Pretreatment of Refractory and Cyanide-Containing Pesticide Wastewater Using Sodium Hypochlorite

The cyanide-containing wastewater mainly derives from chemical Engineering industry such as pesticide production, electroplating and metallurgy. It is very important to treat this kind of wastewater, because of the redundant toxic contaminants it contains.In this paper,using refractory and cyanide-containing pesticide wastewater as the subject investigated the effect of sodium hypochlorite to its pretreatment. The results show that sodium hypochlorite degradation of organic compounds at the same time, on which the cyanide removal efficiency is also good; pH, dosage and dosage form of sodium hypochlorite, reaction time and react to the sodium hypochlorite pretreatment can greatly influence .We found that adding sodium hypochlorite in batches and stirring with aeration achieved optimal effect. Under the optimal conditions, namely pH 11.0, sodium hypochlorite dosage 60 ml·L^-1, the reaction time 60 min,sodium hypochlorite the cyanide concentration is dropped to 15 mg·L^-1, cyanide removal is more than 85%; COD is reduced to 500 mg·L^-1, removal rate is more than 50%.