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POST-MORTEM FINDINGS ON THE PERFORMANCE OF ENGINEERED SRB FIELD-BIOREACTORS FOR ACID MINE DRAINAGE CONTROL
Citation:
Zaluski, M. H., Trudnoski,JM, M. A. HarringtonBaker, M. Mansfield, AND D R. Bless*. POST-MORTEM FINDINGS ON THE PERFORMANCE OF ENGINEERED SRB FIELD-BIOREACTORS FOR ACID MINE DRAINAGE CONTROL. Presented at 6th ICARD Acid Rock Drainage International Conf, North Queensland, AUSTRALIA, July 14 - 17, 2003.
Impact/Purpose:
To inform the public
Description:
Sulphate-reducing bacteria (SRB) have the ability to immobilize dissolved metals by precipitating them as sulphides, provided that a favourable biochemical environment is created. Such an environment includes the presence of sulphate, anaerobic conditions and the availability of organic carbon. If such conditions are engineered within a reactive barrier or field-bioreactor, most metals can be effectively removed. To demonstrate this concept, three passive SRB field-bioreactors were constructed in 1998 at an abandoned mine site in the vicinity of Butte, Montana, USA to treat acid mine drainage with characteristic elevated concentration of metals and low pH.
Performance of the field-bioreactors, using aqueous samples, was monitored over 32 months until the project was terminated, field-bioreactors were decommissioned and solid matrix sampling of the reactive matter was performed. The most important analytical results are presented in this paper together with conclusions regarding the appropriateness of the field-bioreactors construction features. Only Zn, Cu, and Cd were being removed as sulphides due to SRB activities. Changes in concentrations of other metals (Fe, Mn, Al, As), which do not necessarily precipitate as sulphide, seemed to be affected by SRB only in an indirect manner by responding to increased pH caused by SRB activity. An innovative cellular containment system used for placing organic matter worked very well in preventing settling of the organic matter and ensuring uniform flow of AMD throughout the entire cross section of the organic carbon with no preferential flow paths
This demonstration was funded by the U.S. EPA and was jointly administered by the EPA and the U.S. DOE under DOE contract number DE-AC22-96EW96405. The project was implemented by MSE Technology Applications, Inc., Butte, Montana, USA.