scope:

This standard specifies a method for the evaluation in aqueous medium of the ultimate biodegradability and, as additional information, the primary biodegradability and the total elimination from water of organic compounds at a given concentration by aerobic micro-organisms. The conditions described in this standard normally correspond to optimal conditions for allowing the maximum value of biodegradation to occur with the chosen inoculum in the test time. These conditions may even be more favourable than in real waste water treatment plants, especially if their hydraulic retention time, sludge age or the adaptation of the activated sludge is not optimal.