scope:

The performance and evaluation of the measurement of the total quantity of odorants contained in a liquid that can escape from the liquid phase into the gas phase is the subject of this standard. The measurement of a liquid's odorant emission capacity (OEC) described here covers the total quantity of odorants contained in the liquid that can be stripped into unpolluted air. This quantity of odorants that can potentially enter the gas phase from the liquid is expressed in odour units per cubic metre of liquid ( OU_E /m_li ³).

The principle of OEC measurement is based on aerating a sample of the liquid under investigation with neutral gas. At certain intervals, the air escaping from the reactor is collected in sample bags. The air samples obtained in this way are then measured olfactometrically in accordance with DIN EN 13725. The possible fields of application are:

• objective characterisation and quantification of liquids in terms of their odour importance, e.g. waste water, sewage treatment plant process waters, industrial process waters, drinking water

• measuring the odorant load of liquids (e.g. industrial discharges)

• setting limit values for the OEC and/or odorant load of discharges and checking compliance with them

• quantification of the effectiveness of chemical metering into odour-charged liquids (see example in Annex C1)

• checking the effects of process changes in the treatment of liquid flows (e.g. discharge of waste water under pressure rather than by gravity)

• estimation of odorant emissions in highly turbulent locations (see example in Annex C2)

• provision of data for the planning and design of emission-reducing measures

The measurement of OEC is applied to liquids.

Note: The emission capacity of other volatile substances can be determined in much the same way as described in this standard.