Theses and dissertations (Engineering and Built Environment)

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A critical analysis of participation using the planning context of the Durban Back of Port Precinct
(2023-05) Ngubane, Sibongiseni Memory; Hansmann, Robynne; Musvoto, Godfrey
Communities located in the Durban Back of Port area experience the compounded burden of environmental degradation with the legacy of untransformed Apartheid neighbourhoods. Despite the documented concerns and priority to deal with the cumulative environmental impacts on the communities of South Durban within planning policy documents, the participation process is unclear. Poorly defined participation processes not only inhibit the substantial issues being raised but fail to inform processes to address the concerns raised. These weakly defined civic engagements were found in the study to reflect some of the implementation challenges in the field of urban planning. The primary aim of the research study is to critically analyse participation processes for development as outlined in planning policy documents to make proposals within the context of the Durban Back of Port case study from sampled stakeholder categories; corporate community, civil society, and government. The Durban Back of Port case study is a geographical area under the authority of eThekwini Municipality in KwaZulu Natal. This precinct represents a situation where communities live near one of Sub-Saharan Africa’s busiest industrial areas, and at the backside area of one of the most active ports in Africa. This research study found the precinct residents to have been subjected to both environmental racism, and post-Apartheid environmental injustice. The study area presents contrasting land uses, where negative externalities of industrial development impact on the adjacent residential uses. In effect, the legacy of Apartheid spatial planning is layered with environmental racism and has evolved into environmental injustice in present time. This is a qualitative research study that applies hybrid analytical tools; document analysis, policy analysis and thematic analysis to critically analysis participation processes within the case study. This research study established three type categories of stakeholders representing varying interest; economic, social, and environmental. The purposely sampled categories comprised of corporate community, civil society, and the spheres of government, these are organisations that are either located or have jurisdictional authority in the Durban Back of Port. It uses the theoretical lenses of Environmental Justice, Advocacy Planning, Communicative Rationality and Action, Collaborative Planning, Participatory Planning, and Arnstein’s Ladder of Participation to better understand participation processes.
Extraction of caffeine from spent coffee grounds using ionic liquids
(2023-05) Singh, Nikita; Chetty, Manimagalay; Deenadayalu, Nirmala
Coffee is the most popular beverage consumed and the second-highest commodity in the world, after crude oil. In 2018, a total of 9,5 million metric tons of coffee were produced globally. This in turn generated 6 million tons of waste coffee grounds. In South Africa alone, it is estimated that approximately 100 million cups of coffee are brewed a year, resulting in 3000 tonnes of waste produced, of which 93% ends up in landfill sites (Lombard, 2021). This abundant waste source has shown promising potential for reusing, recycling, or converting the waste into valuable products like biofuels, fertilizers, animal feed, high-value chemicals, cosmetics and pharmaceutical products such as caffeine for medicinal purposes. Besides coffee being one of the most important agricultural commodities in the world, coffee is also one of the most valuable primary products in world trade. Coffee is also the central and popular activity of many cultures. The most popular reason for the consumption of coffee is its refreshing properties. Large quantities of this waste pose threats to the environment as it is a source of severe contamination and serious health problems. To avoid this catastrophe of the coffee waste, spent coffee grounds can be utilised to generate valuable products. The long-term usage of fossil fuels depletes the finite supply and contributes to greenhouse gas (GHG) and exhaust emissions. The global economic and environmental crisis related to the usage of fossil fuels and the fast depletion of natural resources has raised much awareness and need to find alternate strategies for cleaner and greener energy and chemical products needed for recycling waste has risen drastically. The use of biomass and other lignocellulosic material to produce bio-fuels and other high value products show promising results. Using lignocellulosic material has attracted considerable amounts of attention due its renewable nature and being abundantly available. Lignocellulosic material is used for sustainable development in the world. In this study caffeine extraction is a promising solution for sustainable development, where biomass is valorised. The characterisation of spent coffee grounds (SCGs) using Technical Association of the Pulp and Paper (TAPPI) methods was carried out. The effect of temperature, reaction time and solid-to-liquid loading ratio on the yield of caffeine extracted from spent coffee grounds was investigated. Simultaneously, the best extraction solvent between the (i) ionic liquid (IL) 1-ethyl-3-methylimidazodium chloride (98%), (ii) dichloromethane and (iii) water was determined. Variation of the parameters were established using the Box-Behnken design of experiment (DOE) methodology which varied the (i) temperature (88-120 degrees Celsius), (ii) reaction time (15-35 minutes) and (iii) solid-to-liquid loading ratio (20 g/10-25 mL). For the extraction process, both the conventional method and green method (IL and water) were investigated. The conventional method includes using dichloromethane as the extraction solvent, whereas the green method makes use of the ionic liquid 1-ethyl-3-methylimidazolim chloride and water as the extraction solvents. Extraction was carried out in a Parr pressure reactor where solid-liquid extraction occurs. High performance liquid chromatography (HPLC) was used to quantify the yield of extracted caffeine. Recrystallization of the highest caffeine yield was carried out and thereafter analysed using Scanning Electron Microscopy (SEM), Transition Electron Microscopy (TEM), Energy Dispersive Spectroscopy (EDS) and Differential Scanning Calorimetry (DSC). The maximum yield of caffeine was obtained at the optimum conditions of 120 °C for 25 minutes using 25 mL volume of extracting solvent. The caffeine extracted from 1-ethyl-3-methylimidazolium, water and dichloromethane was 726.22mg/L, 646.33mg/L and 566.12mg/L respectively. Alternatively stated as 1-ethyl-3- methylimidazolium chloride, water and dichloromethane extracted 0.00363 g caffeine / 1 g SCG, 0.00323 g caffeine / 1 g SCG and 0.00283 g caffeine / 1 g SCG respectively. SEM images of the spent coffee grounds prior to extraction displayed a dense morphological chain-like structure, with large lumps present. The structure was tightly bonded together and appeared rough. After extraction using each solvent, the SEM micrographs were analysed. Extractions done with the IL demonstrated full degradation. The structure was loose, multiple open pores on the surface with a smooth and thin appearance. The water extractions appeared almost same to that of the IL, but slightly thicker. Lastly, extractions using DCM appeared to be unsuccessful as the SCG attempted to be broken but were still together. The surface had no open pores, rather an oil coated layer covering the spent coffee grounds. EDS results from 99% pure caffeine standard was compared against the caffeine extracted by all three extraction solvents. Pure caffeine appeared clean, properly formed, big separate particles and distinctive shapes. The caffeine extracted using IL was similar to the structure, crystallinity and appearance of the pure caffeine. Caffeine extracted by water were in long shards, but not fully individual/separated. The caffeine extracted by DCM appeared less crystalline, much smaller in size and more compact. DSC compared the melting points of the pure caffeine standard to those caffeine samples extracted by different solvents, thus providing the purity of the extracted caffeine. The standard caffeine sample had a melting point of 233. 55 ºC equalling 99 % pure. The melting points of 226. 52 ºC; 212. 28 ºC and 200 ºC were obtained for IL, water and DCM respectively. Purity obtained were 96 %, 90 % and 85 % per respective extraction solvent.
Hydrological modelling under limited data availability : a case study of Umdloti River, South Africa
(2016) Mashiyane, Thulasizwe Innocent; Adeyemo, Josiah
Due to the water scarcity in South Africa, new strategies in management planning are needed in order to sustain water resources. The increase of population and economic growth in South Africa has a negative effect on the water resources. Therefore, it should be well managed. The main concerns of the sustainability of water resources are hydropower, irrigation for agriculture, domestic and industries. Hence, the use of integrated water resources management in a single system which is built up by a river basin will help in water resources. This study was focused on water management issues: some of the principal causes of water shortages in UMdloti River are discussed. The current situation of water supply and demand at present is discussed. It also addressed some essential elements of reasonable, cooperative and sustainable water resources management solutions. Many developing countries are characterized as there is limited data availability, water scarcity and decrease of water levels in the dams. The eThekwini municipality is also having similar problems. Water resources have been modelled under this limited data using the hydrological modelling techniques by assessing the streamflow and observed data. The aim of the study was to address the issue of water management how water supply sources can be sustained to be manageable to meet the population growth demand considering the capacity of Hazelmere Dam demand downstream of the dam. Hydrological models, simulation, and decision making support systems were used to achieve all the research objectives. Hazelmere Dam has been modelled so that it can be used efficiently for the benefit of all users downstream of the dam for their economic and ecological benefits. Monthly reservoir inflow data for Hazelmere Dam was obtained from the Department of Water Affairs, South Africa. The nature of data is streamflow volume in mega liter (Ml) recorded for every month of the year. This was converted to mega cubic meter (Mm3) for use in the analysis herein. A period spanning 19 years of data (1994 – 2013) was used for the analysis. Six parametric probability distribution models were developed for estimating the monthly streamflow at Hazelmere Dam. These probability distribution functions include; Normal, Log-Normal (LN), Pearson III, Log-Pearson type III (LP3), Gumbel extreme value type1 (EVI) and Log-Gumbel (LG). It was observed that UMdloti River is smaller when compared with other rivers within the KwaZulu-Natal Province which could make it difficult to implement integrated water resources management. The hydro-meteorological data collected also has some limitations. The meteorological stations are far away to one another and this would make it difficult to attach their readings with the corresponding water basin. The comparison between the observed and simulated streamflow indicated that there was a good agreement between the observed and simulated discharge. Even though, the performance of the model was satisfactory, yet, it should not be generalized equally for all purposes. The erosion on the study area must be addressed by the stakeholders. It must be minimized in order to sustain the water resources of the UMdloti River. Erosion has a bad impact on the environment because it causes environmental degradation as well. Further investigations are recommended that account for the geological characteristics and the source of the base flow to make sure the rate of groundwater is sufficient for any future developments. Harnessing more energy from existing water sources within the frontier of the country is important in capacitating the South African Government’s commitment to reduction of the country’s greenhouse gas emissions and transition to a low-carbon economy while meeting a national target of 3,725 megawatts by 2030. This study also aimed to determine the amount of energy that can be generated from Hazelmere Dam on the uMdloti River, South Africa. Behavioral analyses of the Hazelmere reservoir were performed using plausible scenarios. Feasible alternative reservoir operation models were formulated and investigated to determine the best operating policy and power system configuration. This study determines the amounts of monthly and total annual energy that can be generated from Hazelmere reservoir based on turbines efficiencies of 75%, 85% and 90%. Optimization models were formulated to maximize hydropower generation within the constraints of existing abstractions, hydrological and system constraints. Differential evolution (DE) optimization method was adopted to resolve the optimization models. The methodology was applied for an operating season. The optimization models were formulated to maximize hydropower generation while keeping within the limits of existing irrigation demands. Differential evolution algorithm was employed to search feasible solution space for the best policy. Reservoir behavioural analysis was conducted to inspect the feasibility of generating hydropower from the Hazelmere reservoir under normal flow conditions. Optimization models were formulated to maximize hydropower generation from the dam. DE was employed to resolve the formulated models within the confines of the system constraints. It was found that 527.51 MWH of annual energy may be generated from the dam without system failure. Storage was maintained above critical levels while the reservoir supplied the full demands on the dam throughout the operating period indicating that the system yield is sufficient and there is no immediate need to augment the system.
An inquiry into the socio-economic influence on the architecture of the Quarry Road West informal settlement, eThekwini Municipality
(2023-05) Matangana, Khayakazi; Tecle-Misghina, Belula; Whelan, Deborah
Informal settlements are present worldwide under various names, forms and typologies. According to the UN-Habitat (2015a), over half of the world’s population lives in cities with over a billion people living in informal settlements. The global south appears to be experiencing a dramatic urban population growth, with sub-Saharan Africa expected to double its numbers in the next two decades. In South Africa, the lack of access to adequate and affordable housing in the city forces low-income and urban poor to resort to building their own homes. These dwellings are built precariously, from recycled and affordable materials with sometimes poor performance, given the low wage group of the builders. These dwellings are built to cater to the residents’ immediate housing needs, while also conveying a narrative and meaning through the aesthetics and the configuration of the physical form, defined by their socioeconomic realities. Despite various interventions put in place by developing cities to curb the spread of informal settlements, they continue to grow (UNHabitat 2015a). This research is an enquiry into how the socio-economic status of an informal settlement community influences the architecture of their environment. The analysis of foundational theories on human settlements and housing in the 20th century and literature review, assist to establish a quality benchmark as a reference. Further, the research advances an inquiry into the spatial patterns and dwelling configuration that influence human comfort and security, through a qualitative review of existing spatial studies, interviews with key informants and the use of a case study. The building materials and techniques used to build the structures, which define the built form narrative, is scrutinised from a spatial, technical and economic perspective, and put into context within the city and national building standards. The outcome of this research is intended to give guidance on an alternative design framework that is based on the findings from the analysis of the existing socio-economic parameters and built form. The Quarry Road West Informal Settlement (QRWIS) which is located in the city of Durban, South Africa is selected as a case study.
Life cycle assessment of the production of cement : a South African case study
(2021-12-01) Olagunju, Busola Dorcas; Olanrewaju, Oludolapo Akanni
The relentless ongoing pursuit of innovation, development, urbanization and immigration for a better quality of life has impacted the natural environment. Also, the various consequences of continuous industrial activities are seen in the departure from what is supposed to be the norms of nature and an ideal environment free of toxicity, pollution and unquantifiable instantaneous changes. One of these is variation in temperature experienced in recent times as against what it was about 2000 years ago before the industrial revolution. A world with an increasing population requires infrastructure to support this growth. The construction industry is able to support this growth by building necessary structures that will accommodate environmental sustainability. However, the construction industry is responsible for several environmental impacts as a result of various activities. Concrete is one of the major base materials used in the construction industry and cement is an essential ingredient in concrete production. Several environmental impacts ranging from high greenhouse gas (GHG) levels to high energy consumption (fossil fuel and electricity) to high resource usage are associated with cement production. Quantifying these impacts is a major roadmap to reducing them. In this study an analysis of the production model of South African cement plants was carried out so as to quantify its impacts, and know how they consequently affect the lives of South Africans, her resources as well as the ecosystem; so that proper mitigation strategies can be recommended. The study carried out a Life cycle assessment (LCA) of cement using both the midpoint and endpoint approaches of the LCIA. LCA is a tool used to analyze the environmental impact of a process or product from start to finish. This study carried out a cradle-to-gate analysis of 1kg of cement produced in a typical South African plant using data from the Ecoinvent database and SimaPro 9.1.1 software. The result showed that for every 1kg of cement produced, O.993 CO2 eq, was emitted into the atmosphere; 98.8% was actual CO2 emission and its resultant effect was global warming which causes changes in climatic conditions. Also, 1.6kg of 1,4-Dichlorobenzene (1,4-DCB) eq was emitted into the air and water, which caused high toxicity in these media and for every 1kg of cement produced, 0.139kg of oil eq was produced and its effect was seen in fossil resources scarcity. Of this value, 0.125kg was from the burning of coal In both approaches, the result was further analyzed with respect to five major production processes: (1) Clinker production (2) Raw material consumption (3) Electricity usage (4) Fuel consumption and (5) Transportation. The results showed that the clinker production stage contributed 76.3% to global warming; and raw material consumption contributed 95.9%, 99.9%, 90.7%, and 77.9% to ionization radiation, mineral scarcity, fossil resource scarcity and terrestrial ecotoxicity, respectively. Fuel consumption contributed 98.6%, 96.3%, 85.7% and 76.9% to freshwater eutrophication, marine eutrophication, human carcinogenic toxicity, and human non-carcinogenic toxicity, respectively. Electricity usage contributed 65.8% and 64.8% to stratospheric ozone depletion and fine particulate matter formation, respectively. Though South Africa relies on the importation of clinker and cement, in the endpoint approach an estimation was carried out based on the annual requirement of cement in South Africa without importing either commodity. The result showed that 55 404 was the potential number of human lives that could be endangered annually; 133 species had the potential to be endangered annually, and the effect of a potential scarcity of resources caused total a marginal price increase of R6.2 billion due to these damages. The results of the analysis are in line with previously published literature but with slight variations. In conclusion, the study prescribed mitigation and adaptation strategies to counter these environmental impacts.
A model for integrated, high-rise urban living : learning from Durban's beachfront
(2022-05) Bush, Lindsay Ann; Marks, Monique
This study explores the potential of architecture, specifically the residential high-rise, to act as an instrument of spatial justice. It does so by raising a socio-spatial lens to the flats on Durban Beachfront and to the diverse people who inhabit these blocks today. As the research illustrates, the status quo in the study area stands contrary to persistent economic and racial residential segregation in South Africa, thereby challenging low-density development in the country—still the norm 25 years after apartheid. Framed around the notion of spatial justice and the Right to the City, theoretical investigations consider the relationship between inequality and city form, and the role that new housing should play in moving from fragmented to integrated city fabric. The living environments found on Durban Beachfront are counterposed with contemporary housing in South Africa and abroad, to establish what activates ‘the commons’ and to better understand the advantages, disadvantages, and potentialities of vertical urban living. The dissertation interrogates the high-rise building in terms of its suitability for human habitation, the residential density enabled by height, and the possibilities it engenders for meaningful contact and diverse living. Combining interviews and observational data in an ethnographic approach, the study moves between different types of analysis—descriptive, analytical, and normative—to unlock the operational complexity embedded in this unique place and learn about its successes and failures from the user perspective. Immersive fieldwork comprised 101 questionnaire-based interviews, selfadministered in participants’ flats, enquiring into their dwelling experience at four spatial scales, from Individual to Neighbourhood. Results confirmed the human diversity present in this urban strip and found high satisfaction levels across the board, regardless of demographic profile or moderating factors such as floor level, indoor density, or relationship between occupants. Findings reaffirm the improved quality of life that results from inner-city convenience; access to quality public space and nature; and the peace of mind offered by a secure high-rise in a high-crime society. I develop a term, ‘verticolopa’, to describe a high-rise, high-density structure that combines climatically and culturally responsive architectural design with new social landscapes to optimise vertical urban living in this context. The dissertation ends on a normative note, with a set of design guidelines for a new model of mixed-use, mixed-tenure, mixedincome urban housing—the ideal type Verticolapa—which promises real possibilities for urban living that is integrated, affordable, accessible, attractive, and which takes Anthropocene challenges into account.
Non-revenue water : most suitable business model for water services authorities in South Africa : Ugu District Municipality
(2016) Mwelase, Lorraine Thulisile; Dzwairo, Bloodless; Adeyemo, Josiah; Otieno, Fredrick Alfred O.
Water is a critical resource in Southern Africa. The region thus needs to protect both the quality and the quantity of its water resources through robust water conservation and demand management (WC/DM) measures. Water demand management encompasses activities that aim to decrease water demand, improve the efficiency of water use and prevent the deterioration of water resources. Water conservation refers to policies, measures or consumer practices that promote the conservation of water resources. Water resources should be used wisely to secure a water supply that is of good quality and enough for South Africa’s people and its natural environment, which provides the ecosystem that supports all forms of life. When a water utility systems experience water losses, the amount of water available to consumers is reduced, making it difficult to satisfy demand. Water losses also occur as a result of inaccuracies in customer meters, data errors in the billing system and unauthorised consumption. Such losses result in non-revenue water (NRW), which is a serious threat to the water supply sector. NRW refers to the water that is produced and lost without generating revenue for the utility. This research study investigated strategies that could be used to address the challenge of water losses, by developing a more suitable business model that could be incorporated into Ugu District Municipality (DM)’s existing NRW reduction strategies. The study was carried out in Amandawe and Umzinto zones of the District Municipality and it covered the period 01 March 2014 to June 2015. The study objectives were made up of four components. The first was to identify and prioritise the implementation of NRW reduction strategies. This was achieved by identifying the pipes to be closed off, which were supplying a significant number of consumers. For those pipes that were not closed off, flow meters were installed to measure the flow into and out of a zone. The system was then tested for zero pressure by isolating all closed valves to ensure that there were no potential feed-backs into the zone. Pressure gauges were set up on standpipes for routine pressure monitoring. The test was run at night (between 01.00 and 05.00 hours) when the system was under pressure. When the pressure dropped consistently, this meant that there was no feedback into a zone. Leaks were detected by logging the system in order to obtain night flows, which were analysed to determine the system behaviour. The results for Amandawe Zone after implementation of the pressure management programme, indicated that the average zone’s night pressure (AZNP) decreased from 7.38 bars to 5.95 bars. For Umzinto Zone, the AZNP dropped from 5.5 bars to 3.3 bars. The minimum night flows (MNFs) dropped from 34.80 m3/hr to 15.20 m3/hr in Amandawe Zone and from 6.4 m3/hr to 1.70 m3/hr in Umzinto Zone. The daily cost of excess night flow due to bursts was reduced from R2276.17/day to R862.61/day in Amandawe Zone and from R361.24/day to R40.46/day in Umzinto Zone, which provided huge savings. The second objective was to identify the sources and causes of water losses in the study area by conducting field measurements and observations. This was achieved by physically inspecting the infrastructure using visual observation, mechanical listening sticks, correlators, ground microphones and system loggers. The following indicators were used to physically identify underground leaks: unusually wet surfaces in landscaped areas, pools of water on the ground surface, noticeably green, soft and mouldy areas surrounded by drier surfaces, a notable drop in water pressure or flow volume, unexplained sudden increase in water demand or water use at a fairly steady rate for several billing cycles, cracks in paved surfaces, potholes or sink holes and the sudden appearance of dirty water in the main distribution system. For this study, the water losses in the system were found to be as a result of various causes including leaks, aging infrastructure, high pressure in the system, damaged pipes and illegal connections, among others. The third objective was to construct a water balance in order to determine the key performance indicators for the NRW reduction strategies. This was achieved by determining the system input volume (SIV), billed authorized consumption (BAC), unbilled metered consumption (UMC), unbilled unmetered consumption (UUC), real losses (RL), apparent losses (AL) and IWA Key Performance Indicators. Bulk and domestic meter readings were used to calculate the components of the water balance. The results of the water balance indicated that there was a decrease in the SIV from 904 kL/day to 523 kL/day in Amandawe Zone and from 382 kL/day to 221 kL/day in Umzinto Zone. The physical water losses were reduced from 611 kL/day to 377 kL/day in Amandawe Zone and from 93.8 kL/day to 45.8 kL/day in Umzinto Zone. The NRW was reduced from 659 kL/day to 395 kL/day in Amandawe Zone and from 94.2 kL/day to 46.2 kL/day in Umzinto Zone. The fourth objective was to develop the most suitable business model for Ugu DM based on the results arising from the first three objectives. Ugu DM needs to ensure both operational and financial efficiency. Operational efficiency could be achieved by minimising real water losses through reviewing water services standards, developing district metering areas, pressure management, leak detection and repair, reservoir control to stop overflows and pipe replacement programs. Financial efficiency could be achieved by carrying out regular meter testing and calibration, securing database integrity, managing illegal connections, ensuring that all customer connections have meters and ensuring that the tariff structures were cost reflective in order for the municipality to cover costs and generate revenue. Findings of this study could assist other water utilities operating under similar conditions. The implementation of this study’s results could have positive economic, social and environmental effects on Ugu DM. It was concluded that rezoning, pressure management and leak detection were the most critical NRW reduction strategies as they had a positive impact on the system. The main causes of leaks in the system were identified as aging infrastructure, high pressures in the system, and illegal connections. All the critical KPIs of IWA water balance responded positively after the implementation of the strategies by reducing. The operational and financial efficiencies were identified as critical for a WSA to develop a business model that could sustain itself.
Optimization of distribution static compensator for mitigation of power quality issues in grid-tied photovoltaic systems
(2021-12-01) Adebiyi, Abayomi Aduragba; Lazarus, Ian J.; Saha, Akshay K.; Ojo, Evans E.
The global energy demand is rising above the all-time average, and fossil fuel reserves, which power a large chunk of the existing power generation plants, are being depleted. Hence, Renewable Energy Technologies (RET) have become the alternative to meet demand and provide sustainable power. Solar photovoltaic (PV) energy, an essential aspect of RET, which generates emission-free power, is one of the world's emerging resources. Rooftop PV technology installation is advanced in residential and commercial applications due to government subsidies, lower investment costs, and feed-in tariffs. The rapid penetration of PV systems into conventional distribution grids has created some power quality and power stability issues. Power quality (PQ) distortion is the most critical problem in distribution grids. The literature studied revealed that the several nonlinear loads and PV systems power electronic-based inverters that penetrate the grid and contribute to poor power quality issues, i.e., voltage rise, voltage dip, voltage unbalance, flicker, and harmonics. Also, the PV system maximum power point (MPP) controller's performance was investigated since the current-voltage (I-V) characteristic of PV panels is nonlinear and dependent on variables such as solar radiation and temperature. A comparative analysis conducted showed that the incremental conductance tracks the maximum power point better than the perturb and observe method for better power generation. MATLAB/Simulink system model simulations were run for several case studies to analyze the maximum power point tracking (MPPT) algorithm's performance under varied solar irradiation. The results obtained suggested a course to the implementation of the proposed incremental conductance MPPT algorithm. Selected power quality problems in a grid-tied PV system were analyzed via simulations and enhanced with the application of conventional proportional-integral (PI) controlled DSTATCOM. Also, field measurement-based experiments were conducted to determine system performance in a typical grid-tied PV system. The real-life 110 kW grid-tied PV system installed at the Durban University of Technology (DUT), Steve Biko campus, was used for the fieldwork. Taken into consideration was the impact of solar radiation dynamic variation on the field study. According to the results obtained, the 110 kW PV system's voltage quality data were within the limits of the local and internationally defined standards. The concept of DSTATCOM was implemented with an Enhanced Jaya (E-Jaya) optimization algorithm to mitigate specific power quality issues, such as voltage rise, voltage dip, voltage unbalance, and current harmonics. The precision with which the DSTATCOM reference compensation current is selected is vital to the device's performance. The synchronous reference frame theory of phase lock loop (PLL) for a three-phase system is described in this thesis. The objective was to keep the source current THD below 5% to comply with the recommended limits of the IEEE519 Standard harmonic limits. The implemented novel E-Jaya control optimization algorithm-based D-STATCOM provided continuous and adequate voltage regulation and harmonic compensation to mitigate power quality issues in the grid-tied PV distribution system. Simulation comparative analysis results of the developed control method with Artificial Bee Colony (ABC) and Jaya optimization algorithm indicated that the developed novel E-Jaya optimization algorithm enhanced the grid-tied PV system's performance by providing superior voltage regulation and source current THD compensation significantly declined to 1.01% from 31.93%.
Optimization of donnan dialysis for alum recovery from potable water treatment residues
(2021-02) Asante-Sackey Dennis; Rathilal, Sudesh; Pillay, Visvanathan Lingamurti
Treatment of effluent water to meet fresh water discharge limits is very essential. Aluminium sulphate (alum) is the most widely used coagulant during the pre-treatment process, however, it generates a large amount of residue. Subsequent discharge of these residues from potable water treatment plants (PWTPs) to landfill sites and river bodies, without treatment, poses a great threat to the ecosystem and human health. In essence, the rising concern of managing residues, associated with the disposal cost, toxicity and stringent legislation, calls for more robust and effective technologies. In response, this study comes in handy owing to the green chemistry benefits of aluminium recovery from PWTPs for reuse. Primary recovery methods include acid treatment and alkalization. Although these two recovery processes ensue a minimum of 60% recovery, organics and heavy metals solubilize during the process. Donnan dialysis as a separation, recovery and concentrating technology is investigated in this project. The aims and objectives were to optimize the recovery of aluminium using Donnan dialysis with respect to phase conditions, to evaluate the inhibition effect of selected metals on aluminium transport and finally, to establish the organic transport in Donnan dialysis. Using a statistical approach, the feed phase conditions such as feed flowrate (0.64-2.21 mL/s), feed concentration (100-3300 mg/L), and pH (1.3-3.7) were considered against sweep phase conditions of acid concentration (0.25-1 N) and flowrate (0.64-2.21 mL/s). The response surface methodology’s face-centered central composite design (FC-CCD) statistical method was adapted for the selection of influential factors and establishing the relationship between selected conditions. The FC-CCD used had three levels and six center points for analysis. The effect of Ca, Mg, Mn, Fe, Cu, Zn and Pb on Al permeation through the Nafion 117 membrane was studied at constant flow and concentration conditions. Once the effects in the binary inhibition study were completed, aluminium recovery from a residue obtained from a local PWTP was conducted. Simultaneously, the rejection of organics by the membrane was also assessed during the aluminium recovery process. Preliminary experiment validation experiments showed a high deviation of ±6.4 mg/L at the feed phase, 7.33% deviation at the sweep phase and mass balance closure greater than 95%. Furthermore, study on the water transport across the membrane was directly proportional to the acid concentration. Comparing HCl and H2SO4, HCl had a lower Van’t Hoff factor, hence, was used in proceeding experiments. A one factor at a time experiment to determine the final range of feed concentration to use showed that a maximum of 2000 mg/L was required to meet a 50% recovery target. The FC-CCD experiment showed that the ascending order of the effects of factors was sweep flowrate < feed flowrate < sweep concentration < feed concentration. The sweep flowrate had a negative influence on aluminium permeation and was statistically insignificant (p > 0.05). Quadratic and predictive models developed at different time intervals were statistically significant at a 95% confidence level. Also, a high recovery of 94% and high concentrating effect at the sweep phase was 1.65 in the 2:1 feed to sweep phase volume experiment. Analysis of FC-CCD combinative study of feed concentration, pH of feed phase and feed flowrate showed that a high feed concentration (> 1000 mg/L) at a high pH (> 2.5) will yield an Al-recovery > 60%. At a 95% confidence level, the statistical analysis showed that the pH was the most significant factor. The interacting factors for the statistically significant model was feed concentration-feed flowrate and feed concentration-pH. The one-on-one inhibitive study at equal phase flowrates and feed concentration revealed that Fe gave the highest inhibition while the least transport across the Nafion 117 membrane was Mn2+. In descending order, Fe2+ > Ca2+ > Zn2+ > Mg2+ > Cu2+ . The rejection of organics is limited to 24- 32 hours where a maximum of 98% rejection was achieved under the synthetized solution and acid digested residue runs. In conclusion, Donnan dialysis by RSM has proven to be feasible for the recovery of aluminium from potable water treatment residue. Also, the FC-CCD adapted from the RSM is seen to be very promising, economical and a reliable alternative statistical tool to determine the most influential factor and predict and obtain the optimal operation conditions for a system. Therefore, there are economic, sustainable and research prospects of DD coupled with RSM towards recovery of metal salts and heavy metals from PWTP residues in large scale implementation.
Provision of private student accomodation within sub-urban residential neighbourhoods and the impact on inclusive neighbourhood land use management : a case of Scottsville, Pietermaritzburg, KwaZulu-Natal
(2020-09) Hlope, Edith Nombuso; Musvoto, Godfrey Gombana
Student accommodation, residential neighbourhoods, studentification, inclusion Student accommodation shortage is an international issue that is not unique to South Africa. The role of student accommodation is important to students as it does not only satisfy the need for housing but also in perpetuating student culture. Student accommodation is necessary for safe and secure residential space for students during their term of study. Due to many factors affecting student accommodation provision, a gap in the market has been created which has resulted in a rise in the provision of private student accommodation. This comes with its own challenges such as increased conversion of private residential homes to student housing, eradicating the residential fabric in neighbourhoods that host tertiary institutions, tension between students and original residents over ‘anti-social’ behaviour of students, rise in land use changes and illegal land uses. Based on the background presented, the objective of this study is to investigate the provision of private student accommodation within residential neighbourhoods. The study aims to understand how the provision has affected inclusive land use management within the residential area of Scottsville. While the shortage of student accommodation is a known and accepted fact of modern-day tertiary education life, the literature review presented in this paper indicates that it is still a topic to be explored. The literature suggests that it might take years before the shortages in student accommodation are addressed which implies that between now and then, communities must find a way to either tolerate or accept the land use and peacefully cohabit with the student population. Some of the arguments presented in the literature review originate from Hubbard (2008:323) who states that specific neighbourhoods become dominated by student residential occupation, he argues that this results in unbalanced communities, with an element of antisocial behaviour by students. According to Donaldson et al. (2014:177) studentification causes complete spatial restructuring and re-organisation of an area where eventually only the needs of the student sub-culture are catered for. Barton et al. (2010:3) argue that neighbourhood change is hindered by the absence of integrated and clear policy guidance that represents the diverse perspectives from stakeholders including the local community themselves.. To investigate this study, the research design used is a qualitative and a case study method was adopted. Participants for the research were purposefully selected for primary data collection purposes and secondary data was obtained from the municipality through policy documents, mapping and official municipal registers. The result findings of the study reveal that Scottsville is “studentified”, meaning that the student population is dominating the area and that this comes with social, economic, infrastructural, cultural and environmental changes to the area. The study also revealed that the changes in Scottsville are visible and that there are concerns relating to the lack of forward thinking and planning by the municipality and the university. Lastly, there is a belief that if stakeholders come together, Scottsville can be changed for the better. The study recommends that planning practices in the area must promote a sustainable transition for self-sustaining neighbourhoods. There must be pro-active policy making that is done in consultation with the community. Public participation processes must be consultative and open. There is a need for all affected stakeholders to engage on the issues that affect them, strengthening of enforcement measures and public awareness about private student accommodation in order to reduce the stigmatization of the land use as well as the promotion of public private partnerships that focus on the provision of student accommodation. In summary, private student accommodation plays an important role in addressing the current student accommodation shortage in South Africa, it is important that it is not viewed as a foreign land use but an extension of the residential land use that cater for a specific market demand.
Synthesis of a model for optimising a potable water treatment plant and water usage analysis in the Ugu District
(2017) Magombo, James; Dzwairo, Bloodless; Moyo, Sibusiso; Dewa, Mendon
Access to clean and adequate water is a universal and basic human right that feeds into the 6th of the 17 Sustainable Development Goals (SDGs). This goal aims at ensuring availability and sustainable management of water and sanitation for all. Clean water is referred to as potable water, which is safe for human consumption and offer low risk of immediate or long term harm. Raw water undergoes rigorous processing which consists of coagulation, sedimentation, filtration, disinfection and storage, to produce potable water. Each module or stage consumes chemicals and energy resources and thus incurs costs. To achieve the aim of the study, which was to synthesize an optimised potable water treatment network and a water usage analysis model, the Umzinto Water Treatment Plant (UWTP) and its distribution system was used as the study area. This treatment plant is located within Umdoni, a local municipality of the Ugu District Municipality in KwaZulu-Natal Province, South Africa. This study’s objectives were fourfold and the first objective was to identify and quantify key raw water quality parameters affecting treatment at the UWTP. The second objective was to design a genetic algorithm for the potable water treatment process control. The third objective was to evaluate the Umzinto Water Distribution System’s Non-Revenue Water (NRW) while the fourth objective was to develop a model for water usage analysis. For the first objective, data for water quality parameters for the water treatment from July 2006 to June 2013 were statistically analysed. This data were collected from the UWTP’s historical records. To improve the data’s integrity it was pre-processed using cubic hermite interpolation. After the pre-processing trend lines and box plots were used to determine the parameters’ significance compared to the standard values stipulated in the South African National Standard (SANS 241). The trend lines were used to analyse the frequency of observations that were higher than the standard values according to SANS 241. The box plots were used to determine the minimum, median, maximum and mean of the data sets. The mean values for each parameter were compared to the SANS 241 value to determine their significance. The raw water quality parameters were then correlated to the chemical dosages for lime, polymer, potassium permanganate and chlorine. The key parameters selected from the correlation analysis were algal count, manganese (Mn), iron (Fe), Escherichia coli, total coliforms, colour, odour, conductivity, turbidity, suspended solids (SS), pH, temperature, total organic carbon (TOC,) and Hardness. A number of methods can be used to achieve such optimisation, including artificial neural networks, dynamic programming, linear and non-linear programming, and this study utilised a genetic algorithm as an optimisation tool to achieve the second objective of optimising water treatment at the UWTP. For the model development, data from the correlations obtained for objective 1 were used. The model was aimed at reducing the cost of chemical dosage and four chemical dosage prediction models were developed using genetic algorithms and these were then used to produce a combined chemical dosage cost prediction model. The programming interface utilised for these models was Matlab. In developing these models, the data were first pre-processed to remove outliers and fill in the blanks using a Microsoft Excel Add-in that was developed for this particular purpose. The next step involved a curve fitting exercise in Microsoft Excel 2013. Matlab was then used to code the genetic algorithm that combined and optimised the solutions obtained from the curve fittings. The results showed that genetic algorithms can be reliably used to predict the chemical dosages and hence reduce water treatment costs. After treatment, water is pumped into the distribution system for consumption. It is therefore important to ensure that all the pumped out treated water reaches the consumer. The third objective therefore assessed the NRW for the Umzinto Water Distribution System for the period between July 2013 and June 2014. The data used for this objective was provided by the Ugu District Municipality. The method used combined the top-down approach and the component-based approach. This combined approach was modified to enable the calculation of all the components that are required in a standard South African Water Balance. The results showed that the distribution system had a high value of NRW, which was 27.9% of the System Input Volume. The major component of NRW was Real Losses, that is, losses that can be mitigated by improving maintenance. The fourth objective was to develop a model for water usage analysis that would reduce the time taken to evaluate NRW and also improve the analysis of the NRW components using Microsoft Visual Basics 2012 and Microsoft SQL Server 2012 development interfaces. The Visual Basics enabled the development of a graphic user interface that was user-friendly and minimised the time taken to learn the software. The software platform developed was able to import the data required to construct a standard International Water Asssociation (IWA) Water Balance, calculate all the components of NRW, store historical data for the water distribution systems and report on a rolling year basis. A model for water usage analysis was developed and made available for usage by practitioners in Ugu District. The model was developed for the specific study area and further studies would be required in order to validate it in a different setting. The results obtained for the first objective led to the conclusion that, there was very high pollution emanating from communities and activities close to the raw water sources, especially the EJ Smith Dam. The results from the first objective were also used to determine parameters for the models developed in the second objective. From objective two it was concluded that genetic algorithms can be reliably used to predict chemical dosages and hence reduce water treatment costs. The third objective’s results showed that 27.9% of treated water pumped into the distribution system is NRW. Which is a concern because 65% of this are real losses which have maintenance related problems. The fourth objective’s results showed the practicality of designing model that could be used determine all the important components of NRW that would take time to evaluate manually. It would also store historical data for the water distribution system and report on a rolling year basis. Implementation of this software would help minimise the errors associated with manual calculation of NRW and improve the availability of data for research and analysis. From the research findings, it is recommended that the treatment plant should change the way it is dosing chemicals in the balancing tank. The method currently being used is prone to error. The analysis of NRW showed that Real Losses were a major challenge in the Umzinto Distribution System. There is need to develop a maintenance program to cater for leakage. Communities also need to be educated on the importance of reporting leakage in the network.