This part of this European standard specifies the non-steady state measurement of the oxygen transfer capacity and the oxygen transfer efficiency of aeration tanks (see prEN 12255-6) when filled with clean water. NOTE 1: This is known as the clean water test. NOTE 2: Since the method is based on completely mixed tanks or tanks with evenly distributed aerators or diffusers it may not be applicable for certain aeration installations. NOTE 3: Under process conditions with mixed liquor the oxygen transfer capacity and the oxygen transfer efficiency may be different from the clean water test results.
