Xylenol (C₈H₁₀O) is an important fine chemical raw material, widely used in the fields of synthetic resin, dyes, medicine, pesticides and antioxidants. Its production wastewater has a COD of about 3000mg/L and a salt content of 35g/L (generated by neutralizing acid), containing organic substances such as xylenol, chloroxylenol (C₈H₉ClO), cycloketones and alkanes, as well as inorganic substances corresponding to iron, sodium and chloride ions, which need efficient disposal to achieve resource utilization.

The concentrated salt residue after dehydration by evaporator has the main component ratio: sodium chloride (NaCl) 75%～80%, ferric chloride (FeCl₃) 5%～8%, unseparated xylenol (C₈H₁₀O) 2%～4%, chloroxylenol (C₈H₉ClO) 1%～2%, and the rest are a small amount of impurities. Material recovery is realized through concentration, separation, enrichment, extraction, crystallization and purification processes.

Organic materials: Xylenol and chloroxylenol are purified to industrial grade and reused in fine chemical synthesis; Inorganic materials: Sodium chloride is refined as chemical raw material, and ferric chloride (FeCl₃) is recovered as industrial grade water purifier. Only useless impurities are disposed in accordance with hazardous waste regulations, truly turning waste into treasure, reducing disposal costs, and taking into account environmental and economic benefits.