Phenol-containing wastewater mainly contains phenol-based compounds, such as phenol, cresol, xylenol and nitrocresol. Phenol-based compounds are a kind of protoplasmic poison that can coagulate proteins.
When the mass concentration of phenol in the water reaches 0.1-0.2mg/L, the fish will have peculiar smell and cannot be eaten: increasing the mass concentration to 1mg/L will affect fish spawning, and if the phenol content is 5-10mg/L, fish will be abundant death. Phenol in drinking water can affect human health. Even if the concentration of phenol in water is only 0.002mg/L, disinfection with chlorine will produce chlorophenol foul smell.
Usually, the phenol-containing wastewater with a mass concentration of 1000 mg/L is called high-concentration phenol-containing wastewater. This kind of wastewater must be recycled after phenol is processed.
Phenol-containing wastewater with a mass concentration of less than 1000mg/L is called low-concentration phenol-containing wastewater. Usually this kind of waste water is recycled and phenol is concentrated and recycled for treatment.
Methods of recovering phenol include solvent extraction, steam stripping, adsorption, and closed circulation. Wastewater with a mass concentration of phenol below 300 mg/L can be treated by biological oxidation, chemical oxidation, physical and chemical oxidation and other methods before being discharged or recycled.