The standard applies to water-soluble, poorly water-soluble and relatively volatile substances. The biological degradation is monitored by oxygen uptake and, in the case of soluble substances, also by an analysis of the dis olved organic carbon (DOC). The theoretical oxygen consumption (TZV) and the organic carbon content (T0C) are calculated based on the molecular formula of the test substance. If the formula is not known, the chemical oxygen demand (COD) or the determined organic carbon content can serve as a reference value (see Annexes D and E). Data on the relative proportions of the main components of the test material are useful in interpreting the results obtained, especially in those cases where the values are low or marginal. Data regarding the toxicity of the test substance for microorganis s are desirable for the interpretation of low degradation values and for the selection of suitable test concentrations.
NEN 6515-1992 history
1992NEN 6515-1992 Water - Determination of the biodegradability of organic chemicals by means of the two-phase air-water closed bottle test