Anaerobic Degradation with digested sludge

OECD 311, DIN EN ISO 11734, DIN 38414-8 respectively Council Regulation (EC) No 440/2008, C.43


Determination of the anaerobic biological degradation in digested sludge – by measurement of gas production.


Washed and diluted digested sludge is incubated together with the test substance and a mineral test medium in sealed vessels for 60 days. The production of carbon dioxide and methane as a measure of the anaerobic degradation is determined by measuring the increase in headspace pressure in the test vessels. A substantial part of the CO2 produced will be dissolved in the aqueous phase or transformed into carbonates. This inorganic carbon (IC) is measured at the end of the test. The extent of biodegradation is calculated from the ratio of total carbon produced (minus blank values) and the measured or calculated amount of carbon added as test substance. Additionally, the primary biodegradation can be determined by specific analyses at the beginning and end of the test.

Test substance properties

The test is applicable for soluble and insoluble test substances. For highly volatile substances the test design has to be adapted.