Anaerobic Biodegradation (ISO/DIS 11734 / OECD 311)

Freshwater Anaerobic Biodegradation Study

This method is intended to provide a simple and reliable screening test for the ultimate biodegradability of chemicals under anaerobic conditions. The method is applicable to soluble and poorly soluble organic chemicals.

A known volume of anaerobic sludge (corresponding to 10% of the sludge concentration in a real digester) suspended in an oxygen free medium is placed in a suitable vessel with a headspace into which any gases produced may be evolved. Prior to sealing a small amount of test compound is added. The vessels are incubated at constant temperature (35 ± 1°C) and pH for a period of 8 weeks. The headspace pressure, resulting from the production of gas, is measured.

From the measured values of net gas production the extent of biodegradation is calculated. The kinetics of the degradation are followed by intermediate measurements at suitable intervals during the course of the test.


A simple and reliable screening test for the biodegradability of soluble and poorly soluble organic chemicals under anaerobic conditions.

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