Ozonation and Granular Activated Carbon Adsorption for the Removal of Refractory Organic Matter and Decolorization During Wastewater Tertiary Treatment

摘要

This study investigated two different hybrid processes for the treatment of municipal secondary-treated biologicaleffluents to meet the reuse of recycled water requirements for organic matter and color. The two hybridtreatment approaches were an oxidation-based treatment process (coagulation–sedimentation–deep-bed filtrationCSDF–ozone oxidation) and an adsorption-based treatment process (CSDF-granular activated carbonGAC adsorption). The efficiencies of ozonation and GAC adsorption in removing chemical organic demand(COD), dissolved organic carbon (DOC), and color intensity were evaluated. The effect of CSDF as the pretreatmentwas also studied. Ozonation showed a much higher color removal efficiency (88, 4.7 mg/L ozonedose) than GAC adsorption (23). Organic matter with an apparent molecular weight of 2–3 kDa, being humuslike,might be the colored fraction in the secondary and CSDF effluents. Ozonation had a stronger ability toremove these substances than GAC adsorption, resulting in a visibly higher color removal efficiency. In addition,higher COD and DOC removal were achieved by ozonation when the average ozone dose was increased to9.1 mg/L. Although both hybrid processes were reliable for reducing organic matter and color, the results showthat ozonation is more suitable for simultaneously removing refractory organic matter and color.