Test of the comparability
In its minutes of 31 May 2011, the French Environmental Ministry establishes requirements on how to determine the comparability of models in a range. These are applicable for plants up to 20 PE. The comparability is determined by practical tests on the different models in the range.
The test of comparability includes the following partial tests:
1. Test of the measurement of the oxygen transfer in clean water in aeration tanks.
2. Test of the residence time with a tracer test.
3. Test of the recirculation Qr.
A minimum of two tests is necessary. The model initially tested according to EN 12566-3 Annex B delivers the reference level. Subsequently, all new models of the range have to be tested. Each model of the range has do undergo all three partial tests.