Although the countryâs legislation emphasizes the importance of waste prevention, recovery and re-use,
waste disposal currently forms the basis of waste management within South Africa. Due to the lack of
facilities as well as the high cost of waste disposal by incineration, the most common form of organic
and inorganic waste disposal in South Africa is by landfill. Waste disposal by landfill may be cost
effective and is environmentally acceptable if carried out correctly and appropriately. The prime
environmental media that are affected by waste disposal by landfill are typically water and air, of which
ground water forms one of the major migration pathways for contaminants. Ground water is one of
South Africaâs major water resources and it is thus of utmost importance that the countries ground water
resource be protected. The greatest threat posed by modern landfills to the ground water environment is
the leachate that is generated at the base of the landfill disposal facility. This leachate consists
essentially of water-soluble compounds that accumulate in association with infiltrating water as it
percolates through the waste. The quality of this leachate is variable and due to the processes by which
certain wastes are generated, may contain elements that could potentially have an adverse impact on
the environment if the waste is not disposed of correctly. All waste is required to be assessed and
appropriately disposed of, as currently formalized in the Department of Water Affairs and Forestryâs,
Waste Management Series, Second Edition 1998 - Minimum Requirement Documents. These
documents classify waste into two classes, namely general waste and hazardous waste, according to
the toxological risk that the waste poses on contaminating the environment. The Minimum Requirement
Documents have proposed 10 different landfill liner designs which are required to be installed at landfill
disposal facilities according to the classification of the waste. The two landfill liner designs that are
suitable for hazardous waste disposal are required to entail significant leachate interception and
removal systems, irrespective of the site water balance or site specific conditions and are thus often
unrepresentative for the specific disposal facility. Use was made of site specific parameters, such as the
required site water balance, geochemical composition and analyses of the slag, physical properties of
the slag material as well as the efficiency of the layers within the liner design, to determine the most
optimal liner design for the slag disposal facility investigated. Slag in an inorganic metallurgical waste
that is generically produced at ferrochrome producing plants in South Africa. Slag is disposed of by
means of landfill as a dry aggregate material with an average grain size of 20 mm. The risk that the slag
disposal facility posed on contaminating the environment was assessed in accordance with the current
environmental legislation and the optimized liner design was determined. The optimized liner design for
the 50 ha slag disposal facility investigated consists of 4 layers and is capable of capturing the required
volume of leachate in order to optimally protect the environment from any adverse effects caused by the
leachate. The liner has thus been designed according to the Best Practicable Environmental Option
norm and at the most optimal cost.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-08162012-111405 |
| Date | 16 August 2012 |
| Creators | Turner, Robert Shane |
| Contributors | Prof GJ van Tonder |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-08162012-111405/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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