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The water purification process at Eskom includes a reverse osmosis (RO) treatment plant. There are several limitations to this process depending on the water characteristics. The most common problems limiting the success of water purification include scaling, biological fouling and corrosion. This study is mainly focused on reducing scale forming agents in the RO system. Scaling is the precipitation of calcium and magnesium salts onto the equipment, primarily the RO membrane. These salts start to precipitate once the salt concentration in the water is higher than the allowable solubility constant. These salts can be removed from the water by a process called coagulation-flocculation. The success of such process is partly dependent on the type of flocculant and the dosage used. In this study the performances of one coagulant namely Rheofloc 5023 in combination with three flocculants including Rheofloc 5414, Genesys genefloc and AR floc 100 were tested at various dosages for the reduction of conductivity assimilated with ions in the RO retentate from coal power plant was investigated at 40 and 60oC. The AR floc 100 was determined to be the optimum flocculant required for the RO reject treatment. The optimum flocculant dosage resulted in 1 ppm along with a Rheofloc 5023 coagulant dosage of 0.7 ppm

For environmental and aesthetic purposes it has become essential that mine dump rocks either blend into the environment or be used in the production of other products. Lately, there has been a constant need to produce more durable road and construction material and to develop an alternative for granite countertops and flooring. For the visibility of road surface material and the aesthetic aspect of countertops, the colouring of mine dump rocks was considered. A cost effective and environmentally friendly process was suggested to colour mine dump rocks. In this study different colouring agents for three mine dumping rocks, dolomite, quartzite and dolerite, were investigated. The aim was to create lasting colours that have a high wear resistance to weather conditions. Coloured dolomite can be used as road and construction material, coloured quartzite as countertops while coloured dolerite can serve as a replacement for road surfaces

This study reports on the biodegradation of free cyanide (FCN) by cyanide degrading bacteria (CDB) that were isolated from mining wastewater and in thiocyanate containing wastewater. The performance of these isolates was compared to cryopreserved CDBs that were used in precious studies. The performance of the isolates to degrade FCN was studied in batch cultures. It was observed that the CDB from the thiocyanate wastewater showed higher biodegradation rates (2.114 g CN- .L-1.O.D600nm -1.h-1) compared to the isolates from the mining wastewater. The isolates from the cryopreserved CDBs and from the mining wastewater achieved a biodegradation rate of 1.285 g CN- .L-1.O.D600nm -1.h-1and 1.209 g CN- .L-1.O.D600nm -1.h-1 , respectively. This study demonstrated that the source of the organisms plays a significant role on FCN biodegradation

Several nanoparticles (Cu2O, SnO, ZnO) have been intensively studied and applied in wastewater treatment research, with TiO2 gaining popularity because of its stability, affordability, large band gap, recyclability and its efficiency in photocatalysis. This study reports on the influence of solubilising matrices on TiO2 nanoparticle synthesis. A Wet Chemical Method was used to synthesis TiO2 nanoparticles by solubilising TiCl4 in three types of solvents: water, toluene and methylene chloride. Physical, chemical and optical properties of the TiO2 nanoparticles obtained from these various solubilising agents were characterised by XRD, UV-Vis, FTIR and SEM. Results were compared for each solvent with TiO2 nanoparticles solubilised in water having the best properties

The aim of this study was to evaluate the geochemical background and spatial distribution patterns of selected potential toxic elements (PTEs) in ten sub-surface soil samples (n=10) collected in the former copper mining area, O’Kiep. The major oxides and PTEs in the samples were identified and measured using X-ray fluorescence and X-ray diffractometer. The contaminated soils were compared to prestige soil and Soil Screening Values for All Land-Uses Protective of the Water Resource – references which can elucidate PTE contamination. The examined soils showed a high variability in the PTEs concentrations. O’Kiep soils show some degree of contamination with an average low pH of 3.5 and an Eh of 520 mV. The most abundant PTEs in the soils were S > Cu > F > Mn > Cl > Zn > Cr > V > Pb > Ni > Co. The soil type in downstream was classified as silt with a clay content of 1.1%. The mineralogical study of the soils revealed minerals such as Alumino-silicates, Ca-silicates and Mg-silicates aggregates, with a strong similarity between the downstream and upstream samples from the mining area, while the midstream only differred by the presence of hematite. The median values of oxides contents in soils follow a decreasing order as: SiO2 > Al2O3> Fe2O3 > K2O. Furthermore, factors that influence the distribution and migration of PTEs in soils were largely identified as mine waste heaps and slime dams further north from the sampling sites. Excessive concentration of PTEs in O’Kiep’s soils may lead to elevated potential risks to human health and the local environment. The material of mine waste heaps is very fine and can easily migrate with wind and water erosion. Therefore, further risk assessment analyses of mine waste heaps and the mine are required in O’Kiep