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Blowes, D. W., Ptacek, C. J., Benner, S. G., McRae, C. W. T., & Puls, R. W. (1998). Treatment of dissolved metals using permeable reactive barriers. Groundwater Quality: Remediation and Protection, (250), 483–490.
Abstract: Permeable reactive barriers are a promising new approach to the treatment of dissolved contaminants in aquifers. This technology has progressed rapidly from laboratory studies to full-scale implementation over the past decade. Laboratory treatability studies indicate the potential for treatment of a large number of inorganic contaminants, including As, Cd, Cr, Cu, Hg, Fe, Mn, Mo, Ni, Pb, Se, Tc, U, V, NO3, PO4, and SO4. Small scale field studies have indicated the potential for treatment of Cd, Cr, Cu, Fe, Ni, Pb, NO3, PO4, and SO4. Permeable reactive barriers have been used in full-scale installations for the treatment of hexavalent chromium, dissolved constituents associated with acid-mine drainage, including SO4, Fe, Ni, Co and Zn, and dissolved nutrients, including nitrate and phosphate. A full-scale barrier designed to prevent the release of contaminants associated with inactive mine tailings impoundment was installed at the Nickel Rim mine site in Canada in August 1995. This reactive barrier removes Fe, SO,, Ni and other metals. The effluent from the barrier is neutral in pH and contains no acid-generating potential, and dissolved metal concentrations are below regulatory guidelines. A full-scale reactive barrier was installed to treat Cr(VI) and halogenated hydrocarbons at the US Coast Guard site in Elizabeth City, North Carolina, USA in June 1996. This barrier removes Cr(VI) from >8 mg l(-1) to <0.01 mg l(-1).
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Foucher, S., Battaglia-Brunet, F., Ignatiadis, I., & Morin, D. (2001). Treatment by sulfate-reducing bacteria of Chessy acid-mine drainage and metals recovery. Chemical Engineering Science, 56(4), 1639–1645.
Abstract: Acid-mine drainage can contain high concentrations of heavy metals and release of these contaminants into the environment is generally avoided by lime neutralization. However, this classical treatment is expensive and generates large amounts of residual sludge. The selective precipitation of metals using H2S produced biologically by sulfate-reducing bacteria has been proposed as an alternative process. Here, we report on experiments using real effluent from the disused Chessy-les-Mines mine-site at the laboratory pilot scale. A fixed-bed bioreactor, fed with an H2/CO2 mixture, was used in conjunction with a gas stripping column. The maximum rate of hydrogen transfer in the bioreactor was determined before inoculation. kLa was deduced from measurements of O2 using Higbie and Danckwert's models which predict a dependence on diffusivity. The dynamic method of physical absorption and desorption was used. The maximum rate of H2 transfer suggests that this step should not be a limiting factor. However, an increase in H2 flow rate was observed to induce an increase in sulfate reduction rate. For the precipitation step, the gas mixture from the bioreactor was bubbled into a stirred reactor fed with the real effluent. Cu and Zn could be selectively recovered at pH=2.8 and pH=3.5, respectively. Other impurities such as Ni and Fe could also be removed at pH=6 by sulfide precipitation. Part of the outlet stream from the bioreactor was used to regulate and maintain the pH during sulfide precipitation by feeding the outlet stream back into the bioreactor. The replacement of synthetic medium with real effluent had a positive effect on sulfate reduction rate which increased by 30-40%. This improvement in bacterial efficiency may be related to the large range of oligo-elements provided by the mine-water. The maximum sulfate reduction rate observed with the real effluent was 200 mgl-1 h-1, corresponding to a residence time of 0.9 day. A preliminary cost estimation based on a treatment rate of 5 m3 h-1 of a mine effluent containing 5 gl-1 SO42- is presented.
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Coulton, R., Bullen, C., & Hallett, C. (2003). The design and optimisation of active mine water treatment plants. Land Contam. Reclam., 11(2), 273–280.
Abstract: This paper provides a 'state of the art' overview of active mine water treatment. The paper discusses the process and reagent selection options commonly available to the designer of an active mine water treatment plant. Comparisons are made between each of these options, based on technical and financial criteria. The various different treatment technologies available are reviewed and comparisons made between conventional precipitation (using hydroxides, sulphides and carbonates), high density sludge processes and super-saturation precipitation. The selection of reagents (quick lime, slaked lime, sodium hydroxide, sodium carbonate, magnesium hydroxide, and proprietary chemicals) is considered and a comparison made on the basis of reagent cost, ease of use, final effluent quality and sludge settling criteria. The choice of oxidising agent (air, pure oxygen, peroxide, etc.) for conversion of ferrous to ferric iron is also considered. Whole life costs comparisons (capital, operational and decommissioning) are made between conventional hydroxide precipitation and the high density sludge process, based on the actual treatment requirements for four different mine waters.
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Bowell, R. J. (2000). Sulphate and salt minerals; the problem of treating mine waste. Mining Environmental Management, 8(3), 11–13.
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Kingham, N. W., Semenak, R., Powell, G., & Way, S. (2002). Reverse osmosis coupled with chemical precipitation treatment of acid mine leachate at the Basin-Luttrell Pit, Ten Mile Creek Site, Lewis and Clark County, Montana Hardrock mining 2002; issues shaping the industry..
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