ALSO NUMBERED BS 6068 SECTION 5.13: 1993 Specifies a method for the evaluation of the elimination and the "ultimate: biodegradability of organic compounds at a given concentration by aerobic micro-organisms. Applies to organic compounds which are: non-volatile, or which have a negligible vapour pressure under the test conditions; soluble at the concentration used under the test conditions; not lost by foaming from the test solution; not inhibitory to the test micro-organisms at the concentration chosen for the test. The test method can be used to measure the elimination and biodegradation of organic compounds in waste water. Coverage includes apparatus, procedure and reagents.