<p>This International Standard specifies a method for the evaluation in aqueous medium of the ultimate</p>
<p>biodegradability and, as additional information, the primary biodegradability and the total elimination from water, of</p>
<p>organic compounds at a given concentration by aerobic microorganisms.</p>
<p>The conditions described in this International Standard normally correspond to optimal conditions for allowing the</p>
<p>maximum value of biodegradation to occur with the chosen inoculum in the test time. These conditions may even be</p>
<p>more favourable than in full-scale wastewater treatment plants, especially if their hydraulic retention time, sludge</p>
<p>age or the adaptation of the activated sludge is not optimal.</p>
<p>The method applies to organic compounds which are</p>
<p>a) water-soluble at the concentration used under the test conditions and not expected to be transformed to</p>
<p>insoluble metabolites if biodegradation and not elimination only shall be determined;</p>
<p>b) nonvolatile, or which have a negligible vapour pressure under the test conditions;</p>
<p>c) not lost by foaming from the test solution;</p>
<p>d) not inhibitory to the test microorganisms at the concentration chosen for the test. Inhibitory effects can be</p>
<p>determined using a suitable test method (e.g. see ISO 8192). If the test compound is toxic, the test</p>
<p>concentration must be lowered, or a pre-exposed inoculum can be used.</p>
<p>This International Standard is also applicable to the measurement of biodegradation and elimination of dissolved</p>
<p>organic compounds in wastewater (also called "test compound" in the method).</p>
<p>NOTE If more information is required to predict the behaviour of test compounds or wastewater in a treatment plant, a</p>
<p>simulation test (e.g. the activated sludge simulation test ISO 11733) should be performed. For appropriate use of this method</p>
<p>and for alternative biodegradation methods, see ISO 15462.</p>
Registration number (WIID)
28121
Scope
<p>This International Standard specifies a method for the evaluation in aqueous medium of the ultimate</p>
<p>biodegradability and, as additional information, the primary biodegradability and the total elimination from water, of</p>
<p>organic compounds at a given concentration by aerobic microorganisms.</p>
<p>The conditions described in this International Standard normally correspond to optimal conditions for allowing the</p>
<p>maximum value of biodegradation to occur with the chosen inoculum in the test time. These conditions may even be</p>
<p>more favourable than in full-scale wastewater treatment plants, especially if their hydraulic retention time, sludge</p>
<p>age or the adaptation of the activated sludge is not optimal.</p>
<p>The method applies to organic compounds which are</p>
<p>a) water-soluble at the concentration used under the test conditions and not expected to be transformed to</p>
<p>insoluble metabolites if biodegradation and not elimination only shall be determined;</p>
<p>b) nonvolatile, or which have a negligible vapour pressure under the test conditions;</p>
<p>c) not lost by foaming from the test solution;</p>
<p>d) not inhibitory to the test microorganisms at the concentration chosen for the test. Inhibitory effects can be</p>
<p>determined using a suitable test method (e.g. see ISO 8192). If the test compound is toxic, the test</p>
<p>concentration must be lowered, or a pre-exposed inoculum can be used.</p>
<p>This International Standard is also applicable to the measurement of biodegradation and elimination of dissolved</p>
<p>organic compounds in wastewater (also called "test compound" in the method).</p>
<p>NOTE If more information is required to predict the behaviour of test compounds or wastewater in a treatment plant, a</p>
<p>simulation test (e.g. the activated sludge simulation test ISO 11733) should be performed. For appropriate use of this method</p>
<p>and for alternative biodegradation methods, see ISO 15462.</p>
