Affiliations: State Key Laboratory of Environmental Aquatic
Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of
Sciences, Beijing 100085, China | Changsha Vocational School of Environmental
Technology, Changsha 410004, China
Abstract: ES-DAF, a novel DAF with Iow cost, high reliability and
easy controllability, was studied. Without a costly air saturator, ESDAF
consists of an ejector and a static mixer between the pressure side and suction
side of the recycle rotary pump. The bubble size distribution in this novel
unit was studied in detail by using a newly developed CCD imagination through a
microscope. Compared with MDAF under the same saturation pressure, ES-DAF can
produce smaller bubble size and higher bubble volume concentration, especially
in lower pressure. In addition, the bubble size decreases with the increase of
reflux ratio or decrease of superficial air-water ratio. These results
suggested that smaller bubbles will be formed when the initial number of
nucleation sites increases by enhancing the turbulence intensity in the
saturation system.
Keywords: dissolved air flotation (DAF), bubble size distribution, air saturation system, CCD imagination
