A study on the efficiency of the DAF (dissolved air flotation) process using ozone injection

Abstract

In this study, dissolved ozone flotation system with injecting ozone directly into a DAF pump developed was applied to remove turbidity and organic matter for water treatment. This ozone flotation system was evaluated on the basis of the efficiency of ozone transfer into water and the removal efficiency of turbidity and TOC in the Nakdong river water. The DAF pump system found to be more efficient than the conventional DAF system injecting ozone directly from a ozone generator. The ozone through the DAF pump process was dissolved in water much faster than through the general ozone generator due to the higher mixing efficiency through a pump impeller and high pressure inside the DAF pump. Also, the kinetics of ozone decay injected by the DAF pump was slower than injected by an ozone generator. The DAF pump flotation system shows that 30% difference of removal efficiencies is attained as the ozone dose increases from 1.2 mg/L to 8.2 mg/L. And the turbidity removal was increased with increasing ozone dose. Therefore it can be concluded that ozone in this flotation system facilitates improved removal of organic matter and turbidity due to enhanced destabilization of those.