A new sustainable wastewater management: Simultaneous mineralization and dehalogenation treatment of high salinity dye wastewater

Abstract

Sustainable management of refractory dye wastewater has become an important operational and environmental issue. Catalytic ozonation is commonly used in dye wastewater treatment to enhance the removal efficiency of TOC. However, it is still a challenge to control the formation of adsorbable organic halogens (AOX) during the oxidation process in high salinity dye wastewater. In order to simultaneously remove TOC and AOX, this study developed an innovative O3+MnOx/GAC + H2O2 treatment process. After optimizing the operating factors such as initial pH and H2O2 dosage, the removal rates of TOC and AOX in dye wastewater reached over 70 % and 80 %, respectively. The possible oxidation mechanism was analyzed through kinetic model, free radical detection and scavenging experiments. The results indicated that MnOx/GAC and H2O2 contributed to the decomposition of ozone, the generation of hydroxyl, and the reduction of reactive halogen species. The toxicity experiments of luminescent bacteria, chlorella and zebrafish eggs showed that the acute toxicity of dye wastewater significantly decreased after O3+MnOx/GAC + H2O2 treatment. This study offered novel insights into the sustainable management of high salinity wastewater through simultaneous mineralization and dehalogenation treatment.