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Ye, Z. H., Whiting, S. N., Qian, J. H., Lytle, C. M., Lin, Z. Q., & Terry, N. (2001). Trace element removal from coal ash leachate by a 10-year-old constructed wetland. J. Environ. Qual., 30(5), 1710–1719.
Abstract: This study investigated the ability of a 10-yr-old constructed wetland to treat metal-contaminated leachate emanating from a coal ash pile at the Widows Creek electric utility, Alabama (USA). The two vegetated cells, which were dominated by cattail (Typha latifolia L.) and soft rush (Juncus effusus L.), were very effective at removing Fe and Cd from the wastewater, but less efficient for Zn, S, B, and Mn. The concentrations were decreased by up to 99% for Fe, 91% for Cd, 63% for Zn, 61% for S, 58% for Mn, and 50% for B. Higher pH levels (>6) in standing water substantially improved the removing efficiency of the wetland for Mn only. The belowground tissues of both cattail and soft rush had high concentrations of all elements; only for Mn, however, did the concentration in the shoots exceed those in the belowground tissues. The concentrations of trace elements in fallen litter were higher than in the living shoots, but lower than in the belowground tissues. ne trace element accumulation in the plants accounted for less than 2.5% of the annual loading of each trace element into the wetland. The sediments were the primary sinks for the elements removed from the wastewater. Except for Mn, the concentrations of trace elements in the upper layer (0-5 cm) of the sediment profile tended to be higher than the lower layers (5-10 and 10-15 cm). We conclude that constructed wetlands are still able to efficiently remove metals in the long term (i.e., >10 yr after construction).
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Sottnik, P., & Sucha, V. (2001). Moznosti upravy kysleho banskeho vytoku loziska Banska Stiavnica-Sobov. Remediation of acid mine drainage from Sobov Mine, Banska Stiavnica. Mineralia Slovaca, 33(1), 53–60.
Abstract: A waste dump formed during the exploitation of quartzite deposit in Sobov mine (Slovakia) produces large quantity of acid mine drainage (AMD) which is mainly a product of pyrite oxidation. Sulphuric acid--the most aggressive oxidation product--attacks gangue minerals, mainly clays, as well. This process lead to a sharp decrease of the pH values (2-2.5) and increase of Fe, Al and SO (super 2-) (sub 4) contents (TDS = 20-30 mg/1). Passive treatment system was designed to remediate AMD. Chemical redox reactions along with microbial activity cause a precipitation of mobile contamination into a more stable forms. The sulphides are formed in the anaerobic cell, under reducing conditions. Fe-, Al- oxyhydroxides are precipitated in the aerobic part of the system. Precipitation decreases the Fe and Al contents along with immobilization of some heavy metal closely related to oxyhydroxides. Besides oxidation, the wetland vegetation is an active part of on aerobic cell. The system has been working effectively since September 1999. The pH values of outflowing water are apparently higher (6.2-6.8) and contents of dissolved elements (Fe from 2.260 to 4.1; Al from 900 to 0.18; Mn from 51 to 23; Cu from 4.95 to 0.03 mg/l) is significantly lowers.
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Gusek, J. J., & Wildeman, T. R. (1995). New developments in passive treatment of acid rock drainage Pollution prevention for process engineering. In P. E. Richardson, B. J. Scheiner, & Jr. F. Lanzetta (Eds.),. New York: Engineering Foundation.
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Goodman, G. T. (1974). Ecology and the problems of rehabilitating wastes from mineral extraction. Proceedings of the Royal Society of London, Series A Mathematical and Physical Sciences, 339(1618), 373–387.
Abstract: Environmental problems which may be associated with mineral extraction are: (a) the visual ugliness of open pits, waste tips, and working mess; (b) the nuisance of wind- and water-borne dusts; (c) the health hazards to wildlife, crops, livestock and man of locally increased environmental burdens of potentially toxic metals (e.g. Pb, Cd, As, Zn, Cu, Ni) derived from wind- and water-borne mine dusts and smelter smokes; (d) the safety hazards of surface subsidence and tip-slippage from deep-mining. All these disamenities can be cured or reduced by the reclamation process which involves a blend of socio-economic, legal, planning, civil engineering and biological expertise devoted to development planning, site purchase, land clearance, land forming, stabilization, drainage and revegetation of the affected site
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