Experiments for the cyanide biodegradation from industrial wastewater from the processing of gold bearing ores

Abstract

Biological degradation of cyanide in a complex wastewater has been investigated. The wastewater comes from a tailing dam from the processing of gold bearing ores and contains 10–20 ppm of WAD cyanide. Detailed investigations were performed on the growth of bacteria using several wastes of the local industry (whey from a dairy and malt from a brewery) as a replacement for glucose. The tests showed that an addition of 1–5% of these carbon sources resulted in a satisfactory growth of the bacteria. The paper describes the experiments for the degradation of cyanide in the wastewater, using two bacterial strains. The tests involved the biomass growth “in situ”, direclty in the wastewater, in a laboratory unit running in a discontinous mode for 96 hours. The results revealed that the degradation of the cyanide was in the range of 70–91% for the strain A and 60–78% for the strain B. This study shows that biodegradation can be an economical alternative for the destruction of cyanide in the effluent of the Bozanta dam and outlines some parameters that should be considered in a possible biological approach to wastewater treatment.