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Baker, K. A., Fennessy, M. S., & Mitsch, W. J. (1991). Designing wetlands for controlling coal mine drainage: an ecologic- economic modelling approach. Ecological Economics, 3(1), 1–24.
Abstract: A simulation model is developed of the efficiency and economics of an application of ecotechnology – using a created wetland to receive and treat coal mine drainage. The model examines the role of loading rates of iron on treatment efficiencies and the economic costs of wetland versus conventional treatment of mine drainage. It is calibrated with data from an Ohio wetland site and verified from multi-site data from Tennessee and Alabama. The model predicts that iron removal is closely tied to loading rates and that the cost of wetland treatment is less than that of conventional for iron loading rates of approximately 20-25 g Fe m “SUP -2” day “SUP -1” and removal efficiencies less than 85%. A wetland to achieve these conditions would cost approximately US$50 000 per year according to the model. When higher loading rates exist and higher efficiencies are needed, wetland systems are more costly than conventional treatment. -Authors
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Burgess, J. E., & Stuetz, R. M. (2002). Activated Sludge for the Treatment of Sulphur-rich Wastewaters. Miner. Eng., 15(11), 839–846.
Abstract: The aim of this investigation was to assess the potential of activated sludge for the remediation of sulphur-rich wastewaters. A pilot-scale activated sludge plant was acclimatised to a low load of sulphide and operated as a flow-through unit. Additional sludge samples from different full-scale plants were compared with the acclimatised and unacclimatised sludges using batch absorption tests. The effects of sludge source and acclimatisation on the ability of the sludge to biodegrade high loads of sulphide were evaluated. Acclimatisation to low-sulphide concentrations enabled the sludge to degrade subsequent high loads which were toxic to unacclimatised sludge. Acclimatisation was seen to be an effect of selection pressure on the biomass, suggesting that the treatment capability of activated sludge will develop after acclimation, indicating potential for treatment of acid mine drainage (AMD) by a standard wastewater treatment process. Existing options for biological treatment of AMD are described and the potential of activated sludge treatment for AMD discussed in comparison with existing technologies. (C) 2002 Elsevier Science Ltd.
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Conca, J. L., & Wright, J. (2006). An Apatite II permeable reactive barrier to remediate groundwater containing Zn, Pb and Cd. Appl. Geochem., 21(12), 2188–2200.
Abstract: Phosphate-induced metal stabilization involving the reactive medium Apatite II(TM) [Ca10-xNax(PO4)6-x(CO3)x(OH)2], where x < 1, was used in a subsurface permeable reactive barrier (PRB) to treat acid mine drainage in a shallow alluvial groundwater containing elevated concentrations of Zn, Pb, Cd, Cu, SO4 and NO3. The groundwater is treated in situ before it enters the East Fork of Ninemile Creek, a tributary to the Coeur d'Alene River, Idaho. Microbially mediated SO4 reduction and the subsequent precipitation of sphalerite [ZnS] is the primary mechanism occurring for immobilization of Zn and Cd. Precipitation of pyromorphite [Pb10(PO4)6(OH,Cl)2] is the most likely mechanism for immobilization of Pb. Precipitation is occurring directly on the original Apatite II. The emplaced PRB has been operating successfully since January of 2001, and has reduced the concentrations of Cd and Pb to below detection (2 μg L-1), has reduced Zn to near background in this region (about 100 μg L-1), and has reduced SO4 by between 100 and 200 mg L-1 and NO3 to below detection (50 μg L-1). The PRB, filled with 90 tonnes of Apatite II, has removed about 4550 kg of Zn, 91 kg of Pb and 45 kg of Cd, but 90% of the immobilization is occurring in the first 20% of the barrier, wherein the reactive media now contain up to 25 wt% Zn. Field observations indicate that about 30% of the Apatite II material is spent (consumed).
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Blowes, D. W., Ptacek, C. J., Benner, S. G., McRae, C. W. T., Bennett, T. A., & Puls, R. W. (2000). Treatment of inorganic contaminants using permeable reactive barriers. J Contam Hydrol, 45(1-2), 123–137.
Abstract: Permeable reactive barriers are an emerging alternative to traditional pump and treat systems for groundwater remediation. This technique has progressed rapidly over the past decade from laboratory bench-scale studies to full-scale implementation. Laboratory 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 demonstrated treatment of Cd, Cr, Cu, Fe, Ni, Pb, NO3, PO4 and SO4. Permeable reactive barriers composed of zero-valent iron have been used in full-scale installations for the treatment of Cr, U, and Tc. Solid-phase organic carbon in the form of municipal compost has been used to remove dissolved constituents associated with acid-mine drainage, including SO4, Fe, Ni, Co and Zn. Dissolved nutrients, including NO3 and PO4, have been removed from domestic septic-system effluent and agricultural drainage.
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Johnson, D. B., & Hallberg, K. B. (2005). Acid mine drainage remediation options: a review. Science of the Total Environment, 338(1-2), 3–14.
Abstract: Acid mine drainage (AMD) causes environmental pollution that affects many countries having historic or current mining industries. Preventing the formation or the migration of AMD from its source is generally considered to be the preferable option, although this is not feasible in many locations, and in such cases, it is necessary to collect, treat, and discharge mine water. There are various options available for remediating AMD, which may be divided into those that use either chemical or biological mechanisms to neutralise AMD and remove metals from solution. Both abiotic and biological systems include those that are classed as “active” (i.e., require continuous inputs of resources to sustain the process) or “passive” (i.e., require relatively little resource input once in operation). This review describes the current abiotic and bioremediative strategies that are currently used to mitigate AMD and compares the strengths and weaknesses of each. New and emerging technologies are also described. In addition, the factors that currently influence the selection of a remediation system, and how these criteria may change in the future, are discussed.
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