Thesis (MSc)--Stellenbosch University, 1998. / One copy microfiche. / ENGLISH ABSTRACT: The biologically catalysed oxidation of pyrite in the outer layers of coal waste dumps leads to the formation of acid mine drainage. The oxidation of pyrite to ferric iron and sulphate is a complex process involving various abiotic and biologically catalysed reactions. Pyrite is abiotically oxidized by ferric iron, with the formation of thiosulphate and ferrous iron. Thiosulphate decomposes to form various inorganic sulphur compounds. Bacterial catalysis of pyrite oxidation is achieved by iron-oxidizing bacteria oxidizing ferrous iron to ferric iron. Bacteria that oxidize sulphur compounds assist the catalysis by oxidizing thiosulphate and its decomposition products. Heterotrophic organisms may play a role by consuming organic substances inhibitory to the lithotrophic bacteria. Abiotic ecological factors, acid formation and populations of iron-oxidizing bacterial groups were studied in 10 differently constructed pilot scale coal waste dumps, as the second phase of a study which started in September 1993. Gas samples were withdrawn weekly from coal waste through permanently buried stainless steel probes, for analysis in the field using a portable oxygen/carbon dioxide meter. Samples of coal waste were extracted by auger for analysis of moisture, pH and microbial populations. The analyses of oxygen and pH can be recommended for the routine monitoring of rehabilitated waste dumps. Covers of Avalon soil 0.3 or 0.5 m thick, were not adequate to prevent acidification. Coal waste covered with 0.7 m compacted beneath 0.3 m uncompacted Avalon soil, showed a slow pH decline, but reached approximately pH 3 in 1997. Covers of compacted Estcourt soil beneath tmcompacted Avalon soil to a cover depth of 1 m were effective in preventing acidification and generally kept the coal waste anaerobic. However, all covers developed cracks during drought conditions in 1995, allowing aeration. Low pH of some samples from these dumps during 1995/1996 may have indicated the start of acidification. Bacteria oxidizing high concentrations of ferrous iron and considered to be Thiobacillus ferrooxidans, were monitored routinely, but may not have been the dominant iron-oxidizer, as population counts using media with a lower ferrous iron concentration were higher. The majority of the latter organisms could also not oxidize sulphur, hence were not T. ferrooxidans. The populations of the high ferrous iron-oxidizing bacteria were affected by pH, tending to be high in acidified and low in non-acidified coal waste. Investigations of microbial populations forming iron-oxidizing consortia in enrichment cultures from coal waste and acid drainage samples showed the presence of T. ferrooxidans, the heterotrophic bacterial genus Acidiphilium, fungi of the genus Penicillium, unidentified filamentous fungi, including Cladophialophora-like morphological types, and a yeast of the genus Dipodascus. In interaction studies, the Penicillium isolate had an inhibitory effect on T. ferrooxidans (subjected to organic compound stress), but the Cladophialophora-like fungi reduced inhibition by organics. Fungi have not previously been studied in detail as components of iron-oxidizing consortia, but the bacterial isolations agree with those elsewhere, indicating that appropriate conclusions from acid mine drainage research in other parts of the world can be applied in KwaZulu-Natal. / AFRIKAANSE OPSOMMING: Die biologies gekataliseerde oksidasie van piriet in die buitenste lae van steenkoolafvalhope lei tot die vorming van suur mynafloopwater. Die oksidasie van piriet tot ferri-yster en sulfaat is 'n komplekse proses wat abiotiese en biologies gekataliseerde reaksies insluit. Piriet word abioties deur ferri-yster geoksideer, met die vrystelling van tiosulfaat en ferro-yster. Tiosulfaat verval om verskeie anorganiese swawelverbindings te vorm. Bakteriese katalise van pirietoksidasie word deur ysteroksiderende bakteriee wat ferro-yster na ferri-yster oksideer, bewerkstellig. Bakteriee wat swawelverbindings oksideer maak 'n bydrae tot die katalise deur tiosulfaat en vervalprodukte daarvan te oksideer. Heterotrofe organismes mag ook 'n rol speel deur organiese verbindings wat die litotrofe bakteriee mag inhibeer, te verbruik. Abiotiese ekologiese faktore, suurvorming en bevolkings ysteroksiderende bakteriee is in 10 verskillend gekonstrueerde loodsskaal steenkoolafvalhope bestudeer, as die tweede fase van 'n studie wat in September 1993 begin het. Gas monsters is weekliks uit die steenkoolafval onttrek deur vlekvrye staal peilers wat permanent daarin begrawe is, en met behulp van 'n draagbare suurstoflkoolstofdioksiedanaliseerder in die veld ontleed. Monsters van die steenkoolafval is met behulp van 'n kleiboor vir die analise van vog, pH en mikrobepopulasies geneem. Die analise van suurstof en pH kan aanbeveel word vir die roetiene monitering van gerehabiliteerde afvalhope. Bedekkings van 0.3 of 0.5 m Avalongrond was nie voldoende om suurvorming te verhoed nie. Steenkoolafval wat met 0.7 m gekompakteerde en 0.3 m ongekompakteerde Avalongrond bedek is, het 'n stadige pH-daling getoon, maar het in 1997 ongeveer pH 3 bereik. Bedekkings van gekompakteerde Estcourtgrond onder ongekompakteerde A valongrond met 'n totale dikte van 1 m, was effektief in die voorkoming van suurvorming. Hulle het oor die algemeen die steenkoolafval anaerobies gehou, maar aile bedekings het tydens die droogte in 1995 krake ontwikkel, wat suurstof laat binnedring het. 'n Lae pH gedurende 1995/1996 by sommige monsters uit hierdie hope mag die begin van suurvorming aangedui het. Bakteriee wat hoe konsentrasies ferro-yster oksideer en wat as Thiobacillus ferrooxidans beskou is, was moontlik nie die dominante ysteroksideerder nie, aangesien bevolkingstellings waar 'n medium met 'n laer konsentrasie ferro-yster gebruik is, hoer bevolkings getoon het. Die meerderheid van laasgenoemde organismes kon ook nie swawel benut nie en dus nie T. ferrooxidans was nie. Die bevolkings van die hoe ferro-ysteroksiderende bakteriee is deur pH beInvloed, met 'n geneigdheid tot hoe bevolkings in suur en lae bevolkings in minder suur steenkoolafval. Ondersoeke na die rnilcrobebevollcings wat in ysteroksiderende konsortia in verryldngslculture vanaf steenkoolafval- en suur mynafloopwatermonsters voorgekom het, het die teenwoordigheid van 7'. ferrooxidans, die heterotrofe balcteriegenus Acidiphilium, fungi van die genus Penicillium, ongeIdentifiseerde fungi, insluitend Cladophialophora-agtige tipes en 'n gis van die genus Dipodascus aangetoon. By interaksiestudies het die Penicillium-isolaat 'n inhiberende effek op T ferrooxidans (onderworpe aan organiese verbindingstres) gehad, maar die Cladophialophora-agtige fungi het die inhibisie deur organiese verbindings verminder. Fungi is nog the in detail as komponente van ysteroksiderende konsortia bestudeer the, maar die isolasies van bakteried stem saam met die van elders wat aandui dat toepaslike gevolgtreldcings ten opsigte van suur mynafloopwatemavorsing vanaf ander dele van die wereld ook in KwaZulu-Natal toegepas kan word.

The objective of this study was to investigate the feasibility of the application of low cost high capacity inorganic ion exchange material, synthesized form collected fly ash and acid mine drainage solid residues, for the decontamination of secondary co-disposal process waters, with emphasis on investigating the processes governing the solid/solution interface.

The objective of this study was to investigate the feasibility of the application of low cost high capacity inorganic ion exchange material, synthesized form collected fly ash and acid mine drainage solid residues, for the decontamination of secondary co-disposal process waters, with emphasis on investigating the processes governing the solid/solution interface.

This study focuses on Acid Mine Drainage (AMD) in the three basins of the Witwatersrand’s goldfields in the Vaal River System in South Africa. AMD has become a highly contested issue. A difference in its definition exists between two groups of role-players identified in the study: government and consultants/activists/NGOs. This study unpacks the differences in the way AMD is defined, the situation of AMD in each of the three basins and the socio-economic implications caused by AMD. A crucial finding was that these definitions determine how the issue is understood and what solutions these role-players propose. The main purpose of the study was to determine whether the South African government’s policy response was appropriate given the socio-economic impacts of AMD and imperatives of sustainable development. This study concluded that, in the policy, there was no clear indication as to what the socio-economic impacts are, and limited attention was therefore given to these impacts. / Development Studies / M.A. (Development Studies)

Dissertation submitted in fulfilment of requirements for the degree Master of Technology: Chemical Engineering In the FACULTY OF ENGINEERING 2014 / In South Africa only 5% of the coal fly ash produced annually by power stations finds use. Due to the high quantities of Si and Al in the coal fly ash researchers have explored the opportunity to use the fly ash as a feedstock in zeolite synthesis. Two principal methods have been successfully employed on a micro scale namely the 2-step method and fusion assisted method. However, in order to scale-up these processes some fundamental process design changes are required. Fly ash contains various elements including highly toxic elements such as As, Pb and Hg. The fate of these elements during the synthesis processes is not known. Both these processes generate large quantities of liquid supernatant waste. Disposal of these wastes would be expensive and environmentally harmful, thus making these processes industrially unfeasible. The well known fusion assisted process, contains an energy intensive fusion step operating at 550 C. Construction and operation of a furnace to implement fusion would be too expensive on an industrial scale. The 2-step method has a time consuming pre-hydrothermal treatment step (aging step). In order to improve the feasibility of the 2-step process the processing time of the aging step needs to be reduced. In order to breach the scale gap between micro and pilot plant scale a principal reactor design has been suggested. However, to date, no consideration has been given to the safety and operational reliability of this design. A HAZOP study is required to prevent costly incidents from occurring during the operation of this reactor. The aim of this study formed part of the overall initiative to scale-up the synthesis of zeolites to pilot and ultimately do at industrial scale. The aim of this study specifically was to perform some principal process design activities in order to prepare these processes for scale-up. The objectives were to perform material balances on the two principals synthesis approaches in order to determine the distributional fate of elements. Secondly, to make critical process design changes and develop protocols whereby the supernatant waste resulting from these processes can be minimised. Thirdly, to replace the fusion step (used in the fusion assisted process) and the aging step (used in the 2-step process) with a short high intensity sonochemical treatment step. Lastly, to perform a HAZOP study on the principal bench scale reactor design, and make design changes based on the outcome of the study. Material balances illustrated that most of the elements originating from the coal fly ash (Fe, Mn, Mg, Ca, Ti, Ba, Ce, Co, Cu, Nb, Ni, Pb, Rb, Sr, Y and Zn) do not leach out into solution during either of the two synthesis approaches. This was due to the CaO content in the ash retarding the mobility of these elements. This meant that during the 2-step process these elements reported to the overall zeolite product but did not form part of the zeolite crystal structure. On the other hand, during the fusion assisted process these elements reported to the solid residue waste. The yield efficiency of the fusion assisted process was found to be poor with only 19.6% of the Si and 21.6% Al reporting to the zeolite A product. The 2-step process on the other hand incorporated 72.2% of the Si and 81.5% Al into the zeolite product. However, the 2-step process produced a mixed phase zeolite product while the fusion assisted process produced a pure phase zeolite A product. Therefore there is a trade-off between yield efficiency and product purity. It was found that the liquid supernatant waste produced during both the synthesis processes contained toxic elements such as As, Pb, Hg, Al and Nb. This highlighted the importance to minimise the liquid supernatant waste generated. The waste minimisation studies illustrated that the liquid supernatant waste can be recycled while still producing highly crystalline zeolite products, in both the synthesis approaches. During the 2-step process the supernatant waste was recycled as a source of NaOH. By recycling the waste it was found that 40% of the supernatant could be recycled. However, by making a minor process design change a protocol was developed whereby 100% of the supernatant waste could be recycled. Also, by recycling the liquid waste, zeolite analcime became the dominant phase due to the accumulation of Si in the waste. In the fusion assisted process, protocols were developed whereby the liquid supernatant waste was recycled as a source of water. It was found that 100% of the supernatant could be recycled without compromising the relative crystallinity and purity of the zeolite A product. Both the fusion step (used in the fusion assisted approach) and the 48 hr aging step (used in the 2-step process) could be replaced with 10 min of sonochemical treatment. It was found in both cases that the introduction of ultrasound, during the pre-hydrothermal stage, increased the rate of crystal formation during the hydrothermal treatment step. It was also found that by replacing the high temperature fusion step, in the fusion assisted process, the required hydrothermal treatment temperature could be reduced to 90 C. By introducing sonochemical treatment in these two synthesis approaches their synthesis time and energy demands could be reduced successfully. A HAZOP study on the principal bench scale reactor design enabled design changes to be made preventing future loss during operation. A final optimised reactor design was proposed based on the outcome of the HAZOP study. This study effectively prepared both zeolite synthesis approaches for up-scale operation. Scale-up of this process will reduce disposal of coal fly ash offering relief to the financial and environmental strain caused to the country.

M.Sc. (Zoology) / Pans are endorheic wetlands, and are abundant in South Africa in a band from the western Free State into Mpumalanga. The pan environment experiences daily and seasonal fluctuations in physico-chemical conditions. The physico-chemical variables are influenced by the local climatological and hydrological conditions, and are all inter-related. An imbalance of one variable can have countless effects on the others. The physico-chemical composition of the water ultimately determines the existence of the biota in such wetlands. Branchiopod crustaceans are a unique group of fauna which have various morphological, physiological and behavioural adaptations which enable them to survive in these variable environments. One such adaptation is the production of dormant egg banks. These eggs reside within the sediment through the dry phase and hatch during a following wet phase when conditions are favourable. Due to the endorheic nature of pans they are more vulnerable to anthropogenic stress. Anthropogenic activities are having profound effects on the integrity of these ecosystems. Agricultural and mining activities have some of the largest influences. The impacts that the following activities have include: the over utilisation of water, decreased periods of inundation, erosion and sedimentation, effluent discharge and direct habitat destruction. Many wetlands as a result are experiencing a rapid loss in biodiversity. Mining activities are on the increase especially in the Highveld region of southern Africa. Many of these wetlands are already (and will be in the future) affected by mining activities, making the effect of acid mine drainage (AMD) on the biota a priority concern. In conjunction with the uniqueness and vulnerability of pan ecosystems it is necessary to find new ways of monitoring such environmental impacts in the shortest time possible with minimal efforts, for the benefit of both the environment and researchers involved. This study therefore aimed to assess the diversity of branchiopod crustaceans hatching from egg banks of selected pans and obtain a reference community structure. It also aimed to assess the impacts AMD could have on the hatching success of branchiopods from these egg banks with the objective to determine whether these egg banks are still viable after exposure. To achieve the stated aims and objectives, sediment samples were collected from selected pans in mining regions of the country. Regions selected included Chrissiesmeer in the Mpumalanga province, Wesselsbron in the Free State province and Delareyville in the North West province. The sediment was used for hatching experiments in the laboratory. Pan sediment was exposed to three different treatments which included two salt solutions (1000 mg/l and 1500 mg/l respectively) and AMD. The salt solutions served as controls while the AMD served as an exposure. The number of nauplii hatching was counted in the controls and compared to the number of nauplii hatching in the AMD. The diversity of nauplii was also assessed and compared between controls and the AMD. The recovery potential of eggs exposed to AMD was also assessed by exposing the sediment treated with AMD to distilled water after its removal to get a better understanding on the effects of AMD at the community level. Results from the control treatments indicated that most pans have a range of taxa hatching that follow patterns of pan succession. Between the 1000 mg/l and 1500 mg/l controls there was no treatment that proved superior to the other. Representatives of all four orders of branchiopoda hatched from the experiments. The North West and Free State pans were the most diverse and had had the greatest abundances of individuals hatching. Spatially all three provinces differed in the diversity of individuals hatching from pans, as there were distinct differences in the taxonomic compositions. Although taxonomic composition of pans grouped together per province, pans from just a single province were largely dissimilar. Results from the AMD treatments indicated that AMD has a negative effect on the hatching ability of branchiopod crustacean eggs. Eggs that were initially exposed to AMD were unable to hatch in its presence. The recovery experiments indicated that recovery after exposure is limited as recovery only occurred in a few pans. The taxonomic composition of nauplii in the pans where recovery took place was altered and less diverse than the taxonomic composition found in the respective control treatments. Overall it was found that hatching experiments can be used as a monitoring tool in lieu of field sampling. Hatching experiments showed that AMD is detrimental to the branchiopod egg banks, inhibiting the ability of eggs to hatch in its presence. Recovery can take place but the recovery potential is low. Since the recovery potential of the egg banks is low, pans which are affected by AMD could experience extinction of the entire branchiopod community in years to come. As branchiopod communities are unique among pans, and serve as an important food source for many aquatic bird species, their extinction will bring about further losses in biodiversity.

Thesis (M. Sc. (Geography)) -- University of Limpopo, 2021 / Acid Mine Drainage (AMD) is the acidic water emanating from the mine tailing dams into the surrounding environment. AMD is regarded as a major environmental threat associated with mining. The lower Olifants River in the Kruger National Park (KNP) is considered an environmentally sensitive area, which exhibits high levels of aquatic ecosystems and supports a variety of terrestrial ecosystems within and around the KNP. The Phalaborwa mining industries have been discharging the acid mine drainage contaminated-water into the Ga-Selati River, a tributary to the Olifants River. Although the impacts in the upper Olifants River catchment have been well documented, it was the amount of AMD witnessed at KNP and the dying of fish within the lower Olifants River that raised issues of concerns. Hence, the study investigated the impact of acid mine drainage on water quality of the lower Olifants River, modelled the distribution of the dissolved heavy metals in the stream, and evaluated the applied mine wastewater management strategies at Phalaborwa mining industries. In this study, water samples were collected seasonally (winter, spring, and summer) from 2019 to 2020, and the analytical methods and procedures were optimized for the determination of selected elements in the water samples. During the study, ion chromatography (IC) was used to detect chloride (Cl), sulphate (SO4 - ), nitrate (NO3), and fluoride (F), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was used to detect pH, turbidity, electrical conductivity (EC), total dissolved solids (TDS), magnesium (Mg), manganese (Mn), sodium (Na), potassium (K), aluminium (Al) and calcium (Ca). Modelling of the distribution of dissolved heavy metals was performed using the inverse distance weighted (IDW) interpolation technique available in ArcGIS 10.8 software. The range of pH across four sampling sites was between 7.77 and 9.11, indicating an alkaline pH. The concentration of measured parameters elevated downstream points with some exceeding the target water quality range (TWQR) for aquatic ecosystems. The elevated concentration of SO4 - at sites 3 and 4 (downstream points) showed that the acid mine drainage is still a matter of concern at the lower Olifants River catchment. However, the GIS models showed a decreasing trend of the concentration of heavy metal towards the KNP.

MENVSC / Department of Ecology and Resource Management / Mine tailings (MT) have been a global problem due to the environmental impacts the waste generates such as air, soil and water pollution. The detrimental impacts include a global problem such as acid mine drainage (AMD) which has been difficult to cleanup. Several studies have been conducted to find alternative measures in reducing or mitigating impacts such as AMD and air pollution. Several studies have revealed how alumino-silicate mineral waste can be used as raw material to produce construction materials. This study aimed at evaluating the potential of synthesizing a geopolymer material from Musina copper mine tailings. Tailings were characterized for their physicochemical and mineralogical compositions using standard laboratory techniques in order to evaluate suitability in geopolymerization. First section of the results presented physicochemical and mineralogical characterization of the Musina copper tailings together with the bioavailability of the chemical species. It was observed that the tailings are mainly composed of SiO2 and Al2O3 as the major oxides indicating that they are aluminosilicate material. Mineralogical analysis revealed dominance of quartz, epidote and chlorite as the major minerals. The bioavailability assessment showed that largely Cu and Ca are bioavailable and highly soluble in an aqueous solution while Al, Mg, Ni, Co, Cr and Fe have a high proportion in non-labile phase. Second section presented the preliminary results wherein the potential application of Musina copper tailings in geopolymerization was evaluated. The results showed that Musina copper tailings can be used to synthesize a geopolymer material. However, it was recommended that several parameters influencing geopolymerization need to be evaluated. The third section presented the evaluation of optimum parameters that influence the geopolymerization process, which include type of alkali activators, alkali activator concentration, curing temperature, liquid-solid (L/S) ratio and curing regime. It was observed that a mixture of NaOH:Na2SiO3.5H20 at a ratio of 70:30 yields a better geopolymer material. The concentration of 10 M NaOH:Na2SiO3.5H20 at a ratio of 70:30 was observed to be the best that yielded the UCS that is acceptable according to SANS1215 standards. When evaluating curing regime, it was found that the material cured using greenhouse has lower UCS as compared to the material cured using oven. The v effect of temperature showed that the UCS decreases with increasing curing temperature. An admixture of river sand and cement was introduced which resulted in a high UCS of 21.16 MPa when using an admixture of cement. The mineralogical composition of the geopolymer bricks showed formation of secondary minerals such as phlogopite, fluorapatite, diopside and actinolite. Batch leaching conducted on the geopolymer bricks detected high leaching of Na from the bricks. Based on the findings of the study of the raw MT potential to produce geopolymer bricks, it was concluded that the material can be used to produce bricks that are within the SANS 1215 requirements. The study further recommended that the study a focus on using cylindrical moulds, other alkali activators and a mechanical mixer. It was also recommended that the greenhouse be restructured to contain heat within the greenhouse during the evening so as to allow constant temperature within / NRF

PhDENV / Department of Ecology and Resource Management / See the attached abstract below