It is reported that the wastewater f rom w ashing gas of st raw s is t reated w ith aerobic and coagulat ionsedimentation.Contact oxidation method is applied to aerobic stage, poly aluminium chloride is chosen to be coagulant.Throug h ex periments, the best concent ration of polyaluminium chloride is 150 mg/L.The result indicatesinfluent parameter is COD_Cr 814 mg/L,BOD5 302 mg/L, phenols 38 mg/L ;after being treated, effluent parameteris COD_Cr140 mg/L,BOD5 17 mg/L,phenols 0.4 mg/ L.The removal rate is COD_Cr82.8 %,BOD5 93 %, phenols98.9 % respectively.Water quality of the ef fluent can meet GB8978 —1996