scope:

This standard specifies a determination of the biochemical oxygen demand of waters by dilution and seeding with supression of nitrification. This standard is applicable to all waters having biochemical oxygen demands greater than or equal to the limit of determination 3 mg/l of oxygen and not exceeding 6000 mg/l of oxygen. For biochemical oxygen demands greater than 6000 mg of oxygen/l, the method is still applicable, but the errors caused by the necessary dilutions can influence the analytical quality of the test method and the results are to be interpreted with circumspection. The results obtained are the product of a combination of biochemical and chemical reactions. They do not have the rigourous and unambiguous character of those resulting from, for example, a single, well-defined, chemical process. Nevertheless, they can provide an indication from which the quality of waters can be estimated.