Department of Ecology and Resource Management / MENVM

The purpose of this study was to observe high school students as they progressed through a Science-Technology-Society (STS) project that involved the closing of a landfill. In this STS project, students investigated the best vegetation for reseeding a closed landfill. This project was initiated because a highway was to be built across the landfill to Explore Park. The director of Explore Park requested an experimental vegetation instead of the standard vegetation mixture. He wanted a vegetation that was aesthetically pleasing and environmentally acceptable. The study investigated the involvement of students in the construction of knowledge of local environmental issues. Students shared their perceptions about the STS process through interviews, journal entries, a questionnaire, field notes, and written artifacts. All data were transcribed and coded for themes. Ethnographic methods were used to tell this story in twelve vignettes. The results of this study are important because they show how educators can use local issues to build classroom curriculum. Students became actively involved in the learning process as they advanced through identified STS instructional goals. The first goal was the Foundations Level. Basic content associated with landfill management and revegetation issues were introduced. Facts about garbage and the need for reducing, reusing, and recycling were investigated. The second goal was the Issue Awareness Level. This goal included becoming involved, identifying the players, and investigating values and beliefs. The third goal was the Investigation and Evaluation Level. Students were exposed to concepts and strategies necessary to investigate and analyze the issues and evaluate alternative solutions. This level encompassed designing plant experiments. The fourth goal was the Citizenship Responsibility Level. Students were introduced to strategies necessary for making responsible decisions concerning solutions to the issues. The conclusions of this study suggest that for many students, the teaching of science through local technological and societal issues allowed them to become actively engaged in the learning process. Students who took ownership of their investigations created opportunities to enhance self-esteem, made connections, and enhanced their knowledge of scientific investigations and scientific content in the context of real life issues. / Ph. D.

O objetivo do trabalho é aplicar um modelo numérico que simule a propagação da pluma de contaminação derivada de chorume, como ferramenta numérica que permita uma análise dos parâmetros envolvidos no sistema, tendo como caso de estudo o lixão de São Pedro da Aldeia, levando em conta: o mecanismo de perda de massa durante o transporte e a variabilidade estatística dos principais parâmetros de entrada (input) no modelo numérico. A perda de massa durante o fluxo pode ocorrer tanto por sorção, como por decaimento microbiológico, será estimada através da interpretação probabilística de dados experimentais obtidos no lixão de São Pedro da Aldeia. Os resultados obtidos pela modelagem numérica serão comparados com os resultados experimentais de concentração do íon cloreto obtidos por medições em campo. Os resultados experimentais foram obtidos considerando distâncias crescentes em relação ao lixão, para oito intervalos de tempo distintos, permitindo, assim, comparar os resultados alcançados pela modelagem numérica com dados experimentais reais, obtidos em função do tempo e da distância ao lixão. Para a modelagem numérica, foi utilizada a equação diferencial do transporte advectivo-dispersivo, levando em conta um termo de perda de massa estimado a partir de interpretações estatísticas dos resultados experimentais obtidos. A solução da equação diferencial do fluxo advectivo dispersivo foi analisada pelo método dos volumes finitos, que se mostra adequado para problemas de avanço de frentes de saturação e/ou de contaminação. Para a modelagem probabilística, foi utilizado o Método de Rosenblueth (ou método das estimativas pontuais), considerando-se, como variáveis aleatórias mais relevantes: a condutividade hidráulica k, a concentração iônica inicial Co e o decaimento da concentração iônica em função da distância (x) ao lixão expresso por um termo bo em (mg/l/m). A interpretação estatística das concentrações medidas experimentalmente mostrou uma faixa de variabilidade muito bem representada pela faixa de variação obtida pela conjugação da solução da equação de transporte de contaminantes (pelo método dos volumes finitos) com análise de variabilidade por formulação FOSM (pelo método das estimativas pontuais de Rosenblueth). Os resultados obtidos indicam que, embora com a contaminação crescente, podemos avaliar com poucos dados a contaminação ao longo do tempo. As simulações indicaram coerência com o resultado obtido experimentalmente, validando assim o modelo utilizado. Entende-se que o trabalho conseguiu demonstrar a aplicabilidade e relativa praticidade no que diz respeito ao estudo do fluxo de contaminantes em meios saturados. Os resultados se mostraram satisfatórios no que tange ao entendimento das questões abordadas. / The objective of this work is to apply a numerical model that simulates the propagation of the contamination plume stemmed from leachate as a numerical tool that allows an analysis of the parameters involved in the system, having the landfill of São Pedro da Aldeia as study case. The model takes into account the loss of contaminant mass mechanism during transport and the statistical variability, in the numerical model, of the main input variables. The loss of mass during the flow, which can occur either in the form of sorption or as a microbiological decay, will be assed by probabilistic interpretation of experimental data. The results obtained by the numerical modeling will be compared to the experimental results of the ionic chloride concentration obtained by field mediations. The experimental results were obtained taking into account the growing distances in relation to the landfill, for eight different time intervals, allowing, this way, the comparison of the results reached by the numerical modeling with the real experimental data results, obtained due to the time and the distance of the landfill. For the numerical modeling, the differential equation of the advective-dispersive transport was used, taking into account a term of loss of mass estimated from statistical interpretations of the experimental results. The differential equation solution of the advective-dispersive flow was obtained by the finite volumes method, which was proved adequate to problems concerning the propagation of contaminating plumes in saturated soils. For the probabilistic modeling, the Rosenblueth Method (or point estimate method) was used, considering, as more relevant aleatory variables, the hydraulic conductivity k, the initial ionic concentration and the rate of concentration decay. The statistical interpretation of the concentrations experimentally measured showed one variability band well represented by the variation band obtained by the conjunction of the contaminant transport equation solution (finite volumes method) with the variability analysis of the FOSM formularization (Rosenblueths point estimate method). The obtained results indicate that even with the increasing contamination it is possible, with little data, to evaluate the contamination throughout time. The simulations indicated coherence with the experimentally obtained results validating, this way, the used model. The work demonstrates the applicability and the relative practicity concerning the study of the contaminant flow in saturated environments. Considering the understanding of the boarded questions, the results seemed satisfactory.

O objetivo do trabalho é aplicar um modelo numérico que simule a propagação da pluma de contaminação derivada de chorume, como ferramenta numérica que permita uma análise dos parâmetros envolvidos no sistema, tendo como caso de estudo o lixão de São Pedro da Aldeia, levando em conta: o mecanismo de perda de massa durante o transporte e a variabilidade estatística dos principais parâmetros de entrada (input) no modelo numérico. A perda de massa durante o fluxo pode ocorrer tanto por sorção, como por decaimento microbiológico, será estimada através da interpretação probabilística de dados experimentais obtidos no lixão de São Pedro da Aldeia. Os resultados obtidos pela modelagem numérica serão comparados com os resultados experimentais de concentração do íon cloreto obtidos por medições em campo. Os resultados experimentais foram obtidos considerando distâncias crescentes em relação ao lixão, para oito intervalos de tempo distintos, permitindo, assim, comparar os resultados alcançados pela modelagem numérica com dados experimentais reais, obtidos em função do tempo e da distância ao lixão. Para a modelagem numérica, foi utilizada a equação diferencial do transporte advectivo-dispersivo, levando em conta um termo de perda de massa estimado a partir de interpretações estatísticas dos resultados experimentais obtidos. A solução da equação diferencial do fluxo advectivo dispersivo foi analisada pelo método dos volumes finitos, que se mostra adequado para problemas de avanço de frentes de saturação e/ou de contaminação. Para a modelagem probabilística, foi utilizado o Método de Rosenblueth (ou método das estimativas pontuais), considerando-se, como variáveis aleatórias mais relevantes: a condutividade hidráulica k, a concentração iônica inicial Co e o decaimento da concentração iônica em função da distância (x) ao lixão expresso por um termo bo em (mg/l/m). A interpretação estatística das concentrações medidas experimentalmente mostrou uma faixa de variabilidade muito bem representada pela faixa de variação obtida pela conjugação da solução da equação de transporte de contaminantes (pelo método dos volumes finitos) com análise de variabilidade por formulação FOSM (pelo método das estimativas pontuais de Rosenblueth). Os resultados obtidos indicam que, embora com a contaminação crescente, podemos avaliar com poucos dados a contaminação ao longo do tempo. As simulações indicaram coerência com o resultado obtido experimentalmente, validando assim o modelo utilizado. Entende-se que o trabalho conseguiu demonstrar a aplicabilidade e relativa praticidade no que diz respeito ao estudo do fluxo de contaminantes em meios saturados. Os resultados se mostraram satisfatórios no que tange ao entendimento das questões abordadas. / The objective of this work is to apply a numerical model that simulates the propagation of the contamination plume stemmed from leachate as a numerical tool that allows an analysis of the parameters involved in the system, having the landfill of São Pedro da Aldeia as study case. The model takes into account the loss of contaminant mass mechanism during transport and the statistical variability, in the numerical model, of the main input variables. The loss of mass during the flow, which can occur either in the form of sorption or as a microbiological decay, will be assed by probabilistic interpretation of experimental data. The results obtained by the numerical modeling will be compared to the experimental results of the ionic chloride concentration obtained by field mediations. The experimental results were obtained taking into account the growing distances in relation to the landfill, for eight different time intervals, allowing, this way, the comparison of the results reached by the numerical modeling with the real experimental data results, obtained due to the time and the distance of the landfill. For the numerical modeling, the differential equation of the advective-dispersive transport was used, taking into account a term of loss of mass estimated from statistical interpretations of the experimental results. The differential equation solution of the advective-dispersive flow was obtained by the finite volumes method, which was proved adequate to problems concerning the propagation of contaminating plumes in saturated soils. For the probabilistic modeling, the Rosenblueth Method (or point estimate method) was used, considering, as more relevant aleatory variables, the hydraulic conductivity k, the initial ionic concentration and the rate of concentration decay. The statistical interpretation of the concentrations experimentally measured showed one variability band well represented by the variation band obtained by the conjunction of the contaminant transport equation solution (finite volumes method) with the variability analysis of the FOSM formularization (Rosenblueths point estimate method). The obtained results indicate that even with the increasing contamination it is possible, with little data, to evaluate the contamination throughout time. The simulations indicated coherence with the experimentally obtained results validating, this way, the used model. The work demonstrates the applicability and the relative practicity concerning the study of the contaminant flow in saturated environments. Considering the understanding of the boarded questions, the results seemed satisfactory.

Waste minimisation is implemented worldwide and has become an urgent priority in South Africa as evidenced in the promulgated National Environmental Management Waste Act (2008). The most common waste disposal method in South Africa is by landfill, which is unacceptable. Local municipalities have made little progress towards waste minimisation. The aim of this study was to present a solution to waste minimisation for the City of Tshwane Metropolitan Municipality (CTMM) by determining the feasibility of establishing composting facilities on landfill sites. One third of all municipal waste consists of green waste, which is compostable and can be converted on landfill sites. Nine municipal landfill sites were screened. The four most feasible sites were evaluated further by applying identified parameters that address physical, social and operational requirements. It is a possible to establish composting facilities on all four sites investigated, with Hatherley ranking as the most suited. The findings of this study clearly provided the basic parameters and requirements for constructing a composting facility and practical procedures applicable within a South African context. The evaluation method used can be applied as a model to evaluate similar studies in other municipalities to aid them in the decision-making process for waste minimisation. / Environmental Management / M.A. (Environmental Management)

Bibliographical refernces appear at the end of each chapter / This study reviews solid waste management practices in Polokwane City. The study area covered some of the residential areas in Polokwane City; namely; Ivy Park, Fauna Park, Welgelegen, Westernburg and the City Centre. This article describes two main methods that were used to collect data; that is Qualitative and Quantitative method. Field survey was also made to validate data obtained from the participants that were interviewed during qualitative data process. After framing the problem, the objectives of Solid Waste Management Practices in Polokwane City were briefly outlined as follows: • Assess solid waste management practices in Polokwane City. • Make comparison on how households and the municipality take responsibility in storing, collecting, transporting, treating and disposing solid waste. • Investigate what problems the City encounters in managing solid waste. • Make relevant recommendations aimed at improving solid waste management practices within the City. The service management was administered by the municipality and private sector. From the five study residential areas, the Municipality manages waste in the City Centre while the private sector manages waste in the other residential areas. However, the City continues to play an administrative role over the contracted service provider. Statistical results were presented in figures and tables. The results showed the storage habits, frequency of collection, mode of transport and methods of disposal for solid waste in Polokwane City. The only method of disposal in the city was found to be landfilling. Activities that took place at the landfill site, such as reclaiming were outlined together with the economic values that these activities add to the City. The study also revealed that as population increases, the amount of solid waste generated also increased. / Environmental Sciences / M. Sc. (Environmental Management)

Waste minimisation is implemented worldwide and has become an urgent priority in South Africa as evidenced in the promulgated National Environmental Management Waste Act (2008). The most common waste disposal method in South Africa is by landfill, which is unacceptable. Local municipalities have made little progress towards waste minimisation. The aim of this study was to present a solution to waste minimisation for the City of Tshwane Metropolitan Municipality (CTMM) by determining the feasibility of establishing composting facilities on landfill sites. One third of all municipal waste consists of green waste, which is compostable and can be converted on landfill sites. Nine municipal landfill sites were screened. The four most feasible sites were evaluated further by applying identified parameters that address physical, social and operational requirements. It is a possible to establish composting facilities on all four sites investigated, with Hatherley ranking as the most suited. The findings of this study clearly provided the basic parameters and requirements for constructing a composting facility and practical procedures applicable within a South African context. The evaluation method used can be applied as a model to evaluate similar studies in other municipalities to aid them in the decision-making process for waste minimisation. / Environmental Management / M.A. (Environmental Management)

Bibliographical refernces appear at the end of each chapter / This study reviews solid waste management practices in Polokwane City. The study area covered some of the residential areas in Polokwane City; namely; Ivy Park, Fauna Park, Welgelegen, Westernburg and the City Centre. This article describes two main methods that were used to collect data; that is Qualitative and Quantitative method. Field survey was also made to validate data obtained from the participants that were interviewed during qualitative data process. After framing the problem, the objectives of Solid Waste Management Practices in Polokwane City were briefly outlined as follows: • Assess solid waste management practices in Polokwane City. • Make comparison on how households and the municipality take responsibility in storing, collecting, transporting, treating and disposing solid waste. • Investigate what problems the City encounters in managing solid waste. • Make relevant recommendations aimed at improving solid waste management practices within the City. The service management was administered by the municipality and private sector. From the five study residential areas, the Municipality manages waste in the City Centre while the private sector manages waste in the other residential areas. However, the City continues to play an administrative role over the contracted service provider. Statistical results were presented in figures and tables. The results showed the storage habits, frequency of collection, mode of transport and methods of disposal for solid waste in Polokwane City. The only method of disposal in the city was found to be landfilling. Activities that took place at the landfill site, such as reclaiming were outlined together with the economic values that these activities add to the City. The study also revealed that as population increases, the amount of solid waste generated also increased. / Environmental Sciences / M. Sc. (Environmental Management)

MPH / Department of Public Health / See the attached abstract below

MENVSC / Department of Ecology and Resource Management / South Africa is highly dependent on coal for production of electricity. The combustion of coal for electricity generation produces waste by-products which include fine ash (fly ash) and coarse ash. Fly ash (FA) is produced in large amounts while its utilization is low due to its classification as a hazardous material. Sasol produces about 7 million tons of FA, while Eskom produces about 28 million tons of coal FA annually. FA is a fine by-product from pulverized coal with detrimental effects on plants, soil or land, animals and human beings, and pollutes the air. The present investigation focuses on the examination of the chemical elements bioaccumulation and phytoremediation potential of Indian mustard (Brassica juncea) and Spinach (Spinacia Oleracea L). X-ray fluorescence (XRF) was used to analyze the elemental composition of FA and soil, Scanning Electron Microscope (SEM) to examine the morphology, while X-ray diffraction (XRD) analysis was used to evaluate the mineralogy of FA. The concentrations of metal and non-metal species that are released from FA on contact with water at different conditions were quantified using ICP-MS. Pot culture experiment was conducted to grow Brassica juncea and Spinacia Oleracea L. using FA and soil as growth medium. Leachates from the pots were collected and analysed using ICP-MS. Plant parts from harvested Brassica juncea and Spinacia Oleracea L. were cut separately and analysed using ICP-MS for the concentrations of different metal and non-metal species in plant parts. Plant parts were also used to estimate biomass and chlorophyll content (leaves). To prepare these plant samples for analysis, the powdered plant sample (0.5 g) was digested through aqua regia (HCL:HNO3 = 3:1 (v/v)) to near dryness using hotplate and filled to 100 mL of MilliQ water. The samples were filtered and directly used to determine the chemical elements concentrations. Blanks and internal standards were used for quality assurance during analysis. Chemical elements that are present in FA and sometimes in higher concentrations are associated with detrimental effects in plants, animals and human beings, hence phytoremediation is vital. Bioconcentration factor (BCF) was used to estimate the metal species accumulation ability of the plants from the FA, FA/soil mixtures, while translocation factor (TF) was used to assess the plant species potential for phytoremediation of coal fly ash dumps. Analysis of Varience (ANOVA) was used to statistically test data using Graphpad software package. Relationship between chemical elements in soil, FA and FA+soil growth media and also different plant parts (root, stem and leaf) of B. juncea and S. Oleracea L were calculated using the t - test, ANOVA-Bartlett test, Mann-Whitney Test and Kruskal-Wallis Statistic (KW) depending on each data set. The physicochemical characterization of coal fly ash showed that FA from Grootvlei power station can be classified as class F with an alkaline pH level of 10.62. It showed that particle morphology of this FA had a lower degree of sphericity with irregular agglomerations of many particles while there were dominant spherical particles and smaller sharp needle like particles. It is also an alumino-silicate material as confirmed by the high SiO2 and Al2O3 content, while soil leachates had an average/neutral pH of 7.22 with very high amounts of Si. In both soil and FA, elements that were expected to be readily available to plants included Ca, Si, K, Ba, Mo, Na, Al, Mg, Sr and non-essential elements (Si, Ba, Na, Al, Sr), which, if uptaken by plants’ roots can have negative impacts in plants. Physicochemical analysis of soil, FA and FA+soil leachates showed that the alkalinity of the FA changed over time and there was also a decrease in the EC due to dissolution iv of soluble major oxides, which was promoted by continuous water irrigation. The soil and FA+soil growth media showed similar results. Chemical elements like B, Mn, Fe and Ba were occurring at higher concentrations in leachates for most weeks in the pot culture experiments. However, it was observed that in the eleventh week of leachate collection all these chemical elements decreased to very low concentrations. This suggest that these chemical elements can be reduced over time as plants are being irrigated which is either due to uptake by plants or washed off with water. Statistically, there was a significant difference for different chemical elements of leachates from different growth media for each plant species (B. juncea and S. Olearcea L.). The overall growth rate shows that S. Oleracea L was better than that of B. juncea especially in the FA media over time, while the biomass of the two plant species showed similar results. After all, even though S. Oleracea L had carotenoid content below detection limits, it had higher chlorophyll b than B. juncea for all growth media in general. But, statistically there was no significant difference between the two plant species in terms of growth rate and biomass; even between the plant parts denoting similar growth performance for the two plant species under study. The bioaccumulation potential of the two plant species showed that chemical elements such as Fe, Mn, Ba, Zn and B were highly accumulated by the different parts of the plants. However, the chemical elements such as of Mo, Ni, Cu, and Cr showed the least concentrations. This trend was similar for all growth media and both plant species but this changes over time for different growth media and plant species as increasing and decreasing trends can be noticed. This led to no significant difference between plant species and also growth media, statistically. High BCF values of Fe, Mn, Ba, Zn and B were observed in the different parts of the plants for both plant species. However, Mo, Ni, Cu, and Cr had BCF values less than 1 for most growth media over time. BCF values in plant parts differed with time, growth media and plant species. Translocation of chemical elements shows that the B. juncea plant proved to be an effective phytoremediation plant species since it is effective in translocation of many chemical elements for different growth media to shoots while S. Oleracea L failed to translocate most chemical elements from stem to leaves although it translocated some from root to shoots. Hence, it can be concluded from the study that both species can be used in phytoremediation of coal fly ash dumps but with B. juncea being the most effective accumulator and translocator of many chemical elements. However, it can be recommended that chelating agents like ethylene diamine tetra acetic acid (EDTA) be introduced to solubilize chemical elements from growth media matrix into growth media solution to facilitate the quick transport of chemical elements into xylem, and increase