OECD 311 Anaerobic Biodegradability of Organic Compounds in Digested Sludge

Introduction of OECD 311

Organic content in sewage sludge digestion circumstances, anaerobic degradation is measured by the OECD 311 test guideline. OECD 311 test and unlike the aerobic biodegradation tests (OECD 301 series), the other will not determine if something can degrade in oxygen-free environments, e.g., anaerobic digesters, sediments, and groundwater. The global performance characteristic of anaerobic biodegradation is biogas production, mainly methane (CH₄) and carbon dioxide(CO₂). It is a critical aspect of the understanding of chemicals in wastewater treatment plants and natural anaerobic environments as a whole if chemicals degrade anaerobically.

Test Method of OECD 311

OECD 311 Sample Preparation

OECD 311 Results and Interpretation

After this testing, biogas production is measured as the increase in headspace pressure in the sealed containers. The inorganic carbon concentration in the liquid phase is also measured at the end of the experiment. Biodegradation is calculated by taking the total amount of carbon produced (in methane and inorganic carbon) and expressing it as a percentage of the initial carbon content of the test material. A high percentage of conversion of carbon into biogas indicates that the test material is readily biodegradable under anaerobic conditions. A lower percentage indicates that the anaerobic biodegradability may be limited, and further environmental risk assessments may be needed.

Test Related to OECD 311

This test is similar to ISO 11734. 

Materials Commonly Tested with OECD 311

This test is suitable for evaluating the anaerobic biodegradability of a wide range of organic compounds, including those found in detergents, surfactants, and industrial chemicals.

OECD 311 Related Articles

OECD 316 determines the chemical that impacts the aquatic environment. OECD 320  determines the anaerobic transformation of chemicals in liquid manure.