Measurement of Oxygen Transfer in Clean Water

Abstract

Measurement of Oxygen Transfer in Clean Water was developed to calculate the rate of oxygen transfer from diffused gas and mechanical oxygenation devices to water. The Standard is applicable to laboratory-scale oxygenation devices with small volumes of water as well as to full-scale systems with water volumes typical of those found in the activated sludge wastewater treatment process. It is intended that this standard be used by engineers in the preparation of specifications for compliance testing. This test method is based upon removal of dissolved oxygen (DO) from the water volume by sodium sulfite followed by reoxygenation to near the saturation level. The DO inventory of the water volume is monitored during the rearation period by measuring DO concentrations at several points, selected so that each point senses an equal tank volume. The method specifies a minimum number, distribution, and range of DO measurements at each point. This procedure is valid for a wide variety of mixing conditions. The primary result of this testing is expressed as the standard oxygen transfer rate. The Standard also describes how clean water tests can be applied to estimate oxygen transfer rate in process water. In addition, various components of power consumption are defined; methods for measurement of gas rate and power consumption by oxygenation devices are given; and the preparation of data analysis is discussed.