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Gusek, J. J. (2005). Design challenges for large scale sulfate reducing bioreactors. Contaminated Soils, Sediments and Water: Science in the Real World, Vol 9, 9, 33–44.
Abstract: The first large-scale (1,200 gpm capacity), sulfate-reducing; bioreactor (SRBR) was constructed in 1996 to treat water from an underground lead mine in Missouri. Other large-scale SRBR systems have been built elsewhere since then. This technology holds much promise for economically treating heavy metals and has progressed steadily from the laboratory to industrial applications. Scale-up challenges include: designing for seasonal temperature variations, minimizing short circuits, changes in metal loading rate s, storm water impacts, and resistance to vandalism. However, the biggest challenge may be designing for the progressive biological degradation of the organic substrate and its effects on the hydraulics of the SRBR cells.
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Guay, R. (1999). Effect of flooding of oxidized mine tailings on T-ferrooxidans and T-thiooxidans survival and acid mine drainage production: a 4 year restoration-environmental follow-up. Biohydrometallurgy and the Environment toward the Mining of the 21st Century, Pt B 1999, 9, 635–643.
Abstract: A pilot-scale study on the effect of flooding unoxidized and oxidized Cu/Zn tailings demonstrated the technical feasability of this technology to remediate a mining site where over 3 million tons of tailings were impounded. Full-scale flooding of the tailing pond with free running water was undertaken after the construction of an impervious dam; approximately 2 million m(3) of surface water at pH 7,4 completely covered the tailings after 16 months. The minimal water column over the tailings was established at 1,20 m and reached 4,5 m, depending on the site topography. Water and tailings samples were collected from 9 different locations from the surface of the man-made lake using a specially designed borer and were analyzed for pH, conductivity, iron- and sulfur-oxidizing bacteria activity and numbers as well as the sulfate reducing bacteria (SRB) population. We showed that over a four year period of flooding, the overall population of iron-oxidizers decreased considerably; their numbers drastically fell from 1 x 10(6) to 1 x 10(2) active cells per g of oxidized tailings while the SRBs increased from 10(1) to 10(5)/g. The pH of the influent, the reservoir and the effluent water remained fairly constant between 6,9 up to 7,4 over the entire period. During this time, interstitial water pH increased from 2,9 to 4,3 in flooded tailings where lime could not be incorporated in the first 20 cm of tailings; elsewhere, the pH of the tailings suspensions remained fairly constant around neutral values (pH 7,0). Dissolved oxygen was measured at fixed intervals and remained also constant between 6 and 7.5 mg/L while water temperatures fluctuated below freezing point to +20C respectively in winter and summer season.
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Boonstra, J. (1999). Biological treatment of acid mine drainage. Biohydrometallurgy and the Environment toward the Mining of the 21st Century, Pt B 1999, 9, 559–567.
Abstract: In this paper experience obtained with THIOPAQ technology treating Acid Mine Drainage is described. THIOPAQ Technology involves biological sulfate reduction technology and the removal of heavy metals as metal sulfide precipitates. The technology was developed by the PAQUES company, who have realised over 350 high rate biological treatment plants world wide. 5 plants specially designed for sulfate reduction are successfully operated on a continuous base (1998 status).
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Kuyucak, N. (1998). Mining, the Environment and the Treatment of Mine Effluents. Int. J. Environ. Pollut., 10(2), 315–325.
Abstract: The environmental impact of mining on the ecosystem, including land, water and air, has become an unavoidable reality. Guidelines and regulations have been promulgated to protect the environment throughout mining activities from start-up to site decommissioning. In particular, the occurrence of acid mine drainage (AMD), due to oxidation of sulfide mineral wastes, has become the major area of concern to many mining industries during operations and after site decommissioning. AMD is characterized by high acidity and a high concentration of sulfates and dissolved metals. If it cannot be prevented or controlled, it must be treated to eliminate acidity, and reduce heavy metals and suspended solids before release to the environment. This paper discusses conventional and new methods used for the treatment of mine effluents, in particular the treatment of AMD.
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Zou, L. H. (2000). Sulfide precipitation flotation for treatment of acidic mine waste water. Transactions of Nonferrous Metals Society of China, 10, 106–109.
Abstract: Sulfide precipitation flotation of copper-iron-bearing acidic waste water from a large copper mine and the stimulated waste water were studied. The pH of the waste water was 2.2, with 130 mg/L Cu2+ and 500 mg/L Fe3+ (Fe2+). Results show that, when Na2S was added as precipitating agent, sodium butylxanthate as collector and at pH 2.0, the removal of copper could be as high as 99.7 % and the residual copper decreased to 0.2 mg/L, however, almost no iron was removed. When the floated solution was neutralized to pH = 8.0, more than 98 % iron was precipitated and the residual iron was less than 10 mg/L. In experiment on actual mine effluents, after the use of precipitate flotation technology to recover copper and pH neutralization to precipitate iron, the treated waste water does meet the emission standards for sewage and valuable floating copper graded 37.12%. The chemical calculation and mechanism of solution were also presented.
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