Bioplastics, Biodegradability And Compostability – Do You Know The Difference?
We are often being asked what bioplastics are, or what is the significance of a product being biodegradable or compostable? Is there any relationship between bioplastics and biodegradability? How should we consumers deal with these products?
In this blog, we try to break down these concepts through simple explanations that will hopefully help you better understand their meaning and be more aware of the choices you are taking as a consumer. Let’s go step by step:
BIOPLASTICS. These are materials that are either derived from biomass (e.g. plants, such as corn or sugarcane) or are biodegradable; or indeed feature both properties. They differ from conventional plastics in that the latter are made from fossil oil (petrol). The advantages of using renewable materials to produce bioplastics are: increase in resource efficiency (e.g. use of biomass for different purposes), reduction of the carbon footprint and greenhouse gas emissions (those that greatly contribute to climate change); and saving fossil resources by gradually substituting them.
BIODEGRADABLE. Biodegradation is a process - a chemical process - during which microorganisms that are available in the environment convert materials into natural substances such as water, carbon dioxide, and compost (artificial additives are not needed). The process of biodegradation depends on the surrounding environmental conditions (e.g. location or temperature), on the materials involved and on the process itself. This process can take short periods of time (weeks and months) or long periods of time (tens or even hundreds of years).
The property of biodegradation does not depend on the source material of the product but is rather linked to its chemical structure. It is therefore important to understand that ‘Bio-based’ does not mean ‘biodegradable’. In other words, plastic products made from biomass (a type of bioplastic) are not necessarily biodegradable. On the other hand, some petrol-based plastics may be biodegradable.
The family of bioplastics can be divided into three main groups:
- bio-based (or partly bio-based) but non-biodegradable plastics (e.g. PE, PP, PET, PTT or TPC-ET);
- plastics that are both bio-based and biodegradable (e.g. PLA, PHA or PBS);
- petrol-based plastics that are biodegradable (e.g. PBAT).
COMPOSTABLE. Composting is also a process – a chemical process. In fact, it is the process of biodegradation under aerobic conditions (presence of free oxygen) within a time frame of 6-12 weeks. You need certain conditions of temperature, humidity and aeration, for microbes, like bacteria or fungi and their enzymes, to be able to “digest” the chain structure of biodegradable plastics. The resulting end products are water, carbon dioxide and some biomass. The number and type of microbes is also an important element in this process.
There are two ways to perform this process: industrially or home-compost.
Industrially compostable conditions are very specific and they have been defined under the European norm EN 13432 for packaging products and adopted by the British Standard Institution under BS EN 13432 standard. Only those packaging products that fulfill the strict criteria of the EN 13432 standard are granted with the certification of OK-Compost Industrial and can be unambiguously considered industrially compostable. In practice, this means that you can dispose this material in your organic waste bin for it to be sent to the closest industrial composting facility.
Home-compostable packaging instead is not covered under one single widely-known standard but rather within several country-based ones. This is because the conditions in a home-compost are not that controllable as in the case of an industrial compost. Under home-composting condition temperatures and humidity can vary significantly from place to place, and year on year, not always achieving the right decomposition in a reasonable timeframe.
Nowadays, however, society and experts in the field see the need for moving into this direction if we want to become more sustainable. That is why we may see very interesting developments and innovations in this home-composability space in the following decade.
At Moving Beans, we are using bio-based biodegradable material for our coffee pods which are certified as OK-compost Industrial by TUV-Austria, following the EN 13432 standard. We are also working hard in the development of new materials that are suitable for home-compostability.
So that is it! Next time you pick up a product from your local (super)market, be mindful of the words describing the product and the packaging.