Phenolic wastewater mainly comes from coking plant, gas plant, petrochemical plant, insulation material plant and other industrial departments, as well as the production process of petroleum cracking to ethylene, synthetic phenol, polyamide fiber, synthetic dye, organic pesticide and phenolic resin. The waste water containing phenol mainly contains phenolic compounds, such as phenol, cresol, xylenol and nitrocresol. Phenolic compounds are protoplast poisons that coagulate proteins. When the concentration of phenol in the water reaches 0.1-0.2mg/l, the fish will have peculiar smell and cannot be eaten; when the concentration increases to 1mg / L, it will affect the spawning of fish. If the concentration of phenol is 5-10mg / L, a large number of fish will die. Phenol in drinking water can affect human health. Even if the concentration of phenol in drinking water is only 0.002mg/l, chlorine disinfection can produce chlorophenol odor. The wastewater containing phenol with a mass concentration of 1000mg / L is usually called high concentration wastewater containing phenol. This kind of wastewater must be treated after the recovery of phenol. Phenol containing wastewater with mass concentration less than 1000mg / L is called low concentration phenol containing wastewater. Generally, this kind of wastewater is recycled, and phenol is concentrated and recycled for treatment. The methods of phenol recovery include solvent extraction, steam stripping, adsorption, closed cycle and so on. The wastewater with phenol concentration less than 300mg / l can be discharged or recovered by biological oxidation, chemical oxidation, physical chemical oxidation and other methods.