Abstract: The combined process of Fenton reagent, Microelectrolysis and Biological contact oxidation is proposed to treat the Acrylonitrile wastewater. The optimal technological conditions and the effect of this process are discussed. The results show that by providing wastewaters pH of about 3 and reaction time of 2 hours, the quantity of H₂O₂ of 40 mL/L, the concentration of ferrous iron is 0.4 g/L, the effluent of microelectrolysis goes into Biological contact oxidation process, in which DO, HRT and volume load are 4.5 mg/L, 10 hours and 1.0 kg COD_Cr/(m³·d) respectively, satisfying the first grade of the national standard.

Key words: Acrylonitrile wastewater, Fenton reagent, micro-electrolysis, biological contact oxidation