EXPERIMENTAL STUDY ON TREATMENT OF WATER-BASED INK WASTEWATER BY COAGULATION-BAF

Using bio-zeolite as coagulant，water soluble resin link material and pigment in water-based ink wastewater were removed． When the dosage of bio-zeolite was 350 ～ 400 mg /L，COD removal rate could reach 87%． The coagulation supernatant was pale pink and the chromaticity removal rate was improved． Then coagulation supernatant was mixed with sewage after biological aerated filter ( BAF) by 1 ∶ 1． When the influent COD was 450. 1 mg /L，the effluent COD was 131. 4 mg /L，as the effluent COD concentration of water-based ink wastewater less than 262. 8 mg /L after biological treatment，which could reach“Integrated Wastewater Discharge Standard”( GB 8978—1996) ．