DOF (dissolved ozone flotation) technology in wastewater treatment

Effluent of wastewater treatment plant is to be disinfected to protect drinking water sources. DOF(dissolved ozone flotation) was developed to meet this purpose. A DOF is strengthened system with ozone to a DAF(dissolved air flotation) system. A DAF system has good floating power by numerous micro-bubbles, and ozone has strong oxidation capability. And DOF system has good floating power and strong oxidation capability simultaneously. When DOF was applied to secondary wastewater effluent, color of 11CU in raw water that was secondary effluent was reduced to 1CU by the DOF system. Removal rate of other water quality parameters treated by DOF were also higher than that by DAF, which were proved the strength of oxidation capability of ozone. When ozone concentration of 6.1 mg/l were applied in DOF system, general aerobic bacteria were reduced to 5 CFU/ml from TNTC (too many numbers to count). With the same ozone concentration, total coliform were not detected at all. These figures are under the numbers of drinking water regulation. These microbes were the target major parameters of a DOF. It was proved that a DOF was very effective in disinfection of wastewater treatment plant effluent as well as in removal of color, turbidity, and T-P.