Process integration of halogenation and oxidation for recovery and removal of phenols from high strength phenolic wastewater

A process integration of halogenation and oxidation is proposed to achieve the recovery and removal of phenolic compounds from high strength phenolic wastewater, which original COD is 70,600 mg/L. First, sodium chlorate reacted with chloride ion under the suitable acidity condition to produce chlorine, then phenol in wastewater combined with chlorine, converting to the insoluble chlorophenols. It is confirmed phenol will be transformed into trichlorophenol with the yield of 97.8% by GC-MS analysis under the experimental conditions. At the same time, the COD index of wastewater will be reduced 98.3%. Later, Fenton oxidation technology was introduced to remove residual phenols in the halogenated water. The results indicate residual organics can be removed effectively, and COD index of water will be reduced to 72 mg/L under optimized conditions. Studies on feasibility analysis show that the process integration is a simple, inexpensive and feasible step for the high strength phenolic wastewater treatment.