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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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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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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Plant, J. (2006). Removal of base metals from mine waters using passive treatment processes involving autocatalytic oxidation and adsorption.
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Mohan, D., & Chander, S. (2006). Removal and recovery of metal ions from acid mine drainage using lignite-A low cost sorbent. J. Hazard. Mater., 137(3), 1545–1553.
Abstract: Acid mine drainage (AMD), has long been a significant environmental problem resulting from the microbial oxidation of iron pyrite in presence of water and air, affording an acidic solution that contains toxic metal ions. The main objective of this study was to remove and recover metal ions from acid mine drainage (AMD) by using lignite, a low cost sorbent. Lignite has been characterized and used for the AMD treatment. Sorption of ferrous, ferric, manganese, zinc and calcium in multi-component aqueous systems was investigated. Studies were performed at different pH to find optimum pH. To simulate industrial conditions for acid mine wastewater treatment, all the studies were performed using single and multi-columns setup in down flow mode. The empty bed contact time (EBCT) model was used for minimizing the sorbent usage. Recovery of the metal ions as well as regeneration of sorbent was achieved successfully using 0.1 M nitric acid without dismantling the columns. < copyright > 2006 Elsevier B.V. All rights reserved.
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