Biodegradation of Thiocyanate and Cyanide in CIL Leaching Waste’s Liquid Phase

Abstract

The ability of neutrophilic bacterium association to destruct thiocyanates and cyanides was found when working with oxidation of elemental and sulphide sulfur in biocake [1]. It was used for microorganisms association selection, which will oxidize thiocyanates and cyanides in liquid CIL tails of Olimpiada gold recovery plant. Originally selection occurred in laboratory reactors in periodical and later in continuous operation with thiocyanate content of 400-500 ml/l. Molasses in concentration of 0,5 g/l used as a source of carbons. After thiocyanates and cyanides stable oxidation in laboratory conditions the process was transferred to larger reactors (capacity of 2,2 m3). As a result of the research, rhodanides concentration reached 1800 mg/l. During the research rhodanides concentration was reduced from 1800 mg/l to 0,02 mg/l and cyanides concentration was reduced from 20 mg/l to 0,01 mg/l. Oxidation took 24 hours. Microbiological researches with application of molecular genetic analysis have shown that in the selected thiocyanate destructive association prevail the following strains: Pseudomonasaeruginosa, Stenotrophomonasmaltophilia and Enterobacter.