scope:

This procedure covers the measurement of 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 described in Appendixes A and B, respectively.) The procedure 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. 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 (101.3 kPa) under specified gas rate and power conditions. The procedure is intended primarily for clean water testing to meet the requirements of Sections 5.2 and 6.3. The results can be applied to estimate OTR in process water, as described in Commentary C1.1.

Other items of interest that can be calculated are the standard aeration efficiency, or rate of oxygen transfer per unit power input, and the standard oxygen transfer efficiency; reporting items is another item of interest.