|
Dill, S., Cowan, J., Wood, A., & Bowell, R. J. (1998). (L. Nel Petrus Johannes, Ed.). Mine Water and Environmental Impacts. 2: Proceedings International Mine Water Association Symposium.
|
|
Dillard, G. (2000). A win-win way to clean up by changing ionic state, new process can precipitate heavy metals. Pay Dirt, 734, 10–11.
|
|
Diz, H. R. (1997). Chemical and biological treatment of acid mine drainage for the removal of heavy metals and acidity. Ph.D. thesis, Virginia Polytechnic Institute and State University,, Blacksburg.
|
Foucher, S., Battaglia-Brunet, F., Ignatiadis, I., & Morin, D. (2001). Treatment by sulfate-reducing bacteria of Chessy acid-mine drainage and metals recovery. Chemical Engineering Science, 56(4), 1639–1645.
Abstract: Acid-mine drainage can contain high concentrations of heavy metals and release of these contaminants into the environment is generally avoided by lime neutralization. However, this classical treatment is expensive and generates large amounts of residual sludge. The selective precipitation of metals using H2S produced biologically by sulfate-reducing bacteria has been proposed as an alternative process. Here, we report on experiments using real effluent from the disused Chessy-les-Mines mine-site at the laboratory pilot scale. A fixed-bed bioreactor, fed with an H2/CO2 mixture, was used in conjunction with a gas stripping column. The maximum rate of hydrogen transfer in the bioreactor was determined before inoculation. kLa was deduced from measurements of O2 using Higbie and Danckwert's models which predict a dependence on diffusivity. The dynamic method of physical absorption and desorption was used. The maximum rate of H2 transfer suggests that this step should not be a limiting factor. However, an increase in H2 flow rate was observed to induce an increase in sulfate reduction rate. For the precipitation step, the gas mixture from the bioreactor was bubbled into a stirred reactor fed with the real effluent. Cu and Zn could be selectively recovered at pH=2.8 and pH=3.5, respectively. Other impurities such as Ni and Fe could also be removed at pH=6 by sulfide precipitation. Part of the outlet stream from the bioreactor was used to regulate and maintain the pH during sulfide precipitation by feeding the outlet stream back into the bioreactor. The replacement of synthetic medium with real effluent had a positive effect on sulfate reduction rate which increased by 30-40%. This improvement in bacterial efficiency may be related to the large range of oligo-elements provided by the mine-water. The maximum sulfate reduction rate observed with the real effluent was 200 mgl-1 h-1, corresponding to a residence time of 0.9 day. A preliminary cost estimation based on a treatment rate of 5 m3 h-1 of a mine effluent containing 5 gl-1 SO42- is presented.
|
Houston, K. S., Milionis, P. N., Eppley, R. L., Harrington, J. M., & Harrington, J. G. (2005). Field Demonstration of In-Situ Treatment and Prevention of Acid Mine Drainage in the Abandoned Tide Mine, Indiana County, Pennsylvania.
Abstract: A field demonstration of the Green World Science® patented process technology was performed to address acid mine drainage (AMD) at an abandoned bituminous coal mine, the Tide Mine in Center Township, Indiana County, PA. ARCADIS owns an exclusive patent license of the Green World Science® process, which can be used in situ to transform an aerobic, AMD-producing mine pool to a biologically mediated, sulfate-reducing state. The Green World Science® process treats the entire mine pool to address the source of AMD in place. The project was conducted through a grant agreement between the Blacklick Creek Watershed Association, the Pennsylvania Department of Environmental Protection's Bureau of Abandoned Mine Reclamation, and ARCADIS. In conjunction with the characterization of mine pool hydraulics through injection of a bromide tracer, the in situ treatments implemented at Tide Mine include the initial addition of alkalinity to create an environment suitable for biological activity, injection of organic carbon into the mine pool to facilitate microbially mediated metals reduction and precipitation, and injection of carbon dioxide gas into the atmosphere above the mine pool to control the dominant source of oxygen that perpetuates the AMD process. Collectively, these treatments raised the pH from a baseline of approximately 2.5 to over 6 during the demonstration period. The mine pool subsequently maintains a pH above 5 through microbially produced (i.e., bicarbonate) alkalinity. Ferric iron has been reduced to non-detect concentrations within the anaerobic mine pool, and aluminum concentrations have decreased by approximately 30%, with additional metals removal expected as the system becomes controlled by ferrous sulfide precipitation. The injection of carbon dioxide gas into the mine workings decreased oxygen concentrations above the mine pool from over 20% (ambient air conditions) to less than 5% over approximately three months, thus mitigating the source of AMD within the mine.
|
