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Ntengwe, F. W. (2005). An overview of industrial wastewater treatment and analysis as means of preventing pollution of surface and underground water bodies – The case of Nkana Mine in Zambia. Phys. Chem. Earth, 30(11-16 Spec. Iss.), 726–734.
Abstract: The wastewaters coming from mining operations usually have low pH (acidic) values and high levels of metal pollutants depending on the type of metals being extracted. If unchecked, the acidity and metals will have an impact on the surface water. The organisms and plants can adversely be affected and this renders both surface and underground water unsuitable for use by the communities. The installation of a treatment plant that can handle the wastewaters so that pH and levels of pollutants are reduced to acceptable levels provides a solution to the prevention of polluting surface and underground waters and damage to ecosystems both in water and surrounding soils. The samples were collected at five points and analyzed for acidity, total suspended solids, and metals. It was found that the pH fluctuated between pH 2 when neutralization was forgotten and pH 11 when neutralization took place. The levels of metals that could cause impacts to the water ecosystem were found to be high when the pH was low. High levels of metals interfere with multiplication of microorganisms, which help in the natural purification of water in stream and river bodies. The fish and hyacinth placed in water at the two extremes of pH 2 and pH 11 could not survive indicating that wastewaters from mining areas should be adequately treated and neutralized to pH range 6-9 if life in natural waters is to be sustained. < copyright > 2005 Elsevier Ltd. All rights reserved.
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Driussi, C. (2006). Technological options for waste minimisation in the mining industry. J. Cleaner Prod., 14(8), 682–688.
Abstract: Just as the application of technology in mining processes can cause pollution, it can also be harnessed to minimise, and sometimes eliminate, mine-related contaminants. Waste minimisation can be achieved through decreased waste production, waste collection, waste recycling, and the neutralisation of pollutants into detoxified forms. This article reviews examples of how technology can be used to minimise air, water, land and noise pollution in the mining industry. (c) 2005 Elsevier Ltd. All rights reserved.
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Waring, C. L., & Taylor, J. R. (1999). (R. Fernández Rubio, Ed.). Mine, Water & Environment. Ii: International Mine Water Association.
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Guay, R. (1999). Effect of flooding of oxidized mine tailings on T-ferrooxidans and T-thiooxidans survival and acid mine drainage production: a 4 year restoration-environmental follow-up. Biohydrometallurgy and the Environment toward the Mining of the 21st Century, Pt B 1999, 9, 635–643.
Abstract: A pilot-scale study on the effect of flooding unoxidized and oxidized Cu/Zn tailings demonstrated the technical feasability of this technology to remediate a mining site where over 3 million tons of tailings were impounded. Full-scale flooding of the tailing pond with free running water was undertaken after the construction of an impervious dam; approximately 2 million m(3) of surface water at pH 7,4 completely covered the tailings after 16 months. The minimal water column over the tailings was established at 1,20 m and reached 4,5 m, depending on the site topography. Water and tailings samples were collected from 9 different locations from the surface of the man-made lake using a specially designed borer and were analyzed for pH, conductivity, iron- and sulfur-oxidizing bacteria activity and numbers as well as the sulfate reducing bacteria (SRB) population. We showed that over a four year period of flooding, the overall population of iron-oxidizers decreased considerably; their numbers drastically fell from 1 x 10(6) to 1 x 10(2) active cells per g of oxidized tailings while the SRBs increased from 10(1) to 10(5)/g. The pH of the influent, the reservoir and the effluent water remained fairly constant between 6,9 up to 7,4 over the entire period. During this time, interstitial water pH increased from 2,9 to 4,3 in flooded tailings where lime could not be incorporated in the first 20 cm of tailings; elsewhere, the pH of the tailings suspensions remained fairly constant around neutral values (pH 7,0). Dissolved oxygen was measured at fixed intervals and remained also constant between 6 and 7.5 mg/L while water temperatures fluctuated below freezing point to +20C respectively in winter and summer season.
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Olaniran, A. O. (2006). Biostimulation and bioaugmentation enhances aerobic biodegradation of dichloroethenes. Chemosphere, 63(4), 600–608.
Abstract: The accumulation of dichloroethenes (DCEs) as dominant products of microbial reductive dechlorination activity in soil and water represent a significant obstacle to the application of bioremediation as a remedial option for chloroethenes in many contaminated systems. In this study, the effects of biostimulation and/or bioaugmentation on the biodegradation of cis- and trans-DCE in soil and water samples collected from contaminated sites in South Africa were evaluated in order to deter-mine the possible bioremediation option for these compounds in the contaminated sites. Results from this study indicate that cis- and trans-DCE were readily degraded to varying degrees by natural microbial populations in all the soil and water samples tested, with up to 44% of cis-DCE and 41% of trans-DCE degraded in the untreated soil and water samples in two weeks. The degradation rate constants ranged significantly (P < 0.05) between 0.0938 and 0.560 wk(-1) and 0.182 and 0.401 wk(-1), for cis- and trans-DCE, respectively, for the various treatments employed. A combination of biostimulation and bioaugmentation significantly increased the biodegradation of both compounds within two weeks; 14% for cis-DCE and 18% for trans-DCE degradation, above those observed in untreated soil and water samples. These findings support the use of a combination of biostimulation and bioaugmentation for the efficient biodegradation of these compounds in contaminated soil and water. In addition, the results clearly demonstrate that while naturally occurring microorganisms are capable of aerobic biodegradation of cis- and trans-DCE, biotransformation may be affected by several factors, including isomer structure, soil type, and the amount of nutrients available in the water and soil. (c) 2005 Elsevier Ltd. All rights reserved.
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