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No description available.

Processing of petrochemical compounds produces a large amount of wastewater. This wastewater consists of toxic (hazardous) materials that can not be discharged to the environment without treatment. As restrictive environmental constraints increase, new technologies are needed to treat those toxic materials before discharging them to the environment. Wet Air Oxidation (WAO) is one of these new methods. / This study casts light on the effect of initial pH on the WAO of benzene at different temperatures and pressures. It was found that at pH 6, a temperature of 260°C and a partial pressure of oxygen of 1.38 MPa around 97% degradation was achieved in one hour. When the initial pH was lowered to 4 more than 90% degradation was achieved at 220°C and PO2 of 1.38 MPa in only 15 minutes.` It was concluded that the higher the temperature the better the benzene degradation, and the faster benzene degradation has been obtained with the increasing partial pressure of oxygen. The main intermediates were acetic acid and formic acid. / Furthermore, it was found that the degradation of benzene can be further enhanced in the presence of phenol. The main reason can be attributed to the effect of the free radicals generated from the fast phenol degradation. A simplified pathway for oxidation of benzene was proposed.

In South Africa, sustainable development is set in the context of two separate economies. The second of these economies consists of the rural population and is characterised by poverty and stagnant development. Sustainable development is an increasingly topical concept which highlights the need for development to proceed in a manner that does not deplete natural resources. In addition to narrowing the gaps between the various classes (layers) in an economy, the key ‘ingredients’ of sustainable economic development include “natural resource management, food, water, and energy access, provision and security” (Blignaut, 2009: cited in Blignaut and van der Elst, 2009: 14). A biodigester is a potential solution to some of the difficulties faced by remote rural populations. Biodigester systems are submerged tanks capable of producing a nutrient rich fertiliser and combustible gas when consistently fed with organic matter and water. A biodigester may be one simple answer to the key ingredient needs of sustainable development – reducing the depletion of natural resources, providing clean burning energy for cooking and fertiliser for growing food. The potential is clear for biodigesters to aid in the process of sustainable development. The question to be analysed is whether this technology would be financially and economically feasible for installation and use in rural households. This thesis focuses on a typically remote and rural community in KwaZulu-Natal, South Africa, in order to assess the potential feasibility of a biodigester system. The appraisal takes the form of a Cost Benefit Analysis (CBA) and aims to establish whether or not this technology is financially feasible for individual rural households and/or economically beneficial to society. / Thesis (M.Com.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

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No description available.

No description available.

The phenomenon of selective retention of cations from aqueous solutions by microbial biomass has been termed biosorption. Samples of waste microbial biomass, originating from industrial fermentations and biological waste water treatment plants, have been tested for their uranium and thorium biosorption potential. Optimum biosorption conditions have been identified. Rhizopus arrhizus was identified as the biomass presenting the highest U or Th uptake capacity, in excess of 170 mg/g. The effect of solution co-ions (namely Fe('+2), Zn('+2)) on the equilibrium biosorptive uptake capacity of Rhizopus arrhizus has been examined. The study of the rapid kinetics of U and Th biosorption has been initiated. Accumulated experimental and theoretical information led to the formulation of a biosorption mechanism hypothesis for the systems U or Th - Rhizopus arrhizus. Biosorption of both U and Th by Rhizopus arrhizus occurs mainly in the cell wall of the mycelium. Complexation by the cell wall chitin, adsorption, and hydrolysis of the complex are the processes participating in the proposed mechanism hypotheses.

Graduation date: 1994

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 6, 2008) Includes bibliographical references.