Thesis (Ph. D.)--University of Alberta, 1994. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1918. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed May 25, 2009)

Thesis (Ph. D.)--University of Washington. / Bibliography: l. 220-228.

Inaug.-diss.--Leipzig.

Thesis (Ph. D.)--University of Alberta, 1994. / Includes bibliographical references.

Th. 3e cycle--Physiol.--Paris 5, 1981. N°: 20.

Acid mine drainage (AMD) is an environmental hazard across the world. Passive bioreactors utilizing sulfate-reducing bacteria to remediate AMD impacted sites are a promising solution due to their low cost and minimal maintenance. This study profiled the microbial community associated with six in situ, pilot scale bioreactors that were constructed with varying ratios of simple and complex organic substrate and exposed to AMD. Samples were analyzed nine and fourteen months post assembly to ascertain long-term performance. The overall microbial and sulfate-reducing communities were analyzed by 16S rRNA gene and dsrA gene sequencing, respectively. Over the fourteen-month experiment, the results indicated that the microbial community shifted from one dominated by heterotrophic and fermentative microorganisms utilizing the available substrates to one commonly found in untreated AMD. Thus suggesting a decrease in bioreactor performance over time. The data also indicated that the overall microbial communities within the test bioreactors possessed similar members, but in different abundance. Thus it is unlikely that substrate composition played a significant role in community diversity. At the end of the study period, sulfide measurements suggested that the bioreactor containing the highest amount of complex substrate (Barrel 6) resulted in the greatest stimulation of sulfate reduction. Analysis of the dsrA genes from the community in Barrel 6 suggested that bacteria related to thermophilic sulfate-reducers were responsible for the increased sulfate reduction in this bioreactor.

The crystallization kinetics of sodium sulphate from 9N sulphuric acid was studied under cooling conditions. The crystal growth and nucleation rates were determined using the Population Balance concept in a continuous mixed-suspension mixed-product-removal (MSMPR) crystallizer. The effects of supersaturation, crystal suspension density and temperature on the crystallization kinetics were all investigated. The study was conducted at crystallizer temperatures of 45, 50, 55, and 60 °C. The crystal growth rate data were correlated to the supersaturation with a power-law, G = KGSg. The crystal nucleation rate data were fitted to both primary (B° = KBSb) and secondary (B° = KNMTjSu) nucleation models. Growth and nucleation rate data were correlated according to the primary (B° = KbGi) and secondary (B° = KnMTjGv) relative kinetic models. The study determined that the growth rate data fit the expression, (G = KGS⁰‧⁸⁷ ), and that secondary nucleation was the dominant mode of nuclei generation (B° = KNMT⁰‧⁸⁴S¹‧²⁷). The sodium sulphate crystallizes from solution as the acid salt, sodium sesqui-sulphate (Na₃HSO₄) . The rate constants, KG and KN, were both functions of temperature and were fitted to Arrhenius type expressions : [formula omitted] / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

A magnesium-plus-lime coagulation process, incorporating magnesium recovery by sludge carbonation, recently developed for water treatment has been tested for its application to the decolourization of kraft mill effluents. Total bleached kraft mill effluent (BKME), after biological treatment and effluent from the first caustic extraction stage of a conventional bleachery (E₁ or T-20 effluent) were examined in the laboratory. It was shown that a combination of low magnesium and low lime dosages can achieve better decolourization of kraft mill effluents than 3-5 times as much lime alone, (i.e.: 30-60 mg/1 Mg⁺⁺ plus 375-475 mg/1 lime (as Ca0) at pH ≃11.1 for BKME; and 150-300 mg/1 Mg⁺⁺ plus 1875-3750 mg/1 lime (as Ca0) at pH ≃12.1 for T-20 effluent.) Colour removals of 90-95% were achieved using either fresh or recycled magnesium. Results of the study showed that greater than 90% magnesium recovery can be attained by operating the sludge carbonator to a final pH ≃7.5, with complete mixing and a good C02 diffuser system provided. (Key words: magnesium, lime, kraft mill effluent, decolourization, colour removal, Magnesiurn Carbonate Process.) / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The equilibrium phase diagram for the system sodium sulfate-methanol/water-sulfuric acid at 35° was determined. The nucleation, and growth characteristics of sodium sulfate have been studied in a laboratory scale crystallizer (Mixed Suspension Mixed Product Removal 'MSMPR') under carefully controlled conditions of supersaturation, temperature, agitation rate and residence time. From a statistical analysis of the data it was found that supersaturation, temperature, the interactions of supersaturation with temperature and agitation rate with temperature had positive effects on growth and nucleation rates, while agitation rate, residence time, the interactions of agitation rate with supersaturation, residence time with supersaturation had negative effects on growth and nucleation rates. The 'order' of the nucleation process, b, defined by B = K[sub= N]S[sup= B] was about 5. The growth rate, defined by G = K[sub= G]S[sup= c] Was first order (C = 1). For both processes the activation energy varied from 12 to 15 kcal/mol. The growth process was considered to be surface integration controlled for the various conditions tested. The nucleation rate was considered essentially to be homogeneous nucleation. A non-linear mathematical relationship was developed for both growth rate and nucleation rate in terms of the three factors, temperature, supersaturation and residence time. In both the growth and nucleation rate models the measured data fit poorly. This indicates that the model (a reaction rate type) poorly represents the data for crystallization found in this study. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate