Case For Support - Compostable plastics: unlocking existing barriers to systems change
Lead Research Organisation:
University College London
Department Name: Mechanical Engineering
Abstract
In 2018 the UK Plastics Pact set a target to make all plastic packaging 100% recyclable, reusable, or compostable, and to eliminate all unnecessary single-use packaging by 2025. Including compostable plastics in the target was important for two reasons: firstly, there are some items such as food packaging, wipes, tea bags, coffee pods, sachets, that being highly food contaminated are not to suited to recycling or reuse; secondly, food waste is of major environmental importance and compostable liners play an important role in the route out of the home (government target of all UK households by 2023). \
But there is a fundamental problem. The compostables sector is the "wild west" of plastic packaging not just in the UK but also internationally. The materials are largely unregulated and the claims made of environmental credentials are often oversold to the public. Our citizen science research shows that 84% of UK households taking part reported that they are more likely to choose products that are marked as "biodegradable" or "compostable" but they are confused about how to dispose of them. Due to their popularity with the public and brands, the material is starting to displace recyclable plastics such as PET. Plastics Europe estimate the global market for biodegradable plastics is set to grow to 1.3 million tonnes in by 2023 but it could be much greater if compostable drinks bottle, crisp packets and chocolate wrappers start to be produced. The displacement of reusable or recycling products is not the only problem, contamination of other waste streams is another: compostable plastics are currently incompatible with most food waste processing systems. Thus it is it vital to design a workable and sustainable system for compostable tea bags, wipes, caddy liners, food contaminated to-go packaging, ect. The current problems are as follows:
1. Compostable plastics are currently unregulated; while there are certification standards that can be adopted voluntarily, these do not guarantee environmental protection.
2. There is no dedicated UK-wide collection and processing facilities for compostable plastics, without which their environmental impact is high.
3. There is currently no working technical solution to the automatic separation and sorting of compostable plastics, thus they are a growing contaminant in the plastics recycling and food waste collection systems.
4. There is widespread confusion about what they are and how to dispose of them especially in the case of home compostable plastics.
5. There is a growing risk that the confusion around compostable products (and a mistaken belief that they will biodegrade in any conditions) may lead to increased environmental pollution especially in the case of drinks bottles exported to other countries with no waste collection infrastructure.
We have co-created this research programme through a series of meetings with industry partners who have agreed to be part of the industry consortium Veolia, Paper Round, Deliveroo, Vegware, Nemi Teas, BBIA, REA, Xampla, Recycleye, Mamabamboo, Anerotech, Declan Mee Ltd and Closed Loop Partners. The agreed aim of this project is to unlock the barriers to a sustainable system for the use of compostable plastics in the UK and worldwide.
In this project we will synthesise the results from our environmental analysis of different compostable products with our work on labelling and automatic detection to consider how the disposal and industrial composting of these products could create a sustainable system. Specifically we will ask what UK waste processing system needs to be in place for such products to be sustainable, how such a system might operate, and how it could be economically viable. We place special emphasis on assessing the feasibility of using a UK food waste collection system as the means to harvest compostable plastics from domestic households.
But there is a fundamental problem. The compostables sector is the "wild west" of plastic packaging not just in the UK but also internationally. The materials are largely unregulated and the claims made of environmental credentials are often oversold to the public. Our citizen science research shows that 84% of UK households taking part reported that they are more likely to choose products that are marked as "biodegradable" or "compostable" but they are confused about how to dispose of them. Due to their popularity with the public and brands, the material is starting to displace recyclable plastics such as PET. Plastics Europe estimate the global market for biodegradable plastics is set to grow to 1.3 million tonnes in by 2023 but it could be much greater if compostable drinks bottle, crisp packets and chocolate wrappers start to be produced. The displacement of reusable or recycling products is not the only problem, contamination of other waste streams is another: compostable plastics are currently incompatible with most food waste processing systems. Thus it is it vital to design a workable and sustainable system for compostable tea bags, wipes, caddy liners, food contaminated to-go packaging, ect. The current problems are as follows:
1. Compostable plastics are currently unregulated; while there are certification standards that can be adopted voluntarily, these do not guarantee environmental protection.
2. There is no dedicated UK-wide collection and processing facilities for compostable plastics, without which their environmental impact is high.
3. There is currently no working technical solution to the automatic separation and sorting of compostable plastics, thus they are a growing contaminant in the plastics recycling and food waste collection systems.
4. There is widespread confusion about what they are and how to dispose of them especially in the case of home compostable plastics.
5. There is a growing risk that the confusion around compostable products (and a mistaken belief that they will biodegrade in any conditions) may lead to increased environmental pollution especially in the case of drinks bottles exported to other countries with no waste collection infrastructure.
We have co-created this research programme through a series of meetings with industry partners who have agreed to be part of the industry consortium Veolia, Paper Round, Deliveroo, Vegware, Nemi Teas, BBIA, REA, Xampla, Recycleye, Mamabamboo, Anerotech, Declan Mee Ltd and Closed Loop Partners. The agreed aim of this project is to unlock the barriers to a sustainable system for the use of compostable plastics in the UK and worldwide.
In this project we will synthesise the results from our environmental analysis of different compostable products with our work on labelling and automatic detection to consider how the disposal and industrial composting of these products could create a sustainable system. Specifically we will ask what UK waste processing system needs to be in place for such products to be sustainable, how such a system might operate, and how it could be economically viable. We place special emphasis on assessing the feasibility of using a UK food waste collection system as the means to harvest compostable plastics from domestic households.
Publications

Allison A
(2021)
Barriers and Enablers to Buying Biodegradable and Compostable Plastic Packaging
in Sustainability

Allison AL
(2022)
Barriers and Enablers to Food Waste Recycling: A Mixed Methods Study amongst UK Citizens.
in International journal of environmental research and public health

Carter E
(2022)
Mechanoenzymatic reactions with whole cell transaminases: shaken, not stirred
in Green Chemistry

Chau C
(2021)
The environmental performance of protecting seedlings with plastic tree shelters for afforestation in temperate oceanic regions: A UK case study
in Science of The Total Environment
Description | Citation in House of Commons Plastic Waste briefing |
Geographic Reach | National |
Policy Influence Type | Citation in other policy documents |
URL | https://researchbriefings.files.parliament.uk/documents/CBP-8515/CBP-8515.pdf |
Description | Citation in Public Health Wales Horizon Scanning report |
Geographic Reach | National |
Policy Influence Type | Citation in other policy documents |
URL | https://phwwhocc.co.uk/wp-content/uploads/2020/08/PHW-COVID19-IntHorizonScan_Report_13_6Aug2020.pdf |
Description | Consultation response: Defra Consistency in Household and Business Recycling in England |
Geographic Reach | National |
Policy Influence Type | Participation in a national consultation |
URL | https://consult.defra.gov.uk/waste-and-recycling/consistency-in-household-and-business-recycling/ |
Description | Consultation response: Defra Extended Producer Responsibility |
Geographic Reach | National |
Policy Influence Type | Participation in a national consultation |
URL | https://consult.defra.gov.uk/extended-producer-responsibility/extended-producer-responsibility-for-p... |
Description | House of Commons EFRA committee on Plastic Waste |
Geographic Reach | National |
Policy Influence Type | Gave evidence to a government review |
URL | https://parliamentlive.tv/Event/Index/52618ecf-3090-4ea2-9deb-4180d1c3442d |
Description | Inquiry response: House of Commons Environment, Food and Rural Affairs Committee inquiry on plastic waste |
Geographic Reach | National |
Policy Influence Type | Participation in a national consultation |
URL | https://committees.parliament.uk/writtenevidence/38880/html/ |
Description | inquiry response: House of Lords Environment and Climate Change Committee inquiry on 'Mobilising action on climate change and environment: behaviour change' |
Geographic Reach | National |
Policy Influence Type | Participation in a national consultation |
URL | https://committees.parliament.uk/writtenevidence/41689/html/ |
Title | Big Compost Experiment |
Description | Citizen Science Dataset |
Type Of Material | Database/Collection of data |
Year Produced | 2020 |
Provided To Others? | Yes |
Impact | Influence on Policy |
URL | https://www.bigcompostexperiment.org.uk/ |
Title | Website and online survey for the Big Compost Experiment |
Description | The Big Compost Experiment is a nationwide research project about the role and effectiveness of compostable and biodegradable packaging. It is one of the research initiatives of UCL's Plastic Waste Innovation Hub, an 18-month interdisciplinary research project (funded by UKRI and EPSRC) aimed at developing new ways of designing out plastic waste. It comprises a short online survey of your opinions on compostable and biodegradable packaging, and how you process food waste. There is also an optional home composting experiment for those who wish to participate further. |
Type Of Material | Database/Collection of data |
Year Produced | 2019 |
Provided To Others? | Yes |
Impact | There is the opportunity to analyse the data collected on the UK's use and composting of biodegradable and compostable plastics, in order to make more informed recommendations for the use of biodegradable and compostable plastics as alternatives to single-use plastics, i.e. policy-making process and future strategies. This data will also help to build our Live Composting Map, a live map of home-composting activities across the UK. |
URL | https://www.bigcompostexperiment.org.uk |
Description | Centre for Agroecology, Water and Resilience (CAWR), Coventry University |
Organisation | Coventry University |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Jointly drafted NERC BBP research proposal with Centre for Agroecology, Water and Resilience, Coventry (CAWR); internal submission |
Collaborator Contribution | Jointly drafted NERC BBP research proposal with Centre for Agroecology, Water and Resilience, Coventry (CAWR); internal submission |
Impact | Applied for NERC grant, unsuccessful. |
Start Year | 2020 |
Description | Closed Loop Partners |
Organisation | Closed Loop Partners, LLC |
Country | United States |
Sector | Private |
PI Contribution | Signed MOU for an innovation and research partnership with Closed Loop Partners (11 October 2019). |
Collaborator Contribution | Launched Center for the Circular Economy, a collaboration center for public- and private-sector innovators to commercialise products, services, and technologies that are leading the transition to a circular economy. Manages a global innovation challenge, "The Next Gen Cup Consortium", and invites submission from UCL. Also invited UCL to become an innovation partner with our Center for the Circular Economy. |
Impact | N/A |
Start Year | 2019 |
Description | Horniman Museum Compostable Plastic Lids collaboration |
Organisation | Horniman Museum and Gardens |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Collaborative project to try and determine protocols for composting PLA coffee cup drinks lids at the museum. |
Collaborator Contribution | Personnel for meetings |
Impact | Multidisciplinary- currently ongoing. |
Start Year | 2021 |
Description | Woodland Trust |
Organisation | Woodland Trust |
Country | United Kingdom |
Sector | Charity/Non Profit |
PI Contribution | We conducted a Life Cycle Assessment (LCA) to understand the environmental impact of using tree shelters; comparing the emissions when using different materials of tree shelters (PP and PLA), as well as without tree shelters as a whole. |
Collaborator Contribution | WT provided data to better help them understand the environmental impact of tree shelters. |
Impact | C. Chau, A. Paulillo, N. Lu, M. Miodownik, P. Lettieri (pending peer review) 'The Environmental Performance of Protecting Seedlings with Plastic Tree Shelters to Increase Woodland Cover in the UK.' |
Start Year | 2019 |
Description | Cheltenham Science Festival Talk |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Event called If I Do Just One Thing |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.cheltenhamfestivals.com/science-/whats-on/2021/if-i-do-just-one-thing/ |
Description | Compostable packaging in markets |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | Talk in London Fields market with shoppers about compostable packaging |
Year(s) Of Engagement Activity | 2021 |
Description | Environmental Materials |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | Sustainability talk ay St Pauls School |
Year(s) Of Engagement Activity | 2021 |
Description | If I Do Just One Thing |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Cheltenham Science Festival Sustainability Event |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.cheltenhamfestivals.com/science-/whats-on/2021/if-i-do-just-one-thing/ |
Description | Inspiration Talk |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Royal Institution Family talk, Zoe Laughlin, Ben Oldfrey, Mark Miodownik |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.rigb.org/whats-on/your-inspiration-making-material-difference |
Description | Interview for The Guardian |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Mark Miodownik interviewed for "'It comes from bacteria, and goes back to bacteria': the future of plastic alternatives" |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.theguardian.com/environment/2021/oct/15/it-comes-from-bacteria-and-goes-back-to-bacteria... |
Description | Interview for The Guardian |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Mark Miodownik interviewed about nappies for "Reuse? Compost? Dump? Solving the eco-conundrum of nappies" |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.theguardian.com/environment/2021/nov/20/disposable-nappies-plastic-waste-diapers |
Description | Interview for The Guardian |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Mark Miodownik interviewed about tree guard work |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.theguardian.com/environment/2021/aug/24/trees-should-be-planted-without-plastic-guards-s... |
Description | Interview for The Independant |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Charnett Chou interviewed about tree guard work |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.independent.co.uk/climate-change/news/tree-planting-plastic-carbon-reforestation-b190781... |
Description | Interview for the Guardian |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Mark Miodownik interviewed for Article "Not cricket? Scientists suggest bamboo bats are a match for willow" comments on environmental sustainability. |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.theguardian.com/science/2021/may/10/not-cricket-scientists-suggest-bamboo-bats-are-a-mat... |
Description | Lunchtime Lecture |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | UCL Lunchtime Lecture by Prof Paola Letteri and Charnett Chou 'Towards Net Zero: LCA Tools" |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.youtube.com/watch?v=-tHhomYR2dY |
Description | Materials for 21st Century |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | Sustainability talk at Collyers School |
Year(s) Of Engagement Activity | 2021 |
Description | Podcast |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Are plastics really the enemy? How can we tackle this global issue? In the first series of our new podcast, 'Brought to you by chemistry', experts from around the world explore what we can do to create a more sustainable future. Episode 6: Plastics and composting - can it work? |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.rsc.org/new-perspectives/brought-to-you-by-chemistry-podcast/ |
Description | Woodland Trust article |
Form Of Engagement Activity | A magazine, newsletter or online publication |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Article called "What shall we do about tree shelters?" for WoodWise Magazine. |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.woodlandtrust.org.uk/ |