Biodegradation is a chemical process in which materials are metabolised to CO2, water, and biomass with the help of microorganisms. The process of biodegradation depends on the conditions (e.g. location, temperature, humidity, presence of microorganisms, etc.) of the specific environment (industrial composting plant, garden compost, soil, water, etc.) and on the material or application itself. Consequently, the process and its outcome can vary considerably.

Compostable plastics disintegrate after 12 weeks and start to biodegrade after six months. That means that 90 percent or more of the plastic material will have been converted to CO2. The remaining share is converted into water and biomass, which no longer contains any plastic. No heavy metal contents and no harmful substances should be left behind.

Bio-based plastics have the same properties as conventional plastics but also feature the unique advantage to reduce the dependency on limited fossil resources and to potentially reduce greenhouse gas emissions. Moreover, bioplastics can make a considerable contribution to increased resource efficiency through a closed resource cycle and use cascades, especially if biobased materials and products are being either reused or recycled and eventually used for energy recovery (i.e. renewable energy).

Using biodegradable and compostable plastic products such as biowaste bags, fresh food packaging, or disposable tableware and cutlery increases the end-of-life options. In addition to recovering energy and mechanical recycling, industrial composting (organic recovery / organic recycling) becomes an available end-of-life option. The use of compostable plastics makes the mixed waste suitable for organic recycling (industrial composting and anaerobic digestion), enabling the shift from recovery to recycling (a treatment option which ranks higher on the European waste hierarchy). This way, biowaste is diverted from other recycling streams or from landfill and facilitating separate collection – resulting in the creation of more valuable compost.

If a separate recycling stream for a certain plastic type exists, the bioplastic material can simply be recycled together with their conventional counterpart – e.g. biobased PE in the PE-stream or biobased PET in the PET stream – as they are chemically and physically identical in their properties. The post consumer recycling of bioplastics materials for which no separate stream yet exists, will be feasible, as soon as the commercial volumes and sales increase sufficiently to cover the investments required to install separate recycling streams. It is expected, that new separate recycling streams for PLA for example will be feasible and introduced in the short to medium term. Compostability is a clear benefit when plastic items are mixed with biowaste. Under these conditions, mechanical recycling is not feasible, neither for plastics nor biowaste. The use of compostable plastics makes the mixed waste suitable for organic recycling (industrial composting and anaerobic digestion), enabling the shift from recovery to recycling (a treatment option which ranks higher on the European waste hierarchy). This way, biowaste is diverted from other recycling streams or from landfill and facilitating separate collection – resulting in the creation of more valuable compost.