Treatment of wastewater containing azo dye reactive brilliant red X-3B using sequential ozonation and upflow biological aerated filter process.

In this work, the treatment of wastewater containing azo dye reactive brilliant red X-3B using sequential ozonation and upflow biological aerated filter process has been studied. Decolorization was almost complete after 120min with an ozone concentration of 34.08mg/L, the biological oxygen demand for 5 days (BOD5)/chemical oxygen demand (COD) ratio increased from 0.102 to 0.406, which was more effective for the subsequent upflow biological aerated filter (UBAF) to reduce COD concentration. Under the conditions of gas/liquid=3, hydraulic load=4.8m3/m3.d, T=20-25 degrees C, the mass ratio of ozone to dye=4.5, pH 11, the COD and color of the effluent were less than 40mg/L and 20 Pt-Co units, respectively, and the average decolorization and COD removal efficiency were 97% and 90%, respectively. The experimental results showed that the combination of ozone oxidation and upflow biological aerated filter was a promising technique to treat wastewater containing azo dye.