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Sierra-Alvarez, R. (2006). Biological treatment of heavy metals in acid mine drainage using sulfate reducing bioreactors. Water Sci. Technol., 54(2), 179–185.
Abstract: The uncontrolled release of acid mine drainage (AMD) from abandoned mines and tailing piles threatens water resources in many sites worldwide. AMD introduces elevated concentrations of sulfate ions and dissolved heavy metals as well as high acidity levels to groundwater and receiving surface water. Anaerobic biological processes relying on the activity of sulfate reducing bacteria are being considered for the treatment of AMD and other heavy metal containing effluents. Biogenic sulfides form insoluble complexes with heavy metals resulting in their precipitation. The objective of this study was to investigate the remediation of AMD in sulfate reducing bioreactors inoculated with anaerobic granular sludge and fed V with an influent containing ethanol. Biological treatment of an acidic (pH 4.0) synthetic AMD containing high concentrations of heavy metals (100 Mg Cu2+vertical bar(-1); 10 mg Ni2+vertical bar(-1), 10 mg Zn2+vertical bar(-1)) increased the effluent pH level to 7.0-7.2 and resulted in metal removal efficiencies exceeding 99.2%. The highest metal precipitation Cn rates attained for Cu, Ni and Zn averaged 92.5, 14.6 and 15.8 mg metal l(-1) of reactor d(-1). The results of this work demonstrate that an ethanol-fed sulfidogenic reactor was highly effective to remove heavy metal contamination and neutralized the acidity of the synthetic wastewater.
Keywords: mine water treatment
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Simmons, J. A., Andrew, T., Arnold, A., Bee, N., Bennett, J., Grundman, M., et al. (2006). Small-Scale Chemical Changes Caused by In-stream Limestone Sand Additions to Streams. Mine Water Env., 25(4), 241–245.
Abstract: In-stream limestone sand addition (ILSA) has been employed as the final treatment for acid mine drainage discharges at Swamp Run in central West Virginia for six years. To determine the small-scale longitudinal variation in stream water and sediment chemistry and stream biota, we sampled one to three locations upstream of the ILSA site and six locations downstream. Addition of limestone sand significantly increased calcium and aluminum concentrations in sediment and increased the pH, calcium, and total suspended solids of the stream water. Increases in alkalinity were not significant. The number of benthic macroinvertebrate taxa was significantly reduced but there was no effect on periphyton biomass. Dissolved aluminum concentration in stream water was reduced, apparently by precipitation into the stream sediment.
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Totsche, O., Fyson, A., Kalin, M., & Steinberg Christian, E. W. (2006). Titration curves: A useful instrument for assessing the buffer systems of acidic mining waters. ESPR Environmental Science and Pollution Research, 13(4), 215–224.
Abstract: The acidification of mine waters is generally caused by metal sulfide oxidation, related to mining activities. These waters are characterized by low pH and high acidity due to strong buffering systems. The standard acidity parameter, the BNC (Base Neutralization Capacity), is determined by endpoint titration, and reflects a cumulative parameter of both hydrogen ions and all buffering systems, but does not give information on the individual buffer systems. It is demonstrated that a detailed interpretation of titration curves can provide information about the strength of the buffering systems. The buffering systems are of importance for environmental studies and treatment of acidic mining waters. Titrations were carried out by means of an automatic titrator using acidic mining waters from Germany and Canada. The curves were interpreted, compared with each other, to endpoint titration results and to elemental concentrations contained therein. The titration curves were highly reproducible, and contained information about the strength of the buffer systems present. Interpretations are given, and the classification and comparison of acidic mining waters, by the nature and strength of their buffering systems derived from titration curves are discussed. The BNC-values calculated from the curves were more precise than the ones determined by the standard endpoint titration method. Due to the complex buffer mechanisms in acidic mining waters, the calculation of major metal concentrations from the shape of the titration curve resulted in estimates, which should not be confused with precise elemental analysis results. Conclusion. Titration curves provide an inexpensive, valuable and versatile tool, by which to obtain sophisticated information of the acidity in acidic water. The information about the strength of the present buffer systems can help to understand and document the complex nature of acidic mining water buffer systems. Finally, the interpretation of titration curves could help to improve treatment measurements and the ecological understanding of these acidic waters.
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Wiessner, A., Kuschk, P., Buddhawong, S., Stottmeister, U., Mattusch, J., & Kästner, M. (2006). Effectiveness of various small-scale constructed wetland designs for the removal of iron and zinc from acid mine drainage under field conditions. Engineering in Life Sciences, 6(6), 584–592.
Abstract: A system of planted and implanted small-scale SSF (subsurface flow) and SF (surface flow) constructed wetlands together with HP (hydroponic systems) were installed to compare the removal efficiencies of Fe and Zn from AMD (acid mine drainage) under long-term field conditions. Maximum removal of 94 % – 97 % (116 mg/m(exp 2)/d – 142 mg/m(exp 2)/d) for Fe and 69 % – 77 % (6.2 mg/m(exp 2)/d – 7.9 mg/m(exp 2)/d) for Zn was calculated for the planted soil systems. The planted SSF was most sensitive to heavy rain fall. Short-term increases of the metal concentration in the outflows, short-term breakdowns of the Fe removal and continual long-term breakdowns of the Zn removal were observed. In contrast to Zn removal, all wetland types are applicable for Fe removal with maximum removal in the range of 60 % – 98 %. Most of the removed Fe and Zn was transformed and deposited inside the soil bed. The amount absorbed by the plants (0.03 % to 0.3 %) and gravel-associated soil beds (0.03 % to 1.7 %) of the total input were low for both metals. The response of the planted SSF to rainfall suggests a remobilisation of metals accumulated inside the rhizosphere and the importance of buffering effects of the surface water layers of SF systems. The importance of plants for metal removal was shown.
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Wolkersdorfer, C. (2006). Icard 2006. 7: Proceedings, International Conference of Acid Rock Drainage (ICARD).
Abstract: Acid mine drainage, the drainage of metals, and the prediction of mine water rebound after mine closure are major problems for the mining industry. In the literature, the difficulties in evaluating the hydrodynamics of flooded mines are well described, although only a few tracer tests in flooded mines have been published. Increased knowledge about the hydraulic behaviour of the mine water within a flooded mine might significantly reduce the costs of mine closure and remediation. Relatively cheap and reliable results for decision making can be obtained when tracer tests are properly conducted in a flooded mine prior to planning of remediation strategies or numerical simulations. Applying the results of successful tracer tests allows one to optimise remediation designs and thereby diminish the costs of remediation. The paper summarises the results of several tracer tests and draws general conclusions from such tests.
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