Fate and toxic effects of cyanide on aerobic treatment systems

Many industries discharge significant quantities of cyanide into the environment. Removal of cyanide is a vital task of increasing importance. Currently, the chemical methods of treating cyanide wastewater are used worldwide. The high cost, disposal problems and toxic by-products formation of chemical methods for treating cyanide wastewater has opened the door for more investigation of new methods. This paper evaluates the fate and toxic effects of cyanide on aerobic treatment systems. Both batch and continuous flow experiments were performed. The results indicate that the aerobic biological treatment of cyanide wastewater is an effective technology, which offers many advantages over chemical treatment methods. The microbiological experimental results show that among the microorganisms present in the culture, oscillatoria, philodina, carchesium, pseudomonas and bacillus bacteria were resistant to cyanide and capable of biodegrading it. The results of this study indicate that biodegradation and sorption of cyanide are the most important and least important removal mechanisms, respectively.