ácidos voláteis totais, de 1801 para 834 mg L-1, aumento na produção volumétrica de metano (PVM) em 101% e aumento na eficiência remoção de DQO para 53%. O Fe foi considerado o principal elemento traço por seus efeitos de precipitação com sulfeto e participação nas fases acetogênicas e metanogênicas da digestão anaeróbia. As relações Fe/DQO, Ni/DQO e Co/DQO de 12,59, 0,138 e 0,191 mg (g DQOremovida)-1, respectivamente, foram consideradas ideais para o R1, pois, possibilitaram as mais altas PVM atingindo até 1,4 L CH4 (L d)-1. No sistema (R1+R2), a adição de Fe, Ni e Co promoveu estabilidade operacional, e auxiliou na remoção de DQO, melhorando a eficiência total do sistema. Porém, não favoreceu a PVM, que manteve-se com... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this study was evaluated the effects of supplementation with iron, nickel and cobalt on vinasse in reactors upflow anaerobic sludge blanket (UASB, R1 and R2) thermophilic, in series. To determine the effects of the addition of trace elements, the experiment was conducted in 3 phases. During the first phase was characterized by the gradual increase of the organic loading rate (OLR) up to 9.4 g CODtotal (L d)-1, and start-up of system. In the phase II and III the OLR varied between 9.9 to 14.9 g CODtotal (L d)-1, the phase III distinguished of phase II only in trace element supplementation. For R1, trace element supplementation induced a decreased in total volatile acids, from 1801 to 834 mg L-1, increase in methane production rate (MPR) by 101% and increased in chemical oxygen demand (COD) removal efficiency to 53%. The Fe was considered the most relevant in the system due to its ability to precipitate with sulfide and participation in acetogenic and methanogenic phases of anaerobic digestion. The ratios Fe/COD, Ni/COD and Co/COD 12.59, 0.138, 0.191 mg g-1 CODremoved, respectively, they were considered ideal for R1, as they enabled as higher MPR reaching up to 1.4 L CH4 (L d)-1. For the system (R1+R2), the supplementation of Fe, Ni and Co promoted operational stability, and assisted in the removal of COD increasing the total efficiency of the system. However it did not favor the MPR, which remained on average of 0.571 L CH4 (L d)-1, and was similar to phase II, without addition of trace elements, with mean of 0.555 L CH4 (L d)-1. Therefore, it was verified that with the addition of trace elements, only R1 would be sufficient for the treatment of vinasse, but, if the treatment in chosen without the addition of trace elements, R2 would be essential for obtaining methane, but, without assurance of operational stability for the anaerobic digestion system. / Mestre

O objetivo deste estudo foi avaliar o efeito de enzimas sobre a ingestão de matéria seca, digestibilidade dos nutrientes, comportamento alimentar, produção de CH4 entérico e os parâmetros fermentativos, além da produção de metano nas fezes de bovinos, utilizando biodigestores. O experimento foi conduzido na Universidade de São Paulo, Pirassununga/SP, Brasil. Foram utilizadas cinco vacas, com peso médio de 923,04 ± 86,76 kg, canuladas no rúmen, distribuídas em cinco tratamentos utilizando delineamento experimental em quadrado latino 5x5: 1) Controle: dieta sem adição de enzimas; 2) Amilase: dieta com 7,5 g de amilase/animal/dia (Amaize, ALLTECH); 3) Xilanase: dieta com 15 g de xilanase/animal/dia (Fibrozyme, ALLTECH); 4) Celulase + protease: dieta com 7,5 g celulase + protease/animal/dia (Allzyme VegPro PO, ALLTECH); 5) Pool: dieta com 30 g de mistura de enzimas (amilase, xilanase e celulase + protease)/animal/dia. Cada período experimental consistiu de 21 dias (os primeiros 15 dias foram utilizados para adaptação da dieta e os últimos 5 dias para a coleta de dados). Nos dias 10 e 20, foi avaliada a digestibilidade utilizando o marcador de óxido crômico e coleta de fezes. No dia 17, foi avaliada o comportamento ingestivo por 24 horas, através de monitoramento visual a cada 5 minutos. No dia 19, foi mensurado o pH ruminal a cada 10 minutos, utilizando-se probes de mensuração contínua. Para quantificar os ácidos graxos de cadeia curta (AGCC), metano, concentração de N-NH3 e protozoários, coletou-se conteúdo ruminal antes, 3, 6, 9 e 12 horas após a alimentação matinal. A técnica de fermentação consistiu na incubação de conteúdo de rúmen líquido e sólido em frascos em banho-maria 39 ºC durante 30 minutos. Na subsequente medição da produção de metano usou-se cromatografia gasosa. Nos dias 20 e 21, foi avaliada a dinâmica ruminal. Os dados foram analisados pelo programa SAS, através do procedimento PROC MIXED. O modelo, o efeito de tratamento como fator fixo e os efeitos de animal e período como fatores aleatórios, considerado nível de significância de 5%. A adição de enzimas não mostrou diferença significativa em relação ao consumo de matéria seca (CMS), digestibilidade, comportamento ingestivo, produção de CH4, N-NH3, protozoários ou dinâmica ruminal. A associação de enzimas (tratamento Pool) aumentou a produção de acético, propiônico e AGCC totais em relação à dieta controle. As variáveis pH mínimo, médio e máximo, tempo de pH abaixo de 5,8, 6,0, 6,2 e 6,5, assim como área de pH abaixo de 5,8, 6,0, 6,2 e 6,5 não diferiram significativamente entre os tratamentos. Não foram verificadas diferenças para a produção de biogás ou teores sólidos do efluente. Concluiu-se que a utilização destes aditivos, nas proporções usadas, não afetou as variáveis de CMS, digestibilidade, comportamento ingestivo, produção de CH4, pH, protozoários, N-NH3 ou dinâmica ruminal. A associação de enzimas apresentou melhora na produção de AGCC ruminal sem aumentar a emissão de CH4. / The objective of this study was to evaluate the effect of enzymes on dry matter intake, nutrient digestibility, feeding behavior, production of enteric CH4 and fermentative parameters, as well as the production of methane in bovine feces using digester. The experiment was conducted at the University of São Paulo, Pirassununga/SP, Brazil. Five cows were used, with a mean weight of 923.04 ± 86.76 kg, cannulated in the rumen, distributed in five treatments using 5x5 Latin square experimental design: 1) Control: diet without addition of enzymes; 2) Amylase: diet with 7.5 g of amylase/animal.day(Amaize,Alltech); 3) Xylanase: diet with 15 g of xylanase/animal.day(Fibrozyme, Alltech); 4) Cellulase + protease: diet with 7.5 g of cellulase + protease/animal.day (Allzyme VegPro PO, Alltech); 5) Pool: diet with 30 g of enzymes pool (amylase, xylanase and cellulase + protease)/animal.day. Each experimental period consisted of 21 days (first 15 days were used for diet adaptation and the last 5 days for data collection). On days 10th and 20th, digestibility was evaluated using the chromic oxide marker and fecal collection. On the 17th day, ingestive behavior was evaluated for 24 hours, through visual monitoring every 5 minutes. On day 19th, ruminal pH was measured every 10 minutes, using a continuous measurement device. In order to quantify short-chain fatty acids (SCFA), methane, concentration of NH3-N and protozoa, rumen contents were sampled prior to and 3, 6, 9 and 12 hours after morning feeding. The fermentation technique consisted of incubation of liquid and solid rumen contents in bottles in a water bath 39 ºC for 30 minutes. Subsequent measurement of methane production using gas chromatography On days 20th and 21th, ruminal dynamic was evaluated by emptying this organ. Data were analyzed using SAS, through the PROC MIXED procedure. The model included the effect of treatment as fixed factor, animal and period effects as random factors, considered level of significance of 5%. The addition of enzymes showed no significant difference in relation to dry matter intake (DMI), digestibility, ingestive behavior, CH4 production, NH3-N, protozoa or ruminal dynamics parameters. The association of enzymes (pool treatment) increased acetic, propionic and total SCFA production in relation to the control diet. Not significant differences were observed for the pH variables, as minimum, average and maximum pH, as well as time and area which pH was below to 5.8, 6.0, 6.2 and 6.5. No differences were verified for biogas production or solid effluent contents. It is concluded that these additives, in the proportions used, did not affect the variables of DMI, digestibility, ingestive behavior, CH4 production, pH, protozoa, NH3-N or ruminal dynamic. The association of the enzymes showed improvement in the production of rumen SCFA without increasing the CH4 emission.