Thesis (M. Sc.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 76-78).

No description available.

Quantitative modelling of reverse logistics networks and product recovery have been the focus of many research activities in the past few decades. Interest to these models are mostly due to the complexity of reverse logistics networks that necessitates further analysis with the help of mathematical models. In comparison to the traditional forward logistics networks, reverse logistics networks have to deal with the quality of returns issues as well as a high degree of uncertainty in return flow. Additionally, a variety of recovery routes, such as reuse, repair, remanufacturing and recycling, exist. The decision making for utilising these routes requires the quality of returns and uncertainty of return flow to be considered. In this research, integrated forward and reverse logistics networks with repair, remanufacturing and disposal routes are considered. Returns are assumed to be classified based on their quality in ordinal quality levels and quality thresholds are used to split the returned products into repairable, remanufacturable and disposable returns. Fuzzy numbers are used to model the uncertainty in demand and return quantities of different quality levels. Setup costs, non-stationary demand and return quantities, and different lead times have been considered. To facilitate decision making in such networks, a two phase optimisation model is proposed. Given quality thresholds as parameters, the decision variables including the quantities of products being sent to repair, disassembly and disposal, components to be procured and products to be repaired, disassembled or produced for each time period within the time horizon are determined using a fuzzy optimisation model. A sensitivity analysis of the fuzzy optimisation model is carried out on the network parameters including quantity of returned products, unit repair an disassembly costs and procurement, production, disassembly and repair setup costs. A fuzzy controller is proposed to determine quality thresholds based on some ratios of the reverse logistics network parameters including repair to new unit cost, disassembly to new unit cost, repair to disassembly setup, disassembly to procurement setup and return to demand ratios. Fuzzy controller’s sensitivity is also examined in relation to parameters such as average repair and disassembly costs, repair, disassembly, production and procurement setup costs and return to demand ratio. Finally, a genetic fuzzy method is developed to tune the fuzzy controller and improve its rule base. The rule base obtained and the results of sensitivity analyses are utilised to gain better managerial insights into these reverse logistics networks.

Waste management has received very little attention in Lesotho' s Development Planning. Lack of environmental policy and environmental framework law has resulted in waste being illegally dumped. Inadequate services in the country, coupled with increasing population in the urban areas due to rural-urban migration, has led to litter being a serious environmental problem in the whole country, especially in the urban areas. This study aims to analyse the defects of the waste management strategies in Maseru by investigating the waste management systems employed in two residential areas of different income levels. In addition, this thesis attempts to evaluate the impact of socioeconomic and educational factors on solid waste management practices in Maseru. An investigation into trends or similarities in the services rendered by the Maseru City Council was carried out and compared with the literature reviewed. A survey was conducted as two case studies, mainly to assess the present coverage and the standard of refuse generation, collection and disposal service. Waste was collected from the two study areas and compared in terms of the type and amount of waste. generated. The major factors influencing waste generation were found to be the gender and educational level of the household head, income level of the household and the household size. These were found to be proportional to waste generation and inter-related. In this regard, that families headed by men were found to have higher incomes than those headed by women and were found to produce more waste. Furthermore, in households where the household head had attained a higher level of education, income levels increased, there was a concomitant increase in waste generation. In general, high income residential areas generated more waste than low income residential areas. Large families use more money and consume more food than small families, thus generate more waste. The major component of waste was largely paper and plastic, but glass, cans and organic materials were also recorded. In general, waste management in Maseru (Lesotho) was found to be very poor because of lack of policy and contradicting and scattered sectoral laws dealing with waste management, lack of urban planning and infrastructure. More importantly, waive of laws relating to waste has resulted in land degradation due to illegal dumping and littering. / Thesis (M.Sc.)-University of Natal, Pietermaritzubrg, 1998.

An environmental challenge that is currently plaguing the South African townships in the Metropolitan Area is the volume of solid waste being illegally disposed in open spaces along road verges as well as in streams. The research aims to identify the root cause of illegal dumping in the township of Clermont, Kwa-Zulu Natal. The researcher used quantitative, qualitative and observation methodologies to collect data from member’s of the community of Clermont. The severity of the problem will be measured by looking at different age groups; level of income per household as well as gender. In general waste management and environmental management has received little attention compared to other socio-economic problems like un-employment. As the bulk of the world’s population move from rural areas to urban areas, poverty is becoming an increasingly urban phenomenon. Environmental problems range from impairment of human health, economic and other welfare and extinction of the ecosystem. The urban poor bear the greatest burden of urban environmental risks. The most significant environmental challenge in South Africa is effectively management of waste. Currently the focus in South Africa has been on waste disposal rather than on waste prevention. Consequently there are no incentives for reducing waste and industries are not required to submit plans for waste management when commencing a new business. Waste management legislation is fragmented; as a result there is a lack of control in waste management. This research will investigate whether community members are aware of what is expected from them by the municipality and private waste collection companies. It will further analyse at the norm of waste disposal within the developing countries compared to developed countries. The study will attempt to provide practical solutions for the township of Clermont. The study has five chapters. The first chapter introduce the problem, objectives and hypothesis. The second chapter deals with the theoretical review to help the reader understand different cases and how waste management handled in different parts of the world. This has been done by looking at the international, national and local level, comparing waste management trends. The third chapter describe the study area in detail and different scientific methodologies researcher used to prove or disprove the hypothesis and objectives that were set in the first chapter. Chapter four analyses all the data that was collected from the community of Clermont and unpack other underlying factors that lead to poor waste management in this township. For example the researcher will conclude using the data collected if the frequency of waste collection is sufficient for the community and what can be done to minimize illegal dumping. Chapter five, which is the last chapter of this dissertation will suggest recommendations that can be used to correct all problems that associated with illegal dumping in Clermont Township. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

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Thesis (D.P.H.)--University of Hawaii at Manoa, 1991. / Includes bibliographical references (leaves 168-178). / Microfiche. / xiv, 178 leaves, bound ill. 29 cm

Thesis (M. Sc.)--University of Hong Kong, 1997. / Includes bibliographical references (leaf 60-67).

Thesis (M.S.)--Michigan State University. Dept. of Community, Agriculture, Recreation, and Resource Studies, 2008. / Title from PDF t.p. (viewed on Aug. 3, 2009) Includes bibliographical references (p. 141-146). Also issued in print.

M.A. / In present-day society, solid waste can no longer be treated as a non-valuable resource. Municipal waste produced from residential and commercial sources has become an economic resource for the poor on landfill sites. Urban poor, rural-urban migrants and urban-urban migrants are the ultimate symbol of the informal economy on landfill sites. These migrants have identified waste as an economic resource to extract a livelihood. In their presence on landfill sites, South Africa has introduced waste management policies which endorse the notion of sustainable development. Sustainable development is the notion through which South Africa shapes and parallels its environmental directive to avoid destruction and depletion of natural resources. Sustainable development is a theoretical framework adopted by this study to evaluate the effect of legislation on informal waste salvagers and waste salvaging. Waste salvaging is often frowned upon and neglected by local municipal authorities who are constitutionally mandated to ensure preservation of natural resources. Amongst other things, local municipalities need to recreate economic opportunities and curb the unemployment rate. Furthermore, South African municipalities deliberated during the tabling of the Polokwane Declaration to reduce waste disposal by 50% in 2012 through waste recycling and waste minimisation. In the absence of employment opportunities, local municipalities in South Africa are continually faced with the dilemma of incorporating informal waste salvaging into their waste management directives. This study uses Weltevreden landfill site in Polokwane as a case study to evaluate the effects of legislation on informal waste salvaging. A waste management and sustainability framework towards career waste salvagers was developed as a paradigm to incorporate elements of sustainable livelihood approach. The framework allowed the study to comprehend the synergy and the discords that waste management directives in South Africa unravel on informal waste salvaging. Furthermore, this led to the procreation of a model to unlock the economic potential of waste in South African municipalities. The model recognises the elements of waste management directives such as National Environmental Management Act, 1998 (Act No.107 of 1998) and National Environmental Management: Waste Act, 2008 (Act No. 59 of 2008). Despite that, the model resonates on the promulgations made in the Waste Act, 2008 (Act No. 59 of 2008) on informal waste salvaging. This study intends to evaluate the extent to which contemporary waste management directives in South Africa support waste salvaging within the three pillars of sustainable development, namely economic, social and environmental. However, this research hypothesises that waste management directives in South Africa fail to support the three pillars of sustainable development. In light of the hypothesis, this research has identified waste salvagers, waste Thaba Makgafela Richard iii management officials and the public as instrumental respondents to evaluate perceptions and challenges linked to the informal waste economy. A desktop review of available regulatory instruments informed recommendations and the model procreated in this study. The key lessons are highlighted and followed in Chapter 7 which provides analytical conclusions and recommendations for all the chapters.