Application of advanced oxidation processes to remove refractory compounds from dye wastewater

摘要

The purpose of this study was to investigate the efficacy of ozonation and three AOPs (O_3/H_2O_2, O_3/UV, and O_3/H_2O_2/UV) on synthetic dye-containing wastewater with regard to the removal of chemical oxygen demand (COD) and color and biodegradability (BOD_5/COD). At hydrogen peroxide levels above the optimal value, H_2O_2 tended to accumulate in the reactor, leading to a decrease in COD removal efficiency, because it acted as a radical scavenger. Higher recirculation flow rates increased COD and color removal in the combined UV process. Compared with the O_3/ H_2O_2 process, the O_3/UV process enhanced COD removal mildly. Biodegradability increased approximately 12-fold after 150 min of retention time. Although all processes removed color within a short operational time, the O_3/H_2O_2/UV process had the highest removal efficiency of COD and enhancement of biodegradability of the processes that we tested.