OECD 209 Standard Method for Activated Sludge, Respiratory Inhibition Test (Carbon and Ammonium Oxidation)

EUROLAB laboratory provides testing and compliance services within the scope of OECD 209 standard. This test guide is designed to evaluate the effects of a substance on microorganisms from the activated sludge of wastewater treatment plants by measuring respiration rates (carbon or ammonium oxidation) as oxygen consumption.

Test results can also serve as an indication of appropriate non-inhibitory concentrations of test substances to be used in biodegradability tests. The test enables the ECx and/or NOEC values ​​of the test substance to be determined.

Inhibition of three different oxygen uptake, ie total, can only be determined due to nitrification in the absence and presence of N-allylthiourea, a heterotrophic and specific inhibitor of nitrification. To achieve both NOEC and ECx, six control and five treatment concentrations in a geometric series of five replicates are recommended.

In each test vessel, test mixes containing water, synthetic sewage feed, and test substance are incubated under forced aeration at a pH of 60 ± 70 and a temperature of 7,5 ± 0,5°C to maintain the dissolved oxygen concentration above 20-2% saturation.

Oxygen consumption is measured after 3 hours of exposure, and additional measurements can be made at 30 minutes of exposure in case of rapid degradation of the test substance.

The synthetic sewage feed and the test substance are incubated under forced aeration at a pH of 60 ± 70 and a temperature of 7.5 ± 0.5°C to keep the dissolved oxygen concentration above 20-2% saturation. Oxygen consumption is measured after 3 hours of exposure, and additional measurements can be made at 30 minutes of exposure in case of rapid degradation of the test substance.

EUROLAB assists manufacturers with OECD 209 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.