Let's talk 'green' language
When it comes to ‘sustainable words’, there’s a lot of different language out there. Particularly to consumers, it can seem like the terms are used interchangeably, but recyclable, compostable and biodegradable have very specific, technical meanings.
The characteristic of a product, packaging, or associated component that can be diverted from a waste stream through available processes and programmes and can be collected, processed, and returned to use in the form of raw materials or products.
Source: ISO 14021, definition 7.7.1
Compostability is a property of a packaging to be biodegraded in a composting process. To claim compostability it must have been demonstrated that a packaging can be biodegraded and disintegrated in a composting system (as can be shown by standard test methods) and completes its biodegradation during the end-use of the compost. The compost must meet the relevant quality criteria. Quality criteria are e.g. heavy metal content, no ecotoxicity, no obviously distinguishable residues.
A material is deemed biodegradable if it can be decomposed by the action of micro-organisms (bacteria, fungi, algae ...): the result is the formation of water, CO2 and/or methane, and possibly sub-products (residues, new biomass) that are not toxic to the environment.
Biodegradability is assessed by taking into account both the degree of decomposition of a substance, and the time required to obtain this decomposition (test method EN 14046).
Source: this is the definition of biodegradable according to the NF EN 13432 standard on the requirements for packaging recoverable through composting and biodegradation.