Research on Cyanide Toxicity and Its Degradation Mechanism by Activated Sludge

The influence of wastewater with different concentrations of cyanide on microbes toxicity and mechanism of cyanide biodegradation were researched.Results show that when the concentration of cyanide ranges from 0to 2.0mg/L,cyanide has an inhibitory effect on the metabolism of microbe,but not lethal.When the cyanide concentration reaches 2.0 mg/L,nitrifying process is completely suppressed.The inhibitory effect of cyanide on de-nitrification process is mainly on its first step,where nitrate converts to nitrite.The mechanism of cyanide biodegradation is that cyanide is firstly turned into ammonia nitrogen and finally converted to nitrite and nitrate.