APPLICATION OF MBR-FENTON CATALYTIC OXIDATION COMBINED PROCESS IN ADVANCED TREATMENT OF PRINTING AND DYEING WASTEWATER

In view of the characteristics of printing and dyeing wastewater containing refractory organic matters, it is difficult to meet the discharge standard only through biochemical treatment. The wastewater was first subjected to biochemical treatment, an MBR system, and then Fenton catalytic oxidation process was used to treat the Membrane Bio-Reactor (MBR) effluent. The results showed that when the hydraulic retention time (HRT) of biochemical phase was 22 hours, the average COD of the MBR effluent was 100.3 mg/L; the effluent ammonia nitrogen, total nitrogen and total phosphorus all reached the first level A standard listed in GB 18918-2002. Under the conditions of MBR effluent pH=3, hydrogen peroxide dosage of 200 mg/L, ferrous sulfate dosage of 200 mg/L and reaction HRT of 2 hours,the COD of the effluent from the Fenton catalytic oxidation process was 28.1 mg/L, the chromaticity was 10.8 times and the operation cost was RMB 1.01/t. The three-dimensional fluorescence analysis of the inlet and outlet water showed that the wastewater contained aromatic protein like substances which were difficult to be biodegraded, but they could still be effectively decomposed after Fenton catalytic oxidation. From the perspective of treatment effect and treatment cost, the combined process of biochemical treatment and Fenton catalytic oxidation was suitable for printing and dyeing wastewater, which provided a certain reference for further engineering application.