Graduation date: 1972

Thesis (Ph. D.)--University of Florida, 1979. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 117-121).

Abdulrahman Al-Humiany (1999) A Comparison of the Responses to Enviromental Stress of the Gram-Positive Bacterium Staphylococcus xylosus and the Gram-Negative Bacterium Halomonas Halo. PhD Thesis, Department of Molecular Biology and Biotechnology, University of Sheffield. Salt tolerance of the Gram-negative bacterium, Halomonas Halo, was compared with the salt tolerance of a newly isolated Gram-positive coccus Staphylococcus xylosus. Both organisms grew over a range of salinities from 0.1 - 3.0 M NaCI in both rich medium containing yeast extract and in minimal medium. In the absence of yeast extract, growth of S. xylosus was very slow at 3.0 M NaCl and its optimum salinity for growth was 0.1 M NaCl, whereas Halomonas Halo showed optimum growth at 0.5 M NaCl. Growth experiments replacing NaCI with KC1 and the effect of Na+ on the rate of respiration showed that Halomonas Halo had a greater requirement for Na+ for growth than S. xylosus. When betaine was added to the minimal medium, it greatly increased the growth rate of both organisms at 3M NaCl. The precursor of betaine, choline, was also effective in increasing the growth rate of Halomonas Halo, but was much less effective for S. xylosus. Both organisms transported betaine into the cells by an energy dependent transport system; transport rates were broadly similar, but it appeared that the halotolerant S. xylosus took up betaine more efficiently than Halomonas Halo. Halomonas Halo and S. xylosus were shown to grow across a pH range from 5.5 - 8.5, but S. xylosus showed optimum growth across the full range whereas Halomonas Halo showed a distinct optimum at pH 7.0. The proton motive force (Ap) was found to be low in both organisms and at pH 8.5, it fell below the theoretical minimum (150 mV) which is required for ATP synthesis. Ap was significantly reduced by the inhibitor carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and to a much lesser extent by monensin. Both inhibitors completely stopped the growth of both organisms at pH 7.0. The possibility that compatible solutes may protect enzymes from thermal denaturation was examined, but the results were inconclusive.

This PhD thesis proposes a new and possibly cheaper method to desalinate saline water. The method involves utilisation of ion exchange (IX) and nanofiltration (NF) technologies as one hybrid system.

In the Wairau Valley 40 km southwest of Blenheim, elevated salinities are present in the groundwater below a depth of approximately 15 m, to the north of the Wairau Fault. Saline water is present very close to the surface between the Southern Hills and the Wairau Fault. Highest concentrations are located in well O28/w/0219 with total dissolved solids concentrations approximately 31,000 mg/L. Only a few wells in the study area have intercepted the saline groundwater. A report by Taylor (2003) has identified the groundwater below the Holocene terrace surface is recharged from Southern Hills runoff, however the Wairau Fault has a significant impact on the groundwater flow on the south bank acting as a semi-permeable barrier to groundwater flow from the southern Hills streams identified by several spring which emerge on the fault trace. The scope of this investigation was to identify the extent of the saline groundwater in the Homelands area and to attempt to define the origin of the highly saline groundwater. Furthermore, to define the groundwater flow path below the upper terrace surface to recharge the Wairau Valley Aquifer. The Multi-Electrode Resistivity technique was used to define the extent of the saline groundwater. This shows the saline groundwater is ubiquitous at depth in the study area. The depth to the freshwater/saline water interface varies laterally in the resistivity profiles. A major control on the presence of the groundwater salinity is considered to be the permeability of the gravel. Gravels with a higher permeability are probably washed of any residual salinity that may have been present in the past. Investigations into the origins of the saline groundwater were completed using stable isotope analysis (¹⁸O, ²H, and ¹³C), hydrochemistry and age dating techniques (³H and ¹⁴C). Due to the complex chemistry a single source could not be identified, however two methods were identified as the most likely. This was evaporative concentration of fresh water in the Wairau Valley, or the upward migration from the Wairau Fault of formation water probably of seawater origin. The stable isotope data fits best with an evaporative concentration of freshwater within the Wairau Valley, however, ratios of chemical constituents are very similar to other formation waters found in other parts of the world. Stream gauging of streams on the south bank show no significant water loss in the reaches north of the Wairau Fault. Therefore, recharge must be crossing the Fault trace as groundwater. Boundary Creek looses all of its surface flow for most of the year upon reaching the valley floor. Bounday Creek has washed out sections of the Wairau Fault and Major terrace riser between Wr 1 and Wr 2 terrace surfaces. It is proposed that groundwater flowing in the gravels reworked by Boundary Creek is the major recharge source for the Wairau Valley Aquifer.

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The distillation of sea water is of importance for the future demands for potable water and other uses in the world. A novel technique, based on electrohydrodynamic (EHD) principles, was used in this realm to desalinate artificial sea water of 3.3% (w/V) concentration. A single point corona electrode was operated at a potential of 5.3 kV (maximum output current 0.3 mA), and was installed one cm over the surface of sea water. The flux of air ions was about 3.0 $ times$ 10$ sp{12}$ cm$ sp{-2}$ s$ sp{-1}$ which produced an average electric wind of 1.72 m s$ sp{-1}$ at the sea water surface. Space charge from a corona electrode generated forces in the media to enhance the evaporation rate by about a factor of three compared with a control freely evaporating sea water. Water vapour was condensed and the condensate's purity was evaluated by chemical and physical analyses. Electrical conductivity and pH of the EHD distillate were found to be 14 $ mu$S cm$ sp{-1}$ and 5.5, respectively. In the absence of Joule heating, the energy required for EHD-distillation was comparable to the latent heat of vaporization of 2.3 $ times$ 10$ sp3$ kJ kg$ sp{-1}$ for water. The steady-state temperature of EHD solution was below that of the corresponding unventilated freely evaporating sea water. Electric wind caused by the ionic drag is considered to be the principal driving force for the enhancement.