What does "biodegradable" mean?

Generally speaking and in simplified terms, a biodegradable material decomposes or disintegrates in biological, i.e. natural processes within a reasonable period of time. When talking about the biodegradability of a material or a product, it is essential to provide additional information on the time span and the environmental conditions. Degradation can occur in various places, for example in the human body (surgical suture material), in the ocean or at its surface, on the beach or on the seabed, in the soil or on the field, in a biogas plant or in composting. Consequently, there are different kinds of test standards and associated certification systems which, for example, distinguish between industrial and domestic composting.

Biodegradable does not mean compostable at the same time: Biodegradable means that a material or product gradually degrades completely into CO2, water and biomass by means of microorganisms without defined conditions. The time required for this is not decisive or predetermined. Compostable, however, means that the material or product must completely decompose into CO2, water and biomass under defined conditions within a certain period of time (weeks / months). Compostability is not only dependent on the material, but also on the shape and wall thickness of a component. Compostability thus means faster biological degradation under constant conditions.