Treatment of acid rose dye containing wastewater by ozonizing – biological aerated filter

The ozonizing – biological aerated filter process was used to treat the acid rose dye containing wastewater. The most suitable conditions were identified as follows: the mass ratio of ozone to dye = 4.5, temperature t = 18–25 °C, HRT = 3 h and gas/liquid = 4:1. Experimental results showed that ozonizing process had an excellent de-color efficiency and could improve the biodegradability of wastewater. With ozonizing the BOD/COD ratio increased from 0.18 to 0.36, and as a result, the subsequent biological aerated filter could be more effective for further reducing COD and SS concentrations, especially for wastewater with low concentration of SS and COD. After treatment the effluent COD was less than 40 mg/L, SS about 50 mg/L and color less than 20°. It can meet the water quality standards of the treated water reused for industry cooling water.