HOW TO DETERMINE THE ULTIMATE AEROBIC BIODEGRADABILITY OF PLASTIC MATERIALS IN AN AQUEOUS MEDIUM AND IN SOIL

Aerobic biodegradation is the breakdown of organic pollutants by microorganisms when oxygen is present and the sample is characterized by oxidative conditions. More specifically, it refers to the determination of the ultimate aerobic biodegradability of plastic materials by measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved.

The analysis involves the use of aerobic microorganisms in an aqueous medium containing inorganic salts and the organic material to be tested (the only carbon source) with a concentration of organic carbon between 100 and 2000 mg/l. The mixture is stirred in a closed vessel.

Incubation takes place in the dark at an appropriate constant temperature, depending on the inoculum used for a period not exceeding 6 months. The developed carbon dioxide is consumed on a special absorbent compound located in the headspace of the vessel. The consumption of oxygen is determined by the measurement of the pressure difference inside the container, detected via the VELP RESPIROMETRIC Sensor.

Analysis time: 1 to 6 months
Results: Pressure
Incubation Temperature: 20°C – 35°C
 

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The analysis is used to obtain the optimal rate of plastic material biodegradation in test soil by controlling soil moisture, as well as, determining the ultimate biodegradability of the material itself. It is generally applied to the following materials:

• natural and/or synthetic polymers, copolymers or their blends;
• plastics that contain additives such as plasticizers or dyes;
• water-soluble polymers

The plastic material is mixed with the soil. The mixture rests in a container for a period of time during which the amount of oxygen consumed (BOD) is determined or the amount of carbon dioxide is developed. The carbon dioxide is consumed in a special absorbent compound located in the headspace of the container. Oxygen consumption is determined by measuring the pressure difference inside the vessel, detected thanks to the RESPIROMETRIC Sensor.

Analysis time: 1 to 6 months
Results: Pressure
Incubation Temperature: 20±1°C
 

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VELP system used to determine plastic biodegradability comes ready to perform the analysis, with all the required accessories and parts:

• MULTISTIRRER Digital with its Lock feature and precise digital display is the perfect match for these tests
• Thanks to the innovative wireless technology, the sensor transmits the Pressure Value to the Wireless DataBox™, based on the data transmission frequency set before starting the analysis
• Results are then displayed from the intuitive RespiroSoft™ the optimal solution for data management and comparison of the results
• Connect the RESPIROMETRIC Sensors to the exclusive VELP Ermes Cloud Platform to improve your laboratory experience

 

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