Abstract: In this paper, ozone and ozone+active carbon integrative process are used to treat sedimentation discharge in printing and dyeing enterprise. The removal rate of COD is less than 30% through ozone process, and the chroma is still high. The effects of O₃+AC integrative process, by contrast, are much better. The influence of dosage and saturation of active carbon, pH value and hydraulic retention time (HRT) are studied. The results show that COD of the effluent reduces from 300 ～ 400 mg/L to less than 100 mg/L, and chroma reduces from 500 times higher to less than 100 times higher, under the condition of AC 5 g/L, ozone pretreated 15 minutes and HRT 5 h. The quality of the effluent can meet the second grade discharge standard for dyeing and finishing of textile industry.

Key words: ozone; active carbon; printing and dyeing wastewater; sedimentation discharge; chemical oxygen demand