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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Thermal Analysis of Binding of Organic Pollutants to Titanium Dioxide

Annarapu, Shashidhar 01 May 2014 (has links)
Conventional waste water treatment processes are not completely effective in removing highly stable organic compounds. Photocatalytic degradation on titanium dioxide is a possible alternative technique for many classes of these compounds. Several studies have been done by other researchers to study mechanisms of photocatalytic degradation, which occurs either through direct oxidation by holes or via indirect oxidation by radical messengers. Titanium dioxide can oxidize substrates directly through hole oxidation mechanisms or indirectly through free radical mechanisms. Substrates must bind onto the catalyst surface to undergo direct oxidation by holes. Thermogravimetric analysis (TGA) was performed on four different classes of compounds; iodinated contrast agents (iohexol and diatrizoate), polycyclic aromatic hydrocarbons (perylene and pyrene), the antibacterial agent triclosan and the pesticide atrazine, to investigate which of the compounds are adsorbed on the surface of titanium dioxide to undergo direct oxidation through electron holes. Differential scanning calorimetry (DSC) was conducted on triclosan and atrazine to determine if the desorption reaction is endothermic or exothermic. Powder X-ray diffraction was performed on all four classes of compounds to observe diffraction pattern of these compounds.
12

Bioremediation of creosote-contaminated soil by microbial intervention..

Atagana, Harrison Ifeanyichukwu. January 2002 (has links)
No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2002.
13

Humic acid pretreatment for enhancing microbial removal of metals from a synthetic 'wastewater'.

Desta, Tsegazeab Goje. January 2004 (has links)
The presence of heavy metal ions in waste streams is one of the most pervasive environmental issues of present times. A rotating biological contactor (RBC) was used to investigate the potential capacity of microbial biofilms in remediation of the metal ion species from a mixed metal contaminated effluent solution containing Cr+3 , Pb+2 and Cu+2 , each at a concentration of 200 mg r1 • In the first part of this study the effectiveness of various support materials for the development of microbial biofilms capable of removing heavy metals from a synthetic effluent was investigated. EDX analysis showed that none of the support matrices investigated, viz. gravel, polyester batting and sand, adsorbed metal ions on their surfaces; hence, metal adsorption was due purely to microbial activities. The biofilms attached more firmly and uniformly to polyester batting than to gravel and sand. The characteristics of polyester batting which made it a superior support matrix were its surface roughness and porous hydrophilic nature, which provided a larger surface area for the adhesion of microorganisms and attraction of nutrients during the biofilm development process. The selective accumulation of metal ion specIes by various microbial populations grown as biofilm using polyester batting as support matrix in separate compartments of a single-stage RBC bioreactor was examined. Lead ions were readily accumulated by almost all the microbial biofilms tested. Fungus-dominated biofilms selectively accumulated chromium ions whereas biofilms comprising mainly bacteria more readily accumulated copper ions from the mixed metal contaminated effluent solution. However, where interactions between the bacterial and fungal components were encouraged the mechanical stability of the biofilms was enhanced so that large amounts of all three metal ion species were removed by this biofilm. The combined effect of a series of bench-scale columns containing liquid humic acid and a three stage RBC bioreactor on the removal of metal ion species from a mixed metal contaminated effluent was investigated. After seven days of treatment the combined system had removed approximately 99% of the Cr+3, 98% of the Pb+2 and 90% of the Cu+2 ions from the mixed metal contaminated synthetic effluent. Complexation of the metal ions with humic acid was the predominant factor accounting for approximately 68-86% Cr+3 , 70-86% Pb+2 and 53-73% Cu+2 removal levels within the columns. A large proportion of the remaining Cr+3 and Pb+2, but not of the Cu+2, was removed in compartment 1 of the RBC. This suggested that the presence of the former two metals in solution might have reduced the removal of the Cu+2 ions from the system. The removal of substantially large amounts of the competing ions chromium and lead during the initial stages of the treatment process meant that copper was successfully taken up in the second and third RBC compartments. Hence, the economy of the treatment process was improved as larger quantities of the metal ions were removed in a shorter period of time than was possible when using the individual treatments (humic acid-metal complexation and biofilm adsorption) separately. More than 75%,92% and 86% of the adsorbed Cr+3 , Pb+2 and Cu+2 ions, respectively, were recovered from the three RBC bioreactor compartments following repeated washing of the biofilms with 0.1 M HCI. This relatively easy desorption suggested that the metal ions were simply adsorbed onto the surfaces of the biofilm cells rather than being taken into the cytoplasm of the cells. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.
14

A case study exploring the level of awareness of NCP Chlorchem's staff of environmental costs associated with hazardous waste

Tlhapane, Keatlaretse Kefilwe January 2014 (has links)
[Integrative executive summary] NCP Chlorchem (Pty) Ltd manufactures and distributes Chlor alkali products such as chlorine, hydrochloric acid, caustic soda flakes, etc. and in the process generates both hazardous and general waste. Following changes in South African waste management legislation in 2011, the organisation’s waste service provider had to increase the costs associated with the handling of site’s hazardous waste. Top management of NCP Chlorchem (Pty) Ltd requested a meeting with the waste service provider in order to establish the reasons behind the price increase. In that meeting, which the researcher attended, the waste service provider explained the changes in waste legislation and how it was going to impact on their business. Top management understood the reasons behind the price increase; however, they requested the waste service provider to review the price increase. The waste service provider gave the top management of NCP Chlorchem (Pty) Ltd assurance that they were going to discuss the price reduction request with their own senior management and would provide feedback. The researcher did not participate in the feedback meetings; however, to this day, NCP Chlorchem (Pty) Ltd still uses the services of the same waste service provider. The effect the escalating annual waste handling costs has had on NCP Chlorchem (Pty) Ltd’s management team led to the study. Environmental impacts have costs that directly impact on company’s bottom line, such as the costs associated with the generation of waste. Although environmental costs are only one of the many costs incurred by businesses, they deserve management’s attention. According to Jasch (2003), there is an apparent lack of awareness and understanding of the magnitude of the environmental costs generated by organisations, and many opportunities for cost savings through good environmental management are lost. However, using a relatively new tool in environmental management, that is, environmental management accounting (EMA), management would ensure that relevant and significant environmental costs are considered when making business decisions (Jasch, 2003). The main purpose of the thesis is to explore the level of awareness of environmental costs associated with hazardous waste within NCP Chlorchem (Pty) Ltd. In order to carry out the study, literature about environmental and cost accounting as well as literature on waste management was reviewed. Questionnaires were distributed to staff members, and meetings were held with different senior personnel. This case study seeks to answer the following questions: What is NCP Chlorchem (Pty) Ltd’s staff members’ level of understanding of waste management? What is the level of awareness of NCP Chlorchem (Pty) Ltd’s staff of environmental costs with regard to the generation, handling, transportation and disposal of hazardous waste? How can the current traditional accounting within the organisation be integrated with environmental management accounting? The findings of the first research objective revealed that staff members knew the site’s waste streams as per the South African legal definition of waste and as identified in the site’s environmental management system documentation. The conceptual approach to waste management is underpinned by the waste hierarchy. The respondents support the waste hierarchy in its approach to waste management, which is prevention of waste, reduction, reuse, recycle and safe disposal of waste as the last resort. Lack of awareness of environmental management, among other things, was cited as the cause of waste. In addition to that, the respondents believe the waste hierarchy can be achieved by employing recycling facilities, following procedures and by carrying out environmental awareness campaigns. Improving process design and control and including changes in raw material was cited, among other things, as the respondents’ perception on how waste can be reduced. The findings of the respondents’ understanding of waste hierarchy revealed that staff members understood waste management. The respondents cited the impacts of waste on the business as financial impact on the business, impact on their bonuses, and possible loss of business. In relation to the second research objective, it was found that staff members knew the hazardous waste streams and identified amongst other waste, sludge and chlorine emissions as NCP Chlorchem (Pty) Ltd’s hazardous waste. However, with regard to environmental management accounting data, an average of 55.1% of respondents were not familiar with the physical and monetary components of EMA. An average of 19.6% of respondents who were aware of EMA might have been senior personnel. It could further be established that those who were familiar with EMA information were actually working with the data, either for reporting purposes, or for employing waste minimisation strategies, as well as awareness purposes, to their juniors. On average, 80% of the respondents perceived the production department as the area within site that has the EMA information.
15

中國地方政府環保政策執行研究 : 以廣東省貴嶼鎮電子廢棄物回收產業污染問題為例 / 以廣東省貴嶼鎮電子廢棄物回收產業污染問題為例

朱笑涵 January 2010 (has links)
University of Macau / Faculty of Social Sciences and Humanities / Department of Government and Public Administration
16

Environmental risk assessment associated with unregulated landfills in the Albert Luthuli Municipality, Mpumalanga Province, RSA

Mnisi, Fannie 31 August 2008 (has links)
Integrated management of municipal and hazardous waste is one of the challenges facing the new municipalities in South Africa, especially those located in previously disadvantaged rural areas. However, much of the research on solid and hazardous waste management in South Africa has examined waste management problematics in urban areas, the majority of which are located within the jurisdiction of local governments which are comparatively effective in terms of providing adequate disposal services. By contrast, this study has examined the environmental risk assessment associated with unregulated landfill sites in the Albert Luthuli municipality, in the Mpumalanga province. The determination of the environmental risk was achieved by the use of questionnaire surveys and landfill analysis forms in selected study areas. The findings have highlighted a very high environmental risk, nearly four times and above, the threshold limits set by the Department of Environmental Affairs and Tourism (DEAT, 2005:15) for all of the landfill sites examined. Several exposure pathways stemming from associated environmental impacts have also been identified for the study. The higher environmental risk determined for the problem sites is ascribed to numerous factors, including their ill-planned location, the sensitivity and vulnerability of the natural environment and adjacent rural settlements, the lack of appropriate waste pre-treatment processes prior to disposal, and most significantly, the lack of regulatory and control measures to contain the myriad of environmental problems generated. In conclusion, it is recommended that several measures (including closure) should be taken in order to reduce and contain the magnitude of environmental risks involved. / Environmental Sciences / M.Sc.(Environmental Sciences)
17

Environmental risk assessment associated with unregulated landfills in the Albert Luthuli Municipality, Mpumalanga Province, RSA

Mnisi, Fannie 31 August 2008 (has links)
Integrated management of municipal and hazardous waste is one of the challenges facing the new municipalities in South Africa, especially those located in previously disadvantaged rural areas. However, much of the research on solid and hazardous waste management in South Africa has examined waste management problematics in urban areas, the majority of which are located within the jurisdiction of local governments which are comparatively effective in terms of providing adequate disposal services. By contrast, this study has examined the environmental risk assessment associated with unregulated landfill sites in the Albert Luthuli municipality, in the Mpumalanga province. The determination of the environmental risk was achieved by the use of questionnaire surveys and landfill analysis forms in selected study areas. The findings have highlighted a very high environmental risk, nearly four times and above, the threshold limits set by the Department of Environmental Affairs and Tourism (DEAT, 2005:15) for all of the landfill sites examined. Several exposure pathways stemming from associated environmental impacts have also been identified for the study. The higher environmental risk determined for the problem sites is ascribed to numerous factors, including their ill-planned location, the sensitivity and vulnerability of the natural environment and adjacent rural settlements, the lack of appropriate waste pre-treatment processes prior to disposal, and most significantly, the lack of regulatory and control measures to contain the myriad of environmental problems generated. In conclusion, it is recommended that several measures (including closure) should be taken in order to reduce and contain the magnitude of environmental risks involved. / Environmental Sciences / M.Sc.(Environmental Sciences)

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