Article

Biological Methods Applied in the Treatment of Acid Mine Drainage (AMD)

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Abstract

Acidic mine drainage (AMD) is a serious environmental problem in mining areas throughout the world. AMD occurs as a result of the natural oxidation of sulfide minerals when they are exposed to oxygen and water during their disposal and storage at the mining areas. Because it includes low pH and high concentrations of dissolved metals and sulphates, AMD can potentially damage to the environment. If the formation of AMD can't be prevented and controlled, it must be collected and treated to remove acidity and reduce the concentration of heavy metals and suspended solids before its release to the environment. Different types of microorganisms in the treatment of AMD can play a very important role in the development and the application of microbiological prevention, control and treatment technologies. The purpose of this article is to give information about the passive biological methods used in the treatment and the control of AMD and the role of microorganisms in these methods.

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Thesis (Ph. D.)--University of Waterloo, 1990. Includes bibliographical references.
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The rate-determining step in the oxidation of iron pyrite and the formation of acidity in streams associated with coal and copper mines is the oxidation of ferrous iron. Effective pollution abatement necessitates control ling this reaction.
Article
The lifetime of traditional sulfate-reducing bacteria (SRB) bioreactors that utilize a source of reducing equivalents contained within the matrix (e.g. manure) is limited by the amount of readily available reducing equivalents within that matrix. In order to extend bioreactor lifetime indefinitely, the addition of known concentrations of alternative reducing equivalents (methanol and ethanol) to a depleted matrix was tested at low pH and low temperatures. Following acclimation, up to 100% efficiencies of reducing equivalents were directed toward sulfate reduction. Alcohol was added in stoichiometric concentrations to remove 50% of the added sulfate (900 mg/L), producing sufficient sulfide to precipitate all of the iron from solution. An average of 42% of the sulfate was removed following acclimation, reflecting 84% efficiency. An average of 93% of the iron was removed (93 mg/L). Bacteria acclimated to ethanol more rapidly than methanol, although both alcohols were effective as carbon sources. Efficient treatment was observed at the lowest temperatures (6 degrees C) and lowest pHs (pH=2.5) tested. The use of ethanol-fed, highly permeable bioreactor matrices of wood chip, pulverized plastic and rock was also examined to determine which of these porous matrices could be implemented in a field bioreactor. Results indicated that >95% of the 100mg/L iron added was removed by all matrices. Sufficient reducing equivalents were added to remove 450 mg/L of sulfate, wood and rock matrices removed approximately 350 mg/L plastic removed approximately 225 mg/L. A study comparing rock size indicated that small rocks removed iron and sulfate more efficiently than medium- and large-size rocks. The results suggest that wood and rock in conjunction with ethanol are viable alternatives to traditional bioreactor matrices. These findings have direct application to semi-passive sustained operation of SRB bioreactors for treatment of acidic drainage at remote sites.
Article
Simple anaerobic reactors were installed to treat metal-contaminated water in an underground coal mine and at a smelting residues dump in Pennsylvania. The reactors consisted of barrels and tanks filled with spent mushroom compost, within which bacterial sulfate reduction became established. Concentrations of Al, Cd, Fe, Mn, Ni, and Zn were typically lowered by over 95% as contaminated water flowed through the reactors. Cadmium, Fe, Ni, and some Zn were retained as insoluble metal sulfides following their reaction with bacterially generated H(2)S. Aluminum, Mn, and some Zn hydrolyzed and were retained as insoluble hydroxides or carbonates. Reactor effluents were typically circumneutral in pH and contained net alkalinity. The principal sources of alkalinity in the reactors were bacterial sulfate reduction and limestone dissolution. This article examines the chemistry of the reactor systems and the opportunities for enhancing their metal-retaining and alkalinity-generating potential.
Assessment of Existing Natural Wetlands Affected by Low pH, Metal Contaminated Seepages (Acid Mine Drainage), MEND (Mine Environment Neutral Drainage Program)Review of Passive Systems for Treatment of Acid Mine Drainage
MEND, 1990; "Assessment of Existing Natural Wetlands Affected by Low pH, Metal Contaminated Seepages (Acid Mine Drainage)", MEND (Mine Environment Neutral Drainage Program) Project 3.12.1. MEND, 1996; "Review of Passive Systems for Treatment of Acid Mine Drainage", MEND (Mine Environment Neutral Drainage Program) Project 3.14.1.
The Use of Wetlands for Treatment of Environmental Problems in Mining: Non-coal Mining Applications
  • T R Wildeman
  • L S Ve Laudon
Wildeman, T.R. ve Laudon, L.S., 1989; "The Use of Wetlands for Treatment of Environmental Problems in Mining: Non-coal Mining Applications", In: Proceedings of the International Conference on Constructed Wetlands for Wastewater Treatment, Lewis Publishing, Ann Arbor, MI, 221-231.
The Ecological Response of a Bog to Acidic Coal Mine Drainage-Deterioration and Subsequent Initiation of Recovery
  • W N Wheeler
  • M Kalin
  • J E Ve Cairns
Wheeler, W.N., Kalin, M. ve Cairns, J.E., 1991; "The Ecological Response of a Bog to Acidic Coal Mine Drainage-Deterioration and Subsequent Initiation of Recovery. In: The Proceedings of the Second International Conference on the Abatement of Acidic Drainage", Montreal, Quebec, Canada, 2, 449464.
Pyrite Oxidation Mechanisms and Acid Mine Drainage Prevention
  • V P Evengelou
  • Y L Zhang
Evengelou, V.P. ve Zhang, Y.L., 1995; "Pyrite Oxidation Mechanisms and Acid Mine Drainage Prevention", Critical Reviews in Environmental Science and Technology, 25, 141-199.
Selection of Reactive Mixtures for the Prevention of Acid Mine Drainage Using Porous Reactive Walls
  • K R Waybrant
  • D W Blowes
  • C J Ptacek
Waybrant, K.R., Blowes, D.W., Ptacek, C.J., 1995; "Selection of Reactive Mixtures for the Prevention of Acid Mine Drainage Using Porous Reactive Walls", In: The Proceedings of Sudbury '95 Conference on Mining and the Environment, Sudbury, Ontario, Canada, 3, 945-953,
Nickel and Arsenic Removal from Mine Wastewater by Muskeg Sediments
  • A Fyson
  • M Kalin
  • M P Smith
Fyson, A., Kalin, M., Smith, M.P., 1995; "Nickel and Arsenic Removal from Mine Wastewater by Muskeg Sediments", Biotechnology and the Mining Environment, Sudbury, Ontario, Canada. 2, 459-466.
Workshop Report: Mine Waste Technical Forum
  • Us Epa
US EPA, 1995; "Workshop Report: Mine Waste Technical Forum", July 25-27, Las Vegas, USA.