Are biodegradable plastics eco-friendly?

Summary

Because this is a rather long blog with lots of outbound links for you to have a look at, I have put together this summary.

  • The longevity of plastics is an unknown but it could be centuries before it totally degrades.
  • Biodegradable plastics are marketed as an eco-friendly alternative.
  • The UK governments research into bio-degradable plastics before it introduced the 5 pence single-use carrier bag charge concluded there were no bio-degradable plastics that would degrade satisfactorily in any environment and therefore could be used to manufacture a carrier bag that would be exempt from the 5 pence charge.
  • 150 organisations have endorsed a statement calling for oxo-degradableplastics to be banned.
  • Biodegradable plastics are not recyclable as they will contaminate the recycling loop rendering the recycled plastic unsuitable for manufacture of durable plastic products.
  • Compostable plastics are designed to degrade in either industrial composters or domestic composting facilities, not necessarily both, and require elevated temperatures to break down.
  • Biodegradable plastics will not biodegrade in marine environments due to lower temperatures and reduced UV light.
  • Bio-plastics come from renewable biological sources such as plants. These are not necessarily biodegradable.
  • Plastics may be stated as being recyclable or biodegradable, but this depends on the item ending up in the right place, and this is dependent on consumer behaviour.
  • A recent survey of UK households revealed that only 3% have a home compostfacility.

Introduction

Plastics were a major technological breakthrough starting with the first fully synthetic thermoset called BAKELITE in the early 1900’s. Following breakthroughs in plastic development after World War 1, mass production took off around the time of the Second World War. Since then it has become used in virtually every aspect of our life.

The longevity of plastics is unknown, and estimates range from hundreds, to thousands of years. It is likely that most, if not all, of the conventional plastic that has ever been introduced into the environment still remains intact, either as whole items, or as fragments.  

The Search for Biodegradable Plastic

The ultimate aim for many eco-conscious people is to create plastic packaging that will biodegrade in any situation, post use. There are various types of biodegradable plastics which are designed to biodegrade in different environments.

Numerous biodegradable plastics have been developed in response to a growing consumer awareness of environmental issues such as the vast amounts of plastic in the oceans and microscopic plastic particles recently identified in our rivers, with the aim to reduce the devastating effects that plastic litter is having on wildlife.


Creating a point of difference in a competitive market

Packaging manufacturers have developed biodegradable plastics in response to consumer demand. These companies typically have finite research and development budgets, and in a competitive market, packaging companies are looking to create competitive advantage, and meet a demand for biodegradable plastics in the marketplace.

The question is, what constitutes a plastic that is truly environmentally friendly?

In the packaging market, manufacturers have developed plastic films that are strongerand more flexible, and have been able to reduce the thickness of the films used in various packaging applications. 

This has theoretically reduced the impact on natural resources as less is used, and it also reduces the manufacturers costs as plastic polymers are sold by weight.

An example of this is the advent of pre-stretched pallet wrapping films that are typically less than half the thickness of traditional pallet stretch wrap films. 


European Parliament says biodegradable plastics will not solve plastic pollution

EXTRACT: Speaking on behalf of the Rethink Plastic alliance, ECOS programme manager Ioana Popescu said: “Biodegradable or not, plastics are clogging our land and oceans, threatening the health of humans and animals. The Parliament today has acknowledged that biodegradable plastics are not a silver bullet to our plastic pollution crisis, but merely a distraction from real solutions. Policies that dramatically cut our plastic footprint need to be urgently implemented.”


The UK Single Use Carrier Bag Charges

The UK Government (DEFRA) carried out a review of standards for biodegradable plastic carrier bags in 2015 in view of the Single Use Carrier Bag Charges (England) Order 2015 where supermarkets and other retailers have to charge 5 pence for single use carrier bags.

The report acknowledged that there will always be a use for single use carrier bags and these will be disposed of to landfill or incineration, a proportion will be recycled, and others will be littered. Therefore there is a rationale for promoting bags made out of biodegradable material.

There are bags which claim todegrade in certain circumstances including oxo-biodegradable bags which have an additive that catalyses the degradation process in the presence of oxygen there are also Plant-based biodegradable bags which break down in particular composting environments. 

These bags have very different properties and degrade in different ways, and are likely to have different impacts when incorporated into recycling plastic reprocessing streams. The DEFRA review’s intention was to ensure that any bag exempted from the carrier bag charge would biodegrade in a wide range of environments, including on land (in soil), in rivers and in the sea.

DEFRA’s findings

It is not currently possible to assemble a standard specification that would ensure that plastic bags claiming to be biodegradable would biodegrade in all environments, in particular in the open environment.

For some aquatic environments, there are no established biodegradability standards on which to draw, for example, for unmanaged inland waters and for almost all marine habitats (other than open seawater). There is also a lack of authorised toxicity tests to ascertain the degree of toxicity of biodegrading plastics to aquatic organisms and the impact of micro-plastic particles on aquatic organisms.

Considerable investment would very likely be required to establish the knowledge base that would correct these background evidence deficiencies to enable a discussion on a biodegradability specification to proceed.’


Over 150 organisations worldwide endorse a new statement that proposes banning oxo-degradable plastic packaging worldwide

The Ellen MacArthur Foundation’s New Plastics Economy initiative has published a statement calling for a ban on oxo-degradable plastic packaging. 

Oxo-degradable plastics are being produced and sold in many countries, with society being led to believe they safely biodegrade in nature. Yet significant evidence suggests oxo-degradable plastics do not safely biodegrade but fragment into small pieces, contributing to microplastics pollution. 

Over 150 organisations worldwide endorse a new statement that proposes banning oxo-degradable plastic packaging worldwide Signatories include leading businesses, industry associations, NGOs, scientists, and elected officials. 

They include M&S, PepsiCo, Unilever, Veolia, British Plastics Federation Recycling Group, Gulf Petrochemicals and Chemicals Association, Packaging South Africa, World Wildlife Fund (WWF), Plymouth Marine Laboratory, and ten Members of the European Parliament

Click HERE to find out more.

The link to the statement is HERE.


BPF Recycling Group Position Statement on Bioplastics

The term “bioplastic” has become a marketing tool and as yet is not properly defined. There is a CEN committee working on definitions of the word because it is so complex and can include:

  • bio-derived plastic
  • degradable plastic, both biodegradable and oxo-degradable
  • plastic intended for medical applications
  • a combination of two or more of these”

“The recycling industry has no problem with non-degradable bio-derived plastic since these are usually not distinguishable from conventionally derived plastic in terms of formation, properties, recyclability etc.” 

“There are considerable concerns about degradable plastics of all sorts.”  

Generally, it is not possible to distinguish the degradable plastic from conventional by visual inspection.  Depending on the degrading agent (bio or oxo) then mechanical/optical sorting may be possible but will never be 100% effective. 

If degradable material enters the conventional plastics stream and fully degrades in the recycling process it may change the characteristics and specification of the conventional material it is be mixed with.  Equally, if it does not fully degrade it may continue to do so in the finished recycled product, leading to premature failure e.g: Some recyclers report that just one PLA bottle can contaminate a 20 tonne batch of PET by changing the crystallinity such that the material becomes opaque.  

Much recycled film material goes into damp proof membrane production and there is concern about the 
long-term stability of such material. Degradable plastics represent a significant cost to recyclers because they have paid for material they cannot use,must pay to sort it and then pay for its disposal to landfill. It is often claimed that degradable plastics are suitable for composting.

However, composters have no sophisticated sorting equipment and so cannot tell the difference when plastic bags arrive at their receiving bay. To avoid the risk that the material may be conventional plastic they reject all plastic materials which are then sent to landfill (again at a cost).

The general view of the recycling industry is that conventional and degradable plastics should never be mixed and that specific applications for degradable materials should be selected to ensure that this never happens. Some degradable suppliers claim there is no effect on recycling but when examined closely these claims rely on the conventional plastic being considerably reduced in specification already; something which is clearly not true given the extremely high-quality materials that are being recycled and are displacing virgin.

Oxo-degradable suppliers claim their materials are different. The recycling industry view is that it is for any degradable supplier to prove to the satisfaction of the recycling and potential user industries that their materials have no adverse effect. It should not be necessary for the recycling industry to carry out or fund such testing.”

“The BPF Recycling Group believes that degradable plastics should only be used in applications where they will not become mixed with conventional plastics at end of life.” 


European Bioplastics – the extract below is from one of their publications on industrial composting

“Industrial composting is an established process for transforming biodegradable waste of biological origin into stable, sanitised products to be used in agriculture.

Different technologies are available but the general process of composting is the same. It is a controlled process that can be divided into two distinct phases: active composting followed by curing.

The active composting phase lasts a minimum of 21 days. Under these conditions, micro-organisms grow on organic waste, breaking it down to CO2 and water and using it as a nutrient. Part of the energy is released into the surrounding environment as heat. During composting, organic waste is amassed in piles and, as a consequence, the total production of heat can be high.

When the temperature of the composting pile increases, the microbial populations shift: microbes adapted to ambient temperature (mesophiles) stop activity or even die and are replaced by microbes adapted to live at high temperature (thermophiles).

In industrial composting facilities temperatures in the composting heaps range between 50°C and 60°C. For hygienisation purposes, temperatures need to remain above 60°C for at least one week, in order to eliminate pathogenic microorganisms. During the curing phase, the rate of decomposition declines to a slow and steady pace, and the compost matures at temperatures in the lower mesophilic range (< 40°C) with synthesis of humic substances.”

Contaminating the recycling chain – UK Government – DEFRA – extract

Finally, there are unresolved questions on the implications of biodegradable filmic plastics for the reprocessing industry. There is not enough evidence to support technical decisions on how manufacturers of higher specification warranted products, such as damp proof membranes,should manage any increase in the prevalence of biodegradable polymers in the recycling sector.

The operational integrity of such warranted products must be maintained. Technical processing difficulties also occur when some biodegradable plastic films are mixed with conventional polyethylene, raising further questions on how best to manage any increase in the number of biodegradable films. Improvements to technologies for tackling the difficult problem of separating films in the waste stream are being sought and would be very helpful to the reprocessing sector in a situation where conventional and biodegradable bags become routinely mixed

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/485904/carrier-bag-biodegradable-report-2015.pdf – page 6


Environmental Deterioration of Biodegradable, Oxo-biodegradable, Compostable, and Conventional Plastic Carrier Bags in the Sea, Soil, and Open-Air Over a 3-Year PeriodExtract: ‘Collectively, our results showed that none of the bags could be relied upon to show any substantial deterioration over a 3 year period in all of the environments. It is therefore not clear that the oxo-biodegradable or biodegradable formulations provide sufficiently advanced rates of deterioration to be advantageous in the context of reducing marine litter, compared to conventional bags.’

READ MORE : https://pubs.acs.org/doi/10.1021/acs.est.8b06984


Bio-Plastics. Plastic from plants. – Wikipedia

“Plastics that are produced from plants. This means plastic can come from renewable sources. There are arguments that with the world population growing, and millions of people starving, that using agricultural land for plastic rather than food production is only going to exacerbate the food shortages. The irony of this is that the use of plastic packaging in modern times has been paramount to the reduction of food waste.

Bio-Plastics are also derived from renewable biomass sources, such as vegetable fats and oils, corn starch, or microbiota. Bio-Plastic can be made from agricultural by-products and also from used plastic bottles and other containers using micro-organisms.’

Most in the industry use the term bio-Plastic to mean a plastic produced from a biological source. They are not necessarily biodegradable.”

https://en.wikipedia.org/wiki/Bioplastics

European Bioplastics – extract from their website

‘As most conventional plastics, biobased plastics need to be recycled in separate streams for each material type (e.g. PET-stream). Where a recycling stream for a specific plastic type is established (e.g. PE or PET), the biobased alternatives (bio-PE, bio-PET) can be recycled together with their conventional counterparts.

Furthermore, PLA is a bioplastic that is potentially recyclable but for which no separate recycling stream yet exists. The corresponding sorting technology is, however, already available. Specific material recycling of clean production scraps is established and saves valuable resources. The recycling of PLA after its use (so called post consumer plastics) will be feasible as soon as the commercial volumes and sales increase sufficiently to cover the investments required. Numerous research projects and tests have been accomplished or are currently underway organised e.g. by WRAP (UK), COREPLA (Italy), Re-PLA Cycle (Germany), r-PLA (Belgium).’


Oxo-biodegradable Plastics Association

They have published a report titled WHY BIO-BASED IS THE WRONG TECHNOLOGY which concludes:

‘What is the point of bio-based or “compostable” plastics if they cannot be made into compost (because they are required to convert to CO2 gas within 180 days), if they should not be sent to landfill (because they can generate methane in anaerobic conditions), if they cannot be recycled with ordinary plastic, if they are not really renewable (because some of them contain oil-derived materials and fossil fuels are used in the agricultural and polymerisation process), if they use scarce land and water resources, and if they are more expensive and less versatile?’ 

Home Compostable Plastics

A recent survey by Business Waste found that 97% of UK households DO NOT compost!

This raises the question as to the effectiveness on introducing home compostable plastics in to the supply chain, when, at best only 3% will be composted.

The other 97% cannot be recycled, and will still litter the environment, or contaminate rivers and the marine environment.

Remember, compostable plastics require specific conditions to degrade. The sea is cold and dark facilitating the preservation of plastic contamination for centuries.


Biodegradable plastics are not the answer to reducing marine litter, says UN

The report, entitled Biodegradable Plastics and Marine Litter. Misconceptions, Concerns and Impacts on Marine Environments, finds that complete biodegradation of plastics occurs in conditions that are rarely, if ever, met in marine environments, with some polymers requiring industrial composters and prolonged temperatures of above 50°C to disintegrate. There is also limited evidence suggesting that labelling products as “biodegradable” increases the public’s inclination to litter. Read more…..

Concluding

Hopefully this article gives some insights into the issues surrounding plastics, particularly where used in packaging. It is often pointed out that plastic packaging has reduced food waste which is to be welcomed in a world where there are millions of starving people.

Where it is feasible, in the longer run, a ‘closed loop’ recycling system using plastic crates is more environmentally sustainable than one based on cardboard boxes. If plastics can be reused or recycled then that is ideal. In the case of a closed loop re-using system, the longevity and durability of plastic is a boon.

The point of this article is to make people aware that supposedly eco-friendly plastics may not be beneficial to the environment, and large corporates may only promote eco-friendly packaging for marketing purposes. 

Biodegradable plastics are on the market and companies are keen to be seen to be environmentally friendly so may adopt these supposed ‘eco-friendly’ biodegradable plastic packaging options.

We may be better off using plastics that can at least be recycled, or better still, consider paper as an option where appropriate.

Paper is biodegradable AND 100% recyclable.

Plastic is biodegradable OR recyclable.

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