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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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Aytas, S. O., Akyil, S., Aslani, M. A. A., & Aytekin, U. (1999). Removal of uranium from aqueous solutions by diatomite (Kieselguhr). Journal of Radioanalytical and Nuclear Chemistry, 240(3), 973–976.
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Gong, Z., Huang, J., & Jiang, H. (1996). Study of comprehensive retrieval utilization and the treatment of acid mine wastewater. Zhongnan Gongye Daxue Xuebao = Journal of Central South University of Technology, 27(4), 432–435.
Abstract: Impact of precipitating on removing harmful metal ion in the acid mine wastewater with pH neutralizer and sulfide was studied. The possible way of retrieving heavy metal ion in wastewater was probed. The techniques for lime carbonate to reject iron for hydrogen sulfide to precipitate copper and for zinc-lime cream neutralization flocculation to treat, mine acid wastewater were chosen. The final water quality may reach national effluent standard; the copper content was 32% in the sulfide slag.
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Sato, D., & Tazaki, K. (2000). Calcification treatment of mine drainage and depositional formula of heavy metals. Chikyu Kagaku = Earth Science, 54(5), 328–336.
Abstract: Depositional formula of heavy metals after disposal of the mine drainage from the Ogoya Mine in Ishikawa Prefecture, Japan, was mineralogically investigated. Strong acidic wastewater (pH 3.5) from pithead of the mine contains high concentration of heavy metals. In this mine, neutralizing coagulation treatment is going on by slaked lime (calcium hydroxides: Ca(OH) (sub 2) ). Core samples were collected at disposal pond to which the treated wastewater flows. The core samples were divided into 44 layers based on the color variation. The mineralogical and chemical compositions of each layer were analyzed by an X-ray powder diffractometer (XRD), an energy dispersive X-ray fluorescence analyzer (ED-XRF) and a NCS elemental analyzer. The upper parts are rich in brown colored layers, whereas discolored are the deeper parts. The color variation is relevant to Fe concentration. Brown colored core sections are composed of abundant hydrous ferric oxides with heavy metals, such as Cu, Zn, and Cd. On the other hand, S concentration gradually increases with depth. XRD data indicated that calcite decreases with increasing depth, and ettringite is produced at the deeper parts. Cd concentration shows similar vertical profile to those of calcite and ettringite. The results revealed that hydrous ferric oxides, calcite and ettringite are formed on deposition, whereby incorporating the heavy metals.
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Murdock, D. J., Fox, J. R. W., & Bensley, J. G. (1994). Treatment of acid mine drainage by the high density sludge process. In Special Publication – United States. Bureau of Mines, Report: BUMINES-SP-06A-94 (pp. 241–249). Proceedings of the International land reclamation and mine drainage conference and Third international conference on The abatement of acidic drainage; Volume 1 of 4; Mine drainage.
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