A KINETIC-MODEL FOR DISSOLVED AIR FLOTATION IN WATER AND WASTE-WATER TREATMENT

A kinetic model for DAF is presented. The author's kinetic model consi sts of the equations for describing a process of bubble-flee collision and attachment in a mixing zone, and a rise velocity of bubble-flee a gglomerates in a flotation tank. The attachment process is formulated on a population balance model with bubbles and flocs as a flocculation in a turbulent flow. The rise velocity of bubble-flee agglomerates is formulated with size of flocs and composition of flocs including the flee density function and attached bubble number. The experimental ver ification was carried out, using a batch flotation tester and a mini-p lant with synthetic clay suspension and colored water. The results suc cessfully verify the validity of the model. From a given condition suc h as flee size and attached bubble number, the rate and extent of remo val by DAF can be readily assessed by the model. A single-collector co llision model, often discussed in some occasions, seems to be not usef ul to describe the DAF process.