Thesis (Ph.D.)--Ohio University, November, 2008. / Release of full electronic text on OhioLINK has been delayed until November 30, 2010. Includes bibliographical references (leaves 265-284)

Thesis (Ph.D.)--Ohio University, November, 2008. / Title from PDF t.p. Release of full electronic text on OhioLINK has been delayed until November 30, 2010. Includes bibliographical references (leaves 265-284)

Thesis (M.S.)--Brigham Young University. Dept. of Microbiology and Molecular Biology, 2007. / Includes bibliographical references (p. 33-37).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 76-87). Also available via the Internet.

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (M.S.)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: James W. Bauder. Includes bibliographical references (leaves 75-84).

A new method of sea water desalination, Centrifugal Reverse-Osmosis (CRO), is developed from concept to patented design and functional prototype of capacity 11,355 litres of fresh water per day. CRO is shown to have significant benefits relative to the leading existing desalination technology, conventional reverse-osmosis. These benefits include: lower energy consumption, reduced initial and replacement membrane costs, lower noise levels and improved reliability. CRO is projected to show increasing cost efficiency as plant capacity increases. For a relatively large CRO plant, 65lm³ fresh water per day, the total cost of desalinated water is projected to be 25.9% lower than the total cost of water produced by a conventional RO plant of equivalent capacity. The current patented design requires further development in order to realize this potential. Toward this end, a computational and experimental study of rotor windage losses and an experimental study of fluid flow losses through the rotor are conducted. In addition a new method for the analysis of stresses in a filament wound rotor shell under combined centrifugal and pressure loading is developed. / Graduate

M. Ing. / Southern Africa faces an increasingly serious shortage of potable water and will continue to do so for the foreseeable future. Desalination is a process whereby dissolved solids are removed out of a contaminated water source to produce potable water. However, desalination carries an unavoidable energy cost per unit of potable water produced. Minimising this energy cost is an important goal towards making desalination a practical technology for widespread use. A desalination process is proposed by the author which is based on the injection of a brine spray into vacuum conditions. Although a complete desalination process is proposed, only the core components of the desalination process are investigated in the present study. The physical processes taking place in the core components are complex. Computational fluid dynamics is the numerical tool used to investigate the processes taking place in the core components. A commercial computational fluid dynamics code, augmented with user-programming, provides a simulation model for the core components. Due to the complexity of the investigated desalination process not all of its physical aspects are accounted for in the simulation. An analytical as opposed to experimental verification of the simulation is performed. The simulation model is used to perform a number of parametric tests. These tests are used to numerically investigate the effects of a number of process variables on the core components. The results of these parametric tests are presented and discussed

Salinisation has been identified as a major cause of the progressive deterioration in the public water system in South Africa. To deal with this problem Waste Stabilisation Ponding systems have been used by the Leather Processing Industry as zero-dischaJ;ge wastewater evaporation disposal processes in water-limited inland regions of the country. While effective in the evaporation disposal function these systems are plagued by the generation of serious odour nuisance creating intractable environmental problems relating to adjacent residential communities. High loading to ponds of organic compounds, sulphides and ammonia results in strongly reducing anaerobic conditions prevailing in early parts of pond cascades. These are characterised by bright red colours due to the predominance of purple photosynthetic bacteria. Sporadic micro algal blooms of Spirulina sp. and Dunaliella sp. had been previously noted to occur on the latter ponds in these cascades, and were associated with their conversion to facultative function, with aerobic surface layers, and a marked reduction in odour release. This research programme undertook an investigation of the microbial ecology of a tannery waste stabilisation ponding system to describe factors which give rise to these blooms, and to determine whether microalgal growth may be manipulated to achieve a reliable oxygengenerating capping of the anaerobic ponds. The predominance of near pure cultures of Spin/lina platensis was demonstrated for the blooms and factors restricting its growth in the system were described. These include the interaction of ammonia and sulphide toxic effects and laboratory studies were undertaken to show how effluent loading may be regulated to enable effective growth of the cyanobacterium. At appropriate dilutions of tannery effluent an enhancement of growth was noted, compared to growth in defined mineral medium. An investigation of this phenomenon provided preliminary evidence for organic uptake by the pond micro algae and a possible contribution to heterotrophic nutrition. The manipulation of Spirulina sp. growth in a High Rate Algal Pond raceway was undertaken in outdoor pilot plant studies and the effect of microalgal capping of the anaerobic ponds in the cascade was demonstrated by activating a recycle loop from a blooming facultative pond. Heavy metal contaminants were effectively eliminated by an optimisation of the primary anaerobic pond function and precipitation as metal sulphides. Biomass was harvested and dried, during which a range of methods were evaluated. Toxicological studies were undertaken on the dried biomass using Artemia and chick assays, and feed studies showed its useful application in rations for the abalone Haliotlls midae and rainbow trout Onchorhynchlls mykiss. Based on positive independent assessment of research outcomes, a decision was made by the tanning company operating the Waste Stabilisation Ponding system, to proceed to the construction of a full-scale 2 500 m2 High Rate Algal Pond raceway. This would be used for controlled Spirlilina biomass production to effect a practical capping of the anaerobic ponds in the system, and to evaluate its commercial potential in the feed market. The Advanced Integrated Wastewater Ponding System described by Oswald (1991) provided the conceptual basis for the Algal Biotechnology process development undertaken. The studies of the microbial ecology and the biotechnological potential of this system have shown that a Spirulina-based High Rate Algal Ponding process can be engineered in such a way that saline tannery effluents may be treated to effect a significant reduction in overall pollution load, that biomass may be recovered as a value added product of the treatment process and that the operational performance of Waste Stabilisation Ponding systems, and hence their immediate environment, may be improved by the use of the High Rate Algal Pond as a retrofitted upgrading unit operation.

The most widely advocated method of carbon capture and storage involves the injection of CO2 into underground geological formations. Key to the development of this geological sequestration technology is the existence of suitable high-integrity geological sites for the safe, long-term storage of CO2. Unlike depleted oil and gas reservoirs which are historically proven to be well-defined, formations with saline brines may not have a similar proven sealing capacity. In the main, complex geochemical reactions occur in the supercritical CO2 / brine / host rock environment which can cause significant changes in the porosity, permeability and injectivity of the formation. Depending of the nature of the processes, the effects of the underground injection of CO2 may (1) yield increased storage capacity of the target horizon, or (2) lead to increased potential for leakage beyond the confining layers of the saline formation, or (3) impede the injection exercise as a whole. It is conceivable that accelerated, localized mineral carbonation could be induced at strategic places between the CO2 plume and fault zones or facies changes present in deep saline formations, in order to prevent the migration of CO2 outside the confined layers of the reservoir. The South African electricity producer, Eskom, generated 36.01 million tons of coal- combustion fly ash in 2010. About 5.6% were reused for the production of cement. The remaining 33.89 million tons were safely disposed of and managed on Eskom ash dumps and dams which are located adjacent to their corresponding power stations. South Africa has a long history regarding the development of new applications for this material and is very active in the development of ash technologies. Concurrently, the power industry is also a major carbon dioxide (CO2 ) emitter, with Eskom’s emissions approximating 225 million tons for 2010. In this study, the author introduces a theoretical concept whereby fly ash in a slurry form could be injected at strategic sites of deep saline formations. The purpose of this injection strategy is to prevent the migration of injected anthropogenic CO2 plumes beyond the confining layers of the formations, via induced in situ localized, accelerated mineral carbonation. The proposed application falls within the carbon capture and storage (CCS) initiative by geological sequestration and aims at improving the integrity of deep saline formations which may be at risk of leakage upon injection of CO2. The use of coal-combustion fly ash in industrial mineral carbonation and the research involving its applications in carbon capture and storage (CCS) has internationally gained increased attention. However, the work involving fly ash in industrial mineral carbonation has only focused on the sequestration of sub-critical CO2. This work demonstrates for the first time that fly ash can react with supercritical CO2 under varying pressure and temperature conditions. The experiments were conducted following an assumed geothermal gradient for deep saline reservoirs, as described by Viljoen, 2010, i.e. 44°C/80bar and 50°C/100bar. Ultra-pure water was used as a solvent. The duration of experiments ranged from 60 minutes to 7 days. Under these T/ P conditions, carbonates in the form of calcite (CaCO3 ) were only detected at completion of the 7 days experiment. Further investigation was undertaken at 90°C/90bar for 2 hours using synthetic brine as a solvent, in order to mimic the composition of deep saline formations. This work yielded both aragonite and calcite, which formed as sheets at the base and on the walls of the batch reactor. The carbonated sheet fragments were examined using scanning electron microscopy (SEM) and were found to have an approximate thickness of 16 μm. A thinner layer of white precipitate on the walls of the reactor was composed of aragonite and calcite and contained an amorphous phase of carbonate of ca. 1% by volume. The mineralogical composition of these carbonated sheets was confirmed using XRD, which demonstrated the presence of aragonite (23%), calcite (3%) and fly ash minerals (e.g. mullite, quartz). It also contained an XRD-amorphous phase of about 37%. These sheets were thus enriched in calcium and carbon but also other elements were found to be present (Al, Si, Na, Mg and Cl) as shown by SEM. It is, however, unclear whether these elements identified in the spectrum are part of the sheet or are rather indicative of an effect of analytical volume created by the SEM electron beam being larger than the thickness of the sheet. Small amounts of S were also detected. Fly ash particles as well as a small number of needle-shaped gypsum crystals were visibly embedded in the sheet (SEM). Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Geology / unrestricted