Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1940. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed March 23, 2010) Includes bibliographical references (p. 27).

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.

Thesis (Ph. D.)--University of Wisconsin, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Made available in DSpace on 2015-03-03T11:52:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-05-12Bitstream added on 2015-03-03T12:06:20Z : No. of bitstreams: 1 000801492.pdf: 1763859 bytes, checksum: 6119d29067d0782271358dd1d68cf2b9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho foram definidas as combinações escalonadas de gradientes médios de velocidade de floculação em sistemas de câmaras em série e obtidos seus respectivos tempos de floculação total visando atender ao critério do menor tempo de floculação total: nesse sentido foram empregados metologias apresentadas por Argman e Kaufman (1970), Bratby (1981) e Pádua (1994), as quais apresentam modelo de cinética de floculação, metodologia para obtenção dos coeficientes matemáticos por meio de ensaios em escala de laboratório e método para estimativa dos gradientes médios de velocidade de floculação em unidades com escoamento contínuo a partir de ensaios em reatores estáticos. Além disso, foi analisada a sensibilidade do modelo matemático e realizada a aplicação do conjunto obtido pela metodologia concebida por Pádua. Foram obtidos de 15 a 495 combinações de gradiente médio de velocidade de floculação a depender do número de câmaras em série (variando de 2 a 8) resultando em 1.281 combinações distintas, posteriormente foi aplicado a estas combinações 9 diferentes eficiências, resultando em 11.529 valores de floculação total: finalmente aplicou-se uma variação na velocidade de sedimentação (0,5; 2,5 e 5 cm/min) correspondente e diferentes relações entre os coeficientes cinéticos, resultando em 34.587 valores de tempo de floculação total. Foram analisados os percentis desse universo em 5 e 10% para os menores tempos de floculação total, resultando em 1.602 e 3.104 valores respectivamente, com valor mínimo de 2,4 minutos e máximo de 20,1 e 23,8 minutos para percentis de 5 e 10%. Observou-se que o modelo é sensível às variações da razão dos coeficientes cinéticos, quanto maior o valor desta relação menores serão os valores de tempo de floculação. O conjunto de resultados pode ser aplicado à metodologia concebida para obtenção de valores ótimos de tempo de floculação total... / In this paper the scaled average velocity gradients flocculation in camera systems in series and obtained respective times total flocculation combinations were set to meet the criterion of shorter total flocculation were accrodingly employed methodologies presented by Argman and Kaufman (1970), Bratby (1981) and Padua (1994), which have kinetic flocculation method for obtaining the mathematical model coefficients by tests on laboratory scale and method for the estimation of average velocity gradients flocculation units with flow continuous from tests in static reactors. Furthermore, we analyzed the sensibility of the mathematical model and realized the application of the methodology devised jointly obtained by Padua. Were obtained from 15-495 combinations average velocity gradient flocculation depending on the serial number of cameras (varying from 2 to 8), resulting in 1281 different combinations subsequently was applied to nine different combinations of these efficiencies, resulting in 11529 values total time of flocculations, and finally applied to a change in sedimentation rate (0,5, 2.5 and 5 cm/min) corresponding to different relationships between the kinetic coefficients, resulting in 34587 values for total time of flocculation. We analyzed the percentiles of this universe in 5 and 10% for the lowest times total flocculation, resulting in 1602 and 3104 values, respectively, with minimum maximum of 20.1 and 23.8 minutes value of 2.4 minutes and for percentiles of 5 and 10%. It was observed that the model is sensitive to variations of the ratio of the kinetic coefficients, the larger value of this ratio will be smalller time values flocculation. The result set can be applied to the methodology designed to obtain optimal values of total flocculation time, cheking different situations from those observed when the isolated application of the methodology, experiencing a reduction in total time of flocculation in the comparative methods

Bioflocculants produced by two identified bacteria: Actinobacterium sp. Mayor and Methylobacterium sp. Obi were investigated with regard to their physicochemical and flocculating characteristics. The two strains were later combined to form a consortium for further studies. The optimum culture conditions for the bioflocculant production were similar for all strains except in the case of Actinobacterium sp. Mayor and the consortium, where glucose was replaced by sodium carbonate as a carbon source. Multi-nitrogen source was the best nitrogen source compare to individual sources for both strains. The divalent cation, Ca2+ proved to be a better flocculating activity stimulus for all produced bioflocculants in this study. The optimum flocculating activities obtained for both individual strains and the consortium were all at alkaline pH. The yield of purified bioflocculant produced by the consortium was 8.203 g/l, while 4.190 g/l and 4.610 g/l were recovered for single strains of Actinobacterium sp. Mayor and Methylobacterium sp. Obi respectively. Further characterization of pure bioflocculants revealed that a bioflocculant dosage of 0.3 mg/ml resulted in the highest flocculating activity for both individual strains while 1.0 mg/ml of the bioflocculant produced by the consortium was required to enhance maximum flocculating efficiency. These bioflocculants proved to be all thermo stable at a temperature range of 20 to 900°C with a heating rate of 10oC/min under a constant flow of nitrogen gas. The presence of functional groups normally required for bioflocculation such as hydroxyl, carboxyl and amino was also detected. The findings of this study suggest that the producedbioflocculants can be utilized as excellent substitutes for harmful synthetic flocculants in both water and wastewater treatments as well as in other industrial applications.

Abstract This dissertation describes a study of the treatment of wastewater using the flocculation process. Wastewater samples from Barloworld Plascon paints were used for the research. Environmental pressure has necessitated the introduction of a new generation of low-solvent paints. The behaviour of these in coagulation and flocculation treatment processes has not been investigated previously. The optimum flocculent dosage for these paints was investigated. It was found that for paint wastewater to be flocculated, the effect of the dispersants needs to be counteracted, which destabilizes the colloidal suspension, enabling flocculation and settling to occur. Results showed a correlation between the solid content of wastewater and flocculent dosage. Changes in redox potential have been found to be associated with good flocculation. In this work, redox potential was evaluated as an indicator for destabilisation of the dispersants. It was shown that redox potential can be used as an indicator of good flocculation at low dispersant concentrations. Owing to the importance of the hydrolysis reactions of Al3+ in flocculation, which are affected by pH, the pH range in which good flocculation occurs was determined. Results show that optimal flocculation occurred between pH 4 and 5. A strong relationship between flocculent dosage and particle nucleation and growth was observed. Results also showed that mixing improves flocculation kinetics.

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published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy