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Berthelot, D., Haggis, M., Payne, R., McClarty, D., & Courtain, M. (1999). Application of water covers, remote monitoring and data management systems to environmental management at uranium tailings sites in the Serpent River Watershed. CIM Bull., 92(1033), 70–77.
Abstract: Over forty years of uranium mining in the Elliot lake region of Ontario (1956-1996) has resulted in the production of over 300 million pounds of uranium. With the completion of mining activity Rio Algom limited and Denison Mines limited are utilizing progressive environmental technologies and management systems to reduce and manage the environmental risks associated with the 150 million tonnes of potentially acid-generating tailings in nine regional waste management areas. Water covers designed to reduce oxygen entry and, thereby, significantly inhibit acid generation, have been applied at six of the sites with the Quirke site serving as a demonstration site for the Mine Environmental Neutral Drainage program, All five of Rio Algom limited's effluent treatment plants are monitored and controlled from a central control station utilizing a Supervisory Control and Data Acquisition (SCADA) system based on “Fix Dmacs” technology Scheduling, auditing and reporting of plant operating and environmental monitoring programs for the entire watershed are controlled utilizing the Regional Environmental Information Management System (REIMS). Proper application of these technologies and management systems facilitates delivery of cost-effective environmental monitoring, care and maintenance programs at these sites and provides tools to demonstrate compliance with all environmental performance criteria.
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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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Jong, T. (2006). Microbial sulfate reduction under sequentially acidic conditions in an upflow anaerobic packed bed bioreactor. Water Research, 40(13), 2561–2571.
Abstract: The aim of this study was to operate an upflow anaerobic packed bed reactor (UAPB) containing sulfate reducing bacteria (SRB) under acidic conditions similar to those found in acid mine drainage (AMD). The UAPB was filled with sand and operated under continuous flow at progressively lower pH and was shown to be capable of supporting sulfate reduction at pH values of 6.0, 5.0, 4.5, 4.0 and 3.5 in a synthetic medium containing 53.5 mmol l(-1) lactate. Sulfate reduction rates of 553-1052 mmol m(-3) d(-1) were obtained when the influent solution pH was progressively lowered from pH 6.0 to 4.0, under an optimal flow rate of 2.61 ml min(-1). When the influent pH was further lowered to pH 3.5, sulfate reduction was substantially reduced with only about 1% sulfate removed at a rate of 3.35 mmol m(-3) d(-1) after 20 days of operation. However, viable SRB were recovered from the column, indicating that the SRB population was capable of surviving and metabolizing at low levels even at pH 3.5 conditions for at least 20 days. The changes in conductivity in the SRB column did not always occur with changes in pH and redox potential, suggesting that conductivity measurements may be more sensitive to SRB activity and could be used as an additional tool for monitoring SRB activity. The bioreactor containing SRB was able to reduce sulfate and generate alkalinity even when challenged with influent as low as pH 3.5, indicating that such treatment systems have potential for bioremediating highly acidic, sulfate contaminated waste waters. (c) 2006 Elsevier Ltd. All rights reserved.
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Jarvis, A. P., & Younger, P. L. (2001). Passive treatment of ferruginous mine waters using high surface area media. Water Res., 35(15), 3643–3648.
Abstract: Rapid oxidation and accretion of iron onto high surface area media has been investigated as a potential passive treatment option for ferruginous, net-alkaline minewaters. Two pilot-scale reactors were installed at a site in County Durham, UK. Each 2.0m high cylinder contained different high surface area plastic trickling filter media. Ferruginous minewater was fed downwards over the media at various flow-rates with the objective of establishing the efficiency of iron removal at different loading rates. Residence time of water within the reactors was between 70 and 360s depending on the flow-rate (1 and 12l/min, respectively). Average influent total iron concentration for the duration of these experiments was 1.43mg/l (range 1.08-1.84mg/l; n=16), whilst effluent iron concentrations averaged 0.41mg/l (range 0.20-1.04mg/l; n=15) for Reactor A and 0.38mg/l (range 0.11-0.93mg/l; n=16) for Reactor B. There is a strong correlation between influent iron load and iron removal rate. Even at the highest loading rates (approximately 31.6g/day) 43% and 49% of the total iron load was removed in Reactors A and B, respectively. At low manganese loading rates (approximately 0.50-0.90g/day) over 50% of the manganese was removed in Reactor B. Iron removal rate (g/m3/d) increases linearly with loading rate (g/day) up to 14g/d and the slope of the line indicates that a mean of 85% of the iron is removed. In conclusion, it appears that the oxidation and accretion of ochre on high surface area media may be a promising alternative passive technology to constructed wetlands at certain sites.
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Benner, S. G. (1999). Geochemistry of a permeable reactive barrier for metals and acid mine drainage. Environmental Science & Technology, 33(16), 2793–2799.
Abstract: A permeable reactive barrier, designed to remove metals and generate alkalinity by promoting sulfate reduction and metal sulfide precipitation, was installed in August 1995 into an aquifer containing effluent from mine tailings. Passage of groundwater through the barrier results in striking improvement in water quality. Dramatic changes in concentrations of SO4 (decrease of 2000-3000 mg/L), Fe (decrease of 270-1300 mg/L), trace metals (e.g., Ni decreases 30 mg/L), and alkalinity (increase of (800-2700 mg/L) are observed. Populations of sulfate reducing bacteria are 10 000 times greater, and bacterial activity, as measured by dehydrogenase activity, is 10 rimes higher within the barrier compared to the up-gradient aquifer. Dissolved sulfide concentrations increase by 0.2-120 mg/ L, and the isotope S-34 is enriched relative to S-32 in the dissolved phase SO42- within the barrier. Water chemistry, coupled with geochemical speciation modeling, indicates the pore water in the barrier becomes supersaturated with respect to amorphous Fe sulfide. Solid phase analysis of the reactive mixture indicates the accumulation of Fe monosulfide precipitates. Shifts in the saturation states of carbonate, sulfate, and sulfide minerals and most of the observed changes in water chemistry in the barrier and down-gradient aquifer can be attributed, either directly or indirectly, to bacterially mediated sulfate reduction.
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