This method covers the measurement of the oxygen transfer rate (OTR) as a mass of oxygen per unit time dissolved in a volume of water by an oxygen transfer system operating under given gas rate and power conditions. Methods for measurement of gas rate and power are also described in the Annexes A and B, respectively. The method is applicable to laboratory-scale oxygenation devices with small volumes of water as well as the full-scale system with water volumes typical of those found in the activated sludge wastewater treatment process. The procedure is valid for a wide variety of mixing conditions.

The primary result of this test is expressed as the standard oxygen transfer rate (SOTR), a hypothetical mass of oxygen transferred per unit of time at zero dissolved oxygen concentration, water temperature of 20°C, and barometric pressure of 1.00 atm (101.3 kPa) under specified gas rate and power conditions. The method is intended primarily for clean water meeting the requirements of Sections 5.2 and 6.3. The results can be applied to estimate oxygen transfer rate in process water as described in Commentary G.