Foot strike type affects running mechanics and may influence overuse injury occurrence. Measuring the interaction between cumulative load and foot strike type may provide additional information that could eventually help with understanding injury mechanisms. The purpose of this study was to determine how foot strike type affects cumulative loading in runners, and to determine if individual metrics change throughout a 5-kilometer sub-maximal run. 30 participants ran on an instrumented treadmill for 5 km at 3.15 m/s with their preferred foot strike type (14 rearfoot strike, 16 non-rearfoot strike). Stride rate, foot strike angle, loading rate, per stride and per km (cumulative) vertical ground reaction force impulse, impact peak, absolute peak, knee negative work, and ankle negative work were calculated and compared across time and between groups. Per stride between-group main effects were seen for stance time (p=0.003), foot strike angle (p<0.001), and loading rate (p=0.040), all of which were greater for rearfoot strike runners. Per stride and cumulative ankle and knee negative work also showed significant differences, with ankle negative work being greater for non-rearfoot strike runners (p=<0.001 per stride, p=<0.001 cumulative) and knee negative work being greater for rearfoot strike runners (p=0.014 per stride, p=0.008 cumulative). Both loading rate and cumulative vertical ground reaction force impulse decreased significantly over time (p=0.035, p=<0.001 respectively). In summary, we found a few differences in per stride and cumulative metrics between foot strike groups, namely ankle and knee loading as previously observed. However, as a whole, individual variability in vertical ground reaction force loading patterns was more apparent than any group distinctions. We also found patterns in previous research suggesting that study design components, specifically self-selected speed and habituation, affect variables such as stride rate and peak vertical ground reaction force. The common perception that non-rearfoot strike runners have a higher stride rate was not supported in this study. Lastly, we determined that cumulative calculations can be different if taken at the beginning vs the end of a run. Quantifying injury risk is complicated and cumulative damage models should take into account individual load capacity and training session characteristics (e.g., warm-up time, length, intensity, and rest time).

A presente pesquisa teve como proposta avaliar o reator anaeróbio, operado de forma descontínua ou descontínua alimentada, contendo biomassa imobilizada em suporte inerte e com recirculação da fase líquida (AnSBBR) aplicado à produção de biohidrogênio a partir da codigestão de glicerina (efluente da produção de biodiesel) e soro de leite (efluente da produção de laticínios). A estabilidade, os índices de desempenho (referentes à produtividade e rendimento molar do hidrogênio) e o fator de conversão (entre biogás produzido e matéria orgânica consumida) foram analisados em função da composição afluente (porcentagem de cada substrato alimentado ao sistema), da variação da carga orgânica, do tempo de enchimento e da temperatura (20, 25, 30 e 35ºC). Os ensaios foram realizados em diferentes proporções dos substratos utilizando-se variadas cargas orgânicas volumétricas (10,3; 17,1 e 24,0 gDQO.L-1.d-1), as quais foram modificadas em função: (i) da concentração afluente (3, 5 e 7 gDQO.L-1) e (ii) do tempo de ciclo (4, 3 e 2 h, ou seja, 6, 8 e 12 ciclos diários). Também foram realizados ensaios para a produção de biometano a partir da codigestão proposta nesta pesquisa (com COAV de 7,6 gDQO.L-1.d-1) em diferentes proporções de mistura. Para a produção de biometano, a condição com 75% de soro e 25% de glicerina (base DQO) obteve os melhores resultados: produtividade molar de 101,8 molCH4.m-3.d-1 e rendimento por carga aplicada de 13,3 molCH4.kgDQO-1; o que representa um aumento de produtividade de cerca de 9% e 30% quando comparado com a digestão anaeróbia de soro e glicerina puros, respectivamente. A produção de metano no melhor ensaio aconteceu predominantemente pela rota hidrogenotrófica. Para a produção de biohidrogênio, a maior produtividade e rendimento do reator foram obtidas no ensaio operado com razão de mistura de 75% soro e 25% glicerina, com 7 gDQO.L-1 de concentração afluente, tempo de ciclo de 3 h e tempo de enchimento de 1,5 h (modo batelada alimentada - COAV de 23,9 kgDQO.m-3.d-1), a 30°C: foi obtida uma produtividade molar de 129,0 molH2.m-3.d-1 e rendimento de 5,4 molH2.kgDQO-1. Esses resultados representam um aumento de produtividade de 145% em relação a mono-digestão do soro na condição inicial, o que indica o benefício significativo da adição de glicerina ao afluente, provavelmente devido à sua capacidade tamponante, e a otimização das condições operacionais. A adição de glicerina e o aumento da COAV balancearam as rotas de produção de hidrogênio, sendo produzido de forma mais equilibrada pelas vias do ácido acético, butírico e valérico. A caracterização do consórcio microbiano desse ensaio indicou que a comunidade microbiana presente no AnSBBR foi dominada por Ethanoligenens e Megasphaera. / The current research evaluated an anaerobic reactor, operated in batch or fed-batch mode, containing immobilized biomass in inert support and with recirculation of the liquid phase (AnSBBR), applied to the production of biohydrogen co-digesting glycerin (effluent from biodiesel production process) and whey (effluent from dairy industry). Stability, performance (regarding productivity and molar hydrogen yield) and conversion factor (between biogas produced and organic matter consumed) were analyzed according to the percentage of each substrate fed to the system, organic loading rate, filling time and temperature (20, 25, 30 and 35ºC). Assays were carried out using different substrates proportions and organic loading rates (10.3; 17.1 and 24.0 gCOD.L-1.d-1), which have been modified in function of: (i) influent concentration (3, 5 and 7 gCOD.L-1) and (ii) cycle length (4, 3 and 2 h, i.e. 6, 8 and 12 cycles daily). Assays were also carried out aiming for biomethane production using the proposed co-digestion (with AVOL of 7.6 gDQO.L-1.d-1) with different proportions of substrate mixture. For biomethane production, the assay conducted with 75% whey and 25% glycerin (COD basis) obtained the best results: molar productivity of 101.8 molCH4.m-3.d-1 and yield per applied load of 13.3 molCH4. kgCOD-1; which is an increase in productivity of about 9% and 30% when compared with the anaerobic mono-digestion of whey and glycerin, respectively. Methane production in this assay came mainly from the hydrogenotrophic route. For biohydrogen production, the highest productivity and yield were achieved in the assay operated with 75% whey and 25% glycerin, with 7 gCOD.L-1 of influent concentration, 3 h of cycle time and filling time of 1.5 h (fed batch mode - AVOL of 23.9 kgCOD.m-3.d-1), at 30°C: a molar productivity of 129.0 molH2.m-3.d-1 and yield of 5.4 molH2.kgCOD-1 were obtained. These results represent a productivity increase of 145% in relation to whey mono-digestion at its initial condition, which indicates the significant benefit of glycerin addition to the influent, probably due to its buffering capacity, and improvement of operational conditions. The addition of glycerin and the increase in AVOL balanced the hydrogen production routes, since hydrogen was produced similarly by the acetic, butyric and valeric acid routes. The characterization of the microbial consortium of this assay indicated that the microbial community present in the AnSBBR was dominated by Ethanoligenens and Megasphaera.

Under år 2008 användes globalt en energimängd motsvarande nästan 144 000 TWh ochav dessa stod fossila bränslen för 81 %. I Sverige uppgick energitillförseln under år2010 till totalt 616 TWh och av detta stod råolja/oljeprodukter för 30,4 %. Vidförbränning av fossila bränslen frigörs koldioxid, en gas som bidrar till att förstärkaväxthuseffekten. År 2000 uppmättes halten av koldioxid i atmosfären till 370 ppmv ochför att den globala temperaturen inte ska öka med mer än 2°C bör halten stanna på 450ppmv innan år 2100. Ett sätt att minska andelen av fossila bränslen är att öka andelen avförnybara energikällor, som t.ex. biogas, som i Sverige uppskattas kunna ge enenergimängd motsvarande 10-15 TWh/år i framtiden.Vid biogasanläggningen Kungsängens gård, Uppsala, samrötas slakteriavfall samtorganiskt avfall från hushåll och livsmedelsindustri i en termofil rötningsprocess. Underår 2011 producerades ca 3 400 000 Nm3 biogas och den största andelen uppgraderadestill fordonsgas. Behovet fordonsgas i Uppsala ökar och i detta examensarbete utreddestvå sätt att effektivisera processen och öka gasproduktionen. Dels undersöktes om enökad belastning skulle ge en ökad biogasproduktion utan att riskera processensstabilitet. Detta gjordes i två labskalereaktorer där belastningen ökades gradvis i denena. Dels studerades möjligheten att minska energiförbrukningen på anläggningengenom att byta hygieniseringsmetod. Innan substratet matas in i rötkamrarna måste dethygieniseras, vilket i dagsläget görs genom pastörisering (upphettning till 70oC under entimme). Då detta är väldigt energikrävande finns det planer på att byta metod ochistället låta substratet hygieniseras i rötkamrarna (52°C) i minst 10 timmar. Det är dockviktigt att beakta huruvida metanpotentialen för pastöriserat och opastöriserat materialskiljer sig åt, varför detta utreddes i sk satsvisa utrötningsförsök.Genom hela belastningsökningen (från 3 till 6 kg VS/m3,d) ökade biogasproduktionenoch vid den högsta belastningen var ökningen 100 % jämfört med dagens nivå. Andraviktiga processparametrar, så som specifik gasproduktion, kvoten CO2/CH4, pH,halterna av fettsyror och utrötningsgraden, låg på en jämn nivå under försöket, vilkettyder på att processen var stabil trots den ökade belastningen. Utrötningsförsöket visadeatt pastöriseringen inte hade någon effekt på metanproduktionen, troligtvis eftersomsubstratet redan var lättnedbrytbart. Beräkningen av energiförbrukning visade attenergianvändningen skulle minska med ca 33 % vid byte av hygieniseringsmetod. / During 2008 an amount of energy equivalent to almost 144,000 TWh was used globally,of which fossil fuels accounted for 81 %. In Sweden, during 2010, an amount of energyequivalent to 616 TWh was used, of which crude oil/oil products accounted for 30.4 %.Carbon dioxide, a gas that contributes to the global warming, is produced during thecombustion of fossil fuels. In 2000 the levels of carbon dioxide in the atmosphere wasmeasured to be 370 ppmv and if the global temperature is not to increase with morethan 2°C, the levels should stay at 450 ppmv by 2100. One way of decreasing the use offossil fuels is to increase the use of renewable energy, such as biogas. In the futurebiogas can, approx., provide with energy equivalent to 10-15 TWh/year in Sweden.At the biogas plant Kungsängens gård, in Uppsala, slaughterhouse byproducts are codigestedwith source separated household waste and waste from the food processingindustry in a thermophilic process. During the year 2011 approximately 3,400,000 Nm3of biogas was produced at the plant, of which most was upgraded to vehicle fuel. Theconsumption of vehicle fuel is increasing in Uppsala and thus there is a need forincreased biogas production. The aim of this master thesis was to investigate two waysto increase the efficiency and consequently the gas production at the biogas plant atKungsängens gård. Firstly, it was studied if an increased organic loading rate (OLR)would give an increased biogas production, without disturbing the process. This wasdone in two lab scale reactors, where the load was increased gradually in one. Secondly,the possibility to decrease the energy consumption by means of a change of sanitizationmethod was studied. The substrate has to be sanitized before it is fed to the digesters,currently this is done by pasteurization. This process is, however, energy-demandingand there are plans to change the method of sanitization. It is, however, important toconsider whether the methane potential differs for the pasteurized and the nonpasteurizedsubstrate. This was studied in small scale biogas batch reactors.Through all stages of increased OLR (from 3 to 6 kg VS/m3, d) the biogas productionincreased, and at the largest load the increase was 100 % compared to the present level.Other important process parameters, such as specific methane production, CO2/CH4-ratio, pH, levels of fatty acids and degree of digestion, were at regular levels and thisindicates that the process was maintained stable in spite of the increased load. The testin the small scale biogas batch reactors showed that pasteurization of the substrate hadno effect on the methane potential, probably due to that the substrate already is readilybiodegradable. The estimation of the energy consumption showed that the use of energyshould decrease with approx. 33 % if the sanitization was replaced.

Biomass and biomass-derived waste are important renewable energy sources which plays a vital role in greenhouse gas reduction from fossil fuel.  Biomass can be degraded in a process known as anaerobic digestion (AD) to produce biogas. Biogas is a mixture of methane and carbon dioxide which is utilized as a renewable source of energy. This project was based on the investigation of AD process in Nordvästra Skånes Renhållnings AB (NSR) a biogas facility in Helsingborg Sweden. A lab simulation of NSR digesters was conducted to evaluate the effects of swine manure on AD using two continuously stirred tank reactors (CSTR) R1 (control) and R2 with a working volume of 4L for 21 weeks. The study was divided into 4 periods and the investigation was carried out by increasing the organic loading rate (OLR) step wise from 2.5 to 3.6 gVSL-1day-1. To assess the effects of swine manure, the performance and stability of the reactors were monitored by collecting data from process parameters. These process parameters included biogas production, pH, volatile fatty acids, methane yield, methane content and organic solids (total and volatile solids). Increase in OLR resulted in increase biogas production in both reactors, however R2 with additional swine manure (15%) produced more biogas than R1. Methane yield was fairly stable during the experiment and had a similar trend in both reactors, but however R2 had a slightly higher average yield (730±60 mLCH4 gVS-1) than R1 (690±60 mLCH4 gVS-1) during the entire experiment. Increase OLR resulted in increase VFA in period 2; R2 with additional swine manure had a lower peak VFA concentration of 25 mM as compared to 33mM in R1.  The characteristics of NSR substrate mix and swine manure provided a good buffering system (stable pH), and reactors were still running stably at 3.6 gVSL-1day-1. Furthermore swine manure was investigated to contain macro-nutrients and trace metals which might have enhanced the AD process in R2 containing more Co, Zn, Ni and Mo than R1. Since this investigation was a simulation, the waste mix used at NSR contained 7% swine manure, this made it difficult to give clearer conclusions about the effects of co-digestion of swine manure on the biogas process since the control (R1) had 7% swine manure. Keywords: Anaerobic digestion, co-digestion, swine manure, substrate mix, organic loading rate, biogas production, methane yield, VFA, process parameters, CSTR.

A presente pesquisa teve como proposta avaliar o reator anaeróbio, operado de forma descontínua ou descontínua alimentada, contendo biomassa imobilizada em suporte inerte e com recirculação da fase líquida (AnSBBR) aplicado à produção de biohidrogênio a partir da codigestão de glicerina (efluente da produção de biodiesel) e soro de leite (efluente da produção de laticínios). A estabilidade, os índices de desempenho (referentes à produtividade e rendimento molar do hidrogênio) e o fator de conversão (entre biogás produzido e matéria orgânica consumida) foram analisados em função da composição afluente (porcentagem de cada substrato alimentado ao sistema), da variação da carga orgânica, do tempo de enchimento e da temperatura (20, 25, 30 e 35ºC). Os ensaios foram realizados em diferentes proporções dos substratos utilizando-se variadas cargas orgânicas volumétricas (10,3; 17,1 e 24,0 gDQO.L-1.d-1), as quais foram modificadas em função: (i) da concentração afluente (3, 5 e 7 gDQO.L-1) e (ii) do tempo de ciclo (4, 3 e 2 h, ou seja, 6, 8 e 12 ciclos diários). Também foram realizados ensaios para a produção de biometano a partir da codigestão proposta nesta pesquisa (com COAV de 7,6 gDQO.L-1.d-1) em diferentes proporções de mistura. Para a produção de biometano, a condição com 75% de soro e 25% de glicerina (base DQO) obteve os melhores resultados: produtividade molar de 101,8 molCH4.m-3.d-1 e rendimento por carga aplicada de 13,3 molCH4.kgDQO-1; o que representa um aumento de produtividade de cerca de 9% e 30% quando comparado com a digestão anaeróbia de soro e glicerina puros, respectivamente. A produção de metano no melhor ensaio aconteceu predominantemente pela rota hidrogenotrófica. Para a produção de biohidrogênio, a maior produtividade e rendimento do reator foram obtidas no ensaio operado com razão de mistura de 75% soro e 25% glicerina, com 7 gDQO.L-1 de concentração afluente, tempo de ciclo de 3 h e tempo de enchimento de 1,5 h (modo batelada alimentada - COAV de 23,9 kgDQO.m-3.d-1), a 30°C: foi obtida uma produtividade molar de 129,0 molH2.m-3.d-1 e rendimento de 5,4 molH2.kgDQO-1. Esses resultados representam um aumento de produtividade de 145% em relação a mono-digestão do soro na condição inicial, o que indica o benefício significativo da adição de glicerina ao afluente, provavelmente devido à sua capacidade tamponante, e a otimização das condições operacionais. A adição de glicerina e o aumento da COAV balancearam as rotas de produção de hidrogênio, sendo produzido de forma mais equilibrada pelas vias do ácido acético, butírico e valérico. A caracterização do consórcio microbiano desse ensaio indicou que a comunidade microbiana presente no AnSBBR foi dominada por Ethanoligenens e Megasphaera. / The current research evaluated an anaerobic reactor, operated in batch or fed-batch mode, containing immobilized biomass in inert support and with recirculation of the liquid phase (AnSBBR), applied to the production of biohydrogen co-digesting glycerin (effluent from biodiesel production process) and whey (effluent from dairy industry). Stability, performance (regarding productivity and molar hydrogen yield) and conversion factor (between biogas produced and organic matter consumed) were analyzed according to the percentage of each substrate fed to the system, organic loading rate, filling time and temperature (20, 25, 30 and 35ºC). Assays were carried out using different substrates proportions and organic loading rates (10.3; 17.1 and 24.0 gCOD.L-1.d-1), which have been modified in function of: (i) influent concentration (3, 5 and 7 gCOD.L-1) and (ii) cycle length (4, 3 and 2 h, i.e. 6, 8 and 12 cycles daily). Assays were also carried out aiming for biomethane production using the proposed co-digestion (with AVOL of 7.6 gDQO.L-1.d-1) with different proportions of substrate mixture. For biomethane production, the assay conducted with 75% whey and 25% glycerin (COD basis) obtained the best results: molar productivity of 101.8 molCH4.m-3.d-1 and yield per applied load of 13.3 molCH4. kgCOD-1; which is an increase in productivity of about 9% and 30% when compared with the anaerobic mono-digestion of whey and glycerin, respectively. Methane production in this assay came mainly from the hydrogenotrophic route. For biohydrogen production, the highest productivity and yield were achieved in the assay operated with 75% whey and 25% glycerin, with 7 gCOD.L-1 of influent concentration, 3 h of cycle time and filling time of 1.5 h (fed batch mode - AVOL of 23.9 kgCOD.m-3.d-1), at 30°C: a molar productivity of 129.0 molH2.m-3.d-1 and yield of 5.4 molH2.kgCOD-1 were obtained. These results represent a productivity increase of 145% in relation to whey mono-digestion at its initial condition, which indicates the significant benefit of glycerin addition to the influent, probably due to its buffering capacity, and improvement of operational conditions. The addition of glycerin and the increase in AVOL balanced the hydrogen production routes, since hydrogen was produced similarly by the acetic, butyric and valeric acid routes. The characterization of the microbial consortium of this assay indicated that the microbial community present in the AnSBBR was dominated by Ethanoligenens and Megasphaera.

Biomechanical testing of cadaveric spinal segments forms the basis for our current understanding of healthy, pathological, and surgically treated spinal function. Over the past 40 years there has been a substantial amount of data published based on a spinal biomechanical testing regimen known as the flexibility method. This data has provided valuable clinical insights that have shaped our understanding of low back pain and its treatments. Virtually all previous lumbar spinal flexibility testing has been performed at room temperature, under very low motion rates, without the presence of a compressive follower-load to simulate upper body weight and the action of the musculature. These limitations of previous work hamper the applicability of published spinal biomechanics data, especially as researchers investigate novel ways of treating low back pain that are intended to restore the spine to a healthy biomechanical state. Thus, the purpose of this thesis work was to accurately characterize the rate-dependent flexibility of the lumbar spine at body temperature while in the presence of a compressive follower-load. A custom spine simulator with an integrated environmental chamber was developed and built as part of this thesis work. Cadaveric spinal motion segments were tested at 12 different rates of loading spanning the range of voluntary motion rates. The testing methodology allowed for comparison of spinal flexibility at room and body temperatures in the three primary modes of spinal motion, both with and without a compressive follower-load. Additionally, the work developed a stochastic model for rate-dependent spinal flexibility that allows for accurate prediction of spinal flexibility at any rate within the range of voluntary motion, based on a single flexibility test. In conclusion, the biomechanical response was significantly altered due to testing temperature, loading-rate, and application of a compressive follower-load. The author emphasizes the necessity to simulate the physiological environment during ex vivo biomechanical analysis of the lumbar spine in order to obtain a physiological response. Simplified testing procedures may be implemented only after the particular effect is known.

This study was carried out to evaluate the performance of Soil Aquifer Treatment (SAT) under different loading regimes, using wastewater of much higher strength than usually encountered in SAT systems, and also to investigate the removal of the endocrine disruptors triclocarban (TCC), estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). SAT was simulated in the laboratory using a series of soil columns under saturated and unsaturated conditions. Investigation of the removal of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Dissolved Organic Carbon (DOC), nitrogen and phosphate in a 2 meter long saturated soil column under a combination of constant hydraulic loading rates (HLRs) and variable COD concentrations as well as variable HLR under constant COD showed that at fixed HLR, a decrease in the influent concentrations of DOC, BOD, total nitrogen and phosphate improved their removal efficiencies. It was found that COD mass loading applied as low COD wastewater infiltrated over short residence times would provide better effluent quality than the same mass applied as a COD with higher concentration at long residence times. On the other hand relatively high concentrations coupled with long residence time gave better removal efficiency for organic nitrogen. Phosphate removal though poor under all experimental conditions, was better at low HLRs. In 1 meter saturated and unsaturated soil columns, E2 was the most easily removed estrogen, while EE2 was the least removed. Reducing the thickness of the unsaturated zone had a negative impact on removal efficiencies of the estrogens whereas increased DOC improved the removal in the saturated columns. Better removal efficiencies were also obtained at lower HLRs and in the presence of silt and clay. Sorption and biodegradation were found to be responsible for TCC removal in a 300 mm long saturated soil column, the latter mechanism however being unsustainable. TCC removal efficiency was dependent on the applied concentration and decreased over time and increased with column depth. Within the duration of the experimental run, TCC negatively impacted on treatment performance, possibly due to its antibacterial property, as evidenced by a reduction in COD removals in the column. COD in the 2 meter column under saturated conditions was modelled successfully with the advection dispersion equation with coupled Monod kinetics. Empirical models were also developed for the removal of TCC and EE2 under saturated and unsaturated conditions respectively. The empirical models predicted the TCC and EE2 removal profiles well. There is however the need for validation of the models developed

Este estudo investigou a aplicação de um reator anaeróbio operado em bateladas sequenciais com biomassa imobilizada (AnSBBR) com agitação na produção de biohidrogênio tratando água residuária sintética a base de sacarose, sendo o desempenho do biorreator avaliado de acordo com a influência conjunta do tempo de alimentação, do tempo de ciclo, da concentração afluente e da carga orgânica volumétrica aplicada (COVAS). O biorreator, com capacidade útil de 5,6 L, foi dividido em 3 partes: volume de meio tratado por ciclo de 1,5 L, volume residual de meio de 2,0 L e volume de suporte inerte com biomassa de 2,1 L. Foram aplicadas 6 condições experimentais de COVAS de 9,0 a 27,0 gDQO.L-1.d-1, combinado diferentes concentrações afluentes (3500 e 5400 mgDQO.L-1), tempos de ciclo (4, 3 e 2h), sendo tempo de enchimento do reator (tC) correspondente a 50% ao tempo de ciclo. Os resultados mostraram que o aumento COVAS contribuiu para a queda no consumo de sacarose de 99% para 86% e para o aumento do rendimento molar por carga removida (RMCRC,n) de 1,02 molH2.molSAC-1 na COVAS de 9,0 gDQO.L-1.d-1 até atingir o valor máximo de 1,48 molH2.molSAC-1 na COVAS de 18,0 gDQO.L-1.d-1 com queda a partir desse ponto. O aumento da COVAS resultou no aumento da produtividade molar volumétrica (PrM) de 24,5 para 81,2 molH2.m-3.d-1. A maior produtividade molar específica (PrME) obtida foi de 8,71 molH2.kgSVT-1.d-1 para a COVAS de 18,0 gDQO.L-1.d-1. A diminuição do tempo de ciclo resultou na diminuição do consumo de sacarose e no aumento da PrM. Foi verificado também que a diminuição do tC de 4h para 3h contribuiu para o aumento da PrME. O aumento da concentração afluente resultou na diminuição do consumo de sacarose apenas na faixa de 2h, no aumento do RMCRC,n e da PrM em todas as faixas de tC, e no aumento da PrME nas faixas de 4h e 3h. A estratégia de alimentação mostrou ser um parâmetro operacional de grande importância, sendo o aumento do tempo de enchimento responsável pelo aumento do consumo de sacarose, da PrM, da PrME e do RMCRC,n para todas as COAVS investigadas. Em todas as condições, houve o predomínio do ácido acético seguido pelo etanol, ácido butírico e propiônico. / This study investigated the feasibility of an anaerobic sequencing batch biofilm reactor (AnSBBR) with agitation on biohydrogen production treating synthetic wastewater from sucrose, the performance of the bioreactor was evaluated according the combined influence of fill time, cycle period, influent concentration and applied organic loading rate (COAVS) . The bioreactor, with working volume of 5,6L, was divided in 3 parts: 1,5L of fed volume per cycle, 2,0L of residual medium and 2,1L of inert support and biomass. The reactor was operated under six operating conditions with different COAVS ranging from 9,0 to 27,0 gCOD.L-1.d-1, obtained by the combination of different influent concentrations (3500 e 5400 mgCOD.L-1), cycle periods (4, 3 e 2h) and fill time corresponding to 50% of cycle period. The results showed that increasing COAVS resulted in lesser sucrose removal from 99% to 86% and improved yield per removed loading rate (RMCRC,n) of 1,02 molH2.molSUC-1 in COAVS of 9,0 gCOD.L-1.d-1 to maximum value of 1,48 molH2.molSUC-1 in COAVS of 18,0 gCOD.L-1.d-1 decreasing after that. Increasing COAVS improved molar productivity (PrM) from 24,5 to 81,2 molH2.m-3.d-1. The higher specific molar productivity (PrME) obtained was 8,71 molH2.kgTVS-1.d-1 in COAVS of 18,0 gCOD.L-1.d-1. Decreasing cycle period resulted in less sucrose consumption and increased PrM. It was observed that decreasing cycle period of 4h to 3h improved PrME. Increasing influent concentration resulted in less sucrose degradation only on range of 2h, in an increase of RMCRC,n and in an increase of PrM in all ranges of tC, and increased PrME on ranges of 4h and 3h. In all operational conditions, the main intermediate metabolic was acetic acid followed by ethanol, butyric and propionic acids. The feeding strategy had a great effective on hydrogen production, longer fill times resulted in better sucrose removal, PrM, PrME and RMCRC,n for all COAVS investigated.

Neste trabalho avaliou-se o desempenho de um reator anaeróbio operado em batelada seqüencial e contendo biomassa imobilizada (ASBBR) em espuma de poliuretano quando submetido a diferentes tempos de alimentação e cargas orgânicas volumétricas, além da aplicação de cargas de choque orgânicas. O reator, com mistura por recirculação da fase líquida e mantido à 30 ± 1 ºC, tratou soro de queijo reconstituído e possuiu 2,5 L de volume reacional. Os resultados mostraram que o tempo de alimentação utilizado exerceu maior influência sobre o desempenho do reator para maiores valores de carga orgânica volumétrica. Durante a operação com carga orgânica volumétrica de 3 gDQO/L.d, a alteração do tempo de alimentação não influenciou na eficiência de remoção de matéria orgânica filtrada, que foi de 98%. Sob carregamento orgânico volumétrico de 6 gDQO/L.d, verificou-se tendência de queda daquela variável para maiores tempos de enchimento: 99, 98 e 97%, para tempos de alimentação de 2, 4 e 6 horas, respectivamente. Na operação com carga orgânica volumétrica de 12 gDQO/L.d, o aumento do tempo de alimentação resultou em queda mais significativa da eficiência de remoção de matéria orgânica filtrada: 97, 95 e 93%, para tempos de alimentação de 2, 4 e 6 horas, respectivamente. Em todas as condições, a aplicação de cargas de choque de 24 gDQO/L.d causaram o aumento da concentração de ácidos no efluente. No entanto, apesar desse aumento, o reator retomou rapidamente sua estabilidade, sendo a alcalinidade otimizada ao afluente suficiente para manter o pH próximo do neutro durante toda a operação. Independente da carga orgânica volumétrica aplicada, a operação com tempo de alimentação de 2 horas foi aquela que proporcionou maior estabilidade e menor suscetibilidade do processo às cargas de choque orgânicas. / This work assessed the performance of an anaerobic sequencing batch reactor containing immobilized biomass (ASBBR) on polyurethane foam when submitted to different feeding times, volumetric loading rate and organic shock loads. The reactor, in which mixing occurred by recirculating the liquid phase, contained 2,5 L reaction medium and was maintained at 30 ± 1 ºC for treating reconstituted cheese whey. Results showed that the effect of feeding time on reactor performance was more pronounced at higher volumetric loading rates. During operation at volumetric loading rate of 3 gDQO/L.d, changing feeding time did not affect filtered organic matter removal efficiency, which amounted to 98%. At volumetric loading rate of 6 gDQO/L.d, removal efficiency showed a tendency to drop at higher feeding times: 99, 98 and 97%, for feeding times of 2, 4 and 6 hours, respectively. At volumetric loading rate of 12 gDQO/L.d, increase in feeding time resulted in a more significant drop in filtered organic matter removal efficiency: 97, 95 and 93%, for feeding times of 2, 4 and 6 hours, respectively. Application of shock loads of 24 gDQO/L.d caused increase in acids concentration in the effluent, at all conditions. However, despite this increase, the reactor readily regained stability and optimized alkalinity supplementation to the influent was sufficient to maintain near neutral pH during the entire operation. Regardless of applied volumetric loading, operation with feeding time of 2 hours was which yielded maximum stability and reduced susceptibility of the process to organic shock loads.

Die anaerobe Vergärung von nachwachsenden Rohstoffen und Gülle zur Biogasproduktion als regenerative Energiequelle erfährt seit einigen Jahren einen erheblichen Boom. Dabei werden in Deutschland in der Regel Nassvergärungs-Biogasanlagen betrieben, in denen kontinuierlich Energiepflanzen und Rinder- oder Schweinegülle gemeinsam eingesetzt werden (Kovergärung). Aber auch die alleinige Nassvergärung von Energiepflanzen ohne Gülle (Monovergärung) ist möglich. Häufig fehlen jedoch belastbare Daten zur Auslegung der Biogasanlage und für die Früherkennung kritischer Belastungszustände. Im vorliegenden Projekt sollen Kenntnisse über die Kinetik der Biogasbildung aus nachwachsenden Rohstoffen in Laborversuchen unter praxisrelevanten Prozessbedingungen gewonnen werden. Über diskontinuierliche Batch-Gärtests lassen sich Biogas- und Methanausbeuten unterschiedlicher Substrate auf einfache Weise ermitteln. Bei einheitlichen Laborbedingungen ist damit eine gute Vergleichbarkeit gegeben. Kontinuierliche Belastungssteigerungsversuche sind hingegen nur als Langzeitversuche möglich. Sie geben jedoch zusätzlich Auskunft über den Einfluß der täglichen Belastung des Biogasreaktors mit organischer Substanz und erlauben mit Einschränkungen Aussagen über die optimale Betriebsweise. Die Versuche wurden mit Mais, Rüben und Roggen in Form von Silage als Mono- und Kosubstrat in der Mischung mit Rinder- und Schweinegülle bei meso- und thermophilen Temperaturstufen durchgeführt. Die Versuchsergebnisse konnten ein neu hergeleitetes kinetisches Modell weitgehend bestätigen, das den Zusammenhang zwischen Biogasausbeute und Raumbelastung in Abhängigkeit von den substrat- und prozessspezifischen Parametern wie maximal mögliche Biogasausbeute, Zulaufkonzentration, Dichte des Biogases und des Ablaufes sowie Reaktionsgeschwindigkeitskonstante aufzeigt. Dies kann damit Betreibern von Biogasanlagen als Richtlinie für eine stabile Prozessführung mit hoher energetischer Effizienz dienen. / Anaerobic digestion of energy crops for biogas production has attracted much interest in recent years. In Germany, the most common process is the continuous wet-fermentation of energy crops with cattle slurry or pig slurry (co-digestion). But also the digestion of energy crops as single substrate without slurry (mono-digestion) becomes more important. Because of the great diversity of substrates and the danger of an overload of the reactor at the digestion of high-energetic substrates, sufficient experience for energy crops is still missing. This project should investigate the kinetics of biogas production from energy crops in lab-scale experiments. Biogas and methane yield of different substrates can be estimated easily by discontinuous batch-experiments. These experiments allow a good comparability in case of equal conditions. On the other hand, the influence of the reactor performance and the optimal operational mode can be identified only by continuous long-term experiments with loading increase. Therefore, long-term lab-scale experiments were conducted with maize silage, whole-crop rye silage and fodder beet silage as mono-substrate and co-substrate in a mixture with both cattle slurry and pig slurry under mesophilic and thermophilic conditions. For calculation of biogas yield as function of the organic loading rate, a hyperbolic equation was developed on base of a first order reaction rate for substrate degradation. The biogas yield also depends on the corresponding maximum biogas yield, the concentration of volatile solids of the input, the density of the effluent, the density of the biogas and the reaction rate constant which are all substrate- and process-specific. The results of the experiments approve this model and allow an estimation of the parameters. This is helpful as a guideline for a stable and efficient biogas process.