Masters Degrees (Geography and Environmental Studies)

Permanent URI for this collection

https://scholar.sun.ac.za/handle/10019.1/618

Browse

Browsing Masters Degrees (Geography and Environmental Studies) by browse.metadata.advisor "De Waal, Jan"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Determining spatial and temporal change in household solid waste composition within Stellenbosch local municipality
    (Stellenbosch : Stellenbosch University, 2020-03) Nell, Charlotte Maria; De Waal, Jan; Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of Geography & Environmental Studies.
    ENGLISH ABSTRACT: The quantities in which solid waste is generated are continuously increasing throughout the world. If waste is not treated or disposed of in an appropriate manner, the consequences for societies and environments are likely to be extremely adverse, if not catastrophic. Consequently, effective management of household solid waste is crucial to ensuring the maintenance of clean and healthy living environments. As it is incumbent upon local authorities in South Africa to provide solid waste management services, they require accurate information pertaining to their waste streams to guide their waste management practices. It is widely recognised throughout the world that waste characterisation studies represent an optimal means of obtaining detailed data pertaining to waste streams. This thesis concerns the findings and a comparative analysis of two waste characterisation studies which were conducted in 2012 and 2017 in the Stellenbosch municipal area. The studies were concerned solely with the residual portion of household solid waste which is landfilled. While the fourteen areas were surveyed in the study of 2012 and samples were sorted into seven fractions, twenty-three areas were surveyed in the study of 2017 and some of the fractions which had been used in 2012 were further sub-divided to yield a total of eighteen fractions. Ten of the areas which were surveyed in 2017 were either similar to or overlapped with those which were surveyed in 2012. In each study, waste profiles were determined by both mass and uncompacted volume for each area. The respective findings from 2012 and 2017 were then compared to identify spatio-temporal changes and statistical analyses were performed to determine the significance of each change. Correlations were also determined between relevant socioeconomic parameters and the data which had been obtained pertaining to the waste streams of individual areas. Organic waste represented the predominant waste fraction by mass in all ten overlapping areas in the two characterisation studies, while the plastic wrap/packaging fraction was the largest by volume in all areas in both studies. The largest and most significant temporal changes from 2012 to 2017 were a very large increase by mass in the case of the plastic wrap/packaging fraction and by volume in that of the hard plastics fraction. The findings revealed that the high rates at which particular fractions of the waste stream were disposed of in low-income areas were skewed as a consequence of the separation at source programme not being implemented in the areas. Consequently, it is recommended that the implementation of the programme should be extended to all areas which fall under the jurisdiction of the Stellenbosch Local Municipality, in the form of a three-bag separation at source programme. Improved education and awareness concerning the waste crisis with which the municipality is faced at present is also equally crucial.
  • Thumbnail Image
    Item
    The potential use of wetland plant species within a renosterveld setting for the phytoremediation of glyphosate and fertiliser
    (Stellenbosch : Stellenbosch University, 2018-12) Jacklin, Dylan Michael; De Waal, Jan; Brink, I. C.; Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of Geography & Environmental Studies.
    ENGLISH ABSTRACT: In South Africa, fertiliser and herbicide pollutants resulting from various agricultural practices lead to a degradation of surface freshwater and groundwater quality. Nitrogen and phosphorous, and glyphosate derived from agricultural fertiliser and herbicide applications, respectively, significantly contribute to watercourse toxicity. Adjacent to many of the surface freshwater systems are some of the South Africa’s most productive agricultural fields, which convert the surrounding natural ecosystems in favour of the crops produced. As a result, the degradation of natural vegetation and deterioration of freshwater quality is observed. The critically endangered status of some Renosterveld vegetation types is the product of agricultural expansion, nutrient loading through fertilisation and the spraying of herbicides. The characteristics of phytoremediation provide an attractive alternative for the pollutant biofiltration of freshwater aquatic ecosystems. A buffer of Renosterveld vegetation along river corridors may be a solution for agricultural pollutant remediation prior to entering the watercourses. As a result of its successful uptake and metabolism capabilities of fertilisers and herbicides, inexpensiveness, aesthetic advantages and long-term use, it has become a remediation technology of choice in developing countries. The utilisation of wetland plants occurring within Renosterveld vegetation for pollutant extraction from agricultural practices will increase river corridor biodiversity, creating indigenous refuges, and facilitating habitat connectivity. Considering this, the study aims to delineate the potential use of wetland plant species indigenous to Renosterveld for the effective removal of agricultural pollutants. The evaluation of plant species’ pollutant removal efficiency in comparison to unvegetated soil will substantiate its use in vegetative buffer strips. The potential use of indigenous species as an alternative to invasive alien plant (IAP) species, currently considered successful phytoremediators, will aid in conserving the Renosterveld ecoregion. An experimental phytoremediation system was designed and constructed under laboratory conditions to investigate the pollutant removal potential of indigenous vegetation. Five pollutant parameters, namely ammonia, nitrate, soluble reactive phosphorous and two glyphosate concentrations (0.7 and 225 mg/L), were selected to reflect environmental stresses on 14 indigenous wetland species. The high but non-lethal glyphosate dosage strength was selected by means of a dual species dilution series experiment, where two plant species were subjected to ten different glyphosate concentrations. The dosage strength was selected at a concentration where plants did not display signs of mortality. Effluent analyses indicated the exceptional removal efficiencies of the indigenous wetland species across both fertiliser and herbicide pollutants, with the two most beneficial species identified as the species selected for this test aquic Phragmites australis and Cyperus textilis. The unvegetated soil control further exhibited efficient pollutant removal. However, indigenous vegetation consistently displayed greater pollutant removal than the unvegetated soil control. When compared to the IAP and Palmiet (Prionium serratum) multi-plant community assemblage, the indigenous species indicated similar pollutant removal efficiencies, justifying the use of indigenous plant species over the alien invasive equivalent. Phytoremediation presented significant potential for the utilisation of non-invasive wetland plant species in agricultural pollutant remediation, ameliorating freshwater aquatic ecosystems, and aiding the conservation of the already fragmented landscape.