This case is the upgrading and transforming of the Egyptian printing and dyeing factory. Our factory's high-efficiency dissolved air flotation tank has a good treatment effect, high removal efficiency, and low sludge production. It can remove the residual colloids, insoluble organic matter, and most of the suspended solids in the effluent of the secondary sedimentation tank and has achieved good results.
The shallow flotation-ozone-BAF combined process was used to carry out a pilot test on the effluent from the secondary sedimentation tank after biochemical treatment to provide reference data for the actual application of the process in the later upgrading and transformation project. The influent was the effluent from the secondary sedimentation tank, and the designed water volume was 50 m3/d. The operation results showed that under the conditions of 1350 mg/L polyferric dosing, 120 mg/L decolorant dosing, and 40 mg/L ozone dosing, the average total removal rates of COD and chromaticity were 65% and 80,% respectively. All effluent indicators met the direct emission limits of the "Discharge Standard of Water Pollutants for Textile Dyeing and Finishing Industry" (GB 4287-2012).
