Orientador: Gustavo Henrique Ribeiro da Silva / Banca: Adriana Ferreira Maluf Braga / Resumo: O presente trabalho estudou o tratamento de água negra simulada (esgoto sanitário com efluente suíno) em reator UASB (upflow anaerobic sludge blancket) mesofílico com DQO (demanda química de oxigênio) de entrada de 958,489 ± 489,2mg/L, TDH (tempo de detenção hidráulica) de 1,8 ± 1,8d e COV (carga organica volumética) de 0,2 ± 0,2 KgDQO/m³d. Avaliou-se, ainda, o efeito da suplementação de metais traço (Fe, Ni, Mn, Ba, Se, Co e Cu) na AME (atividade metanogênica específica) do lodo utilizado como inóculo de partida do reator. Os ensaios com metais traços foram realizados em batelada utilizando o método Plackett Burman para planejar o experimento. Foram observados valores nitrogênio amoniacal junto a entrada do reator de 197,37 ± 84,3mgN/L, no entanto, o reator apresentou remoção de DQO de 61,7% ± 15%, demonstrando que não houve efeito tóxico da amônia no meio. Os resultados dos ensaios em batelada demonstraram efeito negativo estatisticamente significativo das adições de Ba e Mn sobre a AME, contudo, o Cu e o Se apresentaram efeito positivo, embora não estatisticamente significativos, indicando que a produção de metano a partir de água negra pode ser estimulada com a suplementação desses metais / Abstract: The present work studied the treatment of simulated black water (sewage with swine wastewater) in UASB (upflow anaerobic sludge blancket) mesophilic with input COD (chemical oxygen demand) of 958,489 = 489,2 mg/L, HRT (hydraulic retention time) of 1.8 = 1.8d and OLR (organic loading rate) 0.2 = 0.2 kgCOD/m3d. This work also evaluated the effect of supplementation of trace metals (Fe, Ni, Mn, Ba, Se, Co e Cu) on the SMA (specific methanogenic activity) of the seed inoculum used in reactor startup. The trace metals assay were performed in batch mode using Plackett-Burman method of the design of the experiments. Despite of the ammonia nitrogen values at the inffluet of 197.37 = 84.3 mgN/L reactor, the reactor, the reactor presented COD removal of 61.7% = 15%, indicating no toxic effectof the addition of Ba and Mn on the SMA of the sludge, however, Cu and Se presented positive effect, although not statistically significant, which indicates that the methane production from black water might be enhanceb by the supplementation of these metals / Mestre

Orientador: Roberto Alves Oliveira / Resumo: A co-digestão de água residuária da bovinocultura leiteira (ARBL) e água residuária do beneficiamento do café (ARC) em reatores anaeróbios de fluxo ascendente com manta de lodos (UASB, R1 e R2), em série, é inédita e importante para o desenvolvimento dos setores envolvidos. Foram utilizadas proporções de 100:0; 85:15, 70:30 e 50:50 de ARBL:ARC no afluente dos reatores UASB e aplicados tempo de detenção hidráulica (TDH) de 2 (R1) e 4 (R2) dias. Isto proporcionou cargas orgânicas volumétricas (COV) de 11,9 (valor médio obtido nos testes 1 e 2, sem adição de ARC); 12,9 (teste 3); 14,0 (teste 4) e 21,3 (teste 5) g DQOtotal (L d)-1 no R1. As maiores produções volumétricas de metano, de até 0,89 L CH4 (L reator d)-1 foram obtidas com COV de 14,0 g DQO (L d)-1. As concentrações médias de fenóis totais no afluente variaram entre 6 e 132 mg L-1 e as eficiências médias de remoção nos reatores UASB, em dois estágios, foram de 35 a 52% com concentração de 50 mg L-1 para efluente do R2 após adição de ARC que contém elevadas concentrações de fenóis totais e apresentam toxicidade ao tratamento anaeróbio podendo afetar a estabilidade do processo. O sistema foi eficiente para remoção de ovos de helmintos. Os Domínios Bacteria e Archaea, as Ordens Methanobacteriales, Methanomicrobiales e Methanosarcinales e as Famílias Methanosaetaceae e Methanosarcinaceae se apresentaram de forma sincrônica e equilibrada na co-digestão anaeróbia dos resíduos estudados. / Abstract: The co-digestion of dairy manure wastewater (DMW) and coffee processing wastewater (CPW) in up flow anaerobic sludge blanket (UASB, R1 and R2) in series is unprecedented and important for the development of the sectors involved. Proportions of 100: 0; 85:15, 70:30 and 50:50 DMW:CPW were used in the UASB reactors influent and applied hydraulic retention time (HRT) of 2 (R1) and 4 (R2) days. This provided organic loading rate (OLR) of 11.9 (mean value obtained in tests 1 and 2, without addition of CPW); 12.9 (test 3); 14.0 (test 4) and 21.3 (test 5) g CODtotal (L d) -1 on R1. The highest volumetric methane yields of up to 0.89 L CH4 (L reactor d) -1 were obtained with OLR of 14.0 g COD (L d) -1. The mean concentrations of total phenols in the affluent ranged from 6-132 mg L-1 and the mean removal efficiencies in two-stage UASB reactors were 35-52% with 50 mg L-1 concentration for R2 effluent after addition of ARC containing high concentrations of total phenols and toxicity to anaerobic treatment may affect process stability. The system was efficient for removal of helminth eggs. The Bacteria and Archaea Domains, the Methanobacteriales, Methanomicrobiales and Methanosarcinales Orders, and the Methanosaetaceae and Methanosarcinaceae families were presented in a synchronic and balanced manner in the anaerobic co-digestion of the residues studied. / Mestre

Made available in DSpace on 2016-02-05T18:29:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-06-08. Added 1 bitstream(s) on 2016-02-05T18:33:46Z : No. of bitstreams: 1 000857634.pdf: 2687649 bytes, checksum: 921ce0c3510bd4902e13ea9e219c970f (MD5) / 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 / 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

Made available in DSpace on 2016-03-07T19:20:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-27. Added 1 bitstream(s) on 2016-03-07T19:24:46Z : No. of bitstreams: 1 000859543.pdf: 3148559 bytes, checksum: b931ea00b941fe221750b66d00797d66 (MD5) / 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 / 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

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. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-06-26T17:27:11Z No. of bitstreams: 1 Dissertacao Camila DBastiani.pdf: 3648057 bytes, checksum: 6fcb0f38708ea3a24444be3ab47dd30b (MD5) / Made available in DSpace on 2017-06-26T17:27:11Z (GMT). No. of bitstreams: 1 Dissertacao Camila DBastiani.pdf: 3648057 bytes, checksum: 6fcb0f38708ea3a24444be3ab47dd30b (MD5) Previous issue date: 2017-06-26 / 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.

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.

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.

Submitted in complete fulfillment for the degree of Doctor of Philosophy (Biotechnology), Durban University of Technology, Durban, South Africa, 2015. / Anaerobic digestion, a proven and highly efficient biological process for treating industrial wastewater and biogas generation is an underutilized technology in South Africa. Some of the industries that have on-site anaerobic reactors tend to face problems in operating these reactors due to poor understanding of the process and implementation of the technology. This has resulted in high pollutant loads in their final effluents and low energy recovery. In this study, an on-site full–scale upflow anaerobic sludge blanket (UASB) reactor treating brewery wastewater was extensively monitored in order to evaluate the efficiency in terms of effluent quality, biogas production and microbial structure. Furthermore, developed and adopted kinetic models were used to optimize the performance of the full–scale UASB reactor using a combined Pareto differential evolution (CPMDE) algorithm. A preliminary analysis of the raw wastewater has shown that the wastewater produced from the brewery industry was high in organic matter with a total chemical oxygen demand (COD) between 1096.41 to 8926.08 mg/L. The average removal efficiency of COD from the UASB reactor after treatment was 79% with a methane (CH4) production of 60-69% at temperature ranges of 28-32˚C and hydraulic retention time (HRT) of 12 h within the optimal pH range for anaerobic bacteria (6.6 and 7.3) under various organic loading rates. However, the results also showed an increase in total suspended solids (TSS), nitrogen (N2), ammonia (NH3) and orthophosphate concentrations when comparing the influent to the effluent, which indicated the necessity for further optimization of the reactor condition in order to reduce these effluent parameters to acceptable standards and to increase CH4 production. In order to optimize the process, a thorough understanding of microbial interaction was essential. A combination of different molecular techniques viz., fluorescence in–situ hybridization (FISH), polymerase chain reaction (PCR) and quantitative real-time PCR (QPCR) were employed to understand the microbial community structure of the granular sludge samples using species specific primers and probes. The results revealed that the dominance of diverse groups of eubacteria belonging to phyla Proteobacteria, Firmicutes and Chloroflexi and an uncultured candidate division WS6 with four different orders of methanogenic Archaea viz., Methanomicrobiales, Methanococcales, Methanobacteriales and Methanosarcinales belonging to hydrogenotrophic and aceticlastic methanogens were within the reactor samples. Quantification of the 16S rDNA copies of eubacteria and methanogenic Archaea using species-specific primers further confirmed the spatial distribution of these microorganisms within the different compartments of the reactor where, the upper compartments were dominated by eubacteria and the lower compartments by methanogenic Archaea. The concentration of Archaea per nanogram of DNA was much higher (96.28%) than eubacteria (3.78%) in lower compartments, while, the eubacteria concentration increased to 98.34% in upper compartments with a decrease in Archaea quantity (1.66%). A modified kinetic methane generation model (MMGM) was developed on the basis of mass balance principles with respect to substrate (COD) degradation and the endogenous decay rate to predict CH4 production efficiency of the reactor. Furthermore, a Stover–Kincannon kinetic model was adopted with the aim of predicting the final effluent quality in terms of COD concentration and model coefficients were determined using the data collected from the full–scale reactor. Thereafter, a model-based multi-objective optimization was carried out using the CPMDE algorithm with three–objective functions namely; maximization of volumetric CH4 production rate; minimization of effluent substrate concentration and minimization of biomass washout, in order to increase the overall efficiency of the UASB reactor. Important decision variables and constraints related to the process were set for the optimization. A set of non-dominated solutions with high CH4 production rates of between 2.78 and 5.06 L CH4/g COD/day at low biomass washout concentrations were obtained at almost constant solution for the effluent COD concentration. A high COD removal efficiency (85-87%) at ~30-31˚C and 8-9 h HRT was obtained for the multi-objective optimization problem formulated. This study could significantly contribute towards optimization of a full–scale UASB reactor treating brewery wastewater for better effluent quality and biogas production. Knowledge on the activity and performance of microbial community present in the granular sludge taken from the full–scale UASB reactor would contribute significantly to future optimization strategies of the reactor. In addition, optimization using an evolutionary algorithm under different operational conditions would help to save both time and resources wasted in operating anaerobic bioreactors.