Abstract

Aeration for water treatment, the transfer of oxygen, O₂, from air to water, is well-studied. The basic purpose of aeration, used primarily for the treatment of wastewater, is to improve water quality for subsequent usage. Aeration can bring about the physical removal of taste- and odor-producing substances such as hydrogen sulfide, H₂S, and other volatiles as well as the chemical removal of metals (iron, manganese), gases (hydrogen sulfide), and other compounds (organics and inorganics) through oxidation and settling. Additionally, aeration is used extensively for the biological oxidation of both domestic and industrial organic wastes. The function of aeration in a wastewater treatment system is to maintain an aerobic condition. Methods developed to estimate the oxygen demand are biochemical oxygen demand (BOD), chemical oxygen demand (COD), total oxygen demand (TOD), total organic carbon (TOC), and theoretical oxygen demand (ThOD). The oxygen transfer rate for aerators is normally reported at standard conditions. Thus, in order to make meaningful comparisons, the oxygen required for treatment under working or field conditions should be adjusted to standard conditions. Detailed information is given in two basic groups of aerators: Ecto-type and Endo-type.