The right to use the mark of conformity "COMPOSTABLE" on compostable plastic bags and on compostable products is granted only to those manufacturer/distributors that demonstrate that their product conforms with specific performance attributes and adheres to the parameters for "compostability" as set out in the BNQ documents, Compostable Plastic Bags - Certification Program
(BNQ 9011-911/2007) and Compostable Products – Certification Program (CAN/BNQ 0017-988).
It is important to be aware that "compostable" and "biodegradable" are not equivalent. Similarly, "disintegration" cannot be used interchangeably with either of these terms.
The definitions established for the purpose of the program are as follows:
Biodegradation: degradation caused by biological activity especially caused by enzymatic action leading to a significant change in the chemical structure of a material. (Reference: ISO 162929, section 3.3)
Compostable: said of that which is capable of undergoing biological decomposition in a compost site such that the material is not visually distinguishable and breaks down into carbon dioxide, water, inorganic compounds and biomass at a rate consistent with known compostable materials. (Reference: ASTM D 6002) .
Degradation: an irreversible process leading to a significant change in the structure of a material, typically characterized by a loss of properties (eg. integrity, molecular mass or structure, mechanical strength) and/or by fragmentation. Note: degradation is affected by environmental conditions and proceeds over a period of time comprising one or more steps. (Reference: ISO 16929, section 3.2)
Compost: solid mature product resulting from composting (Reference: CAN/BNQ 0413-200)
Composting: managed process of bio-oxidation of a solid heterogeneous organic substrate including a thermophilic phase. (Reference: CAN/BNQ 0413-200)
Compostable plastic bags and compostable products must be compatible with the dynamics involved in the composting process and not detract from the physical and chemical quality of the end product, compost.
In Canada, for a plastic bag or other product to claim compostable, it must:
- disintegrate by at least 90% within 84 days of the composting process
- biodegrade by at least 90% within 180 days of the composting process
- have no ecotoxicological effect greater than 10% on the germination rate of seeds and
vegetation biomass rate