Biodegradable – definition
First we need to understand what we mean by the term ‘biodegradable’.
What are our expectations of ‘biodegradability’?
I think we harbour a hope that biodegradable packaging will degrade harmlessly wherever it ends up, within a reasonably short time frame.
The most visible problem with packaging pollution is fugitive litter on the road side, in the river and oceans, and public areas.
We may expect that biodegradable plastics will kind of dissolve once buried in landfill, or in the sea.
So, first, how do we DEFINE biodegradability?
“Dictionary definition: (of a substance or object) capable of being decomposed by bacteria or other living organisms and thereby avoiding pollution.”
“Biodegradable – materials which can be completely biodegraded (bio-assimilated)by micro-organisms such as bacteria, fungi and algae. On its own the term is to a degree obsolete as most materials will biodegrade given time. There are no defined time limits for the term “biodegradable‟, thus the use of this word can be potentially confusing to the general public both in terms of where to dispose of it and what happens to it once discarded.
Not all biodegradable materials or products will be compostable as the time needed from them to biodegrade may be outside that of industrial or home compostable criteria. This is coupled by the fact that the temperatures often needed to induce bio-degradation may not be reached through a non-composting environment.
If a packaging or plastic material is described or labelled as simply “biodegradable”, this does not convey sufficient meaning about suitable ways to recover it after it has become waste.”
Plastics – biodegradability and compostability
At the time of writing there is no plastic packaging on the market that will degrade in any environment.
Compostable plastics that meet the European Standard EN 13432:2000 – “Packaging: requirements for packaging recoverable through composting and biodegradation”, will only degrade in industrial composters which provide specific conditions that facilitate biodegradation.
Summary of key EN13432 test criteria are:
- Disintegration – after 12 weeks no more than 10 % of material fragments are allowed be larger than 2 mm.
- Biodegradability – Within a maximum of 6 months, biodegradation of the test sample must generate at least 90 % as much as the carbon dioxide given off from the control material.
- Absence of any negative effect on the composting process.
- Low levels of heavy metals
- The composted packaging material must not have adverse effect on the bulk density of the compost
Does this meet your expectations of compostable plastic?
A recent survey by Business Waste found that only 3% of households have access to a composting facility. So, as you cannot recycle compostable plastics, most will have to go to landfill, where there is no guarantee it will find the conditions required to biodegrade. In my opinion there is no such thing as biodegradable plastic packaging that benefits the environment.
Compostable plastic bags will still litter the environment, and pollute the sea, for generations. Even if plastic does degrade it still leaves micro-plasticsthat are ingested by animals and fish. So what packaging is biodegradable?Answer: Paper based packaging that has no plastic coatings or lamination’s Paper is mostly made from a natural renewable resource; paper is biodegradable because it is made from plant materials and most plant materials are biodegradable. Paper is also easily recycled – around 80% of paper is recycled in the UK. Examples of biodegradable packaging
Biodegradability AND Recyclability As far as biodegradable plastics are concerned I believe it is better to use non-biodegradable plastics that have the option of being recycled. Paper and cardboard is readily recycled through kerbside collections, so it easy for the end user to recycle paper. And, there is a market for recycled paper. In contrast, plastics recovered for recycling are being stockpiled in the UK, particularly since China banned imports of waste plastic. Other south east Asian countries are following suit. Low grade recovered plastics require hand sorting, and countries that have cheap labour have previously done this job.
It is down to manufactures and retailers to reduce their plastic packaging usage where at all possible. Biodegradable plastics are not solving the problem of plastic pollution. Some organisations are using returnable plastic packaging, and some are switching to paper alternatives. If we feed less plastic into the supply chain, then there will be less plastic pollution.