Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 291-296).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1974. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 229-237).

Thesis (M.S.)--University of Wisconsin, 1973. / eContent provider-neutral record in process. Description based on print version record. Includes a bibliography.

Thesis (Ph. D.)--University of Wisconsin, 1973. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 185-190).

Thesis (Ph. D.)--University of California, Davis, 2005. / Degree granted in Civil and Environmental Engineering. Also available via the World Wide Web. (Restricted to UC campuses)

Flocculation has been widely adopted as one of the most effective methods to remove colloidal particles in water or wastewater treatment. Synthetic flocculants are conventionally used because of their high flocculating efficiency and cost-effectiveness. However, they have been reported to have hazardous properties and implicated in some serious health problems including senile dementia and neuro-toxicity, as well as being recalcitrant in the environment. Consequently, efforts are being geared away from the use of synthetic flocculants in water and wastewater treatment. Hence, the need for safe and eco-friendly flocculants has become imperative. Compared with synthetic flocculants, bioflocculants have special advantages such as safety, biodegradability and harmlessness to the environment and humans; attributes which make them potential alternatives in water treatment, downstream as well as fermentation processes. In the current study, the potentials of bacterial isolates recovered from Algoa Bay in the Eastern Cape Province of South Africa for bioflocculant production were investigated. The bacterial isolates were identified by polymerase chain reaction (PCR) as belonging to the Bacillus genus. The analysis of 16S ribosomal deoxyribonucleic acid (rDNA) nucleotide sequence of isolate M72 showed 99 percent similarity to Bacillus toyonensis strain BCT-7112 and was deposited in the GenBank as Bacillus toyonensis strain AEMREG6 with accession number KP406731. Likewise, the 16S rDNA nucleotide sequences of isolates M69 and M67 showed 98 percent sequence similarity to Bacillus licheniformis strain W7 and Bacillus algicola strain QD43 respectively; and M67 isolate was subsequently deposited in the GenBank as Bacillus sp. AEMREG7 with accession number KF933697.1. The results of the nutritional requirements and fermentation conditions revealed that optimum inoculum size for REG-6 production was 4 percent (v/v), while 5 percent (v/v) and 3 percent (v/v) were most favourable for MBF-W7 and MBF-UFH production respectively. Glucose was the best carbon source for the production of bioflocculants (REG-6 and MBF-UFH) by Bacillus toyonensis AEMREG6 and Bacillus sp. AEMREG7 respectively, while maltose supported optimum bioflocculant (MBF-W7) production by Bacillus specie. Inorganic nitrogen (NH4NO3) was the favoured nitrogen source for both REG-6 and MBF-W7 production, while mixed nitrogen sources [yeast extract + urea + (NH4)2SO4] supported the maximum production of MBF-UFH. The initial medium pH for REG-6 was 5, while MBF-W7 and MBF-UFH were both maximally produced at the initial pH of 6. After a 96 h cultivation period under optimal culture conditions, 3.2 g of purified REG-6 with a maximum flocculating activity of 77 percent was recovered from 1 L fermented broth of Bacillus toyonensis AEMREG6. Yields of 3.8 g and 1.6 g pure bioflocculants with the respective highest flocculating activities of 94.9 percent and 83.2 percent were also obtained from 1 L, 72 h-fermented broths of Bacillus licheniformis and Bacillus sp. AEMREG7 respectively. Furthermore, all the three bioflocculants (REG-6, MBF-W7 and MBF-UFH), displayed thermal stability within the temperature range of 50 to 100 oC, with strong flocculating activities of over 80 percent against kaolin suspension over a wide range of pH range (3–11) and relatively low dosage requirements of 0.1-03 mg/ml in the presence of divalent cations in the treatment of kaolin clay suspension and Thyme River waters. Chemical composition analyses of the bioflocculants showed them to be glycoproteins with a predominantly polysaccharide backbones as shown by the following carbohydrate/protein (w/w) ratios: 77.8 percent:11.5 percent (REG-6); 73.7 percent:6.2 percent (MBF-W7) and 76 percent:14 percent (MBF-UFH).

D.Phil. / Water quality management in South Africa changed drastically over the last 20 years, from focussing on effluent control to managing the water resource itself. This resulted in the promulgation of the National Water Act (Act 36 of 1998) which introduced amongst others the classification of water resources and the Reserve. The implementation of the Act is currently in process, and this requires the development of a number of "tools". One such a need is to develop a protocol to set water quality objectives for water resources that takes cognisance of both the classification and the Reserve. The move to manage water resources has also taken place in other countries such as the United Kingdom, the United States of America, The Netherlands and Australia. However, most of these countries do not have the same circumstances or the same approach to water quality management as South Africa. In most cases those countries have adopted single value water quality objectives that lead to an on/off assessment of the success of management actions that does not take full cognisance of the natural variability of water quality such as is experienced in South Africa. Water quality is not static and the effect on a user is a function of dose and exposure. In most cases users can recover from short term exposures to undesirable conditions, as long as these effects are still chronic and not acute. Water quality can therefore not be assessed by making use of a single value, but must be based on a description of the central tendency as well as extreme values. This assessment (ideal, acceptable, tolerable, unacceptable) of water quality should also be linked to management actions so that managers of water resources know where to focus the limited resources at their disposal. In this thesis a protocol is developed that can be used to determine water quality objectives that take into account the class of the water resource, as well as the Reserve. Together with this an assessment system is offered that allows managers to prioritise their actions. The protocol was applied to the Jukskei River Catchment, using data that was collected over a six year period. The protocol was found to be robust and yielded water quality objectives that can be used to focus attention on the most pressing problems. / Prof. G.J. Steyn Dr. H. H. du Preez

Stormwater management in urban areas is a major concern today. The problem of disposing of this stormwater runoff in a satisfactory manner is very difficult indeed. Both the quantity and quality aspects of the runoff must be dealt with to obtain a solution of this problem. The water quality of the runoff can vary depending upon the different land uses of the drainage basin. The quantity of the stormwater runoff also depends upon the land uses, the rainfall intensity and duration of the storm. The traditional methods available for determining the quantity of the stormwater runoff are numerous. These traditional methods and recently developed mathematical simulation models are discussed in this paper. Prediction of the water quality of stormwater runoff is in its infancy. Several of the mathematical models have the capabilities of quality simulation, however, the simulation results are usually inconsistent with actual quality data. Of the simulation models currently in use, the EPA Storm Water Management Model is one of the most comprehensive models. Application and verification of these newly developed models is limited. The EPA Model was chosen to simulate the quantity and quality of a small urban drainage area. The study area chosen was an urban commercial section of the Lake Eola drainage basin. Physical data of the study area, such as ground slopes, storm sewer sizes and locations and slopes were determined. This data was then utilized for simulations of actual rainfall events. Verification of the quantity and quality simulation results was performed with actual quantity and quality data obtained for these rainfall events. Quantity simulation was considered successful with good correlation between the simulated and actual runoff. Quality simulation was successful to a lesser degree, the conclusion being that further quality calibration of the Model was required. Correlation between actual and simulated stormwater quality was achieved to some extent. The lack of correlation was felt to be due to calibration of the Model.

Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries