Orientador: Tsunao Matsumoto / Co-orientador: Lilizane Lazzarini Albertin / Banca: Dib Gebara / Banca: Miguel Mansur Aisse / Resumo: A pesquisa utilizou um Reator Aeróbio de Leito Fluidizado com Circulação (RALFC) como dispositivo de pós-tratamento do efluente de um Reator UASB Compartimentado (RUC) o qual tratou esgoto sanitário. O RUC foi constituído de 4 tubos de PVC, de diferentes diâmetros, dispostos de forma concêntrica e o RALFC por dois tubos de PVC, de diâmetros diferentes e concêntricos, e uma unidade de sedimentação na parte superior. A pesquisa foi dividida em partida e quatro fases distintas, denominadas fase 1A, 1B, 2A e 2B, nas quais foram variados os parâmetros de operação, como vazão de ar, vazão de efluentes, tempo de detenção hidráulica (TDH) e carga orgânica volumétrica (COV). De modo que durante a pesquisa foi constatado que a melhor fase de tratamento foi quando o RALFC operou com TDH de 4,7 horas e vazão de ar de 300 L/h. O sistema, nessa fase, apresentou um valor médio de DQO efluente de 55 mg/L, a partir de um valor bruto de 607 mg/L em média, gerando uma remoção total de 90%. Os parâmetros de controle como alcalinidade, pH, temperatura e ácidos orgânicos voláteis sempre estivaram dentro das recomendações da literatura, demonstrando uma baixa oscilação. Mesmo assim o sistema não apresentou bom desempenho na remoção de nutrientes, tendo em sua melhor fase de tratamento um efluente com 31 mg/L em média de nitrogênio total, a partir de um valor de entrada de 50 mg/L sendo que a maior parte desse nitrogênio foi removido durante a passagem pelo RUC. Por outro lado para o fósforo, os valores foram de 25 mg/L na entrada e no efluente 14 mg/L, do mesmo modo como ocorreu ao nitrogênio, a maior parte da remoção de fósforo foi realizada pelo RUC / Abstract: The study used an aerobic fluidized bed reactor with circulation (RALFC) as the effluent post-treatment device of a UASB reactor Compartmented (RUC) which treated wastewater. The RUC was consisted of 4 PVC tubes of different diameters arranged concentrically and RALFC two PVC tubes of different diameters and concentric, and a sedimentation unit in the upper part. The research was divided into four distinct phases and starting, called Phase 1A, 1B, 2A and 2B, in which were various operating parameters such as air flow, flow of wastewater, hydraulic retention time (HRT) and volumetric organic load (VOC). So that during the research it was found that the best treatment phase was when the RALFC operated with HRT of 4.7 hours and air flow of 300 L / h. The system, at this stage, had an average effluent COD value of 55 mg/L, from the affluent valor of 607 mg/L on average, there by generating a complete removal of 90%. The control parameters as alkalinity, pH, temperature and volatile organic acids have always been within the recommended by the literature, demonstrating a low oscillation. Even so, the system hasn't showed good performance in the removal of nutrients, in their best treatment stage an effluent with 31 mg/L on average total nitrogen from an input value of 50 mg/L. The most part of nitrogen removal was during passage through the RUC. As for the phosphorus values were 25 mg/L in the effluent input and 14 mg/L, in the same as was the nitrogen, the majority of phosphorus removal was performed by RUC / Mestre

Orientador: Tsunao Matsumoto / Co-orientador: Liliane Lazzari Albertin / Banca: Milton Dall Aglio Sobrinho / Banca: Katia Sakihama Ventura / Resumo: A aplicação de reatores anaeróbios, como é o caso dos reatores UASB (Upflow Anaerobic Sludge Blanket), passou a ocupar uma posição de destaque, principalmente no Brasil, face às condições ambientais de temperatura favoráveis, baixo custo, simplicidade operacional e baixa produção de sólidos. Dentre os sistemas anaeróbios, tem-se também o Reator Anaeróbio Compartimentado (RAC), um tipo de reator com configuração simples, com divisões internas que buscam separar os tipos de microrganismos da digestão anaeróbia. No presente trabalho estudou-se o comportamento do sistema Reator UASB Compartimentado (RUC), operando com carregamento orgânico volumétrico (COV) em diferentes variações. A melhor condição operacional, relativa à remoção de carga orgânica, foi conseguida quando o RUC foi operado com uma COV de 1,30kgDQO/m3.d (Fase IV), quando apresentou uma média e desvio padrão da eficiência de remoção de DQO de 82,7±7,7% e de DBO de 78,3±3,5%. Quando operando com a maior COV de todas as fases (fase III - 2,17kgDQO/m3.d) apresentou a segunda melhor eficiência de remoção de carga orgânica, com uma média e desvio padrão da eficiência de remoção da DQO de 74,2±8,8% e da DBO de 76,9±8,2%. Com a COV de 1,70kgDQO/m3.d a média e desvio padrão da eficiência de remoção da DQO e DBO foram de 74,2±8,8% e 69,1±6,8%, respectivamente. E com a COV de 0,78kgDQO/m3.d, a média e o desvio padrão da eficiência de remoção de DQO e de DBO foram de 68,9±11% e 69,7±15,7%, respectivamente. Uma desvantagem verificada no RUC foi o arraste de lodo ocasionado pelo aumento da COV, que afetou as características finais do efluente, mas não alteraram significativamente a sua eficiência de remoção da carga orgânica / Abstract: The application of anaerobic reactors, such as the UASB (Upflow Anaerobic Sludge Blanket), has come to occupy a prominent position, especially in Brazil, given the favorable environmental conditions such as temperature, low cost, operational simplicity and low production of sludge. Among the anaerobic systems, there is also the Anaerobic Baffled Reactor (ABR), a type of reactor with simple configuration, with internal divisions that seek to separate the types of microorganisms in anaerobic digestion. Thus, the present work studied the behavior of Compartmented UASB Reactor (CUR), operating with variable volumetric organic loading (VOL). The best operating condition on the removal of organic load was achieved when the CUR was operated with a VOL 1.30kgCOD/m3.day (Phase IV), the CUR had 82.7±7.7% of COD removal efficiency (average and standard deviation) and BOD were 78.3±3.5%. When operating at higher VOL (Phase III - 2.17kgCOD/m3.day) showed the second best organic load removal efficiency with average and standard deviation of the COD removal efficiency of 74.2±8.8% and 76.9±8.2 BOD%. With the VOL 1.70kgCOD/m3d average and standard deviation da the removal efficiency of COD and BOD were 74.2±8.8% and 69.1±6.8%, respectively. And the VOL 0.78kgDQO/m3.day, the average and standard deviation of the COD removal efficiency of BOD and were 68.9±11% and 69.7±15.7%, respectively. A disadvantage found in the CUR was drag sludge resulting from increased VOL, which affected the final characteristics of the effluent, but not significantly modified its removal efficiency of organic load / Mestre

Buscando compreender o comportamento hidrodinâmico de um reator anaeróbio de fluxo ascendente (UASB), o presente trabalho teve por objetivo desenvolver um modelo numérico utilizando ferramentas de Fluidodinâmica Computacional (CFD) para a simulação do comportamento do escoamento trifásico (líquido, gás e sólido) em um reator UASB utilizado na produção de biogás a partir da vinhaça, e validar este modelo utilizando técnicas de Velocimetria de Partículas por Imagem (PIV). Para tanto, inicialmente foi projetado o reator UASB e em seguida foram desenvolvidas a geometria e a malha. As simulações foram executadas no software Fluent, utilizando uma malha com 528.000 volumes de controle. Foram inicialmente realizadas simulações do escoamento monofásico do líquido e em seguida simulações bifásicas gás/líquido e sólido/líquido foram realizadas adotando-se uma abordagem Euleriana-Euleriana, isotérmica, transiente e tridimensional. Por fim, os modelos bifásicos já validados foram associados em um modelo trifásicos. Técnicas de PIV foram utilizadas na validação dos modelos bifásicos e do trifásico. Na etapa de validação dos modelos numéricos, foi verificada uma diferença máxima entre resultados experimentais e computacionais menor de 4% para todos os casos. Foi verificado que a força de arraste é a que exerce a maior influência no perfil do escoamento gás/líquido. Com relação ao escoamento sólido/líquido, o modelo de Gidaspow foi escolhido para o cálculo do coeficiente de arraste, após comparação com resultados experimentais. Nas simulações trifásicas, verificou-se o gás foi o principal responsável pela qualidade da mistura dentro do reator, reduzindo de 44% o percentual de zonas mortas no reator no caso sólido/líquido para 0,02% no caso trifásico e aumentando em cerca de oito vezes a magnitude da velocidade das fases sólida e líquida. O sistema de distribuição de gás exerceu forte influência no perfil do escoamento, tendo induzido recirculação interna no reator. A compreensão do escoamento permitirá otimizações no processo e no reator de forma a buscar o aumento da eficiência de tratamento bem como da geração de biogás. / PETROBRAS, Brasil. / Aiming to understand the hydrodynamics of a Upflow Anaerobic Sludge Blanket (UASB) reactor, this work aimed to apply multiphase modeling through computational fluid dynamics (CFD) to assess the behavior of the three phase flow (liquid, gas and solid) in a UASB reactor, which is used in the biogas production using vinasse as substrate and the to validate the results using Particle Image Velocimetry (PIV) techniques. Therefore, the UASB reactor was designed and then the geometry and mesh were developed. The simulations were performed using the software Fluent and a mesh with 528.000 control volumes. Initially, monophasic simulations of the liquid phase were carried out. Next, two phase simulations were performed considering the pairs of phases gas/liquid and solid/liquid. An Eulerian-Eulerian approach was adopted, together with isothermal, transient and tridimensional conditions. After validated, the two-phase models (solid/liquid and gas/liquid) were combined into a three-phase model. PIV was used for the experimental validation of the two and three-phase models. The numerical model validation showed maximum differences lower than 4% between experimental and computational results for the three cases (gas/liquid, solid/liquid and liquid/gas/solid). Numerical results showed that the drag force plays the major role on the gas/liquid flow profile. Regarding the solid/liquid flow, Gidaspow model was chosen to estimate the drag force coefficient after comparisons between numerical and experimental results. Three-phase simulations showed that the gas was the main responsible for the mixing quality within the reactor. Dead zones were reduced from 44% in the solid/liquid simulations to 0,02% in the three-phase simulations and the liquid and solid velocity magnitude increased in about eight times. The configuration of the gas distribution system played a major role on the overall flow profile and drove liquid recirculation along the axial position. Understanding the multiphase flow within this reactor will allow optimizations on the process as well as on the reactor, in order to seek an increase on the efficiency both in the treatment and biogas in the production.

Este trabalho apresenta e discute os resultados obtidos na operação de um reator anaeróbico com manta de lodo (UASB) de 10,5 L, alimentado continuamente com substrato sintético (DQO = 2000 mg/L) e submetido ao aumento progressivo da concentração de sulfato (de 25 a 10000 mg \'SO IND.4\'POT.2-\'/L). A vazão de 16 L/dia, corresponde ao tempo de detenção hidráulico (e) de 15,6 h foi mantida constante durante os 10 meses do experimento. O monitoramento da operação do reator incluiu a determinação dos principais parâmetros do processo, visando detectar a inibição da metanogênese pelas bactérias redutoras de sulfato (BRS) que competem, com as metanogênicas, pelos mesmos substratos. Constatou-se estimulação do processo até a concentração de 400 mg \'SO IND.4\'POT.2-\'/L, a partir da qual ocorreram sequencias de quedas de eficiência seguidas de recuperação do reator, mantendo sempre a eficiência média de remoção de DQO acima de 80%. Embora a atividade metanogênica tenha sido parcialmente afetada, os balanços de \'SO IND.4\'POT.2-\' mostraram que a redução do sulfato não foi o principal responsável pela inibição ocorrida. / This thesis presents and discuss the results obtained during the operation of a 10.5 L upflow sludge blanket reactor, continuously fed with synthetic substrate (COD = 2,000 mg/L), which was subjected to step-increase of sulfate concentrations ranging from 25 to 10,000 mg \'SO IND.4\'POT.2-\'/L. The flow-rate of 16 L/d corresponding to a hydraulic detention of 15.6 h, was kept constant throughout the 10 months of experimentation. Operation monitoring included the determination of the main process parameters, aiming to detected the inhibition of lhe methanogenesis by the sulfate reducing bacteria (SRB) which autocompete the methanogens in the presence of common substrates. Stimulation effects were obseved up to the sulfate concentration of the 400 mg.\'SO IND.4\'POT.2-\'/L. Further on, sequences of falls of efficiency followed by restoration of the reactor performance defined the behavior pattern of the reactor, which maintained an average COD removal efficiency higher than 80%. Although the methanogenic activity has been parcially affected, \'SO IND.4\'POT2-\' balances showed that the sulfate reduction activity was not the main process responsible for such inhibition.

Das Interesse an der Biogastechnologie in der Landwirtschaft bezüglich der Vergärung von Feststoffen stieg insbesondere mit der Novellierung des Erneuerbare-Energien-Gesetzes (EEG) im Jahr 2004 deutlich an. In diesem wurde unter anderen das Ziel verankert, den Anteil erneuerbarer Energien an der Stromversorgung in Deutschland deutlich zu erhöhen. Biomasse hat das Potential einen deutlichen höheren Beitrag zur Deckung der Energieversorgung zu leisten als bisher. Dieses Potential kann durch verschiedenste Verfahren nutzbar gemacht werden, wozu auch die anaerobe Fermentation von Biomasse zu energiereichem Biogas zählt. Die derzeit in konventionellen Anlagen größtenteils eingesetzten Rührkesselreaktoren sind nur begrenzt für Reststoffe aus der Landwirtschaft geeignet, da sich ihr Durchmischungsaufwand mit der Feststoffzufuhr deutlich erhöht. Ziel der vorliegenden Arbeit war es, das Substrat Pferdemist auf Strohbasis in einem für die Feststofffermentation entwickelten Verfahren, dem Aufstromverfahren, zu erproben. Dazu wurde der Einfluss von zwei Betriebssystemen und von zwei Temperaturniveaus unter Erhöhung der Raumbelastung auf den Fermentationsprozess überprüft. Des Weiteren wurde die überaus wichtige Fragestellung nach der Generierung klimarelevanter Gase (N2O, CH4, CO2) bei der Lagerung von Gärresten in unterschiedlichen Behandlungsformen untersucht. Mesophile Vergärung im Aufstromverfahren Das kontinuierlich betriebene, undurchmischte Aufstromverfahren ist durch seine Funktionsweise besonders für die Vergärung von Feststoffen geeignet. Dieses beruht auf dem Dichteunterschied zwischen den organischen Feststoffpartikeln und der Prozessflüssigkeit. Die abzubauenden Feststoffpartikel steigen aufgrund einer geringeren Dichte und durch Anlagerung von Gasbläschen im Reaktor auf, worauf sich der Name des Verfahrens und des Reaktors, des Aufstromfeststoffreaktors (AFR) bezieht. In diesem zweiphasigen System aus fester und flüssiger Phase, wird die Prozessflüssigkeit durch den Feststoffpropfen geleitet, wobei gelöste Intermediate abtransportiert werden. Die Flüssigkeit wird beim 1-stufigen System dem AFR wieder zugeführt. Bei dem 2-stufigen System wird der AFR durch einen Festbettreaktor (FBR) erweitert, welcher mit Aufwuchsträgern befüllt ist und in welchem die gelösten Intermediate abgebaut werden. Der erste Teilbereich dieser Arbeit beschäftigte sich mit der generellen Erprobung des Aufstromverfahrens mit dem Substrat Pferdemist bei mesophilen Temperaturen (37°C). Dazu wurden beide Betriebssysteme eingesetzt und die Raumbelastung der Reaktoren stufenweisen erhöht. Das im Prozess entstehende Biogas wurde auf sein Volumen sowie auf die Zusammensetzung überprüft und auf Normbedingungen korrigiert. Im Verlauf des Versuches, welcher bei einer Raumbelastung von 2,5 g organischer Trockensubstanz pro Liter Reaktorvolumen und Tag (goTS L-1 d-1) begann und auf 4,5 goTS L-1 d-1 erhöht wurde, wurden die Menge an zugeführtem Substrat analog erhöht. Die täglich ermittelten Methan-Produktionsraten zeigten einen signifikanten Anstieg (P<0,05) mit jeder Erhöhung der Raumbelastungsstufe. Ein Unterschied zwischen dem 1- und 2-stufigen System konnte nicht ermittelt werden. Schlussfolgernd zeigen die Ergebnisse, dass das Aufstromverfahren für die Vergärung von Pferdemist auf Strohbasis bei mesophilen Temperaturen durchaus geeignet ist und dass das 2-stufige Verfahren gegenüber dem 1-stufigen Verfahren bei den getesteten Raumbelastungen keinen Vorteil brachte. Thermophile Vergärung im Aufstromverfahren Ein weiterer Bestandteil dieser Arbeit war es, den Einfluss von thermophilen Temperaturen auf den Biogasprozess zu testen. Dazu wurde der Versuchsaufbau beider Betriebssysteme übernommen und die Reaktoren auf 55°C geheizt. Die Raumbelastung wurde ebenfalls stufenweise von 2,5 auf 5,5 goTS L-1 d-1 erhöht. Die produzierte Menge an Biogas sowie dessen Zusammensetzung wurde täglich ermittelt und auf Normbedingungen korrigiert. Wie auch im mesophilen Versuch verzeichneten die Methan-Produktionsraten einen signifikanten Anstieg (P<0,05) mit der Erhöhung der Raumbelastung bei beiden Betriebssystemen. Das 2-stufige Verfahren erreichte dabei nahezu gleich hohe Methanraten wie das 1-stufige. Der Vergleich der Methanraten zwischen dem mesophilen und thermophilen Durchgang verdeutlicht, dass diese durch die Erhöhung der Betriebstemperaturen hochsignifikant (P<0,0001) um 58,1% gesteigert werden konnte. Die Teilversuche haben gezeigt, dass es möglich ist Pferdemist und Stroh kontinuierlich im Aufstromverfahren bei mesophilen und thermophilen Temperaturen zu vergären. Den größten Einfluss auf die Methan-Produktion nahmen dabei die Raumbelastung und die Temperatur ein. Die Erweiterung durch einen Festbettreaktor im 2-stufigen Aufbau führte bei den geprüften Raumbelastungen zu keinen Vorteilen gegenüber dem 1-stufigen System. Effekt der Gärrest-Stabilisierung auf Treibhausgasemissionen während der Lagerung Eine weitere Problemstellung dieser Arbeit war die Ermittlung von treibhaus- und klimarelevanten Emissionen bei der Lagerung von Gärresten. Bei der Vergärung von Biomasse entsteht ein Anteil an Gärrest, welcher beim Prozess nicht abgebaut werden kann. Der Anteil ist abhängig von der Zusammensetzung des eingesetzten Substrats. Der durch den Einsatz von Pferdemist und Weizenstroh generierte Gärrest wurde in einer weiteren Untersuchung über 30 Tage in gasdichten Behältern gelagert und dessen Emissionen untersucht. Die eingesetzten Varianten wurden zuvor bei 60°C und verschiedenen Haltezeiten (6h, 12h, 24h) thermisch stabilisiert. Des Weiteren wurde unbehandelter Gärrest als Kontrolle getestet und jeweils eine Charge mit den Additiven Biokohle und Zeolith versetzt. Innerhalb der 30 Tage Lagerdauer wurden stündlich aus jeder Lagertonne Gasproben genommen und auf folgende Gase untersucht: NH3, CH4, N2O, CO2 und H2O. Die thermische Stabilisierung des Gärrests durch 24 h Trocknung bei 60°C erreichte die größte Minderung bei den gemessenen Treibhausgasen. Alle anderen Varianten (6- und 12h Trocknung, Zugabe von Biokohle und Zeolith) reduzierten die auftretenden Emissionen im Gegensatz zum unbehandelten Gärrest ebenfalls. Die Zugabe von Zeolith und Biokohle zeigte sich besser geeignet für die Kurzzeit-Lagerung der Gärreste (10-20 Tage). Die thermische Stabilisierung zeigte insgesamt den größten Minderungseffekt, solange die benötigte Wärme für die Trocknung aus dem eigentlichen Biogasprozess gedeckt werden kann. Die Untersuchung hat gezeigt, dass das Substrat Pferdemist für die Produktion von Biogas in höchstem Maße geeignet ist. Beim Einsatz in Aufstromfeststoffreaktoren konnten keine prozesstechnischen Probleme festgestellt werden, sodass sich das Betriebssystem als geeignet herausstellte. Da das Verfahren derzeit noch keine Anwendung in der Praxis findet, ist die Erforschung zur Vergärung von Pferdemist und der Gärrestbehandlung unter Praxisbedingungen essentiell.

Please read the abstract in the dissertation. Copyright / Dissertation (MEng)--University of Pretoria, 2011. / Chemical Engineering / unrestricted

Thesis (PhD (Food Science))--University of Stellenbosch, 2009. / In the absence of anaerobic granules, anaerobically digested sewage sludge is frequently used to seed industrial upflow anaerobic sludge blanket (UASB) reactors. Because of its flocculent nature, start-up with digested sludge instead of granular sludge proceeds much slower and presents various operational problems. Any manner in which the granulation of digested sludge can be enhanced would benefit UASB reactor start-up and application in developing countries such as South Africa. The main objective of this dissertation was to improve granulation and reduce UASB reactor start-up by using pre-treated digested sludge as seed. The sludge was pre-treated based on the batch granulation-enhancement model of Britz et al. (2002). The main aim of the model was to improve extracellular polymer (ECP) production of lactate-utilising populations by applying short-term controlled organic overloading in a mechanically agitated environment. The batch granulation-enhancement (pre-treatment) process was applied to an ECP-producing digester strain, Propionibacterium jensenii S1. Non-methanogenic aggregates were formed when batch units were incubated on a roller-table instead of a linear-shake platform. Larger, more stable aggregates were obtained in the presence of apricot effluent medium. Preliminary batch granulation-enhancement studies confirmed that using the roller-table as mixing system had a positive influence on batch granulation-enhancement. The roller-table showed the most potential for handling larger volumes in comparison to a linear-shake waterbath and linear-shake platform. The addition of 450 mg.L-1 Fe2+ at the start of the study also influenced aggregate numbers positively. These studies revealed that pre-treatment results varied depending on the seed sludge source. A denaturing gradient gel electrophoresis (DGGE) method was applied for the detection of Archaea in digested sludges and UASB granules. In addition, a methanogenic marker containing methanogens important to the granulation process was constructed to aid identification. The positive influence of DMSO and “touchdown” PCR on the elimination of artifactual double bands in DGGE fingerprints were also demonstrated. Results revealed that only one of the four digested sludges tested contained Methanosaeta concilii (critical to granular nuclei formation) while it was present in all the UASB granules regardless of substrate type. Four digested sludges were obtained from stable secondary digesters. DGGE indicated the presence of M. concilii in all sludges. The Athlone 4Sb-sludge was the only sludge which exhibited measurable methanogenic activity during substrate dependent activity testing. The ST-sludge showed the highest increase in volatile suspended solids (VSS) particles ≥0.25 mm2. Laboratory-scale UASB reactor start-up was done with both sludges and start-up proceeded better in the Athlone 4Sb-reactor. Athlone 4Sb-sludge batches were pre-treated in a rolling-batch reactor in the presence of either lactate or sucrose and used to seed lab-scale UASB reactors B (sucrose seed) and C (lactate seed). Start-up efficiencies were compared to a control (Reactor A). Overall Reactor B was more efficient that the control. At the end of the study the Reactor B sludge had a higher methanogenic activity than the control reactor. It also had the highest increase in VSS ≥1.0 mm2. Pre-treatment of digested sludge in the presence of sucrose, therefore, aided granulation and reduced UASB reactor start-up time.

A dupla filtração pode ser considerada como uma das mais promissoras tecnologias para tratamento de água, estimando-se que grande parte das necessidades de tratamento poderiam ser satisfeitas com o uso desta tecnologia. Alguns aspectos ainda não devidamente esclarecidos até o presente sobre esta tecnologia estão relacionados ao tratamento de água com turbidez elevada. Com a montagem e operação de uma instalação piloto, constituída de dois sistemas de dupla filtração (sistema 1: filtro ascendente de areia grossa e filtro descendente de areia e sistema 2: filtro ascendente de pedregulho e filtro descendente de areia), foi realizada uma investigação experimental com águas de estudo preparadas com caulinita (água tipo I com turbidez em torno de 100 uT e água tipo II com turbidez em torno de 300 uT). A coagulação foi realizada com o sulfato de alumínio, sem o uso de alcalinizante ou de acidificante, para que resultasse potencial zeta próximo de zero. A operação de ambos os sistemas foi efetuada com e sem descargas de fundo intermediárias nos filtros ascendentes, e foram variadas as taxas de filtração em ambos os filtros (de 120 a 240 m&sup3/m&sup2.d nos filtros ascendentes e de 180 a 300 m&sup3/m&sup2.d nos filtros descendentes). Concluiu-se principalmente que os dois sistemas foram capazes de produzir água filtrada com turbidez consistentemente menor que 0,5 uT e que a produção efetiva de água depende da turbidez da água de estudo, das taxas de filtração, da execução das descargas de fundo intermediárias e da carga hidráulica disponível para retenção de sólidos. / Double filtration may be considered one of the most important technologies for water treatment. It has been estimated that most of water treatment can be efficiently achieved with the use of this technology, although some design and operational aspects related to the high turbidity of the influent water have not been fully studied until the present time. A pilot plant was built comprising two double filtration systems (system 1 with an upflow coarse sand filter followed by a downflow fine sand filter; system 2 with an upflow gravel filter followed by a downflow filter identical to that used in system 1). The experimental investigation was carried out using influent waters prepared with kaolin (water type I with turbidity of approximately 100 NTU and water type II with turbidity of approximately 300 NTU). Coagulation was accomplished by using aluminum sulfate (no acid or alkaline products) so that the zeta potential resulted approximately zero. The operation of both systems was carried out with and without intermediate down flushes during the runs. Filtration rates in the filters of both systems varied from 120 to 240 m&sup3/m&sup2.d in the upflow filters and from 180 to 300 m&sup3/m&sup2.d in downflow filters. It was mainly concluded that both systems resulted capable to produce filtered water with turbidity consistently lower than 0.5 NTU and that the net production was related to the influent water turbidity, filtration rates, execution of intermediate down flushes and the hydraulic head provided for solids retention in both filter of each double filtration system.

Modelos matemáticos oferecem grandes benefícios para a compreensão dos mecanismos envolvidos nos processos de tratamento de águas residuárias uma vez que fornecem interpretações e possibilitam previsões de desempenho, comparações de alternativas de tratamento, otimização de futuras plantas ou o aprimoramento das existentes, podendo subsidiar a elaboração de projetos em escala real. Em virtude disto, nesta pesquisa visou-se o desenvolvimento de um modelo bioquímico-matemático para descrever o processo de degradação da glicose em um reator anaeróbio de leito fixo com fluxo ascendente, com a resultante produção biológica de hidrogênio por meio do processo de fermentação. O desenvolvimento do modelo foi baseado em estudos sobre a cinética bioquímica e as características hidrodinâmicas do sistema. Os parâmetros de ajuste do modelo aos dados experimentais foram as constantes de velocidade das reações bioquímicas envolvidas na produção de hidrogênio. A calibração foi realizada manualmente buscando minimizar o desvio global. Para a determinação dos parâmetros foi utilizada a técnica de geração de números aleatórios com distribuição de freqüência uniforme e em seguida, o método de inversão de matrizes. O modelo matemático se revelou bastante adequado para a previsão do perfil de concentrações ao longo do reator, e possibilitou a representação das rotas de utilização da matéria orgânica. A reação de oxidação do ácido propiônico pelas bactérias acidogênicas produtoras de hidrogênio constitui a principal via de produção de \'H IND.2\' no sistema. / Mathematical models bring benefits to the understanding of mechanisms involved on wastewater treatment processes because they provide interpretations and make possible performance predictions, evaluation of design alternatives, optimization of future plants or the improvement to existing systems. Therefore, in this work a mathematical model to describe the glucose degradation process, with hydrogen production through the fermentation, in an upflow anaerobic packed-bed reactor is developed. The model equations were based on studies of biochemical kinetics and hydrodynamics features of the system. The parameters considered were the rates of the biochemical reactions involved in the hydrogen production. The calibration was made through the minimization of the global deviation. The parameters determination was obtained with the use of a technique of generation of aleatory numbers, and after that, the method of matrices inversion for the solution of the system of linear equations. The mathematical model developed showed to be adequate for the concentrations prediction along the reactor, and it made possible the representation of the routes of organic material utilization. The oxidation reaction of propionic acid is the main hydrogen production route in the reactor.

O presente trabalho estudou o aumento de capacidade de tratamento de um reator UASB (Upflow Anaerobic Sludge Blanket) por meio da adição de material suporte para adesão celular (Biobob®), avaliando-se as eficiências de remoção de matéria orgânica (expressa como DQO demanda química de oxigênio) e sólidos em suspensão (expressos como SST sólidos em suspensão totais). O reator híbrido, no qual a biomassa está presente em suspensão e imobilizada no material suporte, foi submetido a baixos tempos de detenção hidráulica (TDH) e altas velocidades ascensionais (vs). A operação do reator anaeróbio, de volume útil igual a 12,5 m³, foi conduzida em duas etapas. Na primeira o sistema foi operado como um reator de manta de lodo e escoamento ascendente (UASB), com TDH de 8,8 h e velocidade ascensional de 0,63 m.h-1. Na segunda etapa, introduziu-se 5,0 m³ de material suporte Biobob® no leito reacional do reator, transformando-o em reator anaeróbio híbrido (HAnR). Nessa condição, variou-se a vazão de alimentação, tendo o TDH variado entre 7,4 h (vs de 0,66 m.h-1) a 3,9 h (vs de 1,25 m.h-1). Para ambas as etapas o sistema foi alimentado com esgoto sanitário à temperatura ambiente, após tratamento preliminar (gradeamento e caixa de areia). Para condições de operação similares, o reator anaeróbio híbrido (HAnR) apresentou melhor desempenho na remoção de DQO e SST que o reator UASB, acrescendo em até 18% e 30% a eficiência de remoção, respectivamente. Para a velocidade ascensional de 1,25±0,02 m.h-1 e TDH de 3,9±0,1 h, o HAnR apresentou concentrações médias no efluente tratado de 205±46 mg DQOt.L-1 e 73±30 mg SST.L-1 e eficiências de remoção de 55±9% DQOt e 63±14% SST. / The increase of the treatability capacity of a UASB (Upflow Anaerobic Sludge Blanket) reactor by introducing an innovative packing material (Biobob®) in its reaction zone was evaluated. The hybrid anaerobic reactor (HAnR) containing suspended and immobilized biomass was evaluated regarding its efficiency of removing organic matter (expressed as COD chemical oxygen demand) and suspended solids (expressed as TSS total suspended solids) under lower hydraulic detention time (HDT) and higher upflow velocities (v s). The anaerobic reactor operation, with 12.5 m³ of working volume, was conducted in two phases. In the first phase, the system was operated as a conventional UASB reactor with HRT of 8.8 h and vs of 0.63 m.h -1 . In the second phase, 5.0 m³ of packing material Biobob® was introduced inside the reaction bed, changing the reactor configuration from suspended growth to hybrid growth. In this condition, the hybrid anaerobic reactor (HAnR) was subjected to decreasing flowrates with HDT ranging from 7.4 h (vs of 0.66 m.h-1) to 3.9 h (vs of 1.25 m.h-1). For both phases, the feed was domestic wastewater (after screens and grit chambers) at ambient temperature. Under similar operation conditions, the HAnR performed better than the UASB reactor increasing at 18% and 30% the COD and TSS removal efficiencies, respectively. For vs of 1.25±0.02 m.h-1 and HDT of 3.9±1.0 h, the HAnR produced a very high quality effluent, with average COD and TSS concentration of 205±46 mg DQOt.L-1 and 73±30 mg SST.L-1 and removal efficiencies of 55±9% and 63±14% for CODt and SST, respectively.