Aerobic biodegradability of plastic materials in an aqueous medium
ISO 14851:2019 specifies a method, by measuring the oxygen demand in a closed respirometer, for the determination of the degree of aerobic biodegradability of plastic materials, including those containing formulation additives in an aqueous system. The test mixture contains an inorganic medium, the organic test material (the sole source of carbon and energy) with a concentration between 100 mg/l and 2000 mg/l of organic carbon and activated sludge as the inoculum. The mixture is stirred in closed flasks in a respirometer for a period not exceeding 2 months. The consumption of oxygen (BOD) is determined, for example by measuring the amount of oxygen required to maintain a constant volume of gas in the respirometer flasks, or by measuring the change in volume or pressure (or a combination of the two) either automatically or manually. The level of biodegradation is determined by comparing the BOD with the theoretical amount and expressed in percentage.
The test result is the maximum level of biodegradation determined from the plateau phase of the biodegradation curve. Optionally, a carbon balance may be calculated to give additional information on the biodegradation. Moreover, the absorbed carbon dioxide in the adsorber at the end of test may be determined to give additional information on the biodegradation.
Gas Endeavour® can be easily coupled with our patented in-situ carbon dioxide absorption kit to function as a fully automated closed-respirometer for continuous and on-line measurement of oxygen consumption or depletion caused by aerobic respiration of microorganisms. The apparatus is suitable for all test protocols which the measurement principle is based on oxygen demand measurement.
Read more about ISO 14851 at iso.org.