The complexity of cementitious matrices and their application in the immobilisation of radioactive waste has led to detailed examination of their ability to condition permeating water to high pH by both experimental and thermodynamic studies. This thesis considers the stability and solubility of pure hydrate phases: Ca(OH)₂; CaO-SiO₂-H₂O gel, Ca:Si = 0.85, 1.1, 1.4, 1.8; 3CaO.Al₂O₃.6H_zO; 3CaO.Al₂O₃.CaSO₄.12H₂O and 3CaO.Al₂O₃.3CaSO₄.32H₂O, and the phase formation and stability within CaO-SiO₂-CaCO₃-H₂O and CaO-Al₂O₃-SiO₂-H₂O compositions aged in saline solutions, up to 1.5M NaCl and 0.05M MgSo₄, at 25°, 55° and 85°C. The two main high pH conditioning phases of cementitious systems are Ca(OH)₂ and C-S-H gel. Sodium chloride enhances the solubility of Ca(OH)₂ and causes a slight reduction in the Ca:Si ratio of C-S-H gels by the progressive leaching of calcium. Silicate polymerisation within C-S-H phases is inhibited by sodium chloride though it is uncertain how this alters the crystallisation kinetics. The pH buffering capacity is maintained when aged in sodium chloride concentrations 0.5, 1.0 and 1.5M at 25°, 55° and 85°C. The stability of calcium sulfoaluminate aged in sodium chloride is greater than of 3CaO.Al₂O₃.6H₂O, which is unstable with respect to 3CaO.Al₂O₃.CaCl₂.10H₂O in NaCl < 0.5M. These phases undergo a progressive phase change to the 3CaO.Al₂O₃.0.5CaSO₄.0.5CaCl₂.10-12H₂O and 3CaO.Al₂O₃.CaCl₂.10H₂O at increasing aqueous Cl:SO₄ ratios. The formation of a limited solid solution region within 3CaO.Al₂O₃.xCaSO₄.l-xCaCl₂.yH₂O: 0.00 ≤ SO₄:Cl ≤ 0.06, was characterised. In magnesium sulfate, 5 - 50m.mol/l, calcium within hydrate phases is progressively replaced by magnesium with formation of Mg(OH)₂, MgO-SiO₂-H₂O gel, 4MgO.Al₂O₃.xH₂O and gypsum. The pH conditioned by the resultant solid assembly decreases to less than that desirable for containment of radioactive waste, to < 9. Consideration of the phase formation and persistence within the CaO-SiO₂-CaCO₃-H₂O and CaO-Al₂O₃-SiO₂-H₂O systems was examined in solutions containing both sodium chloride and magnesium sulfate. The chemical interactions observed were dominated by the replacement of calcium by magnesium within the solid phases with the formation and persistence of mixtures of Mg(OH)₂, MgO-SiO₂-H₂O gel and gypsum. At low Mg:Ca-CO₃ ratios the persistent stability of gehlenite hydrate at 25°C was observed in appropriate samples. The chemistry of the aqueous phase is dependent on the Mg:Ca-CaCO₃ ratio as well as the Ca:Si ratio. At high Mg:Ca-CaCO₃ ratios the high pH conditioning properties are destroyed and buffering occurs at a value below pH 9.

No description available.

The central focus for this creative project was to explore the possibilities of found object and recycled art with emphasis on function and design. After researching the art and the artists who made/make it, a collection of functional art was created. The project resulted in a body of work that consisted of thirteen bags and purses that were made from gift cards and gameboards. The design of 1970's and 1980's art was used as inspiration. Traditional metalsmithing techniques were required for the completion of each work. Copper wire was used as both a structural and ornamental element. The awareness of recycled art will be heightened. Found object and recycled art is significant, purposeful, and important in both the history and future of art. / Department of Art

Ever-increasing amounts of industrial and residential wastes and their environmental footprint dictates the need for effective Waste Management practices. Thermal waste processing technologies play an important role in energy recovery from the waste. Conventional and more importantly Plasma-assisted Gasification, an advanced thermal processing technology, have been introduced as promising and environmentally benign ways for energy utilization from biomass and municipal solid waste (MSW). This work aims to study the thermal technologies, which result in production of synthesis gas that is useful for heat and power generation; therefore, conventional and plasma-assisted gasification of biomass/MSW are reviewed. In addition, various economic, environmental and policy-related issues are examined in this study. From the experimental and modeling perspective, this study also reports on the work conducted to characterize the gasification process using a gasification reactor called Gasifier Experimenters Kit (GEK) level IV. Both the syngas quality and quantity have been investigated based on a variety of feedstock, such as wood charcoal, poplar and tamarack wood chips. Moreover, the composition of the gas has been analyzed using a Gas Chromatography (GC) unit and the exact concentrations of carbon monoxide, hydrogen, methane and nitrogen were measured. In this study, a thermochemical model based on the experimental setup (GEK IV) has also been developed in the AspenPlus?? environment, an established simulation tool in chemical engineering and the energy industry. This model is capable of predicting the syngas composition, the energy required for the gasification reactions. A comparative analysis involving the experimental and simulation results is presented in this study.

Rapid population growth and urbanisation has resulted in a drastic increase in the volume of waste produced by the World populace. The resulting pressure on the country’s somewhat underdeveloped waste management infrastructure emphasizes the need for waste management solutions which balance environmental protection with economic sustainability. Waste is seen as an unwanted or surplus by-product, emission or residue of any process or activity which has been discarded, accumulated or stored for the purpose of discarding or future processing. Hazardous waste is waste that may, by circumstance of use, quantity, concentration or inherent physical, chemical or infectious characteristics, cause ill-health or an increased mortality rate in humans, fauna and/or flora. General waste on the other hand, is waste that does not pose an immediate threat to human health or the environment. Currently household waste is considered general waste even though it may contain hazardous components such as fluorescent tubes and/or other household chemicals. Promulgation of NEM: WA (no 59 of 2008) provides instruments for the implementation of the steps taken by the Department of Environmental Affairs to improve waste management in South Africa. Successful implementation and enforcement of the act will place the country at the forefront of progressive international standards in waste management. One of South Africa’s largest environmental and waste management challenges remains the presence of historical, hazardous waste landfill sites. Characterisation of the dangers that these sites pose to the environment is providing extremely difficult and expensive, as is the ongoing maintenance and management of these facilities – placing economic strain on national municipalities. This study was done in two phases. The first related to the hazardous waste components of household waste that is being dumped at landfill site and the methods of classification, handling and dumping of hazardous waste have been investigated. All the legislation was taken into consideration to see if the landfill sites comply with the latest legislation. The second phase was a comparison between three landfill sites. The management, work activities and general appearance of the sites have been compared internally. Then a comparison have been done between the following landfill sites Kwaggasrand landfill site in Tshwane, Weltevreden landfill site in Brakpan and an ideal landfill site developed in accordance with the Minimum Requirements documents published by of DEAT in 1998. / Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2011.

During the past few decades the focus of waste management in South Africa has been emphasised, especially in view of the increase in economic development which has resulted in an increase in commercial, industrial, hazardous, mining, power generation as well as radioactive waste. The iron and steel making industry in South Africa provides for a vast amount of recycling opportunities of various materials resulting from the iron and steelmaking process. The regulation of waste management in South Africa may have some significant implications on this particular industry. In this dissertation the history of waste management legislation in South Africa is researched. It is found that initially only waste disposal was regulated, but over time, in addition to disposal, other aspects were also regulated in terms of other pieces of environmental legislation, such as the recycling, recovery and storage of waste. In an attempt to provide for uniform waste management regulation in South Africa, and in order to achieve sustainable development by the provision of a new waste hierarchy, the National Environmental Management: Waste Act was introduced. As part of this legislation, a new definition of waste was also introduced. It is indicated as part of this dissertation that various interpretations of the definition of ‘waste’ are possible. It is also indicated that these various interpretations may not only have some significant implications for the iron and steelmaking industry in South Africa, but may also have significant implications for the implementation of the waste hierarchy, as envisaged in terms of current waste management legislation. In the light of the above, and after taking comments by the members of the South African Iron and Steel Institute into consideration, recommendations are made for an improved legislative framework for waste management in South Africa. It is recommended that there should be a trade–off between the protection of the environment and the re–use, recovery and recycling opportunities of materials available to industry in the short–term as well as the long–term. In order to achieve such a trade–off, it is suggested that the ‘End–of Waste’ criteria in South Africa be reconsidered and re–evaluated to ensure more legal certainty with regard as to exactly constitutes waste and to provide for a definition of ‘waste’ which is clearly defined. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2012.

Waste, that is any matter whether gaseous, liquid or solid or any combination thereof, originating from any residential, commercial or industrial area identified as undesirable or superfluous by-product, emission, residue or remainder of any process or activity tends to be a hazard to the environment. Waste is generated in all processes which transform materials from one state, form or medium to another. The management of waste in the Sedibeng District Municipality is a very complex problem. There are many reasons for this and these include: the diverse and voluminous waste stream; progressive accumulation of waste in the environment; large numbers of unpermitted waste disposal sites; the severe shortage of hazardous waste disposal sites and shortage of personnel in local municipalities qualified to implement existing legislation. The accumulation of waste in the district not only poses a serious and growing threat to health and quality of life, but also causes infrastructural damage such as the blocking of storm water drains and sewer by litter which ultimately leads to costly road and pavement destruction and increase in maintenance costs. The objective of the study was to investigate waste management activities in the Sedibeng District Municipality and to explore best practices as strategies for recommendations. The Sedibeng District Municipality comprises three local municipalities namely the Emfuleni, Lesedi and Midvaal Local Municipalities. Due to the fact that the Municipality forms part of the industrial hub of the Gauteng Province, there has been an excessive influx of the people into the district and, as a result, more houses had to be built and more normal urban services such as electricity, sanitation, water and waste, had to be provided. The study intended to investigate different waste management strategies that are employed by the three local municipalities that could help reduce the impacts and volumes of waste that are generated by residents before such waste could pollute the environment. A further objective was to explore possible waste reduction mechanisms such as recycling that can help reduce waste volumes before they reach the disposal site. Arising from the problem statement on waste management for this study, it is important that the locus of this study be directed towards the solution of the problem on waste management activities in the Sedibeng District Municipality The following hypothesis was accordingly formulated: Waste management strategies and practices as currently practised in the Sedibeng District Municipality are obsolete, outdated and inadequate to attain a cleaner environment and as a result, there is a need to explore the development of more cost effective strategies in waste management. Comparative study of the different strategies that are employed in the three local municipalities as well as the challenges they face when providing the required service, were made. Similar study was applied to the achievements that are recorded as findings of the study. The challenges and success stories highlighted in the study were found through the use of questionnaires that were distributed to respondents in the three local municipalities. Questionnaires for the study were compiled for both councilors and municipal officials. The research instruments for the study included questionnaires, interviews and consultations with members of the community. Further technique was participant observation, the researcher being responsible for the provision of refuse removal services to the Evaton and Sebokeng communities. Amongst others, it was found that: discrepancies existed in the waste management processes and these include the following: • There was a serious problem of personnel shortage in municipalities as a result of financial constraints that led to nonreplacement of personnel who went on retirement, resigned or died; • Existing equipment do not compliment the growing population figures as well as the sizes of the municipality and as a result, residents opted to dump waste at their backyards as an alternative procedure for disposal of waste from their homes, and • Problems attributed to illegal dumping increase each day and their resolution will be a function of implementation of compliance with legislation. • Community awareness of refuse collection schedule is at minimum, a situation which leads to illegal dumping of waste, and • Tariff on refuse removal is deemed to be prohibitive to African residential areas. The study ends with recommendations for management action on waste, and for further research. / Thesis (Ph.D. (Public Management and Administration))--North-West University, Vaal Triangle Campus, 2010.

Waste, that is any matter whether gaseous, liquid or solid or any combination thereof, originating from any residential, commercial or industrial area identified as undesirable or superfluous by-product, emission, residue or remainder of any process or activity tends to be a hazard to the environment. Waste is generated in all processes which transform materials from one state, form or medium to another. The management of waste in the Sedibeng District Municipality is a very complex problem. There are many reasons for this and these include: the diverse and voluminous waste stream; progressive accumulation of waste in the environment; large numbers of unpermitted waste disposal sites; the severe shortage of hazardous waste disposal sites and shortage of personnel in local municipalities qualified to implement existing legislation. The accumulation of waste in the district not only poses a serious and growing threat to health and quality of life, but also causes infrastructural damage such as the blocking of storm water drains and sewer by litter which ultimately leads to costly road and pavement destruction and increase in maintenance costs. The objective of the study was to investigate waste management activities in the Sedibeng District Municipality and to explore best practices as strategies for recommendations. The Sedibeng District Municipality comprises three local municipalities namely the Emfuleni, Lesedi and Midvaal Local Municipalities. Due to the fact that the Municipality forms part of the industrial hub of the Gauteng Province, there has been an excessive influx of the people into the district and, as a result, more houses had to be built and more normal urban services such as electricity, sanitation, water and waste, had to be provided. The study intended to investigate different waste management strategies that are employed by the three local municipalities that could help reduce the impacts and volumes of waste that are generated by residents before such waste could pollute the environment. A further objective was to explore possible waste reduction mechanisms such as recycling that can help reduce waste volumes before they reach the disposal site. Arising from the problem statement on waste management for this study, it is important that the locus of this study be directed towards the solution of the problem on waste management activities in the Sedibeng District Municipality The following hypothesis was accordingly formulated: Waste management strategies and practices as currently practised in the Sedibeng District Municipality are obsolete, outdated and inadequate to attain a cleaner environment and as a result, there is a need to explore the development of more cost effective strategies in waste management. Comparative study of the different strategies that are employed in the three local municipalities as well as the challenges they face when providing the required service, were made. Similar study was applied to the achievements that are recorded as findings of the study. The challenges and success stories highlighted in the study were found through the use of questionnaires that were distributed to respondents in the three local municipalities. Questionnaires for the study were compiled for both councilors and municipal officials. The research instruments for the study included questionnaires, interviews and consultations with members of the community. Further technique was participant observation, the researcher being responsible for the provision of refuse removal services to the Evaton and Sebokeng communities. Amongst others, it was found that: discrepancies existed in the waste management processes and these include the following: • There was a serious problem of personnel shortage in municipalities as a result of financial constraints that led to nonreplacement of personnel who went on retirement, resigned or died; • Existing equipment do not compliment the growing population figures as well as the sizes of the municipality and as a result, residents opted to dump waste at their backyards as an alternative procedure for disposal of waste from their homes, and • Problems attributed to illegal dumping increase each day and their resolution will be a function of implementation of compliance with legislation. • Community awareness of refuse collection schedule is at minimum, a situation which leads to illegal dumping of waste, and • Tariff on refuse removal is deemed to be prohibitive to African residential areas. The study ends with recommendations for management action on waste, and for further research. / Thesis (Ph.D. (Public Management and Administration))--North-West University, Vaal Triangle Campus, 2010.

Rapid population growth and urbanisation has resulted in a drastic increase in the volume of waste produced by the World populace. The resulting pressure on the country’s somewhat underdeveloped waste management infrastructure emphasizes the need for waste management solutions which balance environmental protection with economic sustainability. Waste is seen as an unwanted or surplus by-product, emission or residue of any process or activity which has been discarded, accumulated or stored for the purpose of discarding or future processing. Hazardous waste is waste that may, by circumstance of use, quantity, concentration or inherent physical, chemical or infectious characteristics, cause ill-health or an increased mortality rate in humans, fauna and/or flora. General waste on the other hand, is waste that does not pose an immediate threat to human health or the environment. Currently household waste is considered general waste even though it may contain hazardous components such as fluorescent tubes and/or other household chemicals. Promulgation of NEM: WA (no 59 of 2008) provides instruments for the implementation of the steps taken by the Department of Environmental Affairs to improve waste management in South Africa. Successful implementation and enforcement of the act will place the country at the forefront of progressive international standards in waste management. One of South Africa’s largest environmental and waste management challenges remains the presence of historical, hazardous waste landfill sites. Characterisation of the dangers that these sites pose to the environment is providing extremely difficult and expensive, as is the ongoing maintenance and management of these facilities – placing economic strain on national municipalities. This study was done in two phases. The first related to the hazardous waste components of household waste that is being dumped at landfill site and the methods of classification, handling and dumping of hazardous waste have been investigated. All the legislation was taken into consideration to see if the landfill sites comply with the latest legislation. The second phase was a comparison between three landfill sites. The management, work activities and general appearance of the sites have been compared internally. Then a comparison have been done between the following landfill sites Kwaggasrand landfill site in Tshwane, Weltevreden landfill site in Brakpan and an ideal landfill site developed in accordance with the Minimum Requirements documents published by of DEAT in 1998. / Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2011.

During the past few decades the focus of waste management in South Africa has been emphasised, especially in view of the increase in economic development which has resulted in an increase in commercial, industrial, hazardous, mining, power generation as well as radioactive waste. The iron and steel making industry in South Africa provides for a vast amount of recycling opportunities of various materials resulting from the iron and steelmaking process. The regulation of waste management in South Africa may have some significant implications on this particular industry. In this dissertation the history of waste management legislation in South Africa is researched. It is found that initially only waste disposal was regulated, but over time, in addition to disposal, other aspects were also regulated in terms of other pieces of environmental legislation, such as the recycling, recovery and storage of waste. In an attempt to provide for uniform waste management regulation in South Africa, and in order to achieve sustainable development by the provision of a new waste hierarchy, the National Environmental Management: Waste Act was introduced. As part of this legislation, a new definition of waste was also introduced. It is indicated as part of this dissertation that various interpretations of the definition of ‘waste’ are possible. It is also indicated that these various interpretations may not only have some significant implications for the iron and steelmaking industry in South Africa, but may also have significant implications for the implementation of the waste hierarchy, as envisaged in terms of current waste management legislation. In the light of the above, and after taking comments by the members of the South African Iron and Steel Institute into consideration, recommendations are made for an improved legislative framework for waste management in South Africa. It is recommended that there should be a trade–off between the protection of the environment and the re–use, recovery and recycling opportunities of materials available to industry in the short–term as well as the long–term. In order to achieve such a trade–off, it is suggested that the ‘End–of Waste’ criteria in South Africa be reconsidered and re–evaluated to ensure more legal certainty with regard as to exactly constitutes waste and to provide for a definition of ‘waste’ which is clearly defined. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2012.