Principles of Air Flotation Technology

Abstract

Air flotation, in all its variations, is an efficient way to separate light particulates and oils from wastewater. Particulates that adhere to an air bubble, either by adsorption or absorption, can be floated from the liquid phase. Polymers may be added to improve the attachment of the particle to the bubble. Agglomerization of colloids into floc particles with the aid of chemicals will aid in their removal. Some soluble materials can be precipitated with chemicals, allowing their removal. If the wastewater is chemically pretreated to break the oil emulsion, air flotation units are capable of removing most of the emulsified oil in addition to the free oil. This chapter covers the theory and practice of air flotation and the various flotation processes including electroflotation, dissolved air flotation (DAF), induced air flotation (IAF), and nozzle air flotation (NAF).