Made available in DSpace on 2014-06-11T19:24:38Z (GMT). No. of bitstreams: 0 Previous issue date: 1999-11-05Bitstream added on 2014-06-13T18:52:21Z : No. of bitstreams: 1 breda_cc_me_botfca.pdf: 821980 bytes, checksum: a49ce00ac1caf716ae66bf9ea700c42b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os efluentes de indústrias de chapa dura de fibra de madeira originários da exploração de eucalipto, são caracterizados por altos valores em DQO e material sólido em suspensão, tornando-os altamente poluentes para o ambiente e, principalmente, para os recursos hídricos. As empresas que atuam nesse segmento fazem o tratamento de seus efluentes de diversas maneiras, sendo a disposição por irrigação em solos cultivados, uma das formas utilizadas. Essa prática tem como base a melhoria da qualidade da água pela sua infiltração e principalmente pela evapotranspiração das plantas. Porém o lançamento em solos tem consequências, às vezes, muito graves, principalmente no que se refere a colmatação do solo e também à possível contaminação do lençol freático. O presente trabalho teve como objetivo o desenvolvimento de um sistema de tratamento de tais efluentes através do processo de peneiramento, visando a remoção das fibras em suspensão. Para isso desenvolveu-se um equipamento composto por peneiras rotativas substituíveis, com base em modelo francês, recomendado para o tratamento de efluentes industriais. Optou-se por esse sistema após a verificação da presença de grande quantidade de material sólido presente no efluente. Foram realizados 5 ensaios combinando-se peneiras rotativas de diferentes malhas (0,25 ; 0,50 ; 0,75 ; 1,00 e 1,50 mm) com suas respectivas rotações (13 ; 20 ; 33 ; 41 e 53 rpm) e vazões de entrada do efluente no sistema, que também foram 5 para cada ensaio. Para se verificar a influência do sistema proposto na redução da carga poluidora do efluente foram coletadas amostras na entrada do sistema (efluente “in natura”) e na saída (efluente após peneiramento) totalizando 150 amostras. Nessas amostras foram analisadas as seguintes variáveis:... / The wastewater from hardboard industries coming from the eucalyptus exploration are characterized by high values of COD and suspended solid matter. For this reason, the wastewater significantly pollute the environment, specially the water resources. The industries that act in this area treat their wastewater by different ways. The irrigation of cultivated lands is one of the options for treatment of the wastewater. By using this procedure, there should be an improvement in the water quality because of its infiltration into the soil and because of the plant’s evapotranspiration. However, the wastewater irrigation of the soil sometimes brings severe consequences, which are mainly related to the development of crusts on the soil surface and the possible contamination of the ground water. The objective of the present research was based on the development of a system to treat such wastewater by using the screening process, in order to remove the fibers in suspension. To do so, it has been developed an equipment that contains rotating changeable screens based on a French model that is recommended for the treatment of industry’s wastewater. Five trials have been performed combining rotating screens with different nets (0.25, 0.50, 0.75, 1.00, and 1.50 mm) with their respective rotations (13, 20, 33, 41, and 53 rpm) and also with 5 different flows of the wastewater incoming in the system. In order to verify the influence of the proposed system on the reduction of the pollutant capacity of the wastewater, 150 samples were collected at the inlet of the system (“in natura” wastewater) and at it’s outlet (wastewater after screening). From these samples, the following variables have been analyzed: total solids, fixed total solids, volatile total solids, pH, turbidity, electrical conductivity, COD, BOD, and... (Complete abstract click electronic access below)

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M.Sc. / There has been significant development of new technology for the economic use of mining waste within recent years. The application of these new technologies makes the process of environmental rehabilitation less of a profit loss to mining companies and motivates them to take part in environmental rehabilitation. Apart from the financial benefit through redemption of costs, the economic use of mining waste, especially in the case of retreatment operations, may lead to the removal of waste from site, the removal of harmful substances, the recovery of economic minerals and job creation. The importance of the development and application of these technologies is emphasised through consideration of the different impacts of mining on the environment, the requirements by new environmental laws concerning mining activities in South Africa and the economic survival of the mining industry. This paper discusses the currently available and developing technologies to utilise mine waste economically by highlighting some of the most significant developments over the years. The paper then focuses on the uses of coalmine waste and associated regulations implemented to promote its economic use. The paper then continues to discuss other technology and techniques that can be applied to facilitate the economic use of mining waste. Lastly the paper examines whether mining companies in Gauteng and a few coal mines outside Gauteng are applying any of these technologies or are using their waste economically in other ways.

Chemical synthesis is not complete without waste treatment. There is no chemical process that does not produce waste. The untreated effluent discharged by chemical industries poses a major environmental concern. This dissertation describes the results of an investigation carried out on the formation of by-products (impurities) during the synthesis of atrazine by neutralization of the reaction mixture during the actual synthesis procedure, and prior to disposal using carbon dioxide or hydrochloric acid. The main objectives for the said investigation were: {u100083} To optimise the reaction parameters to obtain a higher yield and purity of atrazine. {u100083} To evaluate the use of carbon dioxide and hydrochloric acid to neutralise the reaction mixture. {u100083} To study the solids present in the effluent. Synthetic reactions were carried out in the presence of an organic solvent, methyl isobutyl ketone (MIBK). The synthesis of atrazine was optimised in terms of addition sequence and rates of amine reagents and base (proton acceptor) additions by means of bench scale reactions. It was found that addition of a neutralising step (hydrochloric acid or carbon dioxide) to neutralise the basic reaction mixture prior to and after addition of the secondary amine and the base minimizes the formation of by-products. Of particular importance in ensuring high yields and selectivity to the atrazine product was temperature control, pH control, reagent ratios, addition rates and mixing. The latter was important in view of the rapid reaction of amine/NaOH with cyanuric chloride, as well as the possible reaction of mono-i, the reaction intermediate, with IPA in cases of excesses of reagent. Under optimum conditions, an atrazine composition of >97% was achieved where the resultant product was well within stipulated product specifications.

Due to the development of intensive livestock production methods -namely, high-density confinement feeding - animal wastes traditionally looked upon as "natural" or "background" wastes, are now being subject to the same restrictions, as regards disposal, as industrial wastes. As a result waste treatment of some nature has become necessary. Such treatment methods would reduce the amount of solids requiring disposal and make the liquid portion more acceptable for disposal to water courses or for re-use. Anaerobic lagooning is one such method of waste treatment of concentrated animal wastes. An investigation on a laboratory-scale of the effects of various parameters on the anaerobic decomposition of hog waste was undertaken. Included in this study was the effect of varied detention times and temperatures on such waste characteristics as oxygen demand, solids, nutrients and gas composition and production. The final outcome of this program was to add some degree of optimization to the anaerobic waste treatment method and to develop improved design guidelines related to this specific field. All recommendations presented are based on laboratory findings. Correlation between laboratory-scale results and field-scale results was not attempted in this portion of the study. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate