Electronic Theses and Dissertations (Masters)

Permanent URI for this collectionhttps://hdl.handle.net/10539/37963

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The Impact of South Africa’s Response to Informal Settlements and Affordable Housing Development when compared to the responses adopted in Brazil and India
(University of the Witwatersrand, Johannesburg, 2024) Mlotsa, Cebile; Biyela, Precious
In South Africa, informal settlements are prevalent in all the major urban centers, including some long-established informal settlements, such as ones within Alexandria township in the City of Johannesburg, Nyanga in the City of Cape Town and Kennedy Road in the City of eThekwini. New informal settlements are continuing to develop across South Africa’s urban centers. Various policies and interventions have been implemented to address this phenomena. This study aimed to investigate the impact and effectiveness of South Africa’s policies and interventions on informal settlements and compared them to policies and interventions of India Brazil. The study begins with a literature review of the policies and strategies of the three countries alongside best practices recommended by international organizations such as UN-Habitat and the World Bank. The effectiveness of the policies was assessed, and the general issues that affect informal settlements globally were identified. Research questions were formulated based on the literature review to gain further insights into South Africa's response strategies. Semi-structured Interviews were conducted with three professionals working in organizations addressing informal settlements across different provinces, focusing on current strategies, their impact and effectiveness, and potential improvements. A field visit to Mahlakong informal settlement in Limpopo was also carried out which included interviews with two residents to understand challenges and interventions underway to address them. The study found some progressive policies and strategies underway in South Africa, such as the strong emphasis on participation and approval by residents of informal settlements when interventions are carried out, and incremental construction of infrastructure in informal settlements. The study also identified areas that if addressed can improve South Africa’s response to informal settlements, such as recognizing multi-storey inner city buildings as informal settlements, encouraging private developers to invest in affordable housing development, and diversifying tenure legalization option.
The removal of diclofenac, cypermethrin, ibuprofen and naproxen from wastewater using advanced membrane technology
(University of the Witwatersrand, Johannesburg, 2024) Ngwamba, Pamela Nadia; Biyela, Precious
In recent years, emerging contaminants (ECs) such as pharmaceuticals, personal care products, endocrine-disrupting compounds, industrial additives, pesticides, nanomaterials, surfactant retardants, surfactants, and their metabolites and transformation products have been widely detected in both wastewater and water bodies. These compounds originate from a diverse range of point and non-point sources, consistently introducing them into wastewater and directly and/or indirectly introducing them to water bodies and the broader environment. The ECs have garnered attention due to their potential environmental impact and potential to induce adverse health effects. Conventional wastewater treatment processes are often not adequate to efficiently remove these compounds, thus leading to residual concentrations entering aquatic ecosystems and eventually, reaching drinking water systems. Although extensive research has been done over the past decade, there is limited literature covering the effects of long-term exposure to ECs, especially their metabolites and by-products, their fate, and toxicity levels. Consequently, additional research is imperative to establish limits and facilitate the regulation of these ECs. Advanced treatment methods, including ozonation, activated carbon filters, and membranes, have proven effective in eliminating ECs from wastewater. It must be noted that the efficiency of these advanced processes varies significantly. Despite extensive testing of various technologies, limitations still exist. Although most of the advanced treatments are highly effective, none of them have the ability to remove a mixture of ECs effectively. This variation is attributed to the nature of the compounds (e.g., hydrophobicity/hydrophilicity and solubility) and operational parameters like temperature, hydraulic retention time, and solids retention time. Nanocomposite membranes have been identified as a viable technology for the removal of ECs from wastewater due to their unique properties and enhanced performance when compared to conventional membranes. They are highly selective and efficient, additionally, they can be designed to specifically remove ECs such as pharmaceuticals, pesticides, and endocrine disruptors. Furthermore, they show greater antifouling properties, reducing the accumulation of contaminants on the membrane surface and extending the lifespan of the membrane, thereby lowering maintenance costs and improving operational efficiency. The aims and objectives of the research report were to compile a comprehensive literature review that highlights the importance of removing ECs from the environment; prepare and characterise four different flat-sheet membranes using polyvinylidene fluoride (PVDF) and imidazolium-based polymeric ionic liquids (PILs) and testing the membranes to determine the retention time and effectiveness of the prepared membranes in removing four different iv pharmaceutical products which are diclofenac, cypermethrin, ibuprofen, and naproxen. The hypothesis assumed that the imidazolium-based PILS/PVDF flat sheet membranes would yield a removal efficiency greater than 90%. This expectation was achieved, and all the membranes achieved a removal efficiency greater than 90%. Various studies have shown that nanocomposite membranes yield high removal rates. The synthesised membranes had better features than PVDF alone. The PVDF alone was found to have the largest pore size and the least retention time, although the removal efficiency was high. The blended membranes lead to higher porosity and retention times. They had smaller pore sizes as compared to plain PVDF; hence, the retention time was increasing. The higher the concentration of the imidazolium, the lower the contact angle measured; this is an indication of a more hydrophilic membrane surface. Hydrophilic membranes are less prone to fouling. The method investigated in this report is simple and can be easily reproduced. Based on the findings of this research report, the methods employed are precise, accurate, highly sensitive, and rapid.