EN ISO 9888:1999

1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Test environment
6 Reagents
7 Apparatus
8 Procedure
9 Calculation and expression of results
10 Validity of results
11 Test report
Annex A (informative) Example of a biodegradation curve
Bibliography
Annex ZA (normative) Normative references to international
                      publications with their relevant European
                      publications

This International Standard specifies a method for the evaluation in aqueous medium of the ultimatebiodegradability and, as additional information, the primary biodegradability and the total elimination from water, oforganic compounds at a given concentration by aerobic microorganisms.The conditions described in this International Standard normally correspond to optimal conditions for allowing themaximum value of biodegradation to occur with the chosen inoculum in the test time. These conditions may even bemore favourable than in full-scale wastewater treatment plants, especially if their hydraulic retention time, sludgeage or the adaptation of the activated sludge is not optimal.The method applies to organic compounds which area) water-soluble at the concentration used under the test conditions and not expected to be transformed toinsoluble metabolites if biodegradation and not elimination only shall be determined;b) nonvolatile, or which have a negligible vapour pressure under the test conditions;c) not lost by foaming from the test solution;d) not inhibitory to the test microorganisms at the concentration chosen for the test. Inhibitory effects can bedetermined using a suitable test method (e.g. see ISO 8192). If the test compound is toxic, the testconcentration must be lowered, or a pre-exposed inoculum can be used.This International Standard is also applicable to the measurement of biodegradation and elimination of dissolvedorganic compounds in wastewater (also called "test compound" in the method).NOTE If more information is required to predict the behaviour of test compounds or wastewater in a treatment plant, asimulation test (e.g. the activated sludge simulation test ISO 11733) should be performed. For appropriate use of this methodand for alternative biodegradation methods, see ISO 15462.