School of Geography, Archaeology and Environmental Studies (ETDs)
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Item Comprehensive contributions of the informal sectors in Solid waste management Systems: A case study of Central Johannesburg(University of the Witwatersrand, Johannesburg, 2025-02) Pursooth, Takshita; Kubanza, Nzalalemba SergeThe informal waste management sector has become one of the most key components of solid waste management and has been part of society and the economy for three decades. Waste picker activities are within the lower spectrum of the waste management value chain. However, their challenges in functioning as waste pickers are misunderstood, given the rise in the waste within areas in Central Johannesburg. Waste pickers are paramount in the effective diversion of solid waste by steering and processing waste, further creating resilient systems in urban environments, and ensuring recycling practices. The study was completed to comprehensively understand the current contributions of the informal waste collectors within Central Johannesburg. The study area of Central Johannesburg, particularly Mayfair and Braamfontein, was selected as these two areas exhibit over population and urbanization coupled with residential and business-related activity. With these factors, Central Johannesburg has a high waste output. The study had four main objectives being the identification of the challenges the informal waste collectors in Central Johannesburg experience, the identification of the effectiveness of waste picker contributions from a citizen perspective, the examination of existing policy documents for solid waste management in Johannesburg as well as the identification of the best theoretical framework for the inclusion of waste pickers into formal solid waste management strategies in Johannesburg. The research used qualitative methodology with aspects of quantitative methodology. Using snowballing and purposive methods, twenty-five (25) waste pickers were surveyed along with twenty-two (22) citizens, four (4) informal waste pickers NGOs and NPOs and two (2) local authoritative figures. Semi-structured interviews were conducted with the relevant individuals, based on ethical grounds. A total of sixty (60) published data such as journals and news articles were analyzed to substantiate the objectives of the study. Furthermore, four (4) solid waste management policy documents from a national, provincial, and local perspective were analyzed. The research identified that waste pickers along with informal waste NGOs and NPOs, have challenges with coordination such as effective trolleys, being accepted by society and the amount of money they earn from their operations. Citizens had stated that they do have their recyclables collected by waste pickers on a weekly basis and have identified that waste pickers do play a role in waste management within Central Johannesburg, and further aid recycling efforts within the area. However, local authorities have stated that there is a need for waste picker involvement in decision-making and policy formulation. Solid waste management policy documents enforce effective waste management strategies for citizens and the city however there are gaps regarding waste picker integration into strategies, as waste management is regulated. The Inclusive Governance Framework is the most effective theoretical framework as it involves all individuals in decision-making, including marginalized groups. The study revealed the various dynamics among citizens, and waste pickers, and local authorities. There is a need for awareness programs for waste management education for citizens. Local authorities within Central Johannesburg identify with the waste picker operations however have also identified challenges such as poor relationships between them and waste pickers. Solid waste management policy documents are integrated however do not cater to waste picker activity more effectively and the Inclusive Governance Framework would allow for all stakeholders, including waste pickers, to deliberate in policy formulation and decision-making, providing them with equity and justice.Item Engaging Collections: Libetshu in the Van Warmelo Collection, Ditsong National Museum of Cultural History, South Africa(University of the Witwatersrand, Johannesburg, 2025) Nzimela, Yola Siyamthanda; Namono, CatherineThis thesis broadly examines curatorial practice of African ritual material culture within museum and related institutional collections in South Africa. Specifically, I focus on divination material known as libetshu, or Mankgwanyana, heir looms, in the Nicolaas van Warmelo collection, the Ditsong National Museum of Cultural History, Pretoria, South Africa. Although many communities from which ritual objects such as these divination materials originate still revere them as sacred, there is a lack of meaningful inclusion of source communities in curatorial decision-making mainly due to elitist or Eurocentric perspectives on culture due to colonial legacies and/or where curatorial practices reside with Western trained professionals. Globally and locally, limited accurate archival contextual data about such divination material constrains connecting the objects to source communities. This thesis therefore sought to enhance understanding of libetshu /Mankgwanyana as ritually activated divination material, to encourage appropriate curation that takes cognisance of their spiritual significance for communities that hold them sacred. Through use-wear analysis, semi-structured interviews with traditional practitioners and curators, and a curatorial justice framework, I show that libetshu / Mankgwanyana are divination materials used in ritual performances, are spiritual and require specific handling and curation. I find that whilst co-curation with source communities and stakeholders is essential, a blanket approach for ritual objects is insufficient as each divination material belongs to different ancestral lineages. These findings highlight the importance of epistemic restitution and demonstrate the effectiveness of a curatorial justice approach that promotes sensitive, respectful, and appropriate curatorial practices cognisant of the integrity of divination materials such as libetshu / Mankgwanyana in collections.Item Factors Affecting Compliance of Wastewater Management: A Study on Waste Water System Operations in the City of Tshwane, Gauteng(University of the Witwatersrand, Johannesburg, 2025-05) Mmotong, Juliet Ramathabathe; Kubanza, Nzalalemba SergeWastewater Treatment Plants (WWTPs) are likely to collapse, the state of water continues to deteriorate, and rivers remain polluted. Wastewater Operational System are now at the centre of economic value systems expected to drive towards sustainability. Factors affecting compliance with wastewater management in the growing City of Tshwane, Gauteng, were investigated to realise wastewater as a valuable resource where other valuable resources can be harnessed. This dissertation explored professionals’ perspectives regarding factors affecting wastewater management compliance in the City of Tshwane (CoT). The research report explored what professionals perceive as challenges that affect compliance at their workstations and their views on which changes can be introduced. The primary objective of the study is determining the elements responsible for challenges to a complying facility; challenges with the current governing wastewater legislation toward realising efforts for a new paradigm shift. Among others, the findings revealed a shortage of staff, a lack of consumables for effluent monitoring, and maintenance irregularities contributing to the shortfalls in achieving complying wastewater. As pollution of the water resource has become a national challenge where treatment plants must continue doing the intended work, the need to explore new technologies that can assist in treatment efficiencies in the City of Tshwane is discussed. Although there was dissatisfaction with the Green Drop incentive programme, with correct consistencies and proper championing, it was found to instil a positive attitude in professionals.Item Evaluating the Use of Mid Infrared Spectroscopy in Predicting Soil Carbon, Nitrogen Contents, and Soil Texture in Varying South African Soil Samples(University of the Witwatersrand, Johannesburg, 2025-05) Mata, Abonga; Adam, Elhadi; Jezile, GoodmanThere is a growing need for soil information to help address problems such as soil nutrient depletion and incorrect fertilizer inputs which affect yields and threaten food security and the environment. Low soil fertility is a significant issue in main grain-producing regions in South Africa. Routine soil analysis addresses these issues as farmers are provided with valuable information to enhance agricultural productivity and sustainability. However, lack of efficient and cost effective soil testing infrastructure is a limitation in South Africa. Soil spectroscopy has proven to be an efficient soil analysis method that complements traditional methods of soil analysis. It is more cost-effective than analytical laboratory procedures since measurements may be completed faster, and multiple soil parameters can be deduced from a single spectral measurement (Nocita et al., 2015). This research aimed at developing a spectral library of South African soils and to test the ability of mid-infrared (MIR; 4000 – 500cm-1) diffuse reflectance spectroscopy coupled with machine learning algorithms to predict total carbon, total nitrogen, and soil texture. Soil samples for this study were selected from the ARC-SCW archive using the Kennard-Stone algorithm to ensure diversity. Chemical analysis of total carbon (%) and nitrogen (%) was conducted through total combustion with a CHNS-O analyser, while physical properties (sand (%), silt (%), and clay (%) content) were determined through the hydrometer analysis technique. This data was then used with corresponding spectra to develop PLSR (partial least squares regression) and MBL (memory-based learner) predictive models. During model assessment, the criteria used to determine a good predictive model was that an R2 value had to exceed 0.7, RMSEp < 10% of the range of the independent validation dataset and RPIQ > 1.7. Predictive regression models were developed successfully, the results for clay, silt, and sand contents showed that soil texture can be predicted well with diffuse reflectance MIR spectroscopy. The highest R2 values were 0.80, 0.78, and 0.81 for clay, silt, and sand contents respectively. Based on these results, these models can be used in real world situations for accurate predictions of sand, silt, and clay content. The best sand and clay content models were developed with UVS- elected variables, selected from a raw spectra dataset. On the other hand, during model assessment, the results were poor for predicting TC (total carbon) and TN (total nitrogen). The highest R2 values were 0.51 and 0.61 for TC and TN respectively. This meant that the predictive models developed in this study for predicting TC and TN were unreliable and may not be applicable for predictions. This poor result was due to highly variable and limited data used during model training. Compared to results obtained with full-spectrum, Boruta, and CARS-selected variables datasets, the raw spectra UVS-selected variables datasets produced better results. Generally, MBL produced better results than PLSR. Pre-processing the spectra with either Savitzky-Golay first derivative filter (SG) or standard normal variate (SNV) was proved to be ineffective in improving model performance. Soil spectroscopy is a data hungry analysis method, therefore it is recommended to develop predictive models with many samples such that the number of samples is greater or equal to the number of predictor variables especially when the data is diverse.Item Improving solid waste management in a coal mining organization: a case of Mafube Coal(University of the Witwatersrand, Johannesburg, 2024-06) Hlomuka, Jackie; Modiba, Duduzile; Evans, MaryWaste can be any substance that is unwanted and discarded. In most definitions, all waste is harmful unless treated (Nyika et al, 2019). Waste, and the management thereof, is a global issue and depending on how it is managed, it tends to be very harmful to the environment (Chen et al., 2019). It is acknowledged that including waste management in the legislature of a country is the best tool to enforce waste management. South Africa only has four decades of such an experience. This has made it slow for industries, such as coal mining, to implement lucrative waste initiatives. This study seeks to determine key issues associated with non-mineral waste management and to assess if a waste transfer station can be used as a tool to improve waste management. The key findings were that waste management at Mafube Coal is not standardized and a waste storage facility with a similar design of a waste transfer station can be used by the operation to improve non-mineral waste management.Item Role of edible insects in food security and livelihoods in Mumbwa District, Central Province, Zambia(University of the Witwatersrand, Johannesburg, 2025-01) Nyawali, John; Knight, JasperThe need to find sustainable sources of food and livelihoods is one of the agendas of many societies. This is in response to an increase in global population and increasing number of hungry people globally. The threat of increasing food insecurity, especially in poor communities of sub-Saharan Africa, entails the need to find sustainable alternative sources of nutrition alongside conventional agriculture and food systems. The use of edible insects is seen as having potential to help bridge nutritional and food insecurity gaps as they are a good source of protein and could be part of resilient and sustainable food systems. Edible insects have also been part of cultural dietary practices in Africa for thousands of years. However, despite these advantages, the use of edible insects as food has declined in recent decades in many African communities that were previously known to have high consumption. This study examined the degree of acceptability of edible insects and their contribution to household food security and livelihoods in rural communities in Mumbwa district of Central Province, Zambia. A mixed method research strategy was used across four administrative zones of the study area to collect data through questionnaires, observation and focus group discussions with adult participants (18 years and above). Ethnographic observations were also made on how rural residents engage and utilize edible insects as a resource, including how they find, harvest and prepare insects from natural settings. Results show that the majority (68%) of surveyed households consumed edible insects. This is attributed to the fact that entomophagy forms part of the food culture of the dominant local Kaonde ethnic group. Edible insects were also used as a means to promote social cohesion and cultural values. Edible insects were also a source of livelihood for 26% of respondents, with income from the sale of edible insects being similar to the total income generated from agricultural activities for the majority of households in the community. It was reported that the income generated from the sale of insects, especially caterpillars, was much higher than maize, as a 5-litre bucket of caterpillars sells for around K300 (about US$11) during the harvest season and K500 (about $19) in the off season. In some cases, the income was higher depending on the type and quantity of the caterpillar species being sold while the same quantity of maize grain sold for K20 ($0.75) during harvest season (June–August) and K50 ($2) off season (October until the next harvest season). This means that trade in edible insects could help mitigate poverty among rural households. Impediments to the utilization of edible insects as a source of livelihood include the reduction in insect population and availability, lack of infrastructure to promote trade, and lack of environmental stewardship to enhance ecosystems protection. Reduced availability of insects in this community was attributed to climate change, habitat destruction and lack of effective management. To ensure sustainable livelihoods and food security in rural communities, there is need to maintain ecosystems in good condition as well as recognizing edible insects as finite valuable resources that should be managed. This requires adequate infrastructure and public policy cutting across socioeconomic, health, education and trade/business systems. Better governance and coordination across different actors involving edible insects as a form of natural capital can help achieve various Sustainable Development Goals of relevance to rural African communities.Item The “Roots” of Early Homo’s Survival: The role of geophyte underground storage organs in the diet of Homo ergaster occupying the Cradle of Humankind during the middle Pleistocene(University of the Witwatersrand, Johannesburg, 2024-09) Cordeiro, Jeanne; Stratford, DominicThis research project explored the seasonal availability of geophyte USOs in the Cradle of Humankind throughout the year with the view of evaluating the energetic and nutritional contributions of USOs in the diet of early Homo. The study adopted an Optimal Foraging Theory and Niche Construction Theory approach to determine whether geophyte USOs in the Cradle could have offered feasible sources of energy and nutrition for Homo ergaster occupying the Cradle during the middle Pleistocene. The nutritional and calorific values were considered in context of the major cognitive and morphological adaptations that define the early Homo lineage, namely encephalisation and bipedalism. The average area required to be searched to achieve a portion of the assumed calorific requirement of H.ergaster, from USOs, was enumerated in this study. The findings support the hypothesis that geophyte USOs contributed to the year-round sustenance of H.ergaster, and may have been more important in the diet of early Homo than traditionally believed.Item Bayesian Belief Networks and Score-Based Network Construction for Nitrate and Nitrite Level Prediction in Water Quality Testing of the Vaal River in South Africa(University of the Witwatersrand, Johannesburg, 2024-09) Stylianou, Nicholas; Evans, MaryThis research addresses the essential task of monitoring water quality, particularly in accurately predicting nitrate and nitrite levels in river water. These parameters are crucial indicators of water's suitability for human consumption and ecological health. Traditional monitoring methods, such as manual sampling and expensive sensors, are often prohibitive due to their high costs and labour-intensive nature. In response to these challenges, this research leverages machine learning (ML) algorithms to more efficiently predict nitrate and nitrite levels, utilising a dataset from one water monitoring station on the Vaal River comprising 1071 data points gathered over 21 years (1995-2016). This dataset includes a variety of water quality variables such as calcium (Ca), chloride (Cl), dissolved major salts (DMS), electrical conductivity (EC), fluoride (F), potassium (K), magnesium (Mg), ammonium (NH4), sodium (Na), phosphate (PO4), sulphate (SO4), silicon (Si), total alkalinity (TAL), and temperature. This research employs a series of Score-Based Constructed Bayesian Belief Network models, including Tree-Based All-Features (AF), Hill Climb (HC) with various criteria like Bayesian Information Criterion (BIC) and Random Features (RF), and a Random Forest model with All-Features with varying number of trees, including optimisations. These models are evaluated for their ability to predict nitrate and nitrite values, aiming to provide a cost-effective and efficient alternative to traditional monitoring techniques. The research assesses each model's prediction accuracy, striving for reliable predictions of nitrate and nitrite levels with the Akaike Information Criterion and Enhanced Bayesian Information Criterion Score-Based models performing with the best accuracy and capable of predicting nitrate and nitrite with Root Mean Square Error (RMSE) on the test data of 0.356 and 0.360 respectively, Mean Square Error (MSE) on the test data of 0.127 and 0.130 respectively, Mean Absolute Error (MAE) on the test data of 0.197 and 0.197 respectively and R-squared of 0.7940 and 0.7944 respectively. The study's findings have significant implications for monitoring and managing water resources, potentially shifting the paradigm for ensuring water quality sustainably.Item Constructed Wetlands: Additional heterogeneous configurations on existing infrastructures in Silvertown, Alexandra Township, Johannesburg(University of the Witwatersrand, Johannesburg, 2024-09) Sepeng, Motshwaedi Collen; Thatcher, AndrewGreywater disposal is a service issue that has yet to be addressed fully in urban informal settlements of South Africa. Greywater exposure poses great health dangers if this wastewater is disposed of incorrectly. Silvertown proved to lack infrastructure for greywater disposal and showed prevailing evidence of physical exposure to disposed greywater. There are no formally defined manners of greywater disposal in Silvertown. Therefore, there is a need for infrastructural development to support safe greywater collection, disposal, and possible treatment. Heterogeneous Infrastructure Configuration (HIC) scholars have pointed out that empirical work still needs to be done to validate the theoretical arguments that infrastructural growth in the Global South does not emphasise uniformity and standardisation. To address the greywater disposal problem, constructed wetlands (CWs) were implemented in Silvertown (a section of an informal settlement) as a proposed solution for greywater disposal. This study investigated how the CWs integrated with existing infrastructure over three years. A participative, iterative design process was implemented to help create links between the residents and the existing heterogeneous infrastructure. In this research, HIC was used as a theoretical framework to help understand the dynamics that shape the engagement with the CWs by the residents of Silvertown and integration with existing infrastructure. Notably, in the absence of the provision of infrastructure and services, the people of Silvertown have actively constructed the environment around them to provide the required services and infrastructure. It was also evident that “people as infrastructure”, as Simone (2004) phrases it, emerged as a prominent process in the provision of services. A qualitative study which included semi-structured interviews, unstructured interviews, and observations collected over three years was used to collect data from Silvertown. The research findings showed that CWs made significant progress beyond just offering a solution for greywater disposal and the controlled/treated release of contaminated water through integration with related infrastructure and services. However, it was also noted that the effectiveness of the CWs was hindered by challenges such as vandalism and negligence. A collective effort was needed from the service providers and the residents to ensure the functionality and sustainability of planned infrastructures such as CWs in Silvertown.Item Assessing the spatiotemporal variability of urban heat island and thermal comfort in Greater Francistown City(University of the Witwatersrand, Johannesburg, 2024-08) Kudoma, Bongayi; Adam, ElhadiClimate change and global warming have increased land surface temperature (LST) in urban areas, causing urban heat islands (UHI), affecting residents' thermal comfort. The UHI effect in Greater Francistown City is causing temperatures to rise, potentially affecting residents' thermal comfort. The study combined remote sensing and statistical techniques to collect Landsat-8 OLI/TIRS-1 data and analyses spatiotemporal variability of LST, vegetation, built-up areas, UHI phenomenon and thermal comfort levels in the city from 2014-2023. Results revealed that built-up areas covered 59.02% of the City in 2023, reducing vegetation to 33.26% and affecting thermal comfort. UHI effects have grown due to LST variations near bareland and built-up areas. Urban hotspots increased, peaking at 3.12% in 2023, with thermal comfort levels varying between 2016 and 2023. Expanding the built-up regions, reduced vegetation, land-cover changes contributed to the UHI effects and changes in thermal comfort patterns. Recommending sustainable urban planning to improve urban liveability.