The future of composting

By Luuk Zonneveld
Product Manager Select Solutions, at Avery Dennison

Terms such as ‘biodegradable’ and ‘compostable’ are often used interchangeably, but they actually have very distinct meanings.

The word ‘compostable’ is especially misunderstood. Whether through a lack of information, a need for education, or emphasis on ways of recycling, many consumers think they can discard compostable packaging freely – associating it with the compost used for plants. In fact, just like any other material, it must be separated from other materials for proper processing and disposal. Consumers can also perceive compostable and biodegradable packaging as being the same, often disposing of both in the same (inappropriate) way.

This article highlights differences between compostable and biodegradable packaging, along with relevant considerations and implications for the future.

The relentless rise of sustainable packaging

The Ellen MacArthur Foundation and UN Environment launched a Global Commitment in October 2018⁽¹⁾. Jan ‘t Hart (senior director, innovation, sustainability and compliance, Avery Dennison) said that the commitment proposes compostability as one of the main ways to fight plastic waste and pollution: “This is an important step forward in addressing the root causes of plastic waste. More than 250 businesses, governments, NGO, universities, and other organisations across the globe are taking part, all committed to a set of ambitious 2025 targets. They are pursuing a threefold strategy: eliminating plastic items we don’t need; innovating so that remaining plastics can be safely reused, recycled, or composted; and circulating everything we use, keeping it in the economy and out of the environment.”

Bio-based and biodegradable plastics are also growing in popularity, as highlighted in a 2019 European Bioplastics market update⁽²⁾. It estimates that total production of biodegradable

bioplastics will rise from over 2.11 million tonnes in 2019 to more than 2.43 million tonnes in 2024 (representing approximately 1% of total plastic production) - enabling a major reduction in landfill waste buildup. Consumer pressure for more sustainable materials is likely to continue, and a key focus for Avery Dennison is the development of materials that not only meet sustainability goals, but also convert well and offer parity of performance in applications.

In 2018, the European Parliament approved updated EU waste legislation, and this includes a revision of the Waste Framework Directive and the Packaging Waste Directive. New recycling and landfilling targets are now in place to boost the re-use of valuable materials in waste, and the Directive also acknowledges that compostable materials for separate bio-waste collection contribute to more efficient waste management.

Jan ‘t Hart (Senior Director, Innovation, Sustainability & Compliance, Avery Dennison): “Such changes in the international regulations are a driver for increased and accelerating adoption. We have already seen a ban on disposable point-of-sale plastic carrier bags in Italy and France, and Italian supermarkets have now implemented a complete replacement of plastic bags by compostable alternatives.”

When plastic is the right choice

Information presented to consumers typically paints plastic in a negative light, but this doesn't tell the whole story. In fact, there are still very good reasons to use plastics in some applications.

The challenge lies in removing plastic where it is possible to do so – where it is being used unnecessarily. Simply removing all plastics creates a food waste problem, which leads to the obvious question: which is the better choice? What matters is being honest with consumers, making it clear that while not all plastics can be replaced and removed, we can nevertheless make sure that remaining plastics are recyclable, and that they are actually being recycled or composted.

Compostable versus biodegradable

Compostable

Compostable materials return to the earth safely and will disappear almost entirely in the compost and can be used as soil-conditioning material or mulch. These materials can be added to home compost piles, but are typically best suited to industrial compost piles (which use specific conditions including raised humidity and temperature).

Compostable materials can be produced using either plant-based or fossil fuel materials. In order to claim compostability, packaging must pass rigorous third-party testing for disintegration, biodegradation and non-toxicity, as described in the EN 13432:2000 standard. Certification is by different independent third parties (with a resulting ‘suitable for composting’ logo). Different logos, lack of promotion and inadequate education are all possible sources of confusion among consumers.

Biodegradable

Biodegradable packaging will completely break down and return to nature within a reasonably short period of time (typically a year or less) after customary disposal (i.e. without requiring special treatment). Within landfill sites, this helps to reduce waste buildup and contributes to a safer, cleaner and healthier environment. To avoid ‘green washing’ it’s recommended to always state clearly the environment in which the product biodegrades, and the time frame involved. There is no official standard for biodegradable products, but TUV-Austria offers "OK Biodegradable" certification for soil, marine, and water.

Compostable, certified label materials from Avery Dennison include starch or cellulose based products such as PLA or Natureflex. Most paper facestocks are also compostable and some are certified as compostable. Most conventional plastics are not compostable or biodegradable, and remain on the planet as waste for decades, potentially in very small pieces (micro plastics).

For completeness, it is also helpful to mention two more types of plastic: bioplastics, and oxo-degradable/oxo-biodegradable plastics.

Bio-based plastic vs Oxo-degradable plastics

Bio-based plastic

Unlike conventional plastics, made from non-renewable and limited fossil resources, bioplastics use renewable biomass sources such as corn starch, fats and oils from crops/microorganisms, or agricultural byproducts. A plastic such as polyethylene can be a conventional plastic or a bioplastic, so not all bioplastics are also biodegradable (e.g. biobased Avery Dennison PE85).

Oxo-degradable plastics

Plastics described as ‘oxo-degradable‘ or ‘oxo-biodegradable’ are conventional plastics (often polyethylene) that use additives to mimic biodegradation by breaking down into smaller particles (micro plastics). Waste remains in the environment, and so these plastics do not meet compostability standards and can contaminate a conventional plastic waste stream, causing problems for recycling companies. In 2017 The Ellen MacArthur Foundation called for a ban, which was widely supported by many large brands including Marks and Spencer, PepsiCo, Unilever, Veolia, British Plastics Federation, Gulf Petrochemicals and Chemicals Association, Packaging South Africa, WWF, and Plymouth Marine Laboratory⁽³⁾.

Real-world performance

To summarise, compostable materials return to the earth safely. However, biodegradable materials will break down under natural conditions but the material can always be traced back.

To be considered compostable, a material should break down into usable compost at approximately the same rate as other materials being composted. A good example is a compostable bag for supermarket self-weighed fruit and vegetables – the bag should compost alongside food waste. Biodegradable materials break down within landfills, whereas compostable materials require special composting conditions. Of course there are important differences in degradability, which we will explore below.

Luuk Zonneveld (product manager, Avery Dennison) said that fresh food packaging is the dominant segment for biodegradable and compostable materials: “compostable labels are important in fruit and vegetable applications because it allows packaging to be disposed of in its entirety, including any food that might remain inside the packaging. This is especially useful when disposing of unused supermarket stocks. Other primary applications being seen are the self-weigh compostable bags in supermarkets, but we also see compostable materials being used more often for agricultural mulching film.”

Other examples of applications in food packaging abound - in both large and small companies. Samova Tea in Germany is using compostable packaging for their tea bags. Traditional confectioner “Van Eigen Deeg” in the Netherlands uses compostable starch-based packaging for cookies. Unilever’s Carte d’Or ice cream has relaunched in compostable packaging. Organic lolly company LICKALIX claims to be the first iced treat company in the world to introduce plastic free, compostable packaging. And Waitrose uses an innovative home compostable bag for its Duchy Organic bananas.

Floating Farm’s sustainability mission and their farming methods are based on the idea of circularity and a closed-loop system. With their new CleanFlake labels, Floating Farm can share the benefits of recyclability of their packaging with their customers and help set the example for other food and beverage companies.

Making sure it’s compostable

A harmonized standard for compostable materials ensures common criteria across Europe (EN 13432:2000 ‘Packaging: requirements for packaging recoverable through composting and biodegradation’). This was introduced by the EU in 2000, this followed the EU Directive on Packaging and Packaging Waste (94/62/EC, followed in 2018 by the Waste Framework Directive and the Packaging Waste Directive mentioned earlier).

Jennifer Bijkerk (development engineer, Avery Dennison) said that strict pass/fail limits ensure dependable compostability in approved products: “The standard focuses on compostability and aerobic digestibility, and includes a range of criteria such as disintegration within 12 weeks; microbial conversion; adverse effects on composting; heavy metal content; and impacts on overall compost chemistry such as pH. Independent laboratory tests are conducted by organisations such as OWS, Itene and ISEGA, and materials must pass every test category to be proved ‘compostable’.”(4)

Similar standards include:

1. American Society for Testing and Materials ASTM-6400-99

2. International Standards Organization ISO14855

3. German Institute for Standardization DIN V490004

4. Australian Standard AS 5810-2010 (home composting)

Industrial versus home composting

Industrial composting facilities use carefully controlled aerobic (with added oxygen) conditions to avoid methane production (methane is an important greenhouse gas). Some bioplastics may also offer reductions in CO2 emissions. As with all measurements of sustainability, however, a proper life cycle assessment is needed to understand the performance of a particular material.

The ASTM, EN, AS and DIN standards specify criteria for biodegradation, disintegration and eco-toxicity for industrial compostable plastics.

Biodegradability is determined by measuring the amount of CO2 produced over a certain time period by the biodegrading plastic. The standards require 60% conversion of carbon into carbon dioxide within 180 days for resins made from single polymer, and 90% conversion for co-polymers or polymer mixes.
Disintegration is measured by sieving the material to determine the biodegraded size and less than 10% should remain on a 2mm screen within 90 days.
Eco toxicity is measured, requiring concentrations of heavy metals below standard limits.
Compost quality is confirmed, testing plant growth by mixing the compost with soil in different concentrations and comparing it with a ‘control’ compost.

Jan ‘t Hart said that although a large proportion of compostable materials are designed to be composted at industrial facilities, there is also a role for home composting: “Material breaks down much faster during industrial composting, but home composting is also important because it can take place at any house with a garden and does not require a special infrastructure for waste collection.” At the time of writing, the only standard for home compostable products is the Australian standard AS 5810, however some other schemes are beginning to emerge, such as the Belgian ‘OK Compost Home’ and Dincertco’s ‘DIN-Geprüft Home Compostable’. Test temperatures and durations are the main differences between home and industrial compostable criteria.

Logos to help consumers

Certification bodies have developed logos to help users and consumers easily recognise how a product should be disposed of. Once certification has been awarded, the logo can be used on product packaging, and an appropriate accompanying explanation can both educate consumers and promote brand values.

Assessment and certification is performed by independent certification bodies, using appropriate laboratories. If a material passes all EN 13432 tests, a unique packaging product 7P certification number and certificate are awarded. The product can then carry the ‘compostable’ seedling logo (licensed to certifying bodies by European Bioplastics).

A certificate lasts for three years, and must then be renewed. Samples of the certified product can also be requested by a certification body to check that standards are being maintained.

When claiming compostability, all of the components of the end product have to be tested including colourants, intermediate materials and printing inks. Note that some certification bodies such as Din Certco and TUV Austria offer a ‘positive list’ of materials, intermediates and additives to aid the design of compostable packaging products.

Proper technical support is important when selecting and qualifying compostable or biodegradable labelling materials, and Avery Dennison works closely with selected partners throughout the process to ensure that regulatory requirements have been met and that the end product compares favourably with less sustainable conventional solutions.

Luuk Zonneveld said that development of compostable label materials fits Avery Dennison’s commitments to sustainability: “This is a relatively new but very important area in terms of large scale applications. Following extensive testing, we have recently been able to launch a new fully ‘OK Compost’ certified self-adhesive label construction (product reference: BR618, Thermal Eco BPA Free FSC SX6030-BG40BR). This BPA-free thermal construction enables the creation of fully compostable packaging, including variable information and complements the range of products using our OK Compost certified adhesive S9500.

Conclusion

Biodegradable and compostable packaging materials are growing in popularity, and have a key role to play when achieving sustainability gains. As an alternative to conventional plastics, they offer the opportunity both to reduce landfill waste and to cut the amount of plastic that ends up in the environment.

With many businesses, NGOs, governments and other organisations working on ways to reduce plastic waste, the importance of biodegradable and compostable materials is clear. This is especially true in light of the benefits of some plastic packaging - notably, reductions in food waste. Jan ‘t Hart: “Sometimes, plastic remains the better choice, but we need to educate consumers, use the right materials in the right applications, and avoid misleading ‘green washing’. Honesty and transparency are the foundations of continued improvements and consumers’ trust. The revolution is already well underway, and we will be seeing rising amounts of industrial and home compostable packaging in the years ahead.”

(1)https://www.ellenmacarthurfoundation.org/assets/downloads/13319-Global-Commitment-Definitions.pdf

(2)https://www.european-bioplastics.org/market/

(3)https://sustainablebrands.com/read/chemistry-materials-packaging/150-companies-ngos-call-for-global-ban-on-oxo-degradable-plastic-packaging

(4)http://www.bpf.co.uk/topics/standards_for_compostability.aspx

Other sources:

http://www.tuv-at.be/certifications/ok-compost-industrial-ok-compost-home/

https://www.wrap.org.uk/sites/files/wrap/Considerations-for-compostable-plastic-packaging.pdf

https://royalbrinkman.com/knowledge-center/crop-rotation/compostable-biodegradable-and-bio-based-what-is-the-difference

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