Thèse--Théologie--Lausanne, 1985. / Publ. dans la collection "Histoire et société" sous le titre "Christianisme spirituel et christianisme social" Bibliogr. p. 453-466. Index.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1972. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

Hypolimnetic oxygen diffusers increase sediment oxygen demand (SOD) and, if not accounted for in design, can further exacerbate anoxic conditions. A study using extracted sediment cores, that included both field and laboratory experiments, was performed to investigate SOD kinetics in Carvin's Cove Reservoir, a eutrophic water supply reservoir for Roanoke, Virginia. A bubble-plume diffuser is used in Carvin's Cove to replenish oxygen consumed while the reservoir is thermally stratified. The applicability of zero-order, first-order, and Monod kinetics to describe transient and steady state SOD was modeled using analytical and numerical techniques. Field and laboratory experiments suggested that first-order kinetics characterize Carvin's Cove SOD. SOD calculated from field experiments reflected diffuser flow changes. Laboratory experiments using mini-diffusers to vary dissolved oxygen concentration and turbulence were conducted at 4°C and 20°C. Similar to field observations, the laboratory results followed changes in mini-diffuser flow. Kinetic-temperature relationships were also observed in the laboratory experiments. A definitive conclusion could not be made on the broad applicability of first-order kinetics to Carvin's Cove SOD due to variability within field experiments. However, in situ experiments are underway that should assist in the overall understanding of the reservoir's SOD kinetics. / Master of Science

Made available in DSpace on 2014-06-12T18:07:42Z (GMT). No. of bitstreams: 2 arquivo8009_1.pdf: 984705 bytes, checksum: 89eefc579e37dd671e5bbfd3326c6a42 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / Este trabalho objetivou o estudo cinético da produção de exopolissacarídeo por Zoogloea sp. em melaço de cana-de-açúcar. Inicialmente foram realizados ensaios em frascos, obedecendo a um planejamento fatorial 23, tendo como variáveis independentes e os seus respectivos níveis, os seguintes valores: temperatura (30 e 35ºC); pH inicial (4,5 e 6,0) e concentração inicial de substrato (10 e 15º Brix). A condição operacional na qual se obteve a maior produção do biopolímero (6,51 g) foi aquela em que se empregou: ºBrix = 10; pH = 4,5 e T = 30ºC. Nesta condição otimizada foram realizados experimentos em frascos, visando determinar os parâmetros cinéticos. Após 18 dias de processo obteve-se uma conversão de substrato em biopolímero de 76,8% e de substrato em biomassa de 2,4%. Os parâmetros cinéticos determinados para os modelos de Monod e Tessier, respectivamente, foram: taxa de crescimento máximo - m0 (dia-1) (4,249 e 4,187); constante de Monod - Km (g/L) (2,947 e 10,000); coeficiente de desaparecimento total de células - Kde (dia-1) (3,961 e 4,089); coeficiente de consumo de substrato pela biomassa - K1 (0,001 e 0,395); coeficiente de manutenção de biomassa - K2 (dia-1) (1,630 e 0,001); coeficiente de produção de exopolissacarídeo - K3 (0,264 e 0,263).As curvas obtidas, segundo os modelos de Monod e Tessier, para os parâmetros de biomassa, substrato e produto, não apresentaram uma boa aproximação dos resultados experimentais. O biopolímero produzido apresentou solubilidade em água (17,9%), em ácido trifluoroacético (72,2%) e a fração solúvel é constituída dos seguintes monossacarídeos: glicose (87,6%); xilose (8,6%); manose (0,8%); ribose (1,7%); galactose (0,1%); arabinose (0,4%) e ácido glucurônico (0,8%). O exopolissacarídeo produzido exibiu diâmetro de poro em torno de 0,07 mm, temperatura de fusão de 118ºC e, quando submetido aos testes de tração mecânica, apresentou os seguintes resultados: espessura (0,08 mm), carga na ruptura (0,01 kN), tensão de ruptura (30,9 MPa), alongamento na ruptura (236%)

The influence of Al 3+ on the anaerobic treatment of a poultry slaughterhouse wastewater was studied in this work. The soluble COD (SCOD), volatile acid (VA) concentrations, and methane yield values were measured and compared for zero, 15, and 40 ppm Al 3+ runs. Methane yields of 55.4, 144.2, and 215.4 ml CH4/g. COD for zero, 15, and 40 ppm Al 3+ concentrations, respectively, were observed. Furthermore, SCOD and VAs were not detectable in the reactor that was seeded with 40 ppm Al 3+. It was concluded that inhibitory effects of long chain fatty acids (LCFAs) on aceticlastic methanogens were reduced by aluminum ion. This conclusion was also corroborated by a new mathematical model for estimating the Monod parameters developed in this work. The main characteristic of this new model is that estimated parameters must satisfy some restrictions, which provides consistency for the estimated parameters.

No description available.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Bioreactors are used to carry out bioprocesses and are commonly used in e.g. biogas production and wastewater treatment. Two common hydraulic models of bioreactors are the continuous stirred tank reactor (CSTR) and the plug-flow reactor (PFR). In this paper, a differential equation system that describes the substrate, biomass and inert biomass in the bioreactors is presented. It is used in a steady-state analysis and design of CSTRs in series. Monod kinetics were used to describe the specific growth rate and the decay of biomass was included. Using the derived systems of differential equations, two optimization problems were formulated and solved for both CSTRs in series and for a CSTR+PFR. The first optimization problem was to minimize the effluent substrate level given a total volume, and the second was to minimize the total volume needed to obtain a certain substrate conversion. Results show that the system of differential equations presented can be used to find optimal volume distributions that solves the optimization problems. The optimal volume for N CSTRs in series decreases as N increases, converging towards a configuration of a CSTR followed by a PFR. Analyzing how the decay rate affects the results showed that when the total volume was kept constant, increasing the decay rate caused less difference between the configurations. When the total volume was minimized, increasing the decay rate caused the configurations to diverge from each other. The presented model can be used to optimally divide reactors into smaller zones and thereby increasing the substrate conversion, something that could be of interest in e.g. existing wastewater treatment plants with restricted space. A fairly accurate approximation to the optimal design of N CSTRs in series is to use the optimal volume for the CSTR in the configuration with a CSTR+PFR and equally distribute the remaining volumes. / Bioreaktorer används för att utföra olika biologiska processer och används vanligen inom biogasproduktion eller för rening av avloppsvatten. Två vanliga hydrauliska modeller som används vid modellering av bioreaktorer är helomblandad bioreaktor (på engelska continuous stirred tank reactor, CSTR) eller pluggflödesreaktor (på engelska plug-flow reactor, PFR). I den här rapporten presenteras ett system av differentialekvationer som används för att beskriva koncentrationerna av substrat, biomassa och inert biomassa i både CSTR och PFR. Ekvationssystemet används för analys och design av en serie CSTRs vid steady-state. Tillväxten av biomassa beskrivs av Monod-kinetik. Avdödning av biomassa är inkluderat i studien. Från ekvationssystemet formulerades två optimeringsproblem som löstes för N CSTRs i serie och för CSTR+PFR. Det första optimerinsproblemet var att minimera substrathalten i utflödet givet en total volym. I det andra minimerades den totala volymen som krävs för att nå en viss substrathalt i utflödet. Resultaten visade att ekvationssystemet kan användas för att hitta den optimala volymsfördelningen som löser optimeringsproblemen. Den optimala volymen för N CSTRs i serie minskade när antalet CSTRs ökade. När N ökade konvergerade resultaten mot de för en CSTR sammankopplad med en PFR. En analys av hur avdödningshastigheten påverkade resultaten visade att en ökad avdödningshastighet gav mindre skillnad mellan de två olika konfigurationerna när den totala volymen hölls konstant. När den totala volymen istället minimerades ledde en ökad avdödningshastighet till att de två konfigurationerna divergerade från varandra. Modellen som presenteras i studien kan användas för att fördela en total reaktorvolym i mindre zoner på ett optimalt sätt och på så vis öka substratomvandlingen, något som kan vara av intresse i exempelvis befintliga avloppsreningsverk där utrymmet är begränsat. En relativt bra approximation till den optimala designen av N CSTRs i serie är att optimera volymerna för en CSTR+PFR, använda volymen för CSTR som första volym i konfigurationen med N CSTR i serie, och sedan fördela den kvarvarande volymen lika mellan de övriga zonerna.

[pt] Neste trabalho, apresenta-se um estudo dos processos de transporte e biodegradação do benzeno e da mistura benzeno/etanol em um solo contaminado, através de simulações em diferentes modelos. Nas simulações foi utilizado o programa de elementos finitos FEFLOW 6.1, para análise de fluxo e transporte de contaminantes. No estudo incorporou-se satisfatoriamente o modelo de reação cinético de Monod multiplicativo, para problemas de transporte de contaminantes, no módulo de reação definido pelo usuário (FEMATHED) do programa FEFLOW 6.1. Este modelo foi utilizado nas diversas simulações realizadas. Para encontrar os valores de parâmetros de Monod e da população bacteriana, simulou-se o comportamento de um bloco de solo in situ contaminado com benzeno usando dados experimentais publicado na dissertação de mestrado de Martins (2010). Como aplicação dos procedimentos estudados, foram simuladas duas colunas em PVC com amostras indeformadas de um solo residual (lisímetros), onde foi fornecida uma solução contaminante na direção vertical, contrário à gravidade, com a finalidade de avaliar ao longo da coluna, a biodegradação dos compostos de benzeno e a influência do etanol nesse processo. Além disso, avaliou-se o atraso da degradação do benzeno por causa da presença do etanol na zona saturada e pelo aumento de biomassa nos domínios simulados. O trabalho também mostra uma descrição do programa utilizado e sua formulação. Finalmente, apresenta-se, comentam-se os resultados e concluem-se a pesquisa. / [en] In this work was studied the transport and biodegradation processes of benzene and of the benzene/ethanol mixture in a contaminated soil using different simulation models. In the simulations, were used the finite element program called FEFLOW 6.1 for flow analysis and transport of contaminants. The study successfully incorporated the kinetic reaction model of multiplicative Monod, for contaminant transport problems, in a reaction module defined by the user (FEMATHED - FEFLOW 6.1). This model was applied in the simulations. To find the values of Monod parameters and bacterial population the behavior of an in situ benzene contaminated soil-block was simulated using experimental data published by Martins (2010). As an application of the studied procedures, two PVC columns filled with undisturbed residual soil were simulated (lysimeters). The lysimeters were vertically provided with a contaminant solution in the vertical direction opposite to gravity, in order to evaluate along the column, the biodegradation of benzene compounds and the influence of the ethanol in the process. In addition, was evaluated the delay of benzene degradation due to the presence of ethanol in the saturated zone and the increasing in biomass in the region of simulated model. This study also shows a description of the program used and its formulation. Finally, the results of the analyses and the incorporation of the model performed are presented, conclude and commented.