Abstract
The Induced Air Flotation (IAF) by using a new kind of micro-bubble generator is developed as an alternative of Dissolved Air Flotation (DAF). In the micro-bubble generator, the air can be self-aspirated, cut and shattered by the rotating flow in the nozzle. As a result, a large quantity of micro-bubbles whose diameter is about 5∼30µm are discharged from the lower part of the nozzleTo determine the optimum operating conditions, a batch IAF reactor was used and kaolin samples were prepared from jar tests using different alum dosages and flocculation times, while the size of micro-bubbles was controlled by changing the flow rates of the recycle water and induced air.The results of the removal efficiency in the batch experiments show that the IAF has the ability to remove particles from water with a lower concentration of particles. The IAF obtains excellent particle removal efficiency in a wide range of alum dosage and flocculation time. Micro-bubbles are generated at various flow rates of recycle water and induced air. Lower flow rate of air performes better particle remova, whereas lower water flow rate obviously shortens the necessary flotation time.
