3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item The industrial viability and characterization of WC-Co alloys produced by acid leaching and recycling techniques(2016) Freemantle, Christopher StuartIn the current study, the well-established zinc recycling process and a prototype acetic acid recycling plant were successfully employed to recycle cemented tungsten carbide scrap material for re-use as production powders. The recycled materials were studied and compared to new materials at each stage along the cemented carbide manufacturing route, in a production environment. Analysis of by-product materials from the zinc recycling process revealed that while some by-product material can be readily converted into powder using the supplementary acetic acid method, the rest is most efficiently recovered by using a second zinc recycling run and by controlling the size and purity of the scrap material introduced into the process. Various analytical techniques, including the novel use of proton induced x-ray emission studies were used to characterize the materials in both the powder and sintered form. The analyses revealed that the recycled materials possessed superior microstructural homogeneity than new materials, and greater than 99% purity. Studies of milling behavior and slurry rheology revealed no adverse effects of using recycled materials, provided that the slurry properties prior to powder spray drying were appropriately controlled. Polymer binder integrity remained intact despite the longer milling times associated with the use of recycled materials, and the superior slurry stability of recycled materials was demonstrated. The flow behavior and powder rheology of the spray dried powders was found to depend on the precursor slurry rheology and particle grain size. This was controlled predominantly by the formation of a sufficient yield stress to produce ideal, dense granules for greater ease of manufacturing, in both new and recycled powders. The acetic acid recycling technique can be used as a complimentary recycling process to the existing zinc recycling process, and can produce useable recycled material at low cost.Item Utilisation of electrical and electronic plastic waste as replacement for aggregate in concrete(2019) Parsons, Lewis AlfredWaste electrical and electronic plastic (WEEP) recycling is complex due to the presence of different hazardous additives, variety in plastic types and degraded polymers among others. This often results in vast quantities of WEEP being discarded of in landfills, incinerated or stored in warehouses, whereby it could have rather been used as an aggregate replacement material in concrete. The main aim of this research was to produce structural concrete with a minimum compressive strength of 25MPa using different types of WEEP. The different types of WEEP used include: acrylonitrile-butadiene-styrene (ABS), polycarbonate acrylonitrile-butadiene-styrene (PC/ABS), high impact polystyrene (HIPS) and an equal blend of the aforementioned WEEP types. To address the concretes strength reduction found from WEEP substitution and to improve its durability, 10% condensed silica fume and 25% metakaolin replaced cement in concrete by mass respectively. Furthermore, a superplasticiser was used to maintain a set workability. In the experimental program WEEP was used at replacement percentages of 0%, 5%, 10%, 20% and 30% in the partial replacement of both fine and coarse natural aggregates in concrete to assess its behaviour for structural applications. By performing test of compressive and tensile strength, durability performance and scanning electron microscopy analysis it has been found that all WEEP types show a real possibility for use as aggregate in concrete. Results showed that all mixes made without and with WEEP substitution for the natural aggregate attained the minimum compressive strength of 25MPa. When concrete with a WEEP replacement of 30% was compared to the control mix there was a large decrease in strength, but when concrete with a WEEP replacement of 5% was compared with the control mix the results showed almost equal strength for all WEEP types. There was a reduction in the oxygen permeability index and water sorptivity and an increase in chloride conductivity for concrete made with a WEEP replacement of 30% compared to the control mix. It was also found that all concrete mixes made using metakaolin or condensed silica fume as partial replacement for cement had a higher strength and improved durability compared to concrete mixes made using only cement as binder material. The use of WEEP in concrete could reduce the amount of WEEP disposed of and reduce the amount of natural aggregates mined. This in turn may produce an environmentally friendly concrete.Item Product carbon footprint analysis for the packaging process of returnable glass and pet containers for a South African carbonated soft drinks business(2016) Ivanov, IvanNon-renewable resources are becoming scarce and current Global Warming Potential (GWP) values are rising. In an effort to promote a successful shift towards a “greener’ planet, governments worldwide are developing policies, which enforce businesses to contribute to the effort. One such policy is the potential upcoming carbon tax (measured in weight of C02e) in South Africa. As a result, industries need to carefully analyse and understand their core processes and their impact on the environment to ensure that their operations have the lowest environmental cost possible. One such industry in South Africa is the fast growing Carbonated Soft Drinks (CSD) beverage packaging industry. CSD are packaged in both Returnable Glass Bottles/Glass (RGB) and PET containers. The Product Carbon Footprint (PCF) of the CSD packaging process for 300ml Glass and 500ml PET containers was of particular interest. Review of academic literature revealed that no similar research has been conducted previously in South Africa. International studies on PCF, which vastly use the (ISO 14040/14044, 2006) for their method, were found to have conflicting results and conclusions regarding the “greenness” of the two types of containers both with respect to the overall GWP of each and the percentage contribution of the packaging process life cycle stage to the total environmental impact. This is mainly because such studies are region and technology specific. A study was therefore required to understand the implications the business' Glass and PET CSD packaging process has on its GWP and hence carbon tax. The GHG (Green House Gas) Protocol PCF guideline (World Resource Institute, 2013) was used to construct the method for this research to ensure best practice, which would allow the study to be expanded into a full blown Fife Cycle Assessment (FCA) as future work. It was found that the 500ml PET packaging process draws 100% of its Cumulative Energy Demand (CED) from purchased electricity (generated by burning coal) and has a GWP of 65 147 gCCTe/hl (hectolitre), which is 4.5 times less than that for 300ml Glass (294 173 gCCEe/hl) which has 71% of its emissions resulting directly from coal fired boilers on site. A dynamic model analysis revealed that packaging in larger containers results in a significant GWP reduction per volume for both Glass and PET containers. It was recommended that short term the business needs to focus on optimising its packaging lines’ equipment, work with suppliers on reducing the weight of the raw materials used for the packaging containers manufacture and promote rate of return of its Glass.Item An evaluation of how the conceptualisation of waste influences separation at source behaviours and waste practices: a case study of Elizabeth Fry Village, Vorna Valley, Midrand South Africa(2017) Dune, Tadiwanashe ChidoWith consumer culture that encourages societies to buy more, waste production increases as well. A lack of site specific data regarding waste conceptualisations and practices inhibits sustainable waste initiatives such as separation at source programmes from being successful and results in poor participation levels. This research report investigates these issues through a case study of Elizabeth Fry Village (EFV) in Vorna Valley, Midrand, particularly focusing on a Separation at Source programme in Elizabeth Fry Village. This research was conducted over a 6 month period between September 2016 and March 2017. There are two approaches within the broad debate around waste that this research engages with. The first is the approach presented by Moore (2012), Gutberlet (2013), Oteng-Ababio (2014) and Parizeau (2015) who argue that the different ways that people understand and conceptualise waste influences their waste practices, including participation in recycling programmes. The second approach focuses on the practical factors that affect participation in recycling programmes (Tonglet et al., 2004 and Martin et al., 2006). Based on mixed methods including participant observation, interviews, desktop studies and a waste composition study conducted in Elizabeth Fry Village, this research report argues that it is necessary to combine both approaches to develop a comprehensive understanding of people‘s participation or lack thereof in recycling programmes such as separation at source (S@S). It is recommended that future research explores mechanisms for the better use of putrescible waste and that aspects such as convenience, time, space, knowledge and awareness are further investigated to increase participation rates in the area. Another major aspect identified for future research is exploring how to shift people‘s conceptualision of waste to recognise it as a positive material. Keywords: Recycling, waste, separation at source (S@S), conceptualisation, participation, Elizabeth Fry Village (EFV), MidrandItem Solid waste management in South Africa: exploring the role of the informal sector in solid waste recycling in Johannesburg(2017) Dlamini, Smangele QondileInformal solid waste recycling has increasingly become part of the urban landscape in many South African cities and towns. In the city of Johannesburg, for example, waste pickers are now playing an important role in waste management and recycling. There is evidence in the literature that suggests these activities have both economic and environmental benefits thereby contributing towards job creation and environmental sustainability. Despite the role that the informal sector contributes to waste management and socio-economic development, as well as environmental sustainability, the urban development and planning policy in South Africa has not embraced and integrated informal systems of municipal waste management in its policy framework. Drawing on field-based study conducted in selected parts of the City of Johannesburg, and using methods inspired by the traditional participatory research, this study explored the institutional framework within which informal solid waste management can be pursued. One solution to this problem could be the integration of the informal sector recycling into the formal waste management system. To achieve informal sector recycling integration, this study identifies barriers that hinder the integration of the informal sector into an inclusive waste management: repressive policy, lack of evidence to support activity, social acceptance, illegal migrants and lack of valid citizenship documents. It is essential to note that the integration of waste pickers should not be grounded on a ‘universal’ model but should instead take into account local context and conditions.Item Trans - form - medium: the transformation of light, space and process through the medium of glass, a glass recycling hub for Waste Reclaimers in Newtown(2015-05-27) Hardman, Murray R.High levels of unemployment are a reality in many of the urban areas of South Africa. Poverty and hardship compel many of the unemployed to venture into the urban informal economy in order to survive. The South African government have found new ways of creating employment opportunities, one of which is within the recycling industry. There is an increased demand for minimizing mankind’s environmental footprint. Glass is a material that has been used for centuries and has the ability to be recycled infinitely without losing its quality (Marson, n.d). This together with the need for glass amongst consumers and the endlessly recycling nature of glass makes glass recycling a significant sustainable measure in considering environmental impacts (2011, 2012 Annual Review: Glass Recycling Company). Despite these properties, glass continues to be an undervalued material that can utilize low technology in its recycling process. This study aimed at investigating the formal and informal recycling economy within the city of Johannesburg by providing the opportunity for the Waste Reclaimers (Trolley Pushers) to be an integral part of the recycling process, specifically with glass. A further aim was to explore the tectonics of a factory to create a space where the Waste Reclaimers could gather, connect and engage with the product of glass. Lastly it aimed to provide a space where the general public could also engage in the product of glass recycling thereby creating awareness and promotion of recycling. The project proposed a glass recycling factory where the process of glass recycling culminates with the production of glass. The site selected for this research is located within the industrial part of the Newtown precinct. This has become a central recycling hub for the Waste Reclaimers of Johannesburg as it links private recycling centres within the city. Newtown is an area of flux, marked by a history of industrial and political disruption. This area represents change and opportunity for growth and life. A space recycled and regenerated throughout the history of Johannesburg. The reason for the choice of topic is that the evolution of recycling in Johannesburg has reached a point where municipalities need to acknowledge the informal sector as a valuable part of the recycling economy. The majority of the literature on recycling and the organization of the recycling process predominantly focuses on the collection of waste as means of job creation. An opportunity therefore presented itself to highlight the production, and craftsmanship of recyclable material. To clarify and further place the Waste Reclaimers within the existing waste management system, the theory of Phenomenology has been explored. It will focus on the phenomenological term of “Lifeworld” which describes a way of life where the individual’s aspiration, perceptions, experiences, beliefs and behaviour forms a holistic unity towards a fulfilling, meaningful, existence (Seamon, 2012). This exploration will give insight to how this building will provide the Waste Reclaimer a sense of identification and orientation within this system of the recycling industry. In order to better understand the complexity of the existing waste management system, the theory of Systems has been explored focusing on the principal of an open system as a way of broadening the lifeworld of the Waste Reclaimers Precedent studies of PFG Building Glass windscreen recovery facility; Zama City Waste; the comparison of factory tectonics between the Crystal Palace, Toledo Museum of Art Glass and the Crucible Glassblowing studio; the Glass Chapel and The Nelson-Atkins Museum of Art were used to inform the design. The network of the Waste Reclaimers was also documented in order to understand their routes and network across the city and the surrounding suburbs. The impact of the design found that the proposed space created opportunities for pause and transformation using light, space and process. The idea of transformation is process. Process is represented by a linear path with adjacent spaces of function and support. These spaces will transform according to their activities and associated light qualities. These spaces will thus become the medium through which people and activities change.Item The wasted years: a history of mine waste rehabilitation methodology in the South African mining industry from its origins to 1991(2013-08-01) Reichardt, MarkusDecades after the commencement of modern mining in the 1870s, the South African mining industry addressed the impacts associated with its mine waste deposits. In this, it followed the pattern its international peers had set. This study aims at chronicling, for the first time, the mining industry’s efforts to develop scientifically sound and replicable methods of mine waste rehabilitation. Mindful of the limitations in accessing official and public written sources for such an applied science, the study seeks to take a broader approach: It considers factors beyond pure experimental results (of which only patchy records exist), and considers the socio-economic context or the role of certain personalities, in an effort to understand the evolution of the applied technology between the 1930s until the passage of the Minerals Act in 1991. The bulk of this mine waste rehabilitation work during this period was done by the Chamber of Mines of South Africa and its members, the gold and (later) coal miners. The focus will therefore be on these sectors, although other mining sectors such as platinum will be covered when relevant. Following decades of ad hoc experimentation, concern about impending legal pollution control requirements in the 1950s spurred key gold industry players to get ahead of the curve to head off further regulation. Their individual efforts, primarily aimed at dust suppression, were quickly combined into an industry initiative located within the Chamber of Mines. This initiative became known as the Vegetation Unit. Well resourced and managed by a dynamic leader with horticultural training – William Cook – the Unit conducted large-scale and diverse experiments between 1959 and 1963 to come up with a planting and soil amelioration methodology. The initial results of this work were almost immediately published in an effort to publicise the industry’s efforts, although Cook cautioned that this was not a mature methodology and that continued research was required. The Chamber of Mines, however, was trying to head off pending air quality legislation and in 1964/65, the organisation publicly proclaimed the methodology as mature and ready for widespread application. With this decision, the Unit’s focus shifted to widespread application while its ability to advance the methodology scientifically effectively collapsed in the 1960s and early 1970s. In addition to this shift of focus and resources to application rather than continued refinement, the Unit was constrained by non-technical and non-scientific factors: Key among them was the industry’s implicit belief, and hope, that a walk-away solution had been found. The Unit’s manager Cook stood alone in driving its application and refinement for most of his time in that position. In his day-to-day work, he lacked an industry peer with whom to discuss rehabilitation results and he compounded this isolation through limited interaction with academia until very late in his career. This isolation was amplified by the lack of relevant technical knowledge among the company representatives on the committee tasked with the oversight of the Vegetation Unit: As engineers, all of them lacked not only technical understanding of the botanical and ecological challenge, some even questioned the legitimacy of the Unit’s existence into the 1980s. In addition, the concentration of all rehabilitation efforts in this single entity structurally curtailed the individual mining companies’ interest in the advancement of the methodology, creating a further bottleneck. Indeed, as late as 1973, the key metallurgy handbook covered mine waste rehabilitation only for information purposes, specifically stating that this was the responsibility of the Chamber’s Vegetation Unit alone. To some extent, the presence of a champion within the Chamber – H. Claussen – obscured some of these challenges until the early 1970s. Indeed, the Unit had acquired additional scientific capacity by this stage, which gave it the ability to renew its research and to advance its methodology. That it failed to do so was mainly due to three factors coinciding: the retirement of its internal champion Claussen, a lack of succession planning for Cook, which left the Unit on ‘auto-pilot’ when he retired, and a rising gold price, which turned industry attention away from rehabilitation towards re-treatment of gold dumps. During this period of transition in the mid 1970s, the Chamber’s approach was thus somewhat half-hearted and vulnerable to alternative, potentially cheaper, rehabilitation proposals such as physical surface sealing advanced by Cook’s eventual successor – Fred Cartwright. Though not grounded in any science, Cartwright’s proposal gained ascendance due to his forceful personality as well as the industry’s desire for an alternative to the seemingly open-ended costs associated with the existing rehabilitation methodology. During this time, the Chamber’s structures singularly failed to protect the industry’s long-term interests: The oversight committee for the Vegetation Unit, remained largely staffed by somewhat disinterested engineers, and relied heavily on a single individual to manage the Unit. Not only did the oversight committee passively acquiesce to Cartwright’s virtual destruction of the Unit’s grassing capacity, it also allowed him to stake the Chamber’s reputation with the regulator by championing an unproven technology for about five years. Only Cartwright’s eventual failure to gain regulator approval for his – still un-proven – technique led to a reluctant abandonment by the Chamber in the early 1980s. Cartwright’s departure in 1983 left the Unit (and the industry) without the capacity to address mine waste rehabilitation, at a time when emerging environmental concerns were gaining importance in social and political spheres in South Africa and across the world. The Unit sought, unsuccessfully, to build alliances with nascent rehabilitation practitioners from the University of Potchefstroom. It furthermore failed to build mechanisms for sharing technical rehabilitation knowledge with fellow southern African or international mining chambers, leading to further stagnation of its method. At the same time, up-and-coming South African competitors such as the University of Potchefstroom seized the opportunity to enter the mine waste rehabilitation field as commercial players during the mid 1980s, at a time when the Unit had been reduced to grassing dumps for a single customer, the Department of Minerals and Energy Affairs (DMEA). Using its status as a part of the Chamber of Mines, the Unit gradually regained its position of prominence through the development of industry guidelines for rehabilitation. Yet, it would never again occupy a position of pre-eminence in practical fieldwork, as industry players, academic capacities and commercial players entered the field in the mid-1980s in response to a growing environmental movement worldwide. When the passage of the Minerals Act in 1991 formally enshrined not merely rehabilitation but environmentally responsible mine closure in law, the Unit had been reduced to a prominent but no longer dominant player in this sector. This lack of pre-eminence ultimately caused the Unit to be among the first Chamber entities to be privatised when the Chamber began to restructure. This ended its role as a central driver of applied rehabilitation techniques for the South African mining sector once and for all. As this privatisation coincided with the broader opening up of South Africa’s society and economy after the unbanning of the ANC, there would never again be an entity (commercial or otherwise) that would dominate the rehabilitation sector as the Chamber’s Vegetation Unit had done in its day.Item To ascertain the implementation of the plastic carrier bags regulations at the local government sphere in Gauteng Province(2012-05-14) Ndzhukula, Sizakele JudithThere has been a genuine problem with plastic carrier bags (PCBs) pollution since the 1970’s. A literature review revealed that very few scientific studies have been undertaken globally on PCB. The South African Government promulgated regulations to reduce numbers, encourage reuse and recycling of plastic bags in 2003. The regulations introduced a charge for PCBs. This study looked at the handling and disposal of PCB after 2003 in Gauteng Province, South Africa; and looked at the movement of PCB from major retailers and informal traders to consumers and recycling and recovery. The study excluded the manufacturers and distributors of PCB. It began with the retailers and informal traders being the source of PCB and extended to consumers during their grocery shopping in large retail stores and purchases from informal traders. The study also looked at the individual waste collectors operating in landfill sites, residential and industrial areas to establish the level of recycling of PCB. Buyisa-e-Bag (B-e-B) was at the end of the collection of PCB pathway where it was supposed to provide leadership in the recovery of the bags. Semi-structured interviews were used to collate data on recycling approach with specific focus on PCB and understanding of the legislation. A total of one hundred consumers were interviewed in the shopping malls. Consumers did not know much about the regulations hence they could not explain the reason they have to pay for PCB. Ninety one percent of consumers did not reuse bags for shopping and 68% reused PCB at home to store waste before it is disposed of. Eighty informal traders were interviewed: all indicated that they did not charge for PCB. Forty chain supermarkets managers were interviewed from the shopping centres covered by the study. The retailers were affected by the PCB regulations; they reduced the number of grocery packers and increased security to prevent theft. Nevertheless, they complied with the regulations by selling only the thick bags. Twenty landfill and recycling facilities managers formed part of the study. All landfill managers encouraged general waste recycling to prolong lifespan of the site. Fifty individual recyclers were interviewed in the landfill sites, recycling facilities and on the road side while pushing their trolleys. They found it economically impractical to collect PCBs. Awareness of plastic litter has increased and less is visible though this was not measured. Legal compliance with regulations and specifications needed to be actively driven by all the relevant parties. PCBs are fully recyclable; hence more public awareness is required aimed at preventing the contamination of bags which deters re-claimers from collecting them. B-e-B has not met most of the objectives of their formation and has since been placed under administration by DEAT. Inadequate communication and collective bargaining between the key role parties resulted in the delays in getting the recycling projects off the ground. Major retailers complied with the Government regulations. Informal traders and consumers were generally unaware of regulations and consequences of PCB use. Consumers bought new PCB and in most cases, failed to reuse them for shopping. Recycling of PCBs is not carried out effectively as it is not economically worthwhile. This requires further research to explore the potential uses of PCBs at the end of their lifecycle