A new kind of flotation system with high dissolved air content was developed through investigating the fundamental principles of oxygen transfer in water and hydromechanics.The air dissolving and releasing performance of the new flotation was studied based on the clean water aeration and coagulation-flotation experiment of reactive yellow KE-4RN simulated waste water.The results showed that the new flotation system had such advantages as high oxygenation capacity

low working pressure

high dissolved air content

small bubble size

no packing and low energy consumption.In the experiments of oxygen-free water aeration

the mass transfer coefficient of O2 KLa(20) was 0.4151 min-1.Meanwhile the content of saturated dissolved oxygen in clean water was high(more than 11.00 mg·L-1) and the produced micro-bubbles had a mean diameter of 38 μm.A removal rate of 99.0% could be achieved for reactive yellow KE-4RN simulated waste water by coagulation and air flotation under the experimental conditions of dye concentration 100 mg·L-1

dosage of polymerization aluminum chloride(PAC)800 mg·L-1 and dosage of polyacrylamide(PAM) 20 mg·L-1.