The truth about bioplastics
Plastics have undoubtedly revolutionised the modern world since their development and global distribution in the late 1950’s. They have enabled manufacturers to innovate and have brought numerous benefits to the way we manufacture, distribute and store food, as well as hundreds of other applications for this wonderfully versatile material. However, we are in an era where we need to reduce the emissions from the fossil fuels needed to produce plastics, as well as to improve management of their end-of-life disposal, as evidenced by Blue Planet II among others.
Bioplastics are essentially a relatively recent development, having only been widely marketed for the past decade, but can be considered among the next generation of plastics. With continual innovation driving the bioplastics industry, they can offer realistic and viable alternatives for a number of applications using conventional plastics today.
When it comes to understanding bioplastics there is still much ambiguity in industry perceptions and it is our role as an expert industry organisation to address those misconceptions and to provide clarity.
Bioplastics are defined both by what they are made of and what happens to them at the end of life:
1. Bioplastics that are organically recyclable
- can be made entirely from non-renewable fossil fuel sources
- can be made from a mix of fossil fuels and renewable sources e.g. plant-based
- can be made from totally renewable resources
The common feature here is they are organically recyclable through industrial anaerobic digestion and/or composting.
These materials are often films and used, for example, to make bio-waste collection bags. Increasingly, they can be used for other products like teabags, coffee pods, carrier bags, fruit and vegetables, cakes and bread bags: wrapping that is associated with food particularly that which has a short shelf-life and can be collected with food waste and composted. Compostable bioplastics are also available for more rigid uses like compostable tableware, or blister packaging; again the common denominator is they can be organically recycled.
In the UK and in accordance with the EU Packaging and Packaging Waste Directive, organic recycling (anaerobic digestion and composting) is equivalent to mechanical recycling.
Bioplastics can also be designed to be compatible with home composting and biodegradable in soil as is the case with agricultural mulch film.
2. Bioplastics that are mechanically recyclable
- These are made from a mix of both renewable plant-based sources and non-renewable fossil fuels, but are designed to be non-compostable, like conventional plastics.
- These materials act, and can be treated exactly like, conventional materials because they do not biodegrade and are not compostable.
- They are considered a bioplastic because they use bio-based sources in their production, but their molecules act like an ordinary plastic polymer. For example, they can be used for drinks bottles, like the Coca-Cola™ PlantBottle™ made from sugar cane extract, or in industrial uses such as tubes. The advantage of using these is often in the higher quality of performance- for example, for applications as tubes, or in the automotive industry.
Their defining characteristic is their renewable content and durability. They are fully compatible with material recycling processes where they exist.
3. Oxo degradable plastics are NOT bioplastics.
- Oxo degradables are conventional plastics with additives to assist their disintegration into micro-plastic particles. Under USA usance, but also in other countries around the world, it is illegal practice to call these plastics biodegradable. Indeed, the European Commission in their 16th January 2018 Plastics Strategy declared they will take measures to limit the use of Oxo plastics in the EU. See http://ec.europa.eu/environment/circular-economy/pdf/oxo-plastics.pdf
The difference between biodegradable and compostable
For clarification, compostable plastics used in consumer applications should not be labelled solely as biodegradable. Whilst they are indeed biodegradable, biodegradability per se is an abstract and meaningless concept, unless it has a time and place within which biodegradability takes place. To better define biodegradability we should talk about compostability, i.e. within a space, time and industrial process. For packaging, the UK & European standard BS EN13432 defines this time, space, output, and toxicity. The UK adopted this standard in 2000.
For home composting, no official European standard exists but the main private certification body; TÜV Austria runs the well-respected OK Compost Home certification scheme.
For soil biodegradable mulch film, the UK has recently adopted the European Standard BS EN 17033:2018
Therefore, when we talk about bioplastics, first we need to be clear about which type we mean – compostable or non-compostable? Are they bioplastics destined to organic or to mechanical recycling?
Once this is clear, then we can look at the issue of recycling. Compostable bioplastics need to go to organic recycling, as with food waste. Non-compostable bio-plastics need to go to mechanical recycling, as per ordinary plastics. It is essentially very simple. Treat compostables like food, treat non-compostables like plastic.
A. Myth: Bioplastics contaminate mechanical recycling streams and there is no infrastructure to recycle bioplastics anyway
Fact: Compostable bio-plastics currently represent approximately 10,000 tonnes of UK sales. That compares to around 2 -3 million tonnes of plastics. Even in a country where bioplastics are used more widely, like Italy, no more than 100,000 tonnes of bioplastics are sold, compared to millions of tonnes of plastics. There is no evidence that bioplastics damage plastics recycling. Tests taken by the plastics recycling industry in Italy demonstrate a tolerance of between 5-10% for plastics to accept bioplastics without damage, but analyses show that current contamination levels are virtually zero.
Conversely, food and green waste, which accounts for over 5 million tonnes of UK recycling, is heavily and continuously contaminated by traditional plastics. The environmental damage, the reduction in yields and the devaluing of compost production this causes to organics recycling is massive. Just 5% contamination represents 250,000 tonnes of plastics that damage organics recycling annually in the UK. Compost/AD plants need to extract these plastics and send them to disposal at considerable cost.
Therefore, while considering the revision of the recycling streams, we must also consider these facts as part of that reform so that we stop conventional plastics going into food waste, reduce the time, energy and money spent by the organics recycling industry sorting the plastic waste out of the organics, and reduce the loss of yields, biogas and quality of compost and digestate produced. Furthermore, we must eliminate micro-plastics contaminating soil through this pathway.
There are 53 compost plants able to accept food waste and compostable packaging in the UK plus some 170 AD plants, some of whom can accept compostable films. UK composting and AD treats over 5 million tonnes of green and food waste. The infrastructure to treat thousands of tons of bioplastics exists. Operators are often reluctant to treat compostable materials because they are wary of contamination from non- compostable plastics. (1) (2) (3)
B. Myth: Consumers can’t recognise compostable packaging
Fact: Food producers often want their customers to see the product inside a clear wrapper and not cover it with too many logos. Therefore the use of a simple, officially recognised logo is vital to ensure that both consumers and organic waste management operators can easily recognise suitable materials. Such logos already exist and our organisation is keen to work with all relevant stake-holders to promote the clear marking of and consumer recognition of certified compostable packaging.
C. Myth: Bioplastics are competing with food for land use
Fact: This is not the case: because a number of bioplastic materials are derived from managed forestry sources; and also because the use of arable land is actually close to zero. In fact, it is only 0.016% of farmland today in Europe and even if that was to double in the next five years, would still only represent 0.032%; this is compared to pasture for meat using 67% of Europe’s farmland. See http://www.european-bioplastics.org/how-much-land-do-we-really-need-to-produce-bio-based-plastics/
D. Myth: Compostable plastic films have a negative impact on conventional plastic film recycling
Fact: The mechanical recycling of plastic film (where compostables are most present) represents a tiny fraction of plastics recycling, consisting mainly of plastic films coming from industrial use such as pallet shrink-wraps. It is highly unlikely that a company making long-lasting plastics from recyclates, for example for damp-proofing films, would use post-consumer single-use flexible packaging plastics. These are heavily contaminated with inks, adhesives and residual food waste, incorporating many different polymers, and thus are impractical to recycle. This is partly why plastic film recycling in the UK is virtually zero; low recycling levels are certainly not attributable to bioplastics. On the other hand, by enabling compostable bioplastic films to be organically recycled, the level of film recycling in the UK would increase.
Should rigid bioplastics enter the mechanical recycling system through consumer mis-sorting, they are easily separated by existing infrared reading systems from where they can be sent for organic recycling.
It is worth remembering, for all recycling but in particular polymer recycling, different materials are incompatible. Contamination widely exists between traditional polymers making recycling very difficult.
E. Myth: Biodegradable and compostable biomaterials produce methane in landfill
Fact: Tests carried out indicate that this is NOT the case for certified biodegradable and compostable packaging material (i.e. materials certified to the BS EN13432 standard). Such materials remain inert in landfill. The ASTM D5526 method determines the ‘biodegradation of plastic materials under accelerated landfill conditions’. Tests conducted on certified compostable plastics have regularly demonstrated them to be inert under typical landfill conditions.
The expert laboratory on Biodegradation, OWS of Belgium, explains: “Most municipal solid waste has a moisture content of 15 to 40 percent, with 25% as typical. Sanitary landfills are managed to keep humidity as low as possible in order not to generate leachate. Under these conditions biodegradation is not favoured, as the water content is limited. Typically only “juicy” organic waste (food scraps such as fruit waste, vegetable, grass from lawn etc.) contain enough water to self-sustain an anaerobic biodegradation process, while dry organic material (paper, lignocellulosic materials, etc.) can only start degradation when water is added to the mass.”
Therefore, whilst our industry calls for compostable biomaterials to be favoured for wider use in applications such as waste bags, foodservice and direct food packaging applications to be directed to composting recovery, there is no cause for concern if in the immediate future such materials do end up in landfill.
F. Myth: There are no standards for biodegradable plastic and packaging
Fact: For packaging, the only standard listed in the Official Journal of the European Communities (4) which covers biodegradability is BS EN13432:2000. This standard links two of the relevant aspects of the packaging Essential Requirements; packaging recoverable in the form of composting and biodegradable packaging, the latter of which must result in the production of compost. For agricultural mulch film the official, recognised European Standard is BS EN17033:2018.
Rather than additional standards to cover littering, what we need is a well-managed and funded resource policy combined with measures that are universally applied, correctly implemented and with full consumer buy-in.
G. Myth: Compostable plastics do not contribute to compost quality
Fact: As a biological process composting needs a balance of different inputs that biodegrade at varying rates and combine synergistically. Our materials behave like cellulose, which is the reference material for biodegradation testing and complement the composting process. There will be a benefit in terms of humus production but the main benefits are drawn from the ability to attract more food and garden waste into collection schemes whilst simultaneously reducing contamination from standard plastics.
H. Myth: Bioplastics do not degrade quickly enough in some composting plants
Fact: The maximum thickness that can assure a satisfactory disintegration of compostable products is determined with a standard test carried out for three months at pilot scale. Disintegration will in reality often occur in shorter cycle compost plants (less than three months). In most cases much lower thicknesses are applied in real products. The maximum allowable thickness is a limit. Thus, lower thicknesses shall be used in compost plants with a short composting cycle, so as to assure a good disintegration.
The bioplastics industry does not claim to be, or advocate the use of, bioplastics as a cure-all to the world’s litter, marine litter, plastics recycling or climate issues. Littering is an economic, social and infrastructure issue which materials cannot resolve.
However, food waste is a major environmental issue and bioplastics are a viable solution to facilitate the collection and management of this critical waste fraction which constitutes some 25-30% of household waste. The bioplastics industry is a ready and willing partner to the plastics and packaging industries working towards a common goal: to develop a system that works to the benefit of our economy, the environment and supports our industries alike.