Treatment Of Triazophos Pesticide Wastewater By Fenton Reagent

Organic phosphorous pesticide wastewater is characteristic of high value of COD, strong toxicity, poor biodegradability, complicated constituents. Therefore, effective treatment of the wastewater is required before discharge. The biochemical treatment including pretreatment processes of adsorption, hydrolysis and coagulation sedimentation process, the chemical treatment processes such as conventional chemical oxidation, supercritical water oxidation, electrochemical oxidation, and photocatalytic oxidation, the physical treatment processes and ultrasonic methods for treatment of organic phosphorous pesticide wastewater were reviewed. Fenton oxidation has lots of advantages, such as high reaction rate, high removal efficiency, broad range of usage, and relative low expanse of treatment.Treating triazophos pesticide wastewater by Fenton reaction was investigated at bench-scale in this study. Effects of key factors including doses of FeSO4 and H2O2, pH, and stirring time on COD removal were evaluated using the model triazophos pesticide wastewater and the optimization conditions for the reactions were obtained. The degradation of the combined wastewater and workshop wastewater from Hunan Tianyu Chemical Pesticide Co., Ltd. by Fenton reagent was also studied. Experimental study demonstrates that the optimization conditions for the treatment of per 500 mL model wastewater were pH=4, dose of FeSO4·7H2O is 1.25 g, and dose of 30% H2O2 is 50 mL, and stirring time is 90 min, comparing with that pH=4, dose of FeSO4?7H2O is 2.5 g, and dose of 30% H2O2 is 37.5 mL, and stirring time is 90 min for both 500 mL combined and workshop pesticide wastewater. The water quality of the effluent can meet the national standards. This is helpful and valuable for selecting and designing processes for treatment of organic phosphorous pesticide wastewater.However, it's hard to meet the stringent environmental discharge standards by the oxidation of triazophos pesticide wastewater only with Fenton reagent. After the Fenton oxidation, the biochemical treatment process should be added as enhancing treatment process, which could reach to a high quality of effluent. Based on the experimental results, a treatment design of Fenton oxidation– CASS process was used for degrading an industrial triazophos pesticide wastewater. Practice has proved that it is feasible for treating industrial trazophos pesticide wastewater by using Fenton oxidation– CASS process, which has the advantages of stable performance and nice removal efficiency. The effluent quality can meet the second level of national standard.