Notice of Retraction Deeply Treatment of Dyeing Wastewater

The characteristics of Dyeing wastewater is high in colourity, high in COD concentration, difficult in degradation, difficult in biological-treatment. Conventional biological process hardly meets environmental discharge standards that are more and more stringent. In this paper, a integraded treatment process that include MgSO 4 -FeSO 4 two-stage flocculation, 03 oxidation, membrane bioreactor and Nanofiltration was studied by experiments. The results showed that COD total removal rate was 85% by MgSO 4 -FeSO 4 two-stage flocculation when MgSO 4 and FeSO 4 was congtrol at 300mg/L and 250 mg/L respectively. Ozone oxidation could not further decrease COD, but obviously rise B/C from 0.22 to 0.46 within 40 min, which very benefited biological treatment, wastewate was further treated by membrane bioreactor and COD was further down to less than 60mg/L when Hydraulic Retention Time(HRT) was 6h. Finally, the COD, colourity and colourity of water treated deeply by nanofiltration were less than 20mg/L, 5 times and 50 us/cm, which completely meets the requirement of reuse for dyeing.