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Chen, M., Li, L., Grace, J., Tazaki, K., Shiraki, K., Asada, R., et al. (2007). Remediation of acid rock drainage by regenerable natural clinoptilolite. Water, Air, Soil Pollut., 180(1-4), 11–27.
Abstract: Clinoptilolite is investigated as a possible regenerable sorbent for acid rock drainage based on its adsorption capacity for Zn, adsorption kinetics, effect of pH, and regeneration performance. Adsorption of Zn ions depends on the initial concentration and pH. Adsorption/Desorption of Zn reached 75% of capacity after 1-2 h. Desorption depended on pH, with an optimum range of 2.5 to 4.0. The rank of desorption effectiveness was EDTAEDTA > NaCl > NaNO3 > NaOAc > NaHCO3 > Na2CO3 > NaOH > CeCa(OH)(2). For cyclic absorption/desorption, adsorption remained satisfactory for six to nine regenerations with EDTA and NaCl, respectively. The crystallinity and morphology of clinoptilolite remained intact following 10 regeneration cycles. Clinoptilolite appears to be promising for ARD leachate treatment, with significant potential advantages relative to current treatment systems.
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O'Sullivan, A. D., McCabe, O. M., Murray, D. A., & Otte, M. L. (1999). Wetlands for rehabilitation of metal mine wastes. Biology and Environment-Proceedings of the Royal Irish Academy, 99b(1), 11–17.
Abstract: Aspects of research work undertaken by the Wetland Ecology Research Group at University College Dublin are summarised here. Wastes from mining activities generally contain high concentrations of heavy metals and other toxic substances. Reclamation methods to treat these wastes include the use of wetlands, for revegetation of mine tailings under flooded conditions and for the treatment of tailings water. Both natural and constructed wetlands are frequently employed for the treatment of mine wastes. Through a complex array of plant, soil and microbial interactions contaminants, such as heavy metals and sulphates, can be successfully removed from wastewater. Suitable vegetation can stabilise the tailings sediment, thereby preventing it from being dust-blown or leached into the surrounding environment. Our research suggests that these two techniques for treatment of mine wastes are successful and economically viable.
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Burt, R. A., & Caruccio, F. T. (1986). The effect of limestone treatments on the rate of acid generation from pyritic mine gangue. Environmental geochemistry and health, 8, 8.
Abstract: Surface water enters the Haile Gold Mine, Lancaster County, South Carolina by means of a small stream and is ponded behind a dam and in an abandoned pit. This water is affected by acidic drainage. In spite of the large exposures of potentially acid producing pyritic rock, the flux of acid to the water is relatively low. Nevertheless, the resulting pH values of the mine water are low (around 3.5) due to negligible buffering capacity. In view of the observed low release of acidity, the potential for acid drainage abatement by limestone ameliorants appears feasible. This study investigated the effects of limestone treatment on acid generation rates of the Haile mine pyritic rocks through a series of leaching experiments. Below a critical alkalinity threshold value, solutions of dissolved limestone were found consistently to accelerate the rate of pyrite oxidation by varying degrees. The oxidation rates were further accelerated by admixing solid limestone with the pyritic rock. However, after a period of about a month, the pyrite oxidation rate of the admixed samples declined to a level lower than that of untreated pyrite. Leachates produced by the pyrite and limestone mixtures contained little if any iron. Further, in the mixtures, an alteration of the pyrite surface was apparent. The observed behaviour of the treated pyrite appears to be related to the immersion of the pyrite grains within a high alkalinity/high pH environment. The high pH increases the rate of oxidation of ferrous iron which results in a higher concentration of ferric iron at the pyrite surface. This, in turn, increases the rate of pyrite oxidation. Above a threshold alkalinity value, the precipitation of hydrous iron oxides at the pyrite surface eventually outpaces acid generation and coats the pyrite surface, retarding the rate of pyrite oxidation.
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Kothe, E. (2005). Molecular mechanisms in bio-geo-interaactions: From a case study to general mechanisms. Chemie Der Erde-Geochemistry, 65, 7–27.
Abstract: The understanding of molecular mechanisms in the cycling of elements in general is essential to our alteration of current processes. One field where such geochemical element cycles are of major importance is the prevention and treatment of acid mine drainage waters (AMD) which are prone to occur in every anthropogenic, modified landscape where sulfidic rock material has been brought to the surface during mine operations. Microbiologically controlled production of AMD leads not only to acidification, but at the same time the dissolution of heavy metals makes them bioavailable posing a potential ecotoxicological risk. The water path then can contaminate surface and ground water resources which leads to even bigger problems in large catchment areas. The investigation of mechanisms in natural attenuation has already provided first ideas for applications of naturally occurring bioremediation schemes. Especially an improved soil microflora can enhance the natural attenuation when adapted microbes are applied to contaminated areas. Future schemes for plant extraction, control of water efflux by increasing evapotranspiration, and by subsequent land use with agricultural plants with biostabilization and phytosequestration potential will provide putative control measures. The mechanisms in parts of these processes have been evaluated and the resulting synthesis applied to derive a bioremediation plan using the former uranium mine in Eastern Thuringia as a case study. (c) 2005 Elsevier GrnbH. All rights reserved.
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Dugan, P. R. (1987). Prevention of formation of acid drainage from high-sulfur coal refuse by inhibition of iron- and sulfur-oxidizing microorganisms. II. Inhibition in run of mine refuse under simulated field conditions. Biotechnol. Bioeng., 29(1), 6.
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