When a fibre-based material reaches its end of life, the best option is to recycle it. As that is not always an option, compostability becomes important.
Many fossil-based materials can be recyclable, but not compostable. For such a material, it may typically take hundreds of years to decompose, while a compostable fibre-based material could turn into soil in weeks.
For recycling to work, a collecting and sorting infrastructure must be in place. In addition, the material in question needs to be clean. If an – otherwise recyclable – sandwich bag, for example, is smothered in mayonnaise, recycling is not an option anymore.
Biodegradability vs. compostability
Fortunately, fibre-based materials are typically biodegradable or even compostable. But wait, what’s the difference?
If a material is biodegradable, it means that it will be broken down by biological processes. Most organic materials, for example food scraps and paper, are biodegradable.
A compostable material is also biodegradable, but the requirements for compostability go further than that: To label a material as compostable, it must biodegrade and disintegrate within a certain time into non-toxic, fertile soil.
A wide range of UPM Specialty Papers’ packaging and label papers have passed the required tests and are now certified as being industrially compostable according to the European standard EN 13432.
Industrial composting vs. home composting
There are different levels in compostability. Let’s look at the difference between industrial compostability and home compostability.
Compostable materials degrade into fertile soil. The differences between a home compost and an industrial compost are found in the temperature and the time it takes before you can expect disintegration and biodegradation to happen.
In many cities, biowaste is picked up and industrially composted at waste facilities. Industrial compostability has controlled temperature and is tested at 58 ± 2°C. At this temperature, disintegration should happen within 12 weeks and biodegradation within 6 months.
How well a material will decompose in a home compost is tested at 20°C - 30°C. This resembles a backyard compost with leaves and other organic matter, where disintegration should not take longer than 6 months and biodegradation should happen within 12 months.
EN 13432 European standard for compostability
The European standard EN 13432, applicable to all packaging materials, defines the requirements for packaging to be industrially compostable. The standard specifies test scheme and evaluation criteria to determine the compostability of packaging materials in controlled composting conditions by 1) Chemical test 2) Biodegradability 3) Disintegration 4) Ecotoxicity test.