NF EN ISO 11733

<p>ISO 11733:2004 specifies a method for the determination of the elimination and the biodegradability of organic compounds by aerobic micro-organisms. The conditions described simulate a wastewater treatment plant. Two test systems can be used: activated sludge plants or porous pots. The tests can optionally be performed under conditions of nitrification and denitrification and coupling of the units.</p> <p>The method applies to organic compounds which, under the conditions of the test, are</p> <ol><li>soluble in tap water at the test concentration and not expected to be transformed to insoluble metabolites if biodegradation, in addition to elimination, is determined;</li><li>poorly water-soluble, but which are satisfactorily dispersible in water and allow detection with suitable analytical means (e.g. organic carbon measurements);</li><li>non-volatile, or which have a negligible vapour pressure under the test conditions;</li><li>not inhibitory to the test micro-organisms at the concentration chosen for the test. Compounds inhibitory at concentrations used in this test may be tested at concentrations less than their EC₂₀ value, followed by higher practical concentrations after a period of acclimatization.</li></ol> <p>The method can also be used to measure the biodegradation and elimination of dissolved organic compounds in waste water (also called "test compound" in the method).</p>