Dissolved Air Flotation Theory Pdf

Types of flotation different methods of producing gas bubbles give rise to different types of flotation processes.

Dissolved air flotation theory pdf.

Upon entering the daf unit the air pressure is re. Air is dissolved under pressure in a clean liquid usually recycled effluent from the daf unit and injected into the raw feed stream. Dissolved air flotation daf is a water treatment process that clarifies wastewaters or other waters by the removal of suspended matter such as oil or solids. Principles of dissolved air flotation daf discussed include.

Dissolved air flotation operates on the principal of the transfer of floc to the surface of water through attachment of air bubbles to the floc. Dissolved air flotation is a method for separating and removing sus pended solids from liquid based on changes in the solubility of gas as pressure varies. The basis of electrolytic or electroflotation is the generation of bubbles of hydrogen and oxygen in a. The flotation model is an important aid for gaining insight into the effect of design parameters such as bubble diameter particle size bubble volume concentration contact time temperature and surface load.

The floc accumulated on the surface known as the float is skimmed off as sludge section 7 19 the clarified water is removed from the bottom and is sometimes called the subnatant or floated water. These are electrolytic flotation dispersed air flotation and dissolved air flotation. Solubility of air in water. This paper presents a physical mathematical model for dissolved air flotation daf.

Phd thesis university of newcastle upon tyne 1998. The released air forms tiny bubbles which adhere to the suspended matter. Induced air flotation iaf and dissolved air flotation daf are techniques that promote the removal of small suspended solids or oil droplets that adhere to the surface of rising air bubbles.