▎ 摘　　要

NOVELTY - A sewage treatment system comprises first processing subsystem (10) for filtering and concentrating sewage; second processing subsystem (20) for making organic matter easy to be fasculated in sewage to carry out condensation polymerization; third processing subsystem (30) for removing salt, fourth processing subsystem(40) for reducing chemical oxygen demand and improving biodegradability. The processing subsystems are orderly connected through pipeline. USE - The sewage treatment systems is used for removing sodium methoxide production waste liquid (claimed). ADVANTAGE - The system can process waste liquid of multiple production lines in same chemical industrial park. The generated sludge is small. The operation cost is low. The device integration degree is high. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of catalyst used in wet catalytic oxidation comprising mixing 3-5 wt.% polystyrene micro-sphere solution and graphene oxide at weight ratio of 100:1-10, uniformly stirring for 20-60 minutes, and drying at 100-120 degrees C to obtain first product; calcining nickel, palladium, silver, platinum and gold at weight ratio of 1:2:3:1:1 at 800 degrees C for 2 hours under nitrogen atmosphere to obtain second product; and uniformly mixing first product and second product at weight ratio of 1:3-5.