Fenton Treatment of Chlorpyrifos, Cypermethrin and Chlorothanonil Pesticides in Aquous Solution

The study examined the effect of operating conditions of the Fenton process on degradation, biodegradability improvement and mineralization of chlorpyrifos, cypermethrin and chlorothanonil pesticides in aquous solution. Also, the degradation of the pesticides under optimum operating cnditions was evaluated. The optimum operating conditions for Fenton treatment of an aqueous solution containing 100, 50 and 260 mg/Lof chlorpyrifos, cypermethrin and chlorothanonil, respectively were observed to be H2O2/COD molar ratio 3, H2O2/Fe2+ molar ratio 10 and pH 3. Pesticide degradation increased with temperature. Under the optimum operating conditions, complete degradation of the pesticides occurred in 1 min. Biodegradability (BOD5/COD ratio) increased from o to 0.35 and COD and TOC removal were 69.03 and 55.61%, respectively in 60 min. Duje to mineralization of organic carbon, decrease in ammonia-nitrogen from 22 to 6.1 mg/L and increase in nitrate from 0.7 to 15.2 mg/L in 60 min were observed. The study indicated that Fenton process can be used for pretreatment of combined chlorpyrifos, cypermethrin and chlorothanonil pesticides in aquous solution or wastewater for biological treatment.