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.

Levando-se em consideração a importância econômica que a indústria sucroalcooleira e do biodiesel representam para o Brasil, bem como a posição de destaque do país neste cenário econômico mundial, uma gestão adequada do efluente gerado pelas indústrias torna-se fundamental. A fim de minimizar os impactos ambientais associados, tendo em vista que um litro de etanol produzido gera até quinze litros de vinhoto e que cada tonelada de biodiesel gera cem quilos de glicerol, tecnologias disponíveis podem ser utilizadas, como no caso de processos anaeróbios. Este estudo avaliou doze experimentos em processo anaeróbio em escala laboratorial utilizando efluente de vinhoto e glicerol pós tratamento por processo de acidogênese, oriundo da indústria sucroalcooleira e do biodiesel. Foram determinados parâmetros de produção de metano, entre outros aspectos. Os três reatores dos quatro experimentos que apresentaram resultados mais significativos em termos de produção de metano no período de tempo monitorado, utilizando somente vinhoto residual, foram o V4.3, V2.3 e o V3.3, em volumes de 6.241 mL, 6.087 mL e 4.845 mL, respectivamente. Já nos experimentos utilizando também glicerol, os resultados apresentaram produções máximas de metano de 8.687 mL, 7.990 mL e 6.640 mL, para relações de proporções de vinhoto e glicerol de 80/20, 60/40 e 20/80, respectivamente. / Taking into account the economic importance that the sugar-alcohol industry and biodiesel represent for Brazil, as well as the country's leading position in this world economic scenario, adequate management of the effluent generated by the industries becomes fundamental. In order to minimize the associated environmental impacts, given that one liter of ethanol produced generates up to fifteen liters of vinasse and that each ton of biodiesel generates one hundred kilos of glycerol, available technologies can be used, as in the case of anaerobic processes. This study evaluated twelve experiments in anaerobic process in laboratory scale using effluent of vinasse and glycerol post treatment by acidogenesis process, coming from the sugar-alcohol industry and biodiesel. Methane production parameters were determined, among other aspects. The three reactors of the four experiments that presented the most significant results in terms of methane production in the monitored time period, using only residual vinasse, were V4.3, V2.3 and V3.3, in volumes of 6,241 mL, 6,087 mL and 4,845 mL, respectively. In the experiments using also glycerol, the results presented maximum methane yields of 8,687 mL, 7,990 mL and 6,640 mL, for vinasse and glycerol ratios of 80/20, 60/40 and 20/80, respectively.

Made available in DSpace on 2014-10-09T12:48:54Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:11Z (GMT). No. of bitstreams: 1 09617.pdf: 5595560 bytes, checksum: 5a054c653d88ec87b2d3c979b79b00b5 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertacao [Mestrado] / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:00/09008-4

Orientador: Lucia Regina Durrant / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-08T21:34:47Z (GMT). No. of bitstreams: 1 Cruz_JulianaGiseleBeloteD'Arcadia_D.pdf: 1094793 bytes, checksum: 9fff23fc94e5bf172cdf4158fde536f3 (MD5) Previous issue date: 2007 / Resumo: O presente estudo avaliou a utilização da tecnologia de tratamento de despejos líquidos de uma indústria cervejeira e de refrigerantes pelo sistema biológico aeróbio. Buscou-se a remoção da carga orgânica mediante quantificação da demanda bioquímica de oxigênio (DBO), demanda química de oxigênio (DQO), nitrogênio amoniacal total, turbidez, sólidos sedimentáveis (SS), fósforo (P), condutividade e toxicidade. O sistema de tratamento proposto foi constituído por quatro reatores em série com volume total de 16 L. A alimentação foi realizada de forma contínua pela parte inferior e por gravidade. Para a imobilização dos microrganismos nos reatores foi utilizado, como suporte, argila expandida. Para o sistema aeróbio foi utilizada aeração prolongada mediante injeção ascendente de oxigênio. As análises foram realizadas diariamente, no afluente do reator e no efluente tratado em diferentes tempos de retenção hidráulica (TRH/h). Os resultados obtidos mostraram que o sistema de tratamento, empregando 4 reatores acoplados, foi eficiente para a remoção da carga orgânica poluente do efluente da indústria. Ocorreu diminuição da DQO em todos os tempos de retenção hidráulica testados. O TRH 1,9 mostrou ser o mais eficiente, visto que é o tempo com a maior vazão, fato de extrema importância para o tratamento de efluentes industriais. Neste TRH houve maior porcentagem de remoção da DBO (67,4%), toxicidade com microcrustáceo Daphinia similis (52,3%), condutividade (13,13%), além de significativa remoção da DQO (58,7%) / Abstract: The present study the treatment of the waste waters of a beer and soft drink industry by an aerobic biological system was evaluated. The removal of the organic load by means of the quantification of the biochemical oxygen demand (BOD), chemical oxygen demand (COD), total ammoniacal nitrogen, turbidity, sedimented solids (SS), phosphorus (P), conductivity and toxicity. Were determined proposed the consisted of four reactors in series with a total volume of 16 L. The feeding was carried out carried out continuous by through the of the bioreactor inferior part and by gravity. Expanded clay was used as support for the immobilization of the microorganisms in the reactors. Continuous aeration by means of ascending injection of oxygen was used for the aerobic system. The analyses were performed daily in samples from the treated and untreated industrial effluent using different times of hydraulical retention (HRT/h). The results showed that the treatment system, using 4 connected reactors was efficient for the removal of the pollutant organic load of the industrys effluent. Reduction of the COD occurred in all the tested hydraulical retention times used HRT of 1.9 was found to be the most efficient HRT, since it was the time with the hioghest outflow, fact that is of extreme importance for the treatment of industrial effluents. In this HRT there was a greater percentage of reduction of the BOD (67.4%), the toxicity with the Daphinia similis (52.3%) and conductivity (13.13%), besides the significant reduction of the COD (58.7%) / Doutorado / Doutor em Ciência de Alimentos

Orientador : Ranulfo Monte Alegre / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T14:22:54Z (GMT). No. of bitstreams: 1 Alberte_TaniaMaria_D.pdf: 9835439 bytes, checksum: 74ab1a7efc7d568bc9c3b37f762f08ec (MD5) Previous issue date: 2003 / Resumo: Reatores "air-lift" são uma classe especial de coluna de bolhas, sendo recentemente utilizados em processos químicos, bioquímicos e em tratamento de águas residuárias. Neste trabalho, estudou-se o desempenho de um reator "air-lift" de tubos concêntricos no tratamento de água residuária sintética utilizando Iodo ativado. O reator construido de aço-inox, com tubos de aeração e reciclo de 1,2 e 1,5 m respectivamente, foi alimentado com água residuária sintética, sendo o Iodo separado em sedimentador na parte superior do reator e reciclado ao mesmo. A pressão manométrica no reator variou de O a 1,2 Kgf.cm-2, vazão de ar de 200 a 1600 mL.min-1 e vazão de substrato de 200 a 400 mL.h-1. Para cada taxa de alimentação, vazão de ar e pressão, o reator foi operado de forma contínua até que o estado estacionário hidráulico e microbiológico fossem atingidos. As amostras foram retiradas na altura média do reator e análises da Demanda Química de Oxigênio (DQO) e biomassa (quantificada como sólidos suspensos voláteis - SSV) foram feitas de acordo com métodos descritos pelo "Standard Methods for the Examination of Water and Wastewater" (1985). Os três parâmetros, vazão de alimentação, vazão de ar e pressão, variaram gradativamente, além da concentração de DQO do substrato (1100 a 8600 mgDQO.L-1), de forma que foi possível aumentar a concentração de Iodo no reator (SSV) de 1010 a 15000 mgSSV.L-1, sendo este último valor cerca de cinco vezes maior que os de processos convencionais de Iodo ativado, que é de 2000 a 3000 mgSSV.L -1 (Ramalho, 1983). Isto permitiu aumentar a eficiência de redução de DQO de 47 a 87%, respectivamente para reator operado a pressão ambiente e com variação de pressão. O coeficiente de transferência de oxigênio (K1a) aumentou com o aumento da vazão de ar até o limite de 1000 mL.min-1 (5,41 h-1), decrescendo para vazões superiores a esta, possivelmente devido à coalescência de bolhas. O coeficiente de retenção de gás (Eg) foi determinado e, para as vazões de ar testadas (200 a 1400 mL.min-1), variou de 2,08.10-3 a 12,95.10-3, proporcionalmente às vazões de ar utilizadas / Abstract: Air lift reaetors are a speeial elass of bubble eolumns and are been reeently used in ehemieal and bioehemical processes, as well as in wastewater treatment. In this work, it was studied the performanee of aeoneentrie tube air lift reaetor in the synthetie wastewater treatment by aetivated sludge. The reaetor was eonstrueted of stainless steel, 1.2 m high of riser and 1.5 m high of downeomer. It was fed with synthetie wastewater and the sludge was separeted in a sedimentator in the top of reaetor and reeyeled. The manometrie pressure varied from O to 1.2 kgf.em'2, the air flow rate from 200 to 1,600 mL.min-1 and the feed solution from 200 to 400 mL.h -1. To eaeh feed solution of synthetie wastewater rate, air flow rate and pressure, the reaetor was operated in eontinuous form until the hidraulie and mierobiologieal steady-state was reaehed. The samples were eolleeted in the half of the reaetor. Chemieal oxygen demand (COO) and volatils solids eoneentration (VSS) was determinated aceording to ín Standard Methods for the Examínation of Water and Wastewater (1985). Feed solution rate, air flow rate and pressure rangedgradually, as well as eoneentration of feed synthetie wastewater (1,100 of 8,600 mgCOO.L- / Doutorado / Doutor em Engenharia de Alimentos

Cette recherche porte sur l’élimination des micropolluants pharmaceutiques des effluents hospitaliers par des procédés biologiques classiques (boue activée) et membranaire. Il est montré que les systèmes à membrane, externe ou immergée, permettent un meilleur traitement, ou une meilleure rétention, de plus de 50% des molécules pharmaceutiques mesurés. Afin d’améliorer l’efficacité des procédés membranaires, des supports bactériens ont été ajoutés dans le bassin biologique permettant de diminuer considérablement le colmatage. Il est montré qu’une des conséquences de la présence de ce garnissage est une diminution globale des EPS produits, donc du colmatage membranaire, et de la rétention des molécules pharmaceutiques,. Afin d’augmenter encore l’efficacité du procédé, du charbon actif en poudre ou en grain a été ajouté avant la filtration (CAP) ou en sortie de filtration (CAG), permettant une élimination quasi complète des molécules mesurées. La qualité des biomasses épuratrices a été suivie par microscopie confocale avec marquage fluorescent des exopolymères et de la viabilité cellulaire. Il est montré que les effluents hospitaliers modifient la structure des flocs et des biofilms, leur composition biochimique, avec une augmentation des concentrations en protéines extracellulaires, et la répartition des populations caractérisées par métagénomique. / This research investigates the removal of pharmaceutics present in hospital wastewaters by conventional activated sludge and MBR systems of treatment and under various operating conditions to elucidate the removal mechanism and increasing the efficiency of removal. In this study, laboratory scales was composed to four types of reactors used: Bach reactors, conventional activated sludge, submerged membrane bioreactor and extern membrane bioreactor and all these reactors were feed in reel hospital wastewaters. Different Technical studies and many experiments were affected to develop the MBR systems: the beginning was with biofilm supports media and the attached growth of biofilms in the reactor and the finish by using the powder activated carbon. En general, the reported results show high performance for the MBR with compared to CAS system in treating the basic organic pollutants. Presence the biofilm supports media was very important for high removal of pharmaceuticals compounds from the hospital wastewaters. The presence of the pharmaceutical compounds stimulated the mechanisms of survival higher production of EPS. Fouling potential seems to be linked more closely to polysaccharides than other EPS. In this study, for the first time, was employed the confocal microscopy for qualities and quantities analyses for the EPS in the biologic reactors. Microscopic observations were confirmed the chemical analyses of EPS compounds. In final experiment 21 pharmaceuticals were eliminated from the hospital effluents during the treatment in extern membrane (UF) with modified granular activated carbon. In addition to many biomolucles analyses which study the principals impact of hospital effluents on the microorganism’s especially the bacteria in using different, recent techniques. This study demonstrates by reel conditions the role the developed MBR systems in treating the hospital effluents and its impact direct on the environment.

La production de protéines recombinantes, d’anticorps, de vaccins, … est de plus en plus réalisée par culture de cellules animales. Le bioréacteur classiquement utilisé en industrie pour réaliser ces cultures est le bioréacteur à cuve agitée. Ce bioréacteur présente un volume important ce qui rend difficile le développement d’un bioréacteur à usage unique dans l’optique de réduire les risques de contaminations entre deux cultures consécutives. L’intensification du procédé et le développement de bioréacteur à usage unique sont donc deux défis intéressants dans la réalisation de cultures cellulaires à l’échelle industrielle. Un bioréacteur particulièrement prometteur pour l’intensification de culture cellulaire est le bioréacteur lit-fixe. Dans cette thèse, nous étudions le bioréacteur lit-fixe à usage unique iCELLis développé par Artelis S.A.<p>Le lit-fixe du bioréacteur iCELLis est composé d’un empilement de porteurs maintenu entre deux grilles perforées. Ces porteurs sont utilisés comme support par les cellules au cours de la culture. Le bioréacteur est équipé d’un système de transfert gaz-liquide par film tombant afin d’oxygéner le milieu de culture en continu. Une pompe centrifuge plongée dans un bac d’immersion assure la circulation du milieu de culture à travers l’ensemble du bioréacteur. Les cultures se déroulent en trois phases :une phase d’adhérence des cellules aux porteurs du lit-fixe, une phase de croissance cellulaire et une phase de production.<p>Les avantages d’un bioréacteur lit-fixe sont nombreux :une concentration cellulaire élevée impliquant une productivité élevée, un petit volume de bioréacteur, une faible exposition des cellules aux contraintes de cisaillement, Les bioréacteurs lits-fixes présentent cependant certains inconvénients qui freinent leur développement à l’échelle industrielle. Le lit-fixe se présente comme un réacteur piston ce qui implique l’apparition de gradients de concentrations de cellule et d’espèces extracellulaires (nutriments et produits) le long du lit-fixe. L’intérieur du lit-fixe est également difficilement accessible au cours de la culture. Le suivi des concentrations de cellules et d’espèces dans cette zone est donc problématique.<p>Une modélisation globale du bioréacteur lit-fixe nous permet de mieux comprendre les différents phénomènes qui prennent place dans le bioréacteur. Grâce à cette modélisation, nous sommes donc capables d’identifier les phénomènes clés contrôlant le procédé et ainsi fournir des pistes de travail pour l’optimisation et la montée en échelle du bioréacteur, ceci sur base de critères rationnels.<p>Nous choisissons de développer un modèle à compartiments du bioréacteur lit-fixe. Dans ce type de modèle, le bioréacteur est représenté par un réseau de compartiments interconnectés. Nous définissons trois compartiments :un premier pour la pompe, un deuxième pour les cellules et le lit-fixe, et un troisième pour le système de transfert gaz-liquide.<p>Pour le premier compartiment, nous souhaitons caractériser divers paramètres identifiés comme pertinents pour une sélection adéquate de la pompe. Dans cette thèse, nous présentons une méthode pour caractériser ces paramètres pour une pompe de référence (celle du bioréacteur iCELLis) et pour une pompe en similitude géométrique à la pompe de référence (dans le but d’étudier la montée en échelle).<p>La pompe de référence est étudiée numériquement (grâce aux logiciels Gambit 2.4 et Fluent 6.3) et expérimentalement. Nous mettons en évidence les liens entre les paramètres de la pompe déterminés numériquement et ceux déterminés expérimentalement. Ces liens définissent notre modèle. En intégrant au modèle les résultats de la simulation numérique de l’écoulement du milieu de culture dans le bac d’immersion contenant la pompe en similitude géométrique à la pompe de référence, nous déterminons entièrement les paramètres recherchés de la seconde pompe sans avoir recours à un prototype. Ceci permet donc de tester différentes échelles avant de choisir la version finale de la seconde pompe.<p>Le deuxième compartiment du modèle caractérise les cellules et le lit-fixe. La sélection de certains paramètres opératoires dépend du métabolisme cellulaire. Nous souhaitons développer un outil de surveillance en ligne de l’évolution des concentrations de certaines espèces extracellulaires sur base de la connaissance de la concentration cellulaire dans le bioréacteur. Cet outil est développé sur base d’un modèle structuré du métabolisme des cellules animales. Dans un tel modèle, nous établissons des bilans de matière sur les espèces extra- et intracellulaires en considérant les voies métaboliques intracellulaires. Un paramètre requis pour l’emploi de cet outil est la connaissance de la concentration cellulaire au cours de la culture. Or, la surveillance de cette concentration est l’un d’un problème évoqué dans les bioréacteurs lits-fixes. Nous développons donc un modèle ségrégé de culture cellulaire en bioréacteur lit-fixe. Dans ce modèle, nous considérons l’entièreté du lit-fixe. Le modèle comprend différentes populations de cellules :les cellules en suspension dans le milieu au début de la culture et les cellules adhérentes au lit-fixe. Le modèle inclut une distribution spatiale de la concentration d’espèces extracellulaires dans le lit-fixe. Par conséquent, le modèle rapporte les gradients potentiels de concentration de cellules et d’espèces extracellulaires dans le lit-fixe.<p>Le troisième compartiment du modèle du bioréacteur caractérise le système de transfert gaz-liquide. L’oxygénation est très souvent un paramètre clé dans la conception d’un bioréacteur. Dans le bioréacteur iCELLis, le système de transfert gaz-liquide est un film liquide tombant turbulent. Dans cette thèse, nous proposons une méthode pour caractériser le transfert d’oxygène à travers ce type de film tombant. Notre méthode, basée sur une approche numérique (grâce à Gambit 2.4 et Fluent 6.3), est scindée en deux parties. Premièrement, nous calculons la forme de l’interface gaz-liquide. Une simulation de l'écoulement est réalisée avec le modèle Volume of Fluid (VOF). A partir de cette simulation, la forme de l'interface est traquée. Deuxièmement, la forme de l'interface est générée dans un nouveau domaine de calcul afin de simuler le transfert d’oxygène. Grâce à cette seconde simulation, le coefficient de transfert d’oxygène de la phase gazeuse vers le milieu de culture est déterminé. Grâce à notre méthode, nous caractérisons ce coefficient pour différentes conditions opératoires. Nous étudions notamment l’influence du débit et de la température du milieu de culture sur le coefficient de transfert d’oxygène. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Experiences in treating wine distillery wastewaters (WDWs) contribute to the field of oenology as many oenologists are concerned with the selection, efficiency and economy of their wastewaters. Wine distillery wastewaters are strongly acidic, have high chemical oxygen demand (COD), high polyphenol content and are highly variable. Primary attention was focussed on sustainable biological treatment of raw wine distillery wastewater (RWDW) and fungally pre-treated wine distillery wastewater (FTWDW) by energy-efficient high rate anaerobic digestion (AD). This study also explored the development of a novel dual-stage anaerobic digestion ultrafiltration (ADUF) process, using a ceramic submerged membrane bioreactor (SMBR) in the treatment of both RWDW and FTWDW. The first stage was for the selection of microorganisms that were able to treat the toxic pollutants from WDWs. It was operated at a high feed-to-microorganism ratio. The second stage, a secondary digester, was operated like a typical membrane bioreactor at a low feed-to-microorganism ratio to sustain a stable efficient population for a long period. The characteristics of RWDW were as follows: pH 3.83, 15 000 mg/l soluble COD (CODs) and 5229 mg/l of phenols. After pre-treatment of RWDW with Trametes pubescens, starting parameters for FTWDW were as follows: pH 6.7, 7000 mg/l soluble COD (CODS) and 1440 mg/l of phenols. During operation of a high rate anaerobic digester for RWDW treatment, K2HPO4 was required for buffering the digester. Volatile fatty acid concentrations were <300 mg/l throughout the study, indicating degradation of organic acids present. Mean CODS removal efficiency for the 130 day study was 87 %, while the mean polyphenol removal efficiency was 85 %. Addition of 50 mg/l Fe3+ increased the removal efficiencies of CODS to 97 % and of polyphenols to 99 %. High removal efficiencies of CODS and polyphenols were attributed to the addition of macronutrients and micronutrients that caused pH stability and stimulated microbial activity. The CODS removal efficiency of high rate anaerobic digestion of FTWDW reached 99.5%. During FTWDW digestion, pH buffering was achieved using K2HPO4. A combination of a SMBR and a secondary digester was tested for the treatment of RWDW and FTWDW during a 30 day study. Results for RWDW showed that pH buffering was achieved by dosing the feed stream with CaCO3 and K2HPO4. Buffering proved to be significant for optimum performance of the system in removal of soluble CODS, and volatile fatty acids (VFAs). Different batches of RWDW used for feeding the reactor had variable compositions with respect to concentrations of nitrates, ammonium and total phenolic compounds. Ammonium accumulated in the secondary digester after 14 days of system operation, indicated the time required for the establishment of anaerobic conditions in the system. Dosing of the SMBR treating FTWDW with CaCO3 and K2HPO4 buffered the pH; iii this proved significant for optimum performance of the system in removal of CODS. The system eliminated an average of 86 (± 4) % of CODS present in the FTWDW. The residual CODS levels in the effluent were approximately 400 mg/l, significantly lower than the concentrations observed when treating RWDW, indicating that fungal pre-treatment might have provided additional nutrients for removal of recalcitrant components of the wastewater. The resulting effluent was rich in nitrates and phosphates and might be used as a fertiliser. Alternatively, a membrane process, such as reverse osmosis (RO) or nanofiltration (NF) could be applied to raise the water quality to meet the levels required for reuse. Biomass samples were obtained from the four treatment systems and population shifts characterization using phospholipids fatty acids (PLFA) and 16S rRNA analysis to provide an indication of limitations within the microbial population. The values of the concentrations of the individual PLFAs detected in the samples indicated that ten bacterial species were present, with the GC content of the 16S rRNA increasing from 1 to 10. Analysis of denaturing gradient gel electrophoresis DGGE data indicated that the composition of the archeal community changed the consortia used for both RWDW and FTWDW treatment. Changes in band intensities indicated the presence of different components of the archeal communities. The results were not conclusive in terms of species identity as cloning, sequencing and phylogenetic analyses were not performed, but they did indicate microbial population shifts and species diversity for high rate anaerobic digestion. The results also confirmed prevalence of relatively few species during operation of SMBRs for treatment of RWDW and FTWDW, which suggested that the microorganisms that survived were either tolerant of toxic components of RWDW and FTWDW or they were able to remove polyphenols.

Master of Science / Department of Geology / Matthew Kirk / A growing body of evidence demonstrates that methanogenesis and Fe(III) reduction can occur simultaneously. However, environmental controls on interactions between each are poorly understood. In this study we considered pH as a control on interactions between Fe(III) reduction and methanogenesis in anoxic sediment bioreactors. The reactors consisted of 100mL of synthetic aqueous media, and 1 g of marsh sediment amended with goethite (1mmol). One set of reactors received acidic media (pH 6), and the other alkaline media (pH 7.5). Each set received media containing acetate (0.25 mM) to serve as an electron donor. Control reactors, deficient in acetate, were also included. We maintained a fluid residence time of 35 days by sampling and feeding the reactors every seven days. For pH 6.0 and pH 7.5 reactors, the measured pH of effluent samples averaged 6.33 and 7.37, respectively. The extent of Fe(III) reduction and methanogenesis varied considerably between each set of reactors. More Fe(III) was reduced in the pH 6 reactors (646.39 μmoles on avg.) than the pH 7.5 reactors (31.32 μmoles on avg.). Conversely, more methane formed in pH 7.5 reactors (127.5 μmoles on avg.) than the pH 6 reactors (78.9 μmoles on avg.). Alkalinity concentrations during the middle and end of the experiment averaged 9.6 meq/L and 5.2 meq/L in pH 6 and pH7.5 reactors, respectively Although much less Fe(III) reduction occurred in pH 7.5 reactors, the relative abundance of Fe(III) reducers in them decreased little from levels observed in the pH 6 reactors. Sequences classified within Geobacter, a genus of bacteria known primarily as dissimilatory metal reducers, accounted for 22% and 13.45% of the sequences in the pH 6 and pH 7.5 reactors and only 0.8% of the sequences in the marsh sediment inoculum. In contrast, sequences classified within orders of methanogens were low in abundance, making up only 0.47% and 1.04% of the sequences in the pH 6 and pH 7.5 reactors, respectively. Mass balance calculations demonstrate that the amount of electron donor consumed by each group varied considerably between the sets of reactors. Expressed as a quantity of acetate, the reactions consumed about 160μM of electron donor each in pH 6 reactors. In contrast, methanogenesis consumed over 30 times more electron donor than Fe(III) reduction in the pH 7.5 reactors. Thus, the results of our experiment indicate that the decrease in electron donor consumption by Fe(III) reduction at basic pH was nearly matched by the increase in electron donor consumption by methanogens. Results of geochemical modeling calculations indicate that more energy was available for Fe(III) reduction in the pH 6.0 reactors than the pH 7.5 reactors, matching variation in Fe(III) reduction rates, and that the density of sorbed ferrous iron was higher in pH 6 reactors than pH 7.5 reactors. Thus, the calculation results are consistent with bioenergetics, but not variation in ferrous iron sorption, as a potential mechanism driving variation in the balance between each reaction with pH.

O presente estudo analisa dois tipos de aços inoxidáveis, o Austenítico AISI 316L e o Duplex AISI 318, para a fabricação de biorreatores. Esses aços possuem propriedades físicas e químicas que podem suprir as necessidades de resistências mecânicas e anticorrosivas dos ambientes dos biorreatores anaeróbicos. Para comparar os dois tipos de aço, foram feitos testes das propriedades mecânicas e químicas antes e depois da exposição ao ambiente de biorreação. Um protótipo de biorreator foi projetado no software Autodesk Inventor 2013 e construído com uma das ligas metálicas em estudo, o aço AISI 316L, criando um ambiente favorável aos testes de campo. Para tal utilizou-se processos de conformação e união de chapas por rebitagem e soldagem. As amostras dos aços para os testes mecânicos e de corrosão foram preparadas e inseridas no biorreator onde permaneceram por 14 meses. Os resultados dos ensaios mostraram que não houve alterações significativas nas propriedades mecânicas dos aços Duplex, porém as amostras de aço Austenítico apresentaram aumento na tensão de escoamento, na tensão limite de resistência e no módulo de elasticidade, demonstrando aumento na rigidez do material após a biorreação. Quanto às propriedades anticorrosivas os resultados apresentam uma leve vantagem do aço Duplex AISI 318 em relação ao Austenítico AISI 316L. Em relação à construção, os aços Austeníticos, por serem mais dúcteis, possuem melhor conformação; o Duplex AISI 318, por ter maior resistência mecânica, possibilita a construção com chapas mais finas, o que acarreta em redução de peso final do biorreator. O aço AISI 318 apresenta maior estabilidade nas propriedades mecânicas do que o AISI 316L. A relação favorável de custo-benefício da aplicação dos aços inoxidáveis na construção de biorreatores anaeróbios é comprovada pelas plantas de produção de biogás existentes em várias partes do mundo, principalmente na Europa. / The present study analyzes two kinds stainless steel, the Austenitic AISI 316L and the Duplex AISI 318 for manufacturing bioreactors. These kinds of stainless steel have the physical and chemical properties to meet the need the anticorrosive and mechanical resistances from the anaerobic bioreactors environments. Before and after the exposition to the bioreaction environment, both kinds of stainless steel were compared by testing their mechanical and chemical properties. A prototype bioreactor was designed in Autodesk Inventor 2013 software and built with on of the alloys in study, the AISI 316L, creating a favorable environment for fielding testing. For this purpose, we used the processes of forming and joining the plates by riveting and welding. The stainless steel samples for the mechanical and corrosion tests were prepared and placed in the bioreactor and they stayed there for fourteen months. Results show that there weren't significant changes in the mechanical properties of Duplex steel. However, Austenitic steel samples showed an increase in yield strength, resistence limit and in the elastic modulus, demonstrating an increase in the stiffness of the materials after bioreaction. The results show that there were not significant changes in mechanical properties, as the corrosive properties, results show a slight advantages of Duplex 318 compared to Austenitic AISI 316L. Regarding the construction, the Austenitic steel has better conformation, because it is more ductile and the Duplex steel has greater mechanical resistance and it enables the construction with thinner plates. Thus, the bioreactor becomes lighter. The AISI 318 steel has higher stability in mechanical properties than AISI 316L. The cost-benefit of the application of stainless steel in the construction of anaerobic bioreactors is proven by production plants of biogas worldwide, mainly in Europe.