Intensified degradation of textile wastewater using a novel treatment of hydrodynamic cavitation with the combination of ozone

Abstract

Abstract Ozone has been applied for the advanced treatment of textile wastewater containing a large number of indigestible dyes and other macromolecular organics. However, due to the poor mass transfer performance of ozone, the efficiency of ozonation was limited, resulted in high operating cost. In the present work, the degradation of dyes and real textile wastewater by hydrodynamic cavitation combined with ozone (HC + O3) was studied in a small-scale pilot plant operating at a capacity of 40 L. The treatment of single HC and HC + Air had minute dye removal within 180 min whereas the treatment of HC + O3 and single O3 could degrade the dyes effectively in 10 min. The removal efficiency of dyes followed the order HC + O3 > single O3 > HC + Air > single HC. The synergetic coefficient of HC + O3 was 1.33, which indicated that HC and O3 had noteworthy synergistic effect in the hybrid system. For the real textile wastewater, the removal rates of HC + O3 on COD, TOC, UV254 and color were 36%, 23%, 71% and 90% in 30 min, which was higher than the single treatment. The removal of UV254 and color showed that macromolecular organics and residual dyes were effectively degraded. Among these treatments, HC + O3 was the most energy-efficient. Therefore, HC + O3 could be used as a potential dye degradation technology and would have a promising engineering application value in the real textile wastewater advanced treatment.