OECD 302A – Inherent Biodegradability: Modified SCAS Test

The OECD 302A method is a modified version of the Soap and Detergent Association semi-continuous activated sludge (SCAS) guideline for assessing the biodegradability of alkyl benzene sulphonate.

OECD 302A is an inherent biodegradability test where the material is exposed to a high concentration of microorganisms over an extended period of time. This biodegradability method uses an activated sludge inoculum derived from a sewage treatment plant. The test includes repeated cycles of aeration of the test substance and inoculum mixture, followed by the removal of supernatant liquor. Biodegradation of the test substance is then evaluated based on the dissolved organic carbon content in the supernatant liquor.

This inherent biodegradation test is intended for materials that are water soluble, non-volatile, and non-toxic to the microorganisms in the inoculum at the test concentration.

There are a variety of chemical and physical properties that can affect biodegradability results; for more information on biodegradation testing and chemical and physical properties, please visit our Biodegradability Testing – Chemical Impacts page.

Choosing the correct biodegradation test method can be challenging and should be determined by the product’s intended use, disposal, and regulatory requirements needed to make performance claims. Please visit our Biodegradation Testing: Challenges and Test Method Selection page for more information on selecting biodegradation test methods.

It is strongly recommended to review testing requirements with the appropriate regulatory agency prior to testing to determine the biodegradation test method that is required for assessment.

For more information about OECD 302 and biodegradability testing, contact our product test lab at info@situtest.com or (847) 483-9950.