Thèses sur le sujet « Granular biomasses »

Successful feeding is critical to biomass utilization processes, but is difficult due to the heterogeneity, peculiar physical characteristics and moisture content of the biomass particles. The objectives of this project were to define what limits screw feeding in terms of the mechanisms of blockage and to examine the effects of key properties like mean particle size, size distribution, shape, moisture content (10-60%), density and compressibility on screw feeding of biomass. Wood pellets, ground wood pellets, sawdust, hog fuel, ground hog fuel and wood shavings were used in a screw feeder/lock hopper system previously employed to feed biomass to a circulating fluidized-bed gasifier. Three hopper levels (0.3, 0.45, 0.6 m), five casing configurations (common straight, tapered and extended sections) and two screws with different configurations were investigated. Experimental results showed that large particles, wide size distributions, irregular shapes, rough particle surfaces, large bulk densities and high moisture contents, as well as higher hopper levels and special casing configurations, generally led to large torque requirements for screw feeding. The "choke section" and seal plug play important roles in determining torque requirements for biomass fuels. The unique characteristics of biomass and system requirements of biomass processes create special challenges for biomass feeding. A fundamental study on a Particulate Flow Loop was also conducted to investigate the probability of blockage/bridging as a function of particle size, shape, density, hardness, flexibility and compressibility. Experimental results showed that large particle size, irregular shape, and large ratio of particle to constriction dimension can all increase the blockage tendency. Reynolds number based on water mean velocity and hydraulic diameter of duct, constriction dimensions and shape, particle density, particle hardness, flexibility and compressibility are also important factors affecting blockage probability. The present study developed a new theoretical model with consideration of compression, aimed to understand the mechanism of biomass screw feeding and to predict torque requirements to turn the screw feeder instead of being blocked. Boundaries around the bulk material within a pocket were considered, and forces acting on these surfaces were analyzed. Two parameters are employed in this model to describe stress in screw pockets in the hopper and to analyze compression in the choke section. The model extends previous models by considering effects of all boundaries on torque, and allowing for compression in the choke section. The torque requirement is approximately proportional to the vertical stress exerted on the hopper outlet by the bulk material in the hopper and to the third power of the screw diameter based on the theoretical analysis. This indicates that large screws and high feed loads require large torque. The starting torque and volumetric efficiency of screw feeding with consideration of compression in the choke section were also estimated with reasonable success based on this model. Special casing configurations (e.g. tapered and extended sections) are also considered in the model, leading to better understanding of blockage in the choke section and approximate prediction of torque requirements for screw feeders of special casing configurations. The choke section length, screw and casing configurations were closely related to plug formation and plug sealing of the reactor, while also affecting the torque requirements. The new theoretical model successfully predicted torque requirements and efficiencies for both compressible and incompressible materials for certain screw configuration. The present experiments and model are expected to be very useful for biomass utilization.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

Una alternativa al tratamiento de aguas residuales urbanas mediante lodos activos son los sistemas de biomasa granular. Las características morfológicas de la biomasa granular le confieren, principalmente, dos ventajas sobre la biomasa floculenta: (i) la habilidad de sedimentar más rápido, y (ii) la posibilidad de realizar simultáneamente procesos aerobios, anóxicos y anaerobios dentro. Dos sistemas basados en biomasa granular han demostrado potencial en el tratamiento de aguas urbanas. En primer lugar, los reactores secuenciales granulares (GSBR), donde se llevan a cabo los mismos procesos biológicos que en los sistemas de lodos activos, pero con las ventajas de la biomasa granular. En segundo lugar, un tratamiento de aguas residuales urbanas basado en tecnología anammox, el cual permitiría una depuración de aguas sin aporte o incluso productora de energía. Esta tesis busca incrementar el conocimiento de estos sistemas de biomasa granular, con el objetivo último de confirmar si la biomasa granular puede ser una alternativa real al tratamiento de aguas residuales urbanas con lodos activos. Para el tratamiento de aguas residuales urbanas con GSBRs, se realizaron dos estudios diferentes. En primer lugar, se estudió el tratamiento un agua residual de baja carga en un GSBR a escala piloto operado durante 11 meses. Se obtuvieron y mantuvieron gránulos maduros durante 5 meses. La eliminación biológica de nitrógeno fue principalmente vía nitrito. La eficacia de nitrificación fue del 75% y se obtuvo desnitrificación simultánea a la nitrificación durante las fases aerobias del GSBR. Se observó una acumulación progresiva de sales de fósforo (probablemente apatita) entre los días 150 y 300, que pudo influir negativamente en desestabilización de los gránulos al final del periodo experimental. En segundo lugar, se llevó a cabo un estudio mediante modelización matemática para determinar estrategias de control automático que permitan mejorar la eliminación biológica de nitrógeno en un GSBR. Se diseñaron simulaciones específicas para elucidar el efecto sobre la eficacia de nitrificación-desnitrificación de la concentración de oxígeno disuelto, el tamaño de gránulo, la ratio C/N del afluente y la carga volumétrica de nitrógeno. Los resultados de las simulaciones mostraron que se pueden obtener altas eficacias de eliminación de nitrógeno simplemente fijando la consigna de oxígeno disuelto apropiada. Esa consigna apropiada se puede encontrar fácilmente en función de la concentración de amonio en el efluente. Se usaron estos resultados para proponer una estrategia de control que mejorara la eficacia de eliminación de nitrógeno. Respecto al tratamiento de aguas residuales urbanas basado en tecnología anammox en un sistema de 2 etapas, se realizaron dos estudios adicionales. En el caso de la nitritación parcial, se operó un reactor granular de 2.5L trabajando en continuo, tratando un agua residual con una concentración de nitrógeno baja y a bajas temperaturas. Se obtuvo, durante más de 450 días, un efluente adecuado para alimentar un reactor anammox posterior, incluyendo más de 365 días a temperaturas iguales o menores a 15 ºC. Se usó un modelo matemático ya existente para explorar las razones que permitieron obtener nitritación parcial a temperaturas tan bajas. Finalmente, se usó la técnica de la pirosecuenciación para explorar cambios en la estructura de la comunidad microbiana de un reactor granular anammox tras un choque térmico. Tras el choque térmico, la capacidad de eliminación de amonio se redujo un 92%. Los resultados de la pirosecuenciación indicaron que la diversidad microbiana en el reactor aumentó a medida que el reactor se recuperaba del choque térmico. En general, los resultados de la pirosecuenciación fueron acordes con los resultados de eliminación de nitrógeno y con los test de actividad anammox realizados durante el proceso de recuperación. Se usó un primer anammox específico para determinar con precisión las especies anammox en el reactor.
Granular biomass has been proposed as an alternative to activated sludge for the sewage treatment. The morphological characteristics of granular biomass, provides granules two main advantages over flocular biomass: (i) the ability of settling faster, and (ii) the possibility of performing aerobic, anoxic and anaerobic processes simultaneously. Two different granular systems have a demonstrated potential for the treatment of urban wastewater. First, aerobic granular sequencing batch reactors (GSBR), which perform the same nutrient removal process occurring in activated sludge systems, but taking advantage of the abovementioned granular sludge properties. Second, an anammox-based sewage treatment, which could allow obtaining a more sustainable (energy-neutral or even energy-positive) wastewater treatment. This thesis is focused in improving the knowledge of these granular biomass systems towards confirming granular biomass as a real alternative to urban wastewater treatment with activated sludge. For urban wastewater treatment with GSBRs, two different studies were done. First, the stability of granules and their performance at pilot scale were first studied in a 100 L GSBR treating low-strength wastewater for simultaneous carbon, nitrogen and phosphorus removal was operated for eleven months. Mature granules prevailed in the GSBR during a period of five months. The biological nitrogen removal with mature granules was mainly performed via nitrite. Nitrification efficiency was higher than 75% and occurred simultaneously with denitrification during the aerobic phase of the GSBR. A progressive accumulation of P-salts (probably apatite), was found from days 150 to 300, which could enhance the destabilization of granules at the end of the experimental period. Second, a model-based study was carried out to determine the guidelines to design an automatic control strategy with the final aim of enhancing biological N-removal in a GSBR. Specific simulations were designed to elucidate the effect of DO concentration, granule size, influent C/N ratio and NLR on the nitrification-denitrification efficiency. Simulation results showed that, in general, high N-removal efficiencies (from 70 to 85 %) could be obtained only setting the appropriate DO concentration. That appropriate DO concentration could be easily found based on effluent ammonium concentration. Those results were used to propose a control strategy to enhance N-removal efficiencies. Regarding the anammox-based sewage treatment in a two-step system, two additional studies were carried out. For the partial nitritation step, a bench-scale granular sludge bioreactor was operated in continuous mode with a low nitrogen concentration wastewater at low temperatures. An effluent suitable to feed a subsequent anammox reactor was maintained stable during more than 450 days, including more than 365 days at temperatures equal or lower than 15ºC. A previously existing mathematical model was used to determine why partial nitritation was feasible. Simulations showed that NOB was only effectively repressed when their oxygen half-saturation coefficient was higher than that of AOB. Simulations also indicated that a lower specific growth rate of NOB was maintained at any point in the biofilm due to the bulk ammonium concentration imposed through the control strategy. Finally, pyrosequencing technique was used to explore the microbial community structure changes during the recovery process of an anammox granular reactor after a temperature shock. The temperatures shock reduced the nitrogen removal rate up to 92% compared to that just before the temperature shock, and it took 70 days to recover a similar nitrogen removal rate to that before the temperature shock. Pyrosequencing results indicated that microbial diversity in the reactor decreased as the reactor progressively recovered from the temperature shock. In general, pyrosequencing results were in agreement with N-removal performance results and SAA measured in the reactor during the recovery process. An anammox specific primer was used to precisely determine the anammox species in the biomass samples.

The full abstract for this thesis is available in the body of the thesis, and will be available when the embargo expires.
Applied Science, Faculty of
Civil Engineering, Department of
Graduate

Nitrogen removal from wastewater has been exstensively addressed by scientific literature in recent years; one of the most widely implemented technologies consists of the combination of partial nitritation and anaerobic ammonium oxidation (ANAMMOX). Compared to traditional nitrification and denitrification techniques such solution eliminates the requirement for an external carbon source and allows for a reduced production of excess sludge; furthermore, it brings down the costs associated to aeration by 60-90% and the emissions of CO2 by 90%. Similar techniques can turn out to be particularly interesting when stringent environmental regulations have to be met. At present, most of the dedicated research dwells on wastewater at high temperatures, high nitrogen loads and low organic content, as it is typical of sidestream effluents; this project, instead, is focused on mainstream wastewater, characterized by lower temperatures and nitrogen content, but higher COD values. At the center of the thesis is the application of a one-stage reactor treating synthetic mainstream municipal wastewater. The chosen approach consisted in maintaining low DO values, allowing for both for the establishment of a proper reaction environment and for the out-selection of nitrite oxidizers; granular biomass was employed for the experiment, aiming at effective biomass retention. The HRT value was gradually decreased, with a minimum at 6 hours. Resulting nitrogen removal rates proved to be satisfactory, with a maximum TN removal efficiency of 54%. Retention of biomass was also positively enhanced throughout the experiment, and yielded a final SRT value of 15.6 days. The whole process was then inserted into a more complete framework, accounting for possible energetic optimizations of similar treatment plants. Employing COD fractionation as a primary step paves the way for anaerobic digestion side processes, which can produce methane and ultimately provide energy for the main nitrogen removal step. Therefore, envisioning energy-sufficient water treatment processes seems a more and more feasible and realistic possibility.

La combustion de résidus de biomasse, généralement peu valorisés, pourrait apporter une solution d’approvisionnement intéressante pour la production d’énergie, allégeant la pression sur les ressources forestières. Toutefois, la composition chimique de ces résidus est à l’origine de problèmes techniques autant qu’environnementaux dans les procédés de combustion existants, ce qui limite leur utilisation. Deux de ces problèmes ont été traités dans cette thèse : les émissions de NOX et la quantité de potassium volatilisée lors de la combustion de différents résidus. Des essais de combustion ont été menés dans des réacteurs à l’échelle du laboratoire, sur des granulés de biomasse pure ou en mélange. Contrairement à la volatilisation du potassium, qui est liée à la teneur en différents éléments inorganiques, une relation linéaire forte (R² = 0,98) entre les émissions de NOX et la teneur en azote du combustible a été établie pour les granulés de biomasse pure. Des écarts par rapport à cette relation linéaire ont été observés dans le cas des essais menés sur des granulés de mélange, mettant en relief que la teneur en azote n’est pas le seul paramètre impliqué. Les travaux menés ont ainsi permis d’établir de manière originale que des synergies peuvent exister dans les granulés de mélange de résidus de biomasse, conduisant à des comportements différant de l’additivité directe des comportements des biomasses prises séparément. Ces synergies permettraient d’atténuer les problèmes causés par l’utilisation de ces résidus dans des chaudières en agissant de manière ingénieuse directement sur les propriétés des combustibles sans modification du procédé
Combustion of biomass residues, which are generally poorly valued, could provide an attractive supply solution for energy production, alleviating pressure on forest resources. However, the chemical composition of these residues is causing both technical and environmental problems in existing combustion processes, which limits their use. Two of these problems have been addressed in this thesis: the amount of volatilized potassium and NOX emissions, when burning different residues. Combustion tests have been conducted in laboratory-scale reactors on pure and mixed biomass pellets. Variations in the amount of volatilized potassium was found to be linked to the content of multiple chemical elements for pure biomass pellets. In the case of NOx emissions, a strong correlation (R² = 0.98) with the nitrogen content of the fuel was found for pure biomass pellets. However, deviations from this linear relationship were observed for trials conducted on mixed biomass pellets, highlighting that the nitrogen content is not the only parameter involved. The work carried out thus made it possible to establish in an original way that synergies can exist in the pellets made of a mixture of biomass residues, leading to beneficial behaviors differing from the direct additivity of the biomass behaviors taken separately. These synergies could allow to mitigate the problems caused by the use of these residues in boilers by ingeniously acting directly on the properties of the fuels without modification of the process

Avaliou-se a influência da carga orgânica volumétrica (COV) aplicada e do tempo de enchimento sobre a estabilidade e a eficiência do ASBR com biomassa granulada, operado em batelada e batelada alimentada seqüenciais, tratando soro de queijo diluído. Os ensaios foram realizados a 30 'graus' C com volume total de meio de 5,0 litros e tempo de ciclo de 8 horas. Na primeira etapa realizou-se a operação em batelada com tempo de enchimento ('T IND.alim') de 10 min e freqüência de agitação de 150 rpm. A cada ciclo foram alimentados 2,0 litros de meio com concentração afluente ('C IND.AF') de 1000, 2000, 4000 e 6000 mg/L, em termos de DQO. A suplementação de alcalinidade foi gradualmente otimizada partindo-se da proporção de 1 a 0,25 da razão 'NA'H'CO IND.3'/DQO. Nestas condições foi possível operar o reator com estabilidade a COV aplicada de 4,8 g/L.d , com suplementação de alcalinidade de 25% e eficiência em remoção de matéria orgânica de 96,0% e 98,4% em termos de DQO filtrada e total, respectivamente. Na segunda etapa devido a problemas operacionais desenvolveram-se dispositivos para assegurar a retenção da biomassa a fim de viabilizar a operação em batelada alimentada. Os dispositivos testados foram ASBR híbrido, sistema de agitação com 2 impelidores, hélice e pá-inclinada (a) e hélice e turbina inclinada (b). A solução utilizada foi hélice e turbina inclinada. Para essa configuração, diminuiu-se a freqüência de agitação para 75 rpm e reduziu-se o volume de biomassa para 1,0 L. Dessa forma foi possível avaliar a influência das estratégias de alimentação ('T IND.alim') de 360, 180 e 10 minutos a COV aplicada constante de 2,4 g/L.d, para 'C IND.AF' de 4000 mg/L e 'V IND.alim' de 1,0 L e para 'C IND.AF' de 8000 mg/L e 'V IND.alim' de 0,5 L. Para a 'C IND.AF' de 4000 mg/L o aumento de 'T IND.alim' resultou em diminuição da eficiência, em termos de DQO solúvel, sendo de 97,8 , 96,7 e 94,5% para os 'T IND.alim' de 10, 180 e 360 minutos, respectivamente. Para a 'C IND.AF' de 8000 mg/L o aumento do 'T IND.alim' resultou em menores valores de DQO total no efluente
The effect of volumetric organic load (VOL) and fill time on the stability and efficiency of an ASBR was assessed. The ASBR containing granular biomass was operated in batch and fed-batch mode and treated diluted cheese whey. Assays were performed at 30 'degrees' C with total medium volume of 5.0 liters and 8-h cycle lengths. In a first stage the reactor was operated batch-wise with fill time ('T IND.feed') of 10 min and agitation frequency of 150 rpm. At each cycle 2.0 liters of medium were fed at influent concentration ('C IND.infl') of 1000, 2000, 4000 and 6000 mg/L, in terms of COD. Alkalinity supplementation was gradually optimized from 100% to 25% of 'NA'H'CO IND.3'/COD ratio. At these conditions the reactor attained stability at applied VOL of 4.8 g/L.d, alkalinity supplementation of 25% and organic matter removal efficiency of 96.0% and 98.4% in terms of soluble and total COD, respectively. In a second stage due to operational problems devices were developed to assure biomass retention and hence make fed-batch operation feasible. The tested devices included hybrid ASBR, agitation system with two impellers: helix and inclined blade impeller (a) and helix and inclined turbine impeller (b). The system chosen was the helix and inclined turbine. With this configuration agitation frequency and biomass volume were reduced to 75 rpm and 1.0 L, respectively. This way, it was possible to assess feed strategies ('T IND.feed') of 360, 180 and 10 minutes at constant applied VOL of 2.4 g/L.d, for 'C IND.infl' of 4000 mg/L at 'V IND.feed' of 1.0 L and for 'C IND.infl' of 8000 mg/L at 'V IND.feed' of 0.5 L. At 'C IND.infl' of 4000 mg/L increase in 'T IND.feed' resulted in decrease in efficiency in terms of soluble COD, which amounted to 97.8, 96.7 and 94.5% for 'T IND.feed' of 10, 180 and 360 minutes, respectively. At 'C IND.infl' of 8000 mg/L the increase in 'T IND.feed' resulted in lower values for COD effluent

Em um reator de fundo redondo e volume útil de 5 L tratando esgoto sintético com carga orgânica de 800 mgDQO.'L POT.-1' com biomassa granulada a influência do tipo de escoamento e velocidade rotacional foi investigada com o uso de cinco impelidores sendo eles turbina e pá de seis pás planas verticais, turbina e pá de seis pás planas inclinadas 45 graus e hélice, comumente aplicados em processos biológicos. Foi também investigada a viabilidade de implementação de tubo de tiragem ao reator em conjunto com os impelidores tipo hélice e tipo pá de pás planas inclinadas alternadamente, com vistas a melhorar a mistura e conseqüente transferência de massa no meio reacional. Os resultados mostram que a alteração do tipo de impelidor e as variações da velocidade rotacional não exerceram influência significativa sobre a estabilidade e desempenho dos sistemas estudados. Entretanto a análise das constantes do modelo cinético de primeira ordem mostrou que a alteração na velocidade rotacional exerceu influência de aumento dos valores das constantes, demonstrando com isto que o aumento da velocidade rotacional melhora a transferência de massa sólido-líquido no meio reacional. A análise das constantes cinéticas também demonstrou que a promoção de escoamento axial em reatores agitados mecanicamente é preferível ao escoamento radial quando comparados os impelidores tipo pá de pás planas verticais e de pás planas inclinadas. A presença do tubo de tiragem demonstrou incrementar significativamente a transferência de massa, através do aumento dos valores numéricos das constantes utilizadas no ajuste do modelo cinético de primeira ordem aos valores experimentais. A potência consumida foi inferior a 1,6.'10 POT.-3' HP/'M POT.3' com rotações abaixo de 200 rpm e os impelidores axiais consumiram 75% a menos de potência do que os radiais
The effect of flow type and rotor speed were investigated in a round-bottom reactor with 5 L useful volume containing granular biomass and treating synthetic wastewater with organic load of 800 mgCOD.'L POT.-1'. Five impellers have been used to this end, namely: turbine and paddle with six-vertical-flat blade, turbine and paddle with six-45 degrees-inclined-flat-blade and helix, commonly used in biological processes. Utilization of a draft tube together with the helix and six-alternately-inclined-flat-blade impellers was also assessed as a means to improve mixing and consequently mass transfer in the reaction medium. Results showed that altering impeller type and variation in rotor speed did not exert significant effect on the stability and performance of the investigated systems. However, analysis of the first order kinetic model constants showed that alteration in rotor speed resulted in increase in the values of the constants, demonstrating that increase in rotor speed improves solid-liquid mass transfer in the reaction medium. Analysis of the kinetic constants also showed that axial flow in mechanically stirred reactors is preferable over radial flow when the vertical flat blade impeller is compared to the inclined flat blade impeller. The presence of the draft tube showed significant improvement in mass transfer, which could be seen by the increase in the values of the constants used in the fit of the first order kinetic model to the experimental values. The power consumed was less than 1.6.'10 POT.-3' HP/'M POT.3' at rotor frequency below 200 rpm and the axial impellers consumed 75% less power than the radial ones

Depuis une dizaine d'années, les procédés de granulation aérobie sont apparus comme une technologie prometteuse pour le traitement des effluents fortement chargés en azote, phosphore et carbone, tels que ceux issus de l'agro-industrie. La complexité microbienne de ces granules et les mécanismes qui leur donnent des propriétés exceptionnelles de décantation et de cohésion, constituent encore des axes de recherche importants. Dans cette thèse, le travail s'est axé sur un mécanisme encore non étudié : les processus de précipitation des phosphates au cœur des granules microbiennes. Différentes techniques d'analyses spectrales, parfois adaptés pour la première fois à ce type de systèmes, comme la spectroscopie Raman, ont permis de caractériser la nature de ces minéraux formés au cœur des granules. L'analyse menée sur des réacteurs de laboratoires a démontré la présence des phosphates de calcium sous forme d'hydroxyapatite [Ca5(PO4)3(OH)]. Cette précipitation est potentiellement induite par les variations locales de pH et de sursaturation provoqués par les réactions microbiennes à l'intérieur des granules. L'étude des phénomènes de biominéralisation à été étendu aux granules anaérobies issus des réacteurs de type UASB de l'industrie laitière. Un modèle physico-chimique sur les processus de précipitation sous forme matriciel sur AQUASIM®, couplé avec des bases de calcul de sursaturation (PHREEQC®), ont permis d'avancer des hypothèses sur les mécanismes influençant ces processus de biominéralisation, tels que la formation d'un précurseur amorphe de l'hydroxyapatite (ACP), ainsi que d'identifier les constantes de précipitation thermodynamiques (pKsp|20ºC=28.07±0.58) et cinétiques dans différentes conditions opératoires. Grâce au suivi d'un système biologique GSBR (Granular Sludge Sequenced Batch Reactor) pendant plus de 900 jours, la contribution de ce phénomène aux processus de déphosphatation a été estimé (46% dans les conditions testées). L'utilisation de ce processus pour immobiliser efficacement le phosphore et apporter des propriétés physiques stables aux granules a été également discutée. Une évaluation des performances et de la stabilité du réacteur à été mis en œuvre en alternant des cycles anoxies/aérobies ou anaérobies/aérobies vis-à-vis d'une future application industrielle. L'induction locale de la précipitation par les variations de pH et par le relargage des phosphates par les réactions microbiennes, nécessite une modélisation appropriée, qui a été également initiée dans cette thèse
Over the last decade, aerobic granulation processes have araised as a promising technology for treating wastewater effluents containing high nitrogen, phosphorus and carbon concentrations. The microbial complexity of granules and the mechanisms by which they acquire excellent settleability properties, still constitute important research goals to investigate. This thesis is focused on a mechanism that has been little addressed in literature, that is, phosphate precipitation in the core of aerobic granules. Different analytical techniques, sometimes adapted for the first time to this type of systems, like Raman spectroscopy, have let an exhaustive characterization of biominerals in the core of granules. Analyses performed on aerobic granules grown with synthetic fed in a lab-scale SBR (Sequential Batch Reactor), revealed a calcium phosphate core made of hydroxyapatite [Ca5(PO4)3(OH)]. This precipitation phenomenon is induced by local pH and supersaturation gradients issued of biological reactions inside granules. The study of the biomineralization phenomenon has been extended into anaerobic granules coming from UASB reactors at different cheese wastewater treatment plants. A physico-chemical model has been described in a form of matrix with AQUASIM® software, and coupled with a thermodynamic database (PHREEQC®), in an attempt to hypothesize the mechanisms that influence the biomineralization phenomena. It has been proposed the formation of an amorphous precursor (ACP) prior hydroxyapatite precipitation in the core of granules, suggesting the thermodynamic constant (pKsp|20ºC=28.07±0.58) and kinetic constants at different operating conditions. It has been also estimated the contribution of the biomineralization to the overall phosphorus removal process (up to 46% at the operating conditions tested), thanks to the development and study of a GSBR (Granular Sludge Batch Reactor) in labscale, for more than 900 days. The fate of the biomineralization process in granules, regarding the contribution to their stabilization and physical properties, has been also dealt in this thesis. The reactor stability and performances have been assessed by alternating anoxic/aerobic and anaerobic/aerobic cycles, in sights of a future industrial application. The induction of precipitation by local variation of pH and supersaturation issued of biological reactions has been here introduced, although it will need further investigation

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
A study was conducted to evaluate the agronomic efficiency of nitrogen fertilizer with slow-release urea, measuring their losses by volatilization of NH3-N, N2O emission and recovery of fertilizer nitrogen applied as top dressing compared with commercioal urea to corn crop. All experiments were conducted at Embrapa Agrobiology. Firstly, the experiments were performed under controlled conditions in a greenhouse using soil layer of 0-10 cm of a haplic planosol. In the first experiment, the plastic trays were used as experimental units for evaluation of losses due to volatilization chambers with the aid of semi-open static free (SALE). Commercial urea was applied (UC), urea + KCl (UK), humic acid + urea (UH), urea + zeolitic sandstone (UZ) and urea + gypsum (UG) in two conditions of pH (5.4 and 6,5). Secondly, the other experiment was conducted using plastic pots containing the same soil samples as experimental units where they were planted three plants of Brachiaria decumbens. In this case, fertilizers were enriched with 15N, in two pH conditions too (pH 5,4 and 6,5). Treatments UZ and UK were more efficient in retaining N in the soil than the UC, with smaller losses through volatilization of NH3-N, and 20,2 and 15,8% on condition of lime and 22 and 17,2% when Liming did not occur, respectively. The UK fertilizer and UG showed overall increase of about 149 and 146% on dry biomass production at the end of the cycle on condition of pH 5,4. At pH 6,5 UG fertilizer showed yield increases of 149,3%. The accumulation of N in the plant and was 279,2 and 270,3 mg N.vaso-1 when no lime was applied to the UK and UG treatments, respectively, and the limed, 207.4 and 200,6 mg N. vaso-1 for the treatments UG and UH, respectively. Treatments UZ and UK had the highest recovery of applied N by plants, with values of 65,5 and 61,9% without lime, 60,2 and 45,7% with lime, respectively. Thirdly, other experiment was conducted at the experimental field at Embrapa Agrobiology in order to quantify the PNV, N2O emissions and efficiency of nitrogen fertilizer use (NFUE) slow-release by a corn crop on N balance Treatments consisted of field application of nitrogen fertilizers in coverage along the rows and a control treatment. Emissions of N2O were evaluated using static chambers closed. Was used fertilizers enriched with 15N in little plots for the assessment of NFUE. The treatments UZ and UK reduced the losses of N-NH3 by volatilization in approximately 18 and 14%, respectively. These losses corresponded to 32,3 and 35,7% of total N applied to soil. For N2O emissions the UK treatment showed the largest emission of N2O losses reaching values of 2.02 kgN.ha-1. The highest yield of grain were obtained by treatments that UG and UZ had a better response of grain production reaching values of 9666 and 9940 kg ha-1 respectively. To NFUE treatment UZ showed the highest values of N recovered reaching 67% of the total N applied system soil plant.
O trabalho objetivou avaliar a efici?ncia agron?mica de fertilizantes nitrogenados de libera??o lenta baseados no uso da ureia, quantificando suas perdas por volatiliza??o de NNH3 (PNV), emiss?o de N2O e a recupera??o do N-fertilizante aplicado em cobertura em compara??o com a ureia comercial na cultura de milho. Todos os esperimentos foram conduzidos na Embrapa Agrobiologia. Os primeiros experimentos foram realizados em condi??es controladas em casa de vegeta??o, utilizando solo da camada de 0-10 cm de um Planossolo H?plico. No primeiro experimento foram usadas bandejas pl?sticas como unidades experimentais para avalia??o das perdas por volatiliza??o com aux?lio de c?maras semi-aberta livre est?tica (SALE). Aplicou-se ureia comercial (UC), ureia + KCl (UK), ureia + ?cido h?mico (UH), ureia +arenito zeol?tico (UZ) e ureia +gesso agr?cola (UG) em duas condi??es de pH (5,4 e 6,5). O outro experimento utilizou vasos pl?sticos contendo amostras do mesmo solo como unidades experimentais onde foram plantados 3 plantas de Brachiaria decumbens. Neste caso os fertilizantes foram enriquecidos com 15N, tamb?m em duas condi??es de pH (pH 5,4 e 6,5). Os tratamentos UZ e UK foram mais eficientes na reten??o do N no solo do que a UC, apresentando menores perdas por volatiliza??o de N-NH3 de 20,2 e 15,8% sob condi??o de calagem e 22 e 17,2% quando sem calagem, respectivamente. Os fertilizantes UK e UG apresentaram aumento total de aproximadamente 149 e 146% na produ??o de biomassa seca ao final do ciclo da cultura em condi??o de pH 5,4. Em pH 6,5 o fertilizante UG apresentou aumento de rendimento de 149,3%. O ac?mulo de N na planta foi de 279,2 e 270,3 mg N.vaso-1 quando n?o foi aplicado calagem para os tratamentos UK e UG, respectivamente e quando com calagem, 207,4 e 200,6 mg N.vaso-1 para os tratamentos UG e UH, respectivamente. Os tratamentos UZ e UK apresentaram maior recupera??o pelas plantas do N aplicado, com valores de 65,5 e 61,9% sem calagem e 60,2 e 45,7% com calagem, respectivamente. O outro experimento foi realizado no campo na ?rea experimental da Embrapa Agrobiologia com objetivo de quantificar as perdas por volatilza??o de am?nio, as emiss?es de N2O e a efici?ncia do uso de fertilizantes nitrogenados (EUFN) de libera??o lenta pela cultura de milho, no balan?o de N. Os tratamentos consistiram da aplica??o no campo em cobertura dos fertilizantes nitrogenados ao lado da linha de plantio e um tratamento controle. As emiss?es de N2O foram avaliadas utilizando-se c?maras est?ticas fechadas. Foi utilizado fertilizantes enriquecidos com 15N em microparcelas para a avalia??o da EUFN. Os tratamentos UZ e UK reduziram as perdas de N-NH3 por volatiliza??o em aproximadamente 18 e 14%, respectivamente. Estas perdas corresponderam a 32,3 e 35,7% do total de N aplicado no solo. Para as emiss?es de N2O o tratamento UK foi o que apresentou maiores perdas por emiss?o de N2O atingindo valores de 2,02 kg N.ha-1. As maiores produtividades de gr?o foram obtidas pelos tratamentos UG e UZ que apresentaram melhor resposta de produ??o de gr?os atingindo valores de 9.666 e 9.940 kg.ha-1, respectivamente. Para EUFN o tratamento UZ apresentou o maior valor de N recuperado chegando a 67% do total do N aplicado no sistema solo-planta.

La gazéification étagée est une technologie innovante pour la production d’énergie renouvelable de petite et moyenne puissances, pour laquelle l'élargissement de la gamme de biomasses utilisables constitue un enjeu majeur de développement. Cette thèse porte spécifiquement sur la pyrolyse oxydante en lit fixe, première étape clé du procédé, qui conditionne fortement la performance et la fiabilité de cette technologie. Trois types de biomasses – pin, miscanthus, et paille – conditionnées sous forme de granulés ont été étudiés. Une étude expérimentale a été réalisée sur un réacteur pilote à lit fixe de 20 cm de diamètre et 1.6 m de hauteur permettant de reproduire des conditions opératoires proches de celles rencontrées durant l'étape de pyrolyse dans les gazéifieurs industriels. Le fonctionnement du procédé pour les trois biomasses a été caractérisé par la mesure du ratio air/biomasse, des températures, des rendements en charbon, gaz permanents et condensables et de leurs compositions. Une attention particulière a été portée à la zone d'oxydation qui se propage verticalement vers le haut dans le lit de biomasse. Une méthodologie a été développée pour mesurer la vitesse de propagation, l'épaisseur et le tassement de cette zone et étudier l'impact de la nature de la biomasse. Dans un lit de granulés de bois, la vitesse et l'épaisseur de la zone d'oxydation est 25 % plus faible que dans un lit de granulés de paille ou miscanthus. L'effet catalytique des matières minérales sur les réactions de pyrolyse primaire et secondaire et son impact sur le fonctionnement du procédé, ont également été mis en évidence
Staged gasification is an innovative technology for small and medium renewable energy production. The expansion of the range of usable biomass remains a major obstacle to development. This thesis focuses specifically on the oxidative pyrolysis in a fixed bed, the first step of the process that strongly influences the performance and reliability of this technology. Three types of biomass- pine, miscanthus and wheat straw - in form of pellets were studied. An experimental study was carried out in a pilot fixed bed reactor of 20 cm diameter and 1.6 m height allowing the reproduction of similar conditions to those existing in the pyrolysis step of an industrial gasifier. The process operation for the three biomasses was characterized by measuring the air/biomass ratio, bed temperature, yields and compositions of char, permanent gases and condensates. A particular attention was paid on the oxidation zone which propagates upward towards the raw biomass. A method was developed to measure the propagation velocity, thickness and the compaction of the oxidation zone and to study the impact of the biomass nature. Velocity and thickness of this zone were 25 % lower in a fixed bed of wood pellets than in beds of wheat straw or miscanthus. Catalytic effect of the mineral matters on primary and secondary pyrolysis reactions and their impact on the process operation have been highlighted

O presente projeto avaliou um reator anaeróbio operado em batelada e batelada alimentada seqüenciais (ASBR), em ciclos de 8 horas, utilizando biomassa granulada e agitação mecânica em um draft-tube, alimentado com água residuária sintética (500 mgDQO/L), contendo sulfato em diferentes relações DQO/[\'SO IND.4\' POT.2-\']. Em todos os ensaios o reator apresentou uma operação estável, produzindo alcalinidade e com concentração de ácidos voláteis totais em níveis adequados. Para os tempos de alimentação de 10 min, 3 h e 6 h, respectivamente, as eficiências de remoção de sulfato foram de 30, 72 e 72% nas operações nas quais o reator foi alimentado com uma relação DQO/[\'SO IND.4\'POT.2-\'] de 1,34. Nos ensaios nos quais o reator foi alimentado na relação DQO/[\'SO IND.4\'POT. 2-\'] de 0,67, as eficiências para a redução de sulfato foram de 25, 58 e 55%, respectivamente. Na operação com relação DQO/[\'SO IND.4\'POT.2-\'] de 0,34, as eficiências para redução de sulfato foram de 23, 37 e 27%, respectivamente. Desta maneira, pode-se concluir que as operações em batelada alimentada favoreceram a remoção de sulfato, enquanto foi observado que nas operações em batelada a remoção de matéria orgânica atingiu melhores eficiências.
This present work evaluate an anaerobic sequencing batch reactor (ASBR), fed in batch and fed-batch, and cycles of 8 hours, using granulated biomass and mechanical stirring in a draft-tube, fed with synthetic wastewater (500 mgCOD/L), enriched with sulfate in some COD/[\'SO IND.4\'POT.2-\'] relations. In all operations the reactor showed a stable operation, producing alkalinity and maintaining the volatile acids in adequate levels. Considering the fed periods of 10 min, 3 h and 6 h, respectively, the removal efficiencies of the sulfate was 30, 72 e 72%, in the operations when the reactor was fed with a COD/[\'SO IND.4\'POT.2-\'] relation of 1,34. In the essays when the reactor was fed in COD/[\'SO IND.4\'POT.2-\'] relation of 0,67, the efficiencies of the sulfate reduction was 25, 58 e 55%, respectively. When the reactor was operated with COD/[\'SO IND.4\'POT.2-\'] relation of 0,34, the efficiencies of sulfate reduction 23, 37 e 27%, respectively. Thus, is possible to conclude that the operations in fed-batch increased the efficiency of sulfate removal, at what time was observed that in batch operations the organic matter removal attained improved efficiencies.

Dans le cadre du projet ANR AGATCO (Advance GAz Turbine for COgeneration) qui a débuté fin 2012, la conception d’un micro-cogénérateur aux granulés de bois permettant de produire 1,5 kW électrique et 10 kW thermique a été entrepris et est présentée dans ce manuscrit. Basé sur la technologie d’une turbine à air chaud à combustion externe, ce micro-cogénérateur utilise la combustion des granulés couplés à un échangeur de chaleur et une micro-turbine. La technologie demande la conception d’un nouveau foyer (brûleur et chambre de combustion) adapté pour la production de fumées à haute température (1200°C). Le défi est grand car le débit de fumées souhaité est important (27g/s) et la puissance de combustible est faible (15kW). Deux solutions sont proposées pour répondre à la problématique, la première utilise de l’air frais à température ambiante et la deuxième utilise le recyclage des fumées chaudes. La haute température des fumées permet d’obtenir une température d’entrée turbine de 1100°C après le transfert de chaleur dans l’échangeur. La caractérisation expérimentale et par simulation numérique de l’échangeur permet de vérifier ses performances. La micro-turbine utilise une technologie nouvelle de canaux hélicoïdaux à la place d’aubes qui lui permettent d’avoir des dimensions faibles pour les performances souhaitées. Les travaux effectués ont permis de mettre en valeur plusieurs résultats : la réalisation de la combustion haute température dans des conditions fortement défavorables, les performances très intéressantes de l’échangeur de chaleur tous en proposant des améliorations pour optimiser les échanges et les améliorations à apporter à la turbine
As part of the AGATCO ANR project (Turbine Advance GAz for cogeneration), which began at the end of 2012, the design of a micro-cogeneration generating 1.5 kW of electricity and 10 kW of heat was started and presented in this manuscript. Based on the technology of an externally fired gas turbine, this micro-CHP uses the combustion of pellets coupled to a heat exchanger and a micro-turbine. This technology requires the design of a new fireplace (burner and combustion chamber) suitable to produce fumes at high temperatures (1200°C). The challenge is significant because the desired smoke flow is important (27 g/s) and the fuel power is low (15 kW). Two solutions are proposed to solve the problem, the first uses fresh air at ambient temperature and the second uses recycled hot fumes. The high temperature of the fumes makes it possible to obtain a turbine inlet temperature of 1100°C after the transfer of heat into the exchanger. Experimental and numerical simulation characterization of the exchanger makes it possible to verify its performances. The micro-turbine uses a new technology using channel instead of blades allowing it to have small dimensions for the desired performance. The work carried out made it possible to highlight several results: the realization of the high temperature combustion in very unfavorable conditions, the very interesting performances of the heat exchanger while proposing improvements to optimize the exchanges and the improvements to be brought to the turbine

O presente trabalho teve por objetivo avaliar a eficiência de remoção do surfactante aniônico alquilbenzeno linear sulfonado (LAS) em reator anaeróbio de leito granular expandido - EGSB (1,5 litros) com recirculação e alimentação com meio mineral. Além de caracterizar filogeneticamente a diversidade de bactérias na presença do surfactante. O sistema foi operado em condição mesofílica em 4 etapas: (I), (II) e (IV) com TDH de 32 horas, e (III) com TDH de 26 horas. Em todas as etapas a DQO foi em média de 609 \'+ OU -\' 137 mg/L e 14 \'+ OU -\' 1,71 mg/L de LAS afluente. As maiores remoções de LAS foram verificada nas etapas II e IV, com valores de 73,6 \'+ OU -\' 5,6% e 63,6 \'+ OU -\' 6,17%, respectivamente de. Na etapa III essa remoção foi de 47,8 \'+ OU -\' 6,2%. Por meio do balanço de massa constatou-se que 56,6% do total de LAS adicionado foram removidos compreendendo 48,4% por biodegradação e 8,2% por adsorção. A remoção de matéria orgânica não foi afetada com a adição do LAS e nem pela exposição prolongada a esse surfactante. Entretanto, a estrutura do grânulo foi comprometida quando da adição do surfactante, observado pelo aumento da concentração de sólidos totais efluente de 0,049 g/L na etapa I (sem LAS), 0,128 g/L na etapa II, 0,064 g/L na etapa III e 0,038 g/L na etapa IV, quando da adição de 14 \'+ OU -\' 1,71 mg LAS/L. Além disso, foi notada diminuição do diâmetro médio dos grânulos no decorrer da operação do reator de 0,36 cm nas etapas I e III para 0,34 cm na etapa IV. Por meio da técnica de tubos múltiplos (NMP) foi constatado aumento das bactérias anaeróbias totais e diminuição das arqueias metanogênicas, em função do tempo de operação do reator. As bactérias redutoras de ferro representaram 8% da biomassa anaeróbia na etapa IV. Por meio do seqüenciamento da região 16S do RNAr para o domínio Bacteria da biomassa da extremidade superior do reator e da biomassa do leito, foi verificado semelhança com os seguintes filos Proteobacteria, Firmicutes e Synergistetes. Notou-se diferença significativa entre as bibliotecas de clones para essas duas amostras.
This study aimed to evaluate the efficiency of removal of linear alkylbenzene sulfonate (LAS) in expanded bed reactor (1.5 liters) using granular sludge (EGSB) with recirculation and feed with mineral medium modified. The system was operated at mesophilic condition in four stages: (I) (II) and (IV) with HRT of 32 hours, and (III) with HRT of 26 hours. At all stages the COD averaged 609 \'+ OR -\' 137 mg/L and 14 \'+ OR -\' 1.71 mg/L LAS influent. The higher removals of LAS were found in stages II and IV, respectively, 73.6 \'+ OR -\' 5.6% and 63.6 \'+ OR -\' 6.17%. In stage III this removal was 47.8 \'+ OR -\' 6.2%. Through mass balance was found that 56.6% of total LAS added were removed by biodegradation comprising 48.4% and 8.2% by adsorption. The organic matter removal was not affected by the addition of LAS and not by prolonged exposure to this surfactant. However, the granule structure was compromised after the addition of surfactant, the observed increase in effluent total solids concentration of 0.049 g/L in stage I (no LAS), 0.128 g/L in stage II, 0.064 g/L in stage III and 0.038 g/L in stage IV when adding 14 \'+ OR -\' 1.71 mg/L. Furthermore, it was noticed significant decrease in mean diameter of the granules during the operation of the reactor of 0.36 cm in stages I and III to 0.34 cm in stage IV. Through the multiple tube method (MPN) was found to increase the total anaerobic bacteria and methanogenic archaea decreased depending on the time of reactor operation. Iron-reducing bacteria accounted for 8% of anaerobic bacteria total in step IV. By sequencing the 16S rRNA for the domain Bacteria biomass from the upper end of the reactor and the biomass of the bed, was found similar to the following phyla Proteobacteria, Firmicutes and Synergistetes. Significant difference was noted between the clone libraries for these two samples.

O uso de reatores de biomassa imobilizada para tratamento de esgoto tem se difundido devido a sua capacidade de manter o tempo de retenção celular (TRC) elevado, mesmo quando operados com baixo tempo de detenção hidráulica (TDH). Neste trabalho, investigou-se o desempenho de dois reatores anaeróbios horizontais de leito fixo (RAHLF) em escala de bancada, usados no tratamento do efluente de uma indústria de refrigerantes, sendo um dos reatores preenchido com grânulos e o outro com espuma de poliuretano. A pesquisa foi dividida em três etapas, referentes aos tempos de detenção hidráulica (TDH) de, respectivamente, 20 h, 10 h e 5 h. O encerramento de cada etapa ocorria quando se verificava a estabilidade operacional do sistema através dos parâmetros: DQO, ácidos voláteis totais e pH. Ao final de cada etapa, foram obtidos os perfis de concentração de DQO ao longo dos reatores. Para TDH de 10 h, os valores obtidos para a constante cinética aparente (klapp) foram de 0,694 h-1, para o reator com grânulos, e de 0,467 h-1, para o reator preenchido com espuma de poliuretano. No decorrer da pesquisa, os reatores apresentaram alguns problemas operacionais, que aumentaram à medida em que se reduzia o TDH. Avaliou-se, também, o tempo de residência real do reator com espumas através de experimentos hidrodinâmicos (traçadores). Ao final do experimento, foram quantificados os sólidos voláteis em cada reator e buscou-se diferenciar o arranjo e a fauna microbiológica, presentes nos dois tipos de imobilização, através de microscopia eletrônica de varredura (MEV).
Immobilized biomass reactors have been increasingly used for wastewater treatment due to their capacity of maintaining high cellular retention time (CRT) even when operating at low hydraulic detention time (HDT). In this work, the performances of two horizontal-flow anaerobic immobilized biomass (HAIB) bench-scale reactors treating soft drinks industry effluents were investigated and compared. One of the reactors was filled with granules and the other one with polyurethane foam matrices. The research was conducted in three stages, concerning to hydraulic detention times of, respectively, 20 h, 10 h and 5 h. A stage was considered finished when reactors operational stability was checked by means of COD, total volatile fatty acids and pH. COD profiles were obtained along the reactors at the end of each stage. In the second stage, when HDT was equal to 10 h, the apparent kinetic constant (klapp) values were 0.694 h-1, to the reactor filled with grains, and 0.467 h-1, to the other one. During the research, the reactors showed some operational problems, that increased when the HDT was reduced. The real hydraulic detention time (HDT) reactor with polyurethane foams was evaluated through the hydrodynamic experiments (tracers). Volatile solids of each reactor were quantified at the end of experiment. The arrangement and microbiological fauna inside the reactors were determined by Scanning Electron Microscopy (SEM).

Thesis (Ph. D.)--Georgia State University, 2006.
Title from title screen. George E. Pierce,committee chair; Eric S. Gilbert, Sidney A. Crow, committee members. Electronic text (135 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Aug. 20, 2007. Includes bibliographical references (p. 120-124).

Obiettivo principale di questa tesi di dottorato è stata la valutazione dell'applicabilità della tecnologia a biomasse granulari per il trattamento di reflui suinicoli, come valida alternativa rispetto ai convenzionali sistemi a fanghi attivi. La ricerca si è concentrata sulla valutazione delle condizioni operative maggiormente vantaggiose per la coltivazione dei granuli aerobici e sulla valutazione dell'effetto inibitorio di antibiotici veterinari comunemente presenti all'interno di reflui suinicoli su due specifici consorzi granulari: i batteri ANAMMOX e i granuli aerobici. The main objective of this thesis was the evaluation of the suitability of granular sludge technology as an economically feasible alternative to conventional activated sludge for the treatment of swine wastewaters. The research mainly focused on the evaluation of the most advantageous operating conditions to improve aerobic granules formation and long-term stability, and on the assessment of the inhibitory effect of veterinary antibiotics commonly present in these kind of wastes on two specific granular consortia: the anammox biomass and the aerobic granules.

Dissertação de Mestrado em Química apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
Atualmente, grande parte dos sistemas de tratamento implementados em Portugal baseiam-se em sistemas de lamas ativadas convencionais com biomassa suspensa e cujas configurações mais comuns são do tipo fluxo pistão, mistura completa e sequencing batch reactor. O avanço tecnológico tem desenvolvido um grande leque de novos sistemas de tratamento que se tornam menos dispendiosos, quer em fase de construção como em fase de exploração. Entre estes, encontram-se os reatores biológicos de biomassa granular do tipo sequencing batch reactor, conhecidos como granular sequencing bacth reactor. Estes já se encontram implementados à escala real e já são bem conhecidas as suas vantagens relativamente aos sistemas de lamas ativadas convencionais, nomeadamente no que respeita aos custos de investimento inicial (espaço requerido) e aos custos de exploração (energia elétrica requerida). Algumas estações de tratamento de água residual em Portugal já se encontram a operar segundo este tipo de tratamento, outras ainda se encontram em fase de projeto. Todavia, os fatores intrínsecos ao crescimento e à formação da biomassa granular não se encontram explícitos na literatura associada. Assim, este estudo focou-se na avaliação da influência de dois parâmetros na formação de grânulos de biomassa: distintos substratos (água residual e efluente sintético de acetato de sódio) e velocidade superficial do ar. A estratégia de controlo processual do reator do tipo de bancada incluiu a análise da carga orgânica aplicada, índice volumétrico de lamas, razão alimento/microrganismo e taxa de consumo de oxigénio específica, verificando fatores operacionais como pH, temperatura e oxigénio dissolvido. Para a avaliação da eficiência de remoção dos diferentes poluentes foram monitorizados com a devida frequência a carência química de oxigénio, carência bioquímica de oxigénio a 5 dias, Azoto Total, Amónia, Nitratos e Fósforo Total do efluente bruto e do efluente tratado. Constatou-se que a utilização de efluente sintético de acetato de sódio como fonte de carbono e o aumento da velocidade superficial do ar potenciou o desenvolvimento de pellets micelares, uma estrutura inicial da formação de grânulos aeróbios.

Tese de mestrado em Tecnologia do Ambiente.
O objectivo desta tese foi a caracterização de biomassa anaeróbia granular utilizando técnicas de análise quantitativa de imagem, de visualização em microscópio electrónico de varrimento, de identificação microbiana com sondas genéticas e de visualização usando técnicas histológicas. A análise quantitativa de imagem foi aplicada a biomassa granular proveniente de dois reactores do tipo manto de lamas. Num dos reactores tentava-se seguir um protocolo experimental que conduzisse à formação de grânulos e noutro reactor, devido ao tipo de substrato alimentado (ácido oleico), os grânulos previamente inoculados sofreram um processo de desgranulação. Os objectivos específicos do presente trabalho foram: (i) definir o protocolo de amostragem da biomassa no reactor de granulação, de modo a preservar a estrutura dos agregrados formados em todas as etapas do processo. (ii) definir o melhor método de aquisição da Imagem, de modo a obter a melhor e maior informação durante as etapas dos processos, (iii) quantificar e minimizar erros devido a processos de diluição das amostras. (iv) demonstrar a utilidade e mais valia de técnicas de análise quantitativa de imagem para monitorização dum processo de granulação e dum processo de desgranulação de consórcios microbianos anaeróbios, nomeadamente na medição da área projectada dos agregados, dos filamentos livres e do número relativo de partículas de pequenas, intermédias e grandes dimensões. A amostragem da biomassa do reactor foi optimizada, tendo-se construído uma sonda que se introduzia pelo topo do reactor e que permitia aspirar uma amostra preservando a integridade dos agregados. O estudo do efeito da diluição na quantificação dos parâmetros morfológicos e de tamanho atrás definidos permitiu concluir que para diluições elevadas há sistematicamente uma sobrestimação de todos os parâmetros e que a diluição óptima depende não só da concentração inicial de biomassa, mas também do seu estado de agregação e provavelmente da sua estrutura. Na definição da diluição óptima em cada um dos estudos realizados, recorreu-se a um parâmetro definido como percentagem de reconhecimento que mede a razão entre os objectos integralmente visualizados numa imagem e todos os objectos, incluindo os que se encontram na fronteira da mesma. A aplicação da análise de imagem a um processo de desgranulação permitiu quantificaras alterações de tamanho ao longo do processo e obter uma boa correlação linear entre parâmetros de análise de imagem tal como área de finos/área total (sendo os finos definidos como partículas com diâmetro inferior a 1 mm) e parâmetros baseados numa selecção física de tamanho e na análise dos sólidos. A aplicação da análise de imagem a um processo de granulação permitiu também quantificar as alterações de tamanho e morfológicas ocorridas nos agregados microbianos durante o processo Mediu-se a área média dos agregados e a área média de três fracções de tamanho de agregados definidas do seguinte modo: pequenos, entre 100 e 1000 μm² de área, correspondendo a um diâmetro equivalente entre 11.3 e 35.8 μm, intermédios, entre 1000 e 20000 μm² de área, correspondendo a um diâmetro equivalente entre 35.8 e 159.6 μm e grandes, superiores a 20000 μm² de área, correspondendo a um diâmetro equivalente superior a 159.6 μm. O número e o comprimento médio de filamentos livres também foram determinados para cada amostra analisada. A microscopia electrónica de varrimento permitiu avaliar a morfologia bacteriana do exterior dos agregados que se formaram durante o processo de granulação, verificando as principais alterações ao longo do mesmo. Observaram-se bactérias filamentosas semelhantes ao género Methanosaeta e agregados de cocos. Observaram-se também os agregados que se encontravam em fase de desgranulação. A aplicação de técnicas de hibridização com sondas genéticas à identificação de grupos de organismos nos grânulos em formação, permitiu dar uma informação meramente qualitativa. Os resultados obtidos são muito preliminares e utilizaram-se apenas duas sondas específicas de grandes grupos (ARC915 — para aqueobactérias e EUB338 para bactérias). Por fim, tentou-se uma abordagem de técnicas histológicas para localizar a presença de ácidos gordos de cadeia longa adsorvidos em agregados de biomassa anaeróbia. Utilizaram-se dois corantes, negro de Sudão e óleo vermelho e pelos resultados obtidos que são também preliminares pareceu que o óleo vermelho permitia obter melhores imagens.
The aim of this work was to characterize anaerobic granular sludge by using quantitative image analysis techniques, scanning electron microscope observations, fluorescent in-situ hibridization (FISH) and histological techniques. Quantitative image analysis was applied to granular sludge from two sludge blanket reactors (an Upflow Anaerobic Sludge Blanket - UASB and an Expanded Granular Sludge Bed — EGSB). The UASB reactor was set to produce granular sludge from a completely dispersed inoculum. In the other reactor and due to the substrate fed (oleic acid) the previously inoculated granular sludge suffered a process of disintegration. The specific aim of this part of the work was: (i) to define the best protocol to withdraw the biomass from the granulation reactor preserving its structure during all the process. (ii) to define the best way of image acquisition, in order to get the highest quality and quantity of information. (iii) to quantify and to minimize the errors due to the diluition processes. (iv) to demonstrate the usefulness of quantitative image analysis for monitoring processes of granulation and granules disaggregation, namely by measuring the projected area, the free filaments and the relative number of small, medium and big particles. Biomass sampling was optimized. A special device was constructed that allowed a sample to be taken from the reactor, preserving the integrity of the aggregates. The effect of the diluition on size and morphological parameters quantification led to the conclusion that for high diluitions, there is an overestimation of all parameters. Furthermore, the optimal diluition depends not only on the initial biomass concentration, but also on the size of the aggregates and possibly on they structure. Optimal diluition was defined by using a parameter denominated percentage of recognition that measures the ratio between the objects that are completely inside the image and all the objects, including those that are in the frontiers. The application of mage analysis to a process of granules disintegration allowed the quantification of size changes along the process. A good linear correlation was obtained between image analysis parameters such as fine area/total area (fines were defined as particles with a diameter smaller than 1 mm) and parameters based on a physical separation and solids determination. The application of image analysis to a process of granulation allowed the quantification of size and morphology along the process. The average area of the aggregates was measured as well as the average area of three ranges of size, defined as: small aggregates between 100 e 1000 mμ² of area, corresponding to equivalent diameters between 11.3 e 35.8 μm, medium aggregates, between 1000 e 20000 μm² of area, corresponding to equivalent diameters between 35 8 and 159.6 μm and big aggregates larger than 20000 μm² of area, corresponding to equivalent diameters higher than 159.6 μm². The number and the average length of the free filaments were also measured for each sample. Scanning Electron Microscopy (SEM) allowed the observation of the bacterial morphology during the process of granulation. Organisms similar to the genera Methanosaeta and Methanococus were observed. The disaggregated granules were also observed by SEM. The application of FISH techniques for the identification of groups of microorganisms in the granular sludge allowed only qualitative information. Preliminary results were obtained by using only two genetic probes (ARC915 for archaebacteria and EUB338 for bactéria). The last technique used was based on histological techniques and the aim was to localize long chain fatty acids adsorved onto anaerobic granular sludge. Two dyes were used: sudan black and red oil and by the preliminary obtained results, the oil red was better for that purpose.

Tese de doutoramento em Engenharia Química e Biológica
Nesta tese foi operado um reator descontínuo sequencial, inoculado com AGS (SBR-AGS) proveniente de um sistema granular à escala real, para o tratamento de água residual sintética, primeiramente sem qualquer adição de fármaco e posteriormente adicionando os estrogénios 17β- estradiol (E2) e 17α-etinilestradiol (EE2) e o antibiótico sulfametoxazol (SMX). Foram ainda desenvolvidas e otimizadas novas metodologias de amostragem e separação das frações baseadas no conteúdo em sólidos suspensos, de aquisição em microscopia de campo claro e em lupa binocular, para a fração de flocos e grânulos, respetivamente, assim como os necessários programas de processamento e análise quantitativa de imagens (QIA). Foram ainda aplicadas diferentes técnicas quimiométricas, incluindo a regressão linear múltipla (MLR), análise de componentes principais (PCA), árvores de decisão (DT) e análise discriminante (DA) aos dados relativos à estrutura e morfologia da biomassa, assim como aos parâmetros operacionais do reator. O sistema de SBR-AGS, após um processo de maturação da biomassa aeróbia, apresentou um claro predomínio da fração granular sobre a fração flocular, caracterizado por uma predominância de grânulos de elevado tamanho (superiores a 2.5 mm em diâmetro), robustos, estruturalmente estáveis e com uma boa sedimentabilidade. Adicionalmente verificou-se o predomínio da fração orgânica nos agregados, face à inorgânica, não tendo sido verificados fenómenos de bulking no sistema. A aplicação de PCA aos dados obtidos permitiu isolar claramente os clusters correspondentes aos períodos operacionais com a biomassa madura e com a adição dos diferentes fármacos e identificar as principais correlações entre os parâmetros estudados. No tocante à previsão por MLR dos sólidos suspensos (totais – TSS e voláteis – VSS) de ambas as frações, da densidade da biomassa e do índice volumétrico de lamas, foram obtidos resultados promissores. A aplicação de DA e DT aos dados obtidos permitiu distinguir, com sucesso, os diferentes períodos operacionais e identificar as amostras contendo PhACs.
In this thesis, a laboratory scale sequencing batch reactor (SBR) inoculated with AGS from a fullscale WWTP was operated for the treatment of a synthetic wastewater, first in the absence of PhACs and later in the presence of the 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) steroid estrogens and the sulfamethoxazole (SMX) sulphonamide antibiotic. New methodologies for sampling and biomass granular and floccular fractions separation, based on the suspended solids content, as well as bright field and stereomicroscopy monitoring and image acquisition, were also developed and optimized, as well as the necessary quantitative image analysis (QIA) routines. In order to best comprehend the collected data, different chemometric tools were also applied, including multilinear regression (MLR), principal component analysis (PCA), discriminant analysis (DA) and decision trees (DT) to the morphological and structural parameters of the biomass and the main operational parameters of the SBR. The SBR-AGS system, after a maturation process of the aerobic biomass, showed a clear predominance of the granular fraction over the floccular one, characterized by a predominance of granules of large size (larger than 2.5 mm in diameter), robust, structurally stable and with good settling properties. Additionally, there was a predominance of the organic fraction in the aggregates, compared to the inorganic one, with no bulking phenomena being observed in the system. The performed PCA allowed to clearly isolate the clusters corresponding to the experimental periods with mature AGS and E2, EE2 and SMX addition, and enlighten the studied parameters interrelationships.Regarding the MLR forecast of both fractions total (TSS) and volatile (VSS) suspended solids, biomass density and sludge volumetric index, promising results were obtained. Besides, the application of DA and DT allowed to identify the different operational periods, and successfully classify the samples in the presence and in absence of the PhAC.
The work presented in this thesis was financially supported by a doctoral advanced training (call NORTE-69-2015-15) funded by the European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.

The widespread occurrence of various types of emerging contaminants (ECs) has become an issue of high concern. Among ECs, pharmaceuticals and its metabolites deserve particular attention as their presence, continuous release and persistence in water bodies pose serious health issues affecting the entire ecosystem. It is important to understand the biodegradation of such molecules to devise strategies to avoid dispersal of these ECs in the environment. The work described in this thesis aimed at investigating of the microbial degradation of two pharmaceutical compounds, carbamazepine (CBZ) and diclofenac (DCF). On a first approach, selective enrichments using activated sludge from a municipal wastewater treatment plant (WWTP) were established for each pharmaceutical. One strain able to degrade DCF (strain Brevibacterium sp. D4) and two strains able to degrade CBZ (strains Starkeya sp. C11 and Rhizobium sp. C12) were isolated and their ability to biodegrade the pharmaceutical compounds supplied as a sole carbon source and with periodic feedings with acetate was assessed in batch cultures. Strain Brevibacterium sp. D4 was able to biodegrade ca. 35% of 10 mg L-1 of DCF supplied as a sole carbon source in 30 days. Supplementation with acetate enhanced biodegradation to ca. 90%. Both strains were able to degrade ca. 30% of 10 mg L-1 CBZ in 30 days, with no improvement in the presence of a supplementary carbon source. On a second approach, the biodegradation of each pharmaceutical compound by the bacterial strain Labrys portucalensis F11 was investigated. This strain was selected due to its ability to biodegrade recalcitrant compounds, including pharmaceuticals. CBZ biodegradation by strain F11 was assessed with the pharmaceutical supplied as sole carbon source, with ca 95% biotransformation of 10 mg L-1 CBZ achieved in 30 days. The supplementation with acetate led to complete CBZ biotransformation at a faster rate. Biotransformation of CBZ by strain F11 resulted in of 14 intermediary metabolites detected and identified using Ultra-high Performance Liquid Chromatography-Quadrupole Time-Of-Flight Mass Spectrometry (UPLC-QTOF/MS/MS), which enabled the proposition of a biotransformation pathway. The toxicity of untreated and treated CBZ solutions was investigated using Vibrio Fischeri and Lepidium sativum acute toxicity tests and Toxi-Chromo Test. At concentrations ranging from 0.5 to 10 mg L-1 only Vibrio Fischeri was moderately affected by the presence of CBZ and/or its degradations products. DCF was supplied to strain F11 cultures as a sole carbon source at concentrations ranging from 0.5 to 10.0 mg L-1 and a biotransformation extent of ca 70% of DCF was achieved in 30 days, for the highest concentration. Supplementation with acetate resulted in complete degradation of 0.5 mg L-1 of DCF in 6 days and 10.0 mg L-1 of DCF in 25 days. Stoichiometric liberation of chlorine was observed. The identification of biodegradation intermediates was performed. A possible degradation pathway was proposed based on the chemical structure of 12 metabolites identified by UPLC-QTOF/MS/MS. The stoichiometric liberation of chlorine and the lack of detection of metabolites at the end of the experiments indicated complete degradation of DCF by strain F11. An aerobic granular sludge sequencing batch reactor (AGS-SBR), established using activated sludge from a WWTP and bioaugmented with strain F11, was used for the treatment of an aqueous stream containing DCF. Overall, the bioreactor main biological processes, such as Chemical Oxygen Demand (COD), nitrogen and phosphorous removal were not affected by the addition of DCF in the feeding stream at 10.0 mg L-1. Even though the AGS-SBR was not able to remove DCF, it was robust to maintain its main biological functions throughout the 286 days at different operational conditions. Along bioreactor operation, microbial community dynamics was monitored. Eleven bacterial culturable isolates were retrieved and tested for DCF biodegradation; the highest degradation obtained was of ca. 34% of 10.0 mg L-1 DCF supplied as a sole carbon source. The AGS displayed a diverse bacterial community, with visible changes along operation. Strain F11 was present throughout the entire reactor operation, as demonstrated by sequencing of bands excised from Denaturing Gradient Gel Electrophoresis of extracted DNA. DCF biodegradation capability of the AGS was tested in batch mode with periodic feedings with acetate, resulting in ca. 72% removal of 10.0 mg L-1 DCF removal. The higher degradation extent of AGS compared to the degradation obtained by the retrieved isolates suggested that strain F11 was contributing to the process.
A ocorrência de vários tipos de contaminantes emergentes (CEs) tornou-se um assunto de grande preocupação. Entre os CEs, os fármacos e os seus metabolitos merecem particular atenção, dado que a sua presença, liberação contínua e persistência nos ambientes aquáticos apresenta sérios problemas de saúde afetando todo o ecossistema. É crucial entender a biodegradação deste tipo de moléculas para planear estratégias para evitar a a sua dispersão no ambiente. O trabalho descrito nesta tese teve como objetivo a investigação da degradação microbiana de dois fármacos, carbamazepina (CBZ) e diclofenac (DCF). Numa primeira abordagem, foram estabelecidos enriquecimentos seletivos para cada fármaco usando lamas ativadas de uma estação de tratamento de águas residuais (ETAR). Uma estirpe capaz de degradar DCF (Brevibacterium sp. D4) e duas estirpes capazes de degradar CBZ (Starkeya sp. C11 e Rhizobium sp. C12) foram isoladas e a sua capacidade de biodegradar os compostos farmacêuticos suplementados como única fonte de carbono e com alimentação periódica com acetato foi avaliada em culturas líquidas. A estirpe Brevibacterium sp. D4 foi capaz de biodegradar ca. 35% de 10 mg L-1 of DCF, alimentada como fonte única de carbono em 30 dias. A suplementação com acetato aumentou a biodegradação ca. 90%. Ambas as estirpes foram capazes de degradar 30% de 10% L-1 de CBZ em 30 dias, sem melhoria na biodegradação com uma fonte suplementar de carbono. Numa segunda abordagem, a biodegradação de cada composto farmacêutico pela estirpe bacteriana Labrys portucalensis F11 foi investigada. Esta estirpe foi selecionada devido à sua capacidade de biodegradar compostos recalcitrantes, incluindo fármacos. A biodegradação da CBZ 10 mg L-1 de CBZ pela estirpe F11 foi de ca 95% em 30 dias. A suplementação com acetato resultou na completa biotransformação com uma taxa mais rápida. A biodegradação da CBZ pela estirpe F11 leva à produção de intermediários, tendo sido detetados e identificados 14 metabolitos intermediários usando Ultra-high Performance Liquid Chromatography-Quadrupole Time-Of-Flight Mass Spectrometry (UPLC-QTOF/MS/MS), permitindo propor uma via de biotransformação. A toxicidade de soluções de CBZ não tratadas e tratadas foi investigada usando testes de toxicidade aguda Vibrio Fischeri e Lepidium sativum e o Toxi-Chromo Test. A concentrações entre 0.5 e 10 mg L-1 apenas Vibrio Fischeri foi moderadamente afetado pela presença de CBZ e/ou seus produtos de degradação. O DCF foi alimentado às culturas de F11 como uma única fonte de carbono a concentrações entre 0.5 to 10.0 mg L-1 e a biotransformação de ca 70% de DCF foi alcançada em 30 dias, para a concentração mais elevada. A suplementação com acetato resultou na completa degradação de 0.5 mg L-1 de DCF em 6 dias e de 10.0 mg L-1 de DCF em 25 dias. Foi observada liberação estequiométrica de cloreto. A identificação dos intermediários de biodegradação foi realizada. Uma possível via de degradação foi proposta com base na estrutura de 12 metabolitos identificados por (UPLC-QTOF/MS/MS). A libertação estequiométrica de cloreto e a não deteção de metabolitos no final das experiências, indicou a degradação completa do DCF pela estirpe F11. Um reator granular sequencial descontinuo de grânulos aeróbios (AGS-SBR) foi estabelecido a partir de lamas ativadas de uma ETAR e bioaumentado com a estirpe F11, e foi usado para o tratamento de um influente sintético contendo DCF. No geral, os principais processos biológicos, como remoção de carência química de oxigénio (CQO), e de nutrientes, azoto e fósforo, não foram afetados pela adição de DCF no fluxo de entrada a 10 mg L-1. Embora o AGS-SBR não tenha sido capaz de remover o DCF, mostrou-se robusto para manter as principais funções biológicas ao longo de 286 dias com diferentes condições testadas. Ao longo da operação, a dinâmica da comunidade microbiana foi monitorizada. Onze isolados bacterianos cultiváveis foram recuperados e testados para a biodegradação do DCF; a maior taxa de degradação obtida foi ca 34% de 10 mg L-1 DCF como única fonte de carbono. O AGS-SBR apresentou uma comunidade bacteriana diversificada, com alterações visíveis nas diferentes condições testadas. A estirpe F11 manteve-se presente durante toda a operação do reator, como demonstrado por sequenciação das bandas excisadas a partir do Gel de Eletroforese em Gradiente Desnaturante. A biodegradação de DCF pelos grânulos aeróbios foi testada em batch com alimentações periódicas com acetato, resultando em ca. 72% de remoção de 10.0 mg L-1 de DCF. A maior extensão de degradação dos grânulos comparativamente com a degradação obtida pelos isolados sugere que a estirpe F11 contribuiu para o processo.

The first part of the graduation thesis deals with renewable resources, utilization possibilities of biomass and plant phytomass. The most common sources from which phytomass is obtained, are also mentioned here. A great deal of attention is paid to selected energetic plants included into the experiment. It is Sorrel Rumex OK-2 (Rumex tianschanicus x Rumex patientia) and Poppy seed (Papaver Somniferum). Further there are summarized the processes necessary for separating and pressing of biomass into granules for direct combustion. Within the research, two-year experience of growing sorrel stand is described. On the basis of performed technological operations in the stand, energy demands of growing are calculated. The real usage of energy at the production of one tonne of granules is measured. When labour costs are taken into account I can say that the expenses for the production of one tonne of briquettes from biomass would be 4 592 CZK, which is a non-competitive sum.

Tese de Doutoramento em Engenharia Química e Biológica
Os principais objectivos desta tese são: Desenvolver estratégias de engenharia de sistemas para a supervisão e controlo de processos combinados de tratamento biológico de efluentes; projectar e construir uma pequena instalação à escala laboratorial, para tratamento de um efluente sintético representativo de um efluente real processado em ETAR; desenvolver um sistema de tratamento integrado para remoção de matéria orgânica e azoto, utilizando biomassa anaeróbia para o processo de desnitrificação; desenvolver regras empíricas, relacionadas com a operação da instalação e com os processos biológicos integrados de remoção de carbono e azoto, para implementação de um sistema inteligente baseado em lógica difusa para diagnóstico e controlo do tratamento integrado. Foi concebida uma instalação à escala laboratorial para tratamento de um efluente sintético representativo de um efluente real processado em ETAR. O tratamento biológico do efluente é efectuado em três etapas principais: o processo anaeróbio onde a matéria orgânica é degradada e transformada em biogás, o processo de desnitrificação para remoção de azoto, usando o carbono remanescente do processo anaeróbio e o processo de nitrificação. Estes processos ocorrerem respectivamente no reactor anaeróbio, no reactor anóxico e no reactor arejado. Os reactores, anaeróbio e anóxico, são do tipo UASB (Uflow Anaerobic Sludge Blanket), com um volume útil de 8.5 L, e são inoculados com biomassa anaeróbia granular. O tratamento de nitrificação ocorre num reactor de lamas activadas com arejamento e agitação. É apresentado um sistema pericial supervisor baseado em regras de lógica difusa desenvolvido para controlo dos processos biotecnológicos em estudo, para remoção integrada de carbono e azoto. As regras desenvolvidas em lógica difusa foram integradas no sistema supervisor, analisando o estado do processo e tomando decisões sobre melhores comandos. Foi aplicada uma sobrecarga de azoto na instalação para testar o sistema pericial desenvolvido, de 20 a 60 mg N/L durante um período de experiência de 73 horas. As variáveis manipuladas (caudal de desvio e de reciclo) foram automaticamente alteradas, quando as novas condições de operação foram reconhecidas pelo sistema pericial. Foi obtida uma eficiência de desnitrificação superior a 85% 30 horas após a aplicação da perturbação e 15 horas após a resposta do sistema, com um TRH de apenas 1.5 hora. A eficiência de nitrificação aumentou gradualmente de 12 para 50% a um TRH de 3 horas. Foi também aplicada uma diminuição brusca na concentração de azoto à entrada para testar a resposta do sistema pericial de controlo baseado em lógica difusa a esta perturbação. O sistema pericial respondeu à perturbação num período de 5 horas tendo provado reagir correctamente no sentido de estabelecer condições de operação que permitam recuperar atempadamente as eficiências de remoção de azoto e carbono. O sistema de análise sequencial desenvolvido neste trabalho, para análise do azoto amoniacal numa gama de 0.5 ppm a 40 ppm apresentou vantagens importantes para aplicação em processos em contínuo, quando comparado com o método convencional, nomeadamente a menor quantidade de amostra e reagentes necessários, facilidade de adaptação do método a novas gamas de concentrações e facilidade e simplicidade de manuseamento do equipamento. A actividade metanogénica específica da biomassa granular na presença de acetato, H2/CO2, propionato, butirato e etanol como substratos individuais foi estudada na presença de nitrato numa gama de concentrações de 5 a 500 mgN-NO3.L-1. Para todos os substratos, a redução da actividade metanogénica específica foi mais acentuada do que esperado, considerando um modelo simples de competição pelo substrato entre sintróficas/metanogénicas e desnitrificantes, provavelmente devido à inibição pelo nitrato ou por intermediários da desnitrificação, como nitrito e óxidos nitrosos. As incubações sucessivas efectuadas para verificar a adaptabilidade da biomassa granular anaeróbia ao nitrato na presença de acetato (1920 mg CQO/L) e nitrato (300 mgN-NO3.L-1) mostraram que a biomassa granular anaeróbia apresenta capacidade de aumentar a produção de azoto gasoso, sendo portanto possível a aclimatização a condições de desnitrificação. Foi desenvolvido um sistema de controlo baseado em lógica difusa para controlar a desnitrificação no modelo BSM1, implementado no controlo do Simulation Benchmark. Os resultados foram comparados com a estratégia PID implementada. O controlador baseado em lógica difusa, apresentou-se vantajoso relativamente ao controlador PID, nomeadamente no que diz respeito à percentagem de tempo de operação em que os limites estabelecidos para as variáveis no efluente final são excedidos.
The main objectives of this thesis are: to develop strategies of systems engineering for the supervision and control of combined processes of biological treatment of effluent; to design and construct a lab-scale plant, for synthetic effluent treatment representative of an real effluent processed in wastewater treatment plant; to develop an integrated biological process treatment for removal of carbon and nitrogen, using anaerobic biomass for the denitrification process; to develop empirical rules, related with the lab-scale plant operation and the integrated biological process treatment for removal of carbon and nitrogen, for implementation of a fuzzy logic based intelligent system for diagnosis and control of the integrated treatment. A lab-scale plant for synthetic effluent treatment representative of a real effluent processed in WWTP, was developed. The biological treatment is processed in three main stages: the anaerobic process, where the organic substance is degraded and transformed into biogas; the denitrification process for nitrogen removal using the remaining carbon from the anaerobic reactor and the nitrification process. These processes occur respectively in the anaerobic reactor, in the anoxic reactor and in the activate sludge tank. Anaerobic and anoxic reactors are sludge bed reactors, with 8 L and 8.5 L, inoculated with granular anaerobic sludge. Nitrification occurs in an activated sludge tank. A supervisory expert system based on fuzzy logic rules developed for diagnosis and control of a lab- scale plant comprising anaerobic/anoxic/aerobic modules for combined high rate biological nitrogen and carbon removal is presented. The fuzzy logic rules were integrated in the supervisory system analyzing the state of the process and taking decisions on better commands. A step increase in ammonia concentration from 20 to 60 mg N/L was applied during a trial period of 73 hours. The manipulated variables (recycle flow and by-pass flow) automatically changed, when new plant conditions were recognized by the expert system. Denitrification efficiency higher than 85% was achieved 30 hours after the disturbance and 15 hours after the system response at an HRT as low as 1.5 hours. Nitrification efficiency gradually increased from 12 to 50% at an HRT of 3 hours. A reduction in the nitrogen concentration was also applied to test the fuzzy logic based control system response to this disturbance. The system proved to properly react in order to set adequate operating conditions that timely led to recover efficient N and C removal rates. The sequential injection analysis (SIA) system developed in this work for ammonium determination in a range of 0.5 ppm to 40 ppm of N-NH4 + presents several advantages namely the low reagent and sample which is very important in continuous processes, facility in adaptation the method to other analytical ranges, easy to manipulate and the simplicity and robustness characteristics of the system. This system can be easily adapted to an on-line analysis which is very important when a process control is need. The specific methanogenic activity (SMA) of granular sludge with acetate, H2/CO2, propionate, butyrate and ethanol, as individual substrates, was assessed in the presence of nitrate concentrations in the range 5 to 500 mgN-NO3.L-1. For all the tested substrates, the reduction of SMA was more acute than expected, considering a simple model of substrate competition between syntrophs/methanogens and denitrifiers, likely due to inhibition by nitrate of by denitrification intermediates, such as nitrite and nitrous oxides. Sequential batch assays with four repeated incubations of anaerobic granular sludge in the presence of acetate (1920 mg COD/L) and nitrate (300 mg N-NO3-/L), showed that anaerobic sludge was able to produce increasing amounts of dinitrogen gas, and therefore could be acclimated to denitrifying conditions. A fuzzy logic based control system was developed to control the denitrification process in model BSM1, implemented in the control of the Simulation Benchmark. The results were compared with implemented PID strategy. The controller based on fuzzy logic, presented itself relatively advantageous to controller PID, namely in respect to the percentage of running time where the limits established for the variables in the effluent are exceeded.
Ministério da Ciência e Tecnologia - PRAXIS XXI (SFRH/BD/1299/2000).