Thesis (M.S.)--Cleveland State University, 2009. / Abstract. Title from PDF t.p. (viewed on Feb. 16, 2010). Includes bibliographical references (p. 82-89). Available online via the OhioLINK ETD Center and also available in print.

Thesis (M.S.)--University of Michigan, 1985. / Project completed May 1984. Degree awarded August 1985.

Thesis (M. Sc.)--University of Hong Kong, 1998. / Includes bibliographical references (leaf 106-111).

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2005. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.Sc.)(Environmental Technology)--University of Pretoria, 2005. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Made available in DSpace on 2014-10-09T12:36:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:30Z (GMT). No. of bitstreams: 1 03996.pdf: 3342659 bytes, checksum: 712f3dbe2d259d924e05243e956d4e94 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:36:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:30Z (GMT). No. of bitstreams: 1 03996.pdf: 3342659 bytes, checksum: 712f3dbe2d259d924e05243e956d4e94 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Chemical synthesis is closely related to waste minimization. There is no chemical process that does not produce waste. The methods used by industry to deal with this waste is a major environmental concern. This thesis describes the laboratory scale waste minimization and waste treatment strategies for the commercial production process of 4-methyl-3-thiosemicarbazide (MTSC). The production process of 4-methyl-3-thiosemicarbazide was investigated with the aim of increasing the isolated yield of MTSC and at the same time decrease the amount and toxicity of effluent obtained. During this study, parameters were investigated such as the use of excess DIPEA and the temperature of the reaction. Preliminary studies clearly showed that both factors have a significant influence on the final yield of the product. The next part of the investigation was to optimize the two parameters influencing the isolated yield of the MTSC. For this investigation, a multi factorial design was used to determine the optimum conditions in the MTSC yield response. From the results obtained, it was clear that the excess of DIPEA and the temperature of the reaction both need to be high to obtain high yields. These theoretical results were confirmed by results obtained practically, where yields of up 82 % were obtained, but it became clear that even higher yields could be obtained since chromatographic results showed yeilds as high as 90 %. The mass balance of the MTSC synthesis showed a loss of approximately 30 grams per reaction. This loss may have an influence on the final yield. The effluent obtained during the synthesis of MTSC was investigated and a waste treatment protocol was established to reduce the high COD value of the MTSC effluent. The protocol consists of two steps used for the clean up of the effluent. The first being a cooling step; the effluent was cooled at 0oC to induce precipitation of a solid, consisting mostly of MTSC. The second step is a high pressure wet oxidation of the effluent with oxygen in a high pressure reactor. The remaining compounds in the effluent were oxidized, resulting in another precipitate, consisting mostly of sulphur. After the oxidation the COD value of the effluent was decreased by 98 % to a value of 0.4 %. The MTSC present in the precipitate obtained after cooling could be isolated and purified, to add to the yield of the synthesis. The sulphur obtained during the oxidation could also be isolated and reused, or sold to prevent it from contaminating the environment.

The general problem involved in this study is one of resource utilization. The specific approach of this study shall take the form of an inquiry into the relation between monopoly and waste.

<p> The procedures used to acclimate activated sludges for design criteria were reviewed. Experiments were performed to determine if cultures could be developed with the same characteristics as activated sludge from an actual treatment plant. Acclimation studies were performed with three refinery wastes. The resultant mixed cultures were compared, using removal rates, with activated sludge mixed cultures from the refinery's waste treatment plants. Soluble organic carbon was monitored for the removal rate curves. An acclimation procedure is proposed to be used in design studies so that a designer can place confidence limits on design data obtained from the batch reactor studies.</p> / Thesis / Master of Engineering (MEngr)