A critical review on destruction of thiocyanate in mining effluents

Thiocyanate and cyanide are formed during the processing of gold ores and the production of coke for steel production. Thiocyanate is also formed biologically from the detoxification of cyanide. Thiocyanate is less toxic than cyanide but more stable and thus more difficult to destroy. There are no direct regulatory requirements for the release of thiocyanate into the environment but a number of regulatory agencies have published guidelines for thiocyanate release. Several species of bacteria have been shown to degrade thiocyanate using different biochemical pathways. Some bacteria degrade thiocyanate autotrophically in order to obtain energy and other bacteria utilize thiocyanate as either a sulfur or nitrogen source. Various chemical and biological technologies have been proposed for the destruction of thiocyanate in industrial effluents. Biological systems varying in size from laboratory to full scale have been shown to successfully remove thiocyanate from both industrial and mining effluents. Additional research should be directed towards improving the understanding of the biochemistry of thiocyanate metabolism and scaling up technologies for thiocyanate degradation from laboratory to full scale. (C) 2012 Elsevier Ltd. All rights reserved.