What are the tests required to qualify for an OK compost certificate?

NOTE – The biodegradation, ecotoxicity and heavy metal content tests focus on the material caracteristics of the product whereas the disintegration test concentrates on the final product’s material and shape.

Is there any difference between "biodegradable" and "compostable"?
People often confuse the terms "biodegradable" and "compostable" even though their meanings differ slightly. A biodegradable product can be broken down by microorganisms but does not necessarily convert into good quality compost.

Biodegradability and compostability levels rely heavily on the environment where the product is broken down. Since every environment (compost, soil, water, etc) varies depending on temperatures and microorganisms present, the speed of the biodegradation process can vary from one site to another.

For example, bioplastics are biodegradable in an industrial composting plant (the most aggressive kind of controlled environment) but are not always biodegradable in water or soil or even in a compost bin in the garden (owing to the lower temperatures of those environments).