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Bechard, G. (1994). Use Of Cellulosic Substrates For The Microbial Treatment Of Acid-Mine Drainage. Journal of Environmental Quality, 23(1), 111–116.
Abstract: A mixed aerobic-anaerobic microbial treatment process was developed previously for acid mine drainage (AMD) using straw as a substrate. The process was effective only if AMD was supplemented with sucrose. The present study was conducted to determine which, if any, of three cellulosic materials could sustain the microbial treatment of AMD without the addition of a sucrose amendment and to determine the effect of the retention time on the performance of the reactors. The performance of small reactors that treated simulated AMD in the continuous mode was evaluated using alfalfa (Medicago sativa L.) hay, timothy (Phleum pratense L.) hay, and straw with a 5 d retention time. Parameters measured were pH, Fe, Al, sulfate, and ammonium. Timothy hay and straw sustained AMD mitigation for 3 wk, and thereafter all activity ceased. After the reactors ceased treating AMD, the mitigative activities were reinitiated by the addition of sucrose, but not by urea. Alfalfa sustained AMD mitigation for a longer time period than either straw or timothy. The effect of three retention times, 3.5, 7, and 35 d, was then investigated for reactors containing fresh alfalfa. Increasing the retention time resulted in better metal removal and a greater pH increase. With a 7-d retention time, 75 L of simulated AMD were neutralized from a pH of 3.5 to a pH value greater than 6.5. Reactors operating with a 3.5-d retention time treated only 58.3 L of simulated AMD before failing. Ammonium was detected in effluents of active reactors. The results of this study indicate that a low maintenance microbial treatment system can be developed with alfalfa as a substrate without the addition of a sucrose amendment.
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Bhole, A. G. (1994). Acid-Mine Drainage And Its Treatment. Impact of Mining on the Environment, , 131–141.
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Swoboda-Colberg, N., Colberg, P., & Smith, J. L. (1994). Constructed vertical flow aerated wetlands.
Abstract: In the report, wetland technology is described in which the main reactive layer is limestone gravel (rather than organic material) which is overlain by a fine gravel filter and soil. The three-year project included laboratory and field studies. Vertical aerated wetlands, simulated by columns, constructed in the field and in the laboratory, were operated during the project. The report presents a summary of results given in previous reports and summaries of results obtained using water from Butte, MT, and field studies at the Rockford Tunnel, near Idaho Springs, CO.
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Stefanoff, J. G., & Kim, Y. K. (1994). Reduction of leachability of heavy metals in acid mine drainage. J. Environ. Sci. Health Part A Environ. Sci. Eng., 29(2), 371–388.
Abstract: The leaching characteristics of sludges from the treatment of acid mine drainage(AMD) from Iron Mountain Mine near Redding, California were compared using two different processes: caustic soda treatment and a modified lime/sulfide treatment process. The modified lime/sulfide process produced a sludge with better dewaterability characteristics than sludge from the caustic soda process. The results of the Cal WET indicated that the modified lime/sulfide process sludge had less leachability than that of sludge from the caustic soda process. Both processes could achieve a substantial reduction of heavy metals in leachate to levels below the federal regulatory limits(TCLP). For cadmium and zinc, however, neither process produced a sludge that met the requirements of the Cal WET procedure.
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St-Arnaud, L. C. (1994). Water covers for the decommissioning of sulfidic mine tailings impoundments. In Special Publication – United States. Bureau of Mines, Report: BUMINES-SP-06A-94 (pp. 279–287). 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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