Edited by: Tomaso Fortibuoni, Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Italy
Reviewed by: Lu Zhang, Beijing Forestry University, China; Maja Rujnic Havstad, University of Zagreb, Croatia
This article was submitted to Waste Management, a section of the journal Frontiers in Sustainability
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Compostable plastics have great potential environmental benefits, however, the damage caused by incorrect waste management offsets them. This study aims to develop a behavior change intervention aimed at improving compostable plastic disposal. We illustrate application of the Behaviour Change Wheel framework to design an intervention in this context. First, the target behavior was understood by specifying it and identifying potential behavioral influences. Second, behavioral influences were systematically linked to potential intervention strategies and refined by evaluating the likely affordability, practicability, effectiveness, acceptability, equity and potential for side-effects (APEASE criteria) in a UK implementation context. Finally, intervention content and implementation options were selected by systematically selecting specific Behavior Change Techniques and refining them by evaluating them against APEASE criteria. The target behavior was identified as UK citizens disposing of compostable plastic waste in the food waste bin meant for collection by local authorities. Influences on compostable plastic disposal were identified as “psychological capability” (i.e., attention and knowledge), “reflective motivation” (i.e., beliefs around environmental impact of compostable plastics) and “physical opportunity” (i.e., access to appropriate waste management). “Education” and “environmental restructuring” were the intervention types selected. “Communications/marketing”, “guidelines” and “restructuring the physical and social environment” were the policy options selected. Selected behavior change techniques were: instruction on how to perform the behavior, prompts/cues, adding objects to the environment and restructuring the physical environment. The resulting intervention is a disposal instruction label for compostable packaging, comprising of instructions and a logo. The next step is user testing the developed disposal instruction labels in terms of their effect on promoting the desired disposal behavior. The novelty of this study includes the development of an intervention to reduce compostable plastic waste and the explicit, step-by-step documentation of the intervention development process. The scientific significance is therefore both applied and theoretical. When evaluated, our intervention has the potential to yield insights relating to what improves compostable plastic disposal amongst citizens. This, in turn, has key policy implications for product and package labeling. By openly documenting our method, we demonstrate a systematic and transparent approach to intervention design, providing an adaptable template and model for others.
In response to the plastic waste crisis, the UK Plastics Pact was launched in April 2018 where members pledged to make all plastic packaging 100% “recyclable, reusable or compostable” by 2025 in order to transition to a circular economy of plastics (WRAP,
A linear economy of compostable plastics.
Compostable packaging labeling is defined by mandatory and non-mandatory labeling requirements as well as manufacture marketing strategies. General Product Safety Regulations 2005 (Government,
Labeling plays a key role in providing packaging and products visibility. It also helps communicate information about material identity and disposal instructions. While special rules apply for precious metals, footwear, food and drink, and products for children e.g., prepacked food and drink must display information that includes best before or use-by date, quantitative ingredients list, and nutrition information (Companion,
Given that citizens struggle to distinguish the biodegradability of a waste material, it is especially important for authorities to provide definitions of biodegradability and biodegradation, and for international testing methodologies to be developed. ISO 14021:2016 standard specifies requirements for self-declared environmental claims, including statements, symbols and graphics, regarding products, not precluding legally required environmental information, claims or labeling (International Organization for Standardization,
Although information about a product's packaging material type and recycled content or disposal instructions is not currently mandatory, UK Government is consulting on the introduction of mandatory labeling of packaging under new Extended Producer Responsibility scheme reforms to be introduced from late 2022 (DEFRA,
In addition, manufacturers can obtain third party certification of industrial and/or home compostable plastic performance from a number of certification bodies that use overarching standard test criteria to demonstrate compliance. In Europe, the most important certification schemes that demonstrate compliance with EN 13432 (suitable for industrial composting conditions), are DIN-CERTCO (Germany), TÜV AUSTRIA (formerly Vinçotte) OK Compost label (Belgium), and COMPOSTABILE – CIC (Italy) (Recycling AfO,
Life cycle assessment shows that the current system, with no dedicated UK-wide collection and processing facilities for compostable plastics, is not environmentally favorable (Yates and Barlow,
Engaging the public is critical for a sustainable compostable plastic packaging system. Citizens are the ones who purchase, use and initiate the end-of-life pathway of compostable plastic waste, ensuring whether or not composting takes place. Citizens' adoption of the required food waste recycling behaviors will therefore be critical for a circular economy of compostable plastics, as food waste collection is the only viable route for their management en masse. Evidence suggests, however, that more work is needed in this area. Not only are there still many UK citizens who lack access to food waste collection services, many with access still do not engage with these services (Allison et al.,
There are various behavioral models and theories that can underpin behavior change intervention development. One example is the Behaviour Change Wheel (Michie et al.,
The primary aim of this paper is to design an implementable behavior change intervention that promotes the desired disposal of compostable packaging. A secondary aim is to document the systematic intervention development process using the Behaviour Change Wheel method.
To improve intervention documentation, we used the GUIDED framework which provides guidance for reporting intervention development studies in health research (Duncan et al.,
GUIDED is a 14-item checklist which contains a description and explanation of each item alongside examples of good reporting. Its objective is to improve the quality and consistency of intervention development reporting in health research. Nonetheless, we believe the checklist items are valuable to the present circular economy context as they offer transferrable principles for good intervention documentation practice. For instance, we used the checklist to ensure that we reported:
The context for which the intervention was developed,
The purpose of the intervention,
The target population,
How published intervention development approaches contributed to the development process,
How evidence from different sources informed the intervention development process,
How published theory informed the intervention development process,
How guiding principles, people or factors were prioritized when making decisions during the intervention development process,
How stakeholders contributed to the intervention development process,
How the intervention changed in content and format from the start of the intervention development process,
Uncertainties at the end of the intervention development process (e.g., requirement for piloting),
According to TIDieR guidance (Hoffmann et al.,
The items we did not report on were “use of components from an existing intervention in the current intervention development process” and “any changes to interventions required or likely to be required for subgroups” as these were not deemed applicable to the present intervention.
Shown in
The Behaviour Change Wheel (Michie et al.,
The definitions of each intervention type, policy option and BCT can be found in
(Affordability) How costly is the proposed intervention going to be?
(Practicability) Can the intervention feasibly be delivered as designed in the intended setting?
(Effectiveness) How effective is the intervention at changing the target behavior?
(Acceptability) Is the intervention deemed appropriate by key stakeholders and those receiving the intervention?
(Side effects) Are there any potential unwanted side effects from delivering this intervention that need to be considered?
(Equity) Does the intervention instigate disparities between different sectors of society?
In terms of methodology, the Behaviour Change Wheel advocates three broad phases: first, to understand the target behavior; second, to identify intervention options and; finally, identify content and implementation options. These broad stages, which in turn can be broken in a series of further steps, are outlined in
The Behaviour Change Wheel's systematic and theory driven intervention development approach.
According to the Behaviour Change Wheel approach, an additional behavior change model may be used to help guide the process of understanding the target behavior. Shown in
Capability-Opportunity-Motivation-Behavior (COM-B) Model (Michie et al.,
A multi-method, iterative approach was used to integrate seven sources of evidence and systematically progress through the phases outlined in
A qualitative study of barriers and enablers to buying compostable plastic packaging (Allison et al.,
A mixed-methods study on barriers and enablers to household food waste recycling (Allison et al.,
Two experiments testing citizens' disposal of compostable plastics (Taufik et al.,
A survey investigating citizen's bioplastic knowledge, perceptions and end-of-life management (Dilkes-Hoffman et al.,
A report summarizing research insights on citizen's behavior toward packaging labeling design by OPRL (OPRL,
A review of research studies into On-pack Labeling and Citizen Recycling Behavior (WRAP,
Stakeholder involvement was assured
Overview of materials and resources used as evidence.
The subsequent section details what we did in each broad stage of the Behaviour Change Wheel approach (as outlined in
Detailed in
The Behaviour Change Wheel guide offers guidance on the types of intervention types and policy options that are most likely to be effective at targeting physical capability, psychological capability, social opportunity, physical opportunity, automatic motivation and reflective motivation. This stage of intervention development therefore involved selecting intervention types (Step 5) and policy options (Step 6) from the Behaviour Change Wheel guidance that were most likely to be effective for changing the behavioral targets identified in our COM-B analysis in the previous step. These steps also involved a critical evaluation of possible intervention types and policy options against APEASE criteria.
The content (Step 7) and implementation (Step 8) options were considered and developed iteratively, in the phased approach shown in
Steps taken to develop content and implementation options.
Content was chosen using the Behavior Change Techniques Taxonomy to select BCTs. The Behaviour Change Wheel guide offers guidance on the BCTs most commonly used per intervention type and so this was used to support consideration. APEASE criteria were applied throughout this selection process too. BCTs found not to meet APEASE criteria were not carried forward to the next stage of intervention design. Practicality and acceptability were deemed to be of particular importance in this evaluative process by the research team given the context for implementation.
To set the scene, at the time of this study in 2022, UK Government is consulting on new mandatory labeling for packaging in the UK as part of Extended Producer Responsibility scheme reforms. The key aim of mandatory labeling is to give citizens clear information about what they can and cannot recycle using simple binary messaging i.e., “recycle” or “do not recycle” (DEFRA,
Compostable packaging, with the exception of compostable packaging used in “closed loop” scenarios (i.e., where products are sold, used and disposed of within a single venue e.g., festivals), is not currently deemed recyclable and so will likely incur higher Extended Producer Responsibility fee rates, payable by obligated producers, and mandatory “do not recycle” labeling from 2023. Nonetheless, the UK Government recognizes that it may support an alternative approach to compostable packaging in the future should greater certainty over a lack of any negative effects and evidence of the benefits in end applications be demonstrated (DEFRA,
UK Government is currently considering two options for Extended Producer Responsibility mandatory labeling. Option 1 is the use of approved labels where Government would set in regulations the criteria that labels must meet such as format, size and appearance. In this scenario obligated producers could establish their own label or subscribe to and use labels from an existing labeling scheme (for example OPRL). A variation of this approach could be to set the requirements for “do not recycle”' in Extended Producer Responsibility regulations thereby restricting how producers label packaging that is not recyclable (DEFRA,
The implementation options for delivery of the BCTs (i.e., prototype interventions) were first developed by two members of the research team, a behavioral scientist (ALA) and architect designer (DP), with input from other members of the research team. They were then iteratively revised based on stakeholder feedback.
In light of the UK Plastics Pact (WRAP,
The waste hierarchy as set out in article 4 of the revised waste framework (Directive 2008/98/EC) (Directive,
To reduce plastic waste, various behaviors relating to reducing, recycling, reusing and composting could have been selected. As highlighted in Section Introduction, disposal of compostable plastics was prioritized because compostable plastics are proliferating on the market, yet there is no system for collection, sorting or processing of compostable plastic in the UK. They are also currently unregulated and there is widespread confusion about what they are and how to dispose of them. Therefore, they are increasingly contaminating other plastics recycling and some food waste collection systems, which are not able to process compostable plastics. Improving the current system for compostable plastics is therefore likely to be an effective way of reducing plastic waste.
A circular economy of compostable plastics.
The selected behavior of compostable plastic disposal was further specified as: UK citizens (who), discarding compostable plastic packaging (what), in the food waste bin meant for collection by local authorities (how), at the point of disposal at an items end-of-life (when) within the home (where). While home/community-composting was another possible option, this was deemed unlikely to be feasible for the majority of urban-dwelling UK citizens who live in densely populated housing often without access to a garden (DEFRA,
As shown in
Table showing factors associated with compostable plastic waste disposal.
Phys Cap | n/a | n/a | n/a | n/a | n/a |
Psych Cap | Compostable plastic familiarity |
Compostable plastic familiarity |
Compostable plastic familiarity |
Compostable plastic familiarity |
Compostable plastic familiarity |
Soc Opp | n/a | n/a | n/a | Tension with neighbors if compostable plastic is put in communal organic/food waste bins | Waste collectors think organic/food waste has been contaminated with plastic bag and so do not take the waste |
Phys Opp | n/a | n/a | n/a | Access to local organic/food waste collection services | Access to local organic/food waste collection services |
Aut Mot | n/a | Environmental concern | n/a | n/a | n/a |
Ref Mot | Belief that plastic should always be recycled and not composted |
Personal moral norms | Perception that it is okay to litter compostable plastics | n/a | n/a |
In summary, the issue was found to be predominantly rooted in psychological capability, reflective motivation and physical opportunity. People lack knowledge of and familiarity with compostable plastics which leads to confusion in terms of what to do with these items at end-of-life. This was also related to issues of attention i.e., not being able to identify compostable packaging over non-compostable plastic packaging and not noticing the wording and logos on packaging that were put there to communicate the appropriate end-of-life instructions. Lack of knowledge and familiarity is also likely related to holding of erroneous beliefs around nature and processing of compostable plastic waste (i.e., that they can actually biodegrade and that they cannot be processed
A mapping process, recommended by Behaviour Change Wheel guidance was followed. We considered and selected from a range of potential intervention types (
Intervention types appropriate for targeting underlying behavioral influences.
Psychological Capability (i.e., attention and knowledge) | Education | Increasing knowledge or understanding | Considered |
Included |
Training | Imparting skills | Considered potentially |
Excluded | |
Enablement | Increasing means/reducing barriers to increase capability (beyond education/ training) or opportunity (beyond environmental restructuring) | Not applicable because a strategy going beyond both education and environmental restructuring unlikely | Excluded | |
Environmental restructuring | Changing the physical or social context | Considered |
Included | |
Physical Opportunity |
Environmental restructuring | Changing the physical or social context | Access to the appropriate waste collection services is going to become available with the introduction of nation-wide food waste collection in 2023 | Excluded |
Enablement | Increasing means/reducing barriers to increase capability (beyond education/ training) or opportunity (beyond environmental restructuring) | Not applicable because a strategy going beyond both education and environmental restructuring unlikely | Excluded | |
Reflective motivation |
Education | Increasing knowledge or understanding | Considered |
Included |
Persuasion | Using communication to induce positive or negative feelings to stimulate action | Considered |
Excluded | |
Modeling | Providing an example for people to aspire to or imitate | Considered potentially |
Excluded |
Policy options appropriate for leveraging proposed intervention options.
Education | Communications/ marketing | Using print, electronic, telephonic or broadcast media | Considered |
Include |
Guidelines | Creating documents that recommend or mandate practice. This includes all changes to service provision | Considered |
Include | |
Regulation | Establishing rules or principles of behavior or practice | Not considered |
Exclude | |
Legislation | Making or changing laws | Not considered |
Exclude | |
Service Provision | Delivering a service | Implementation of nation-wide food waste collection services are already planned by UK government | Exclude | |
Enablement | Guidelines | Creating documents that recommend or mandate practice. This includes all changes to service provision | Considered |
Include |
Fiscal measures | Using the tax system to reduce or increase the financial cost | Not considered |
Exclude | |
Regulation | Establishing rules or principles of behavior or practice | Not considered |
Exclude | |
Legislation | Making or changing laws | Not considered |
Exclude | |
Environmental/ social planning | Designing and/or controlling the physical or social environment | Considered |
Include | |
Service provision | Delivering a service | Implementation of nation-wide food waste collection services are already planned by UK government | Exclude | |
Environmental restructuring | Guidelines | Creating documents that recommend or mandate practice. This includes all changes to service provision | Considered |
Include |
Fiscal measures | Using the tax system to reduce or increase the financial cost | Not considered |
Exclude | |
Regulation | Establishing rules or principles of behavior or practice | Not considered |
Exclude | |
Legislation | Making or changing laws | Not considered |
Exclude | |
Environmental/ social planning | Designing and/or controlling the physical or social environment | Considered |
Include |
Four intervention types were considered inappropriate and so excluded: enablement, persuasion, modeling and training. Persuasion and modeling were not deemed likely to be very effective as the target behavior is not one where people lack motivation or inspiration to enact the desired behavior. In fact, people overwhelmingly have pro-environmental intentions and wish to “do the right thing” when it comes to compostable plastic packaging (Dilkes-Hoffman et al.,
Four policy categories were excluded: service provision, legislation, regulation and fiscal measures. Service provision was excluded as implementation of nation-wide food waste collection services are already planned by UK government; therefore, addressing the physical opportunity related barriers of access to waste management services. Fiscal measures would likely require legislation changes, something that would rely upon elected politicians' willingness to propose such changes. There would also be questions of affordability dependent on the economic climate at the time of the intervention, and thus the use of this policy category could become less acceptable. Legislation was not practical to focus on within this project as the process involved would be out of scope for a research study.
A mapping process, recommended by Behaviour Change Wheel guidance was followed. We considered and selected from a range of potential BCTs, based on the intervention types selected. Selection of potential BCTs was informed by the types of BCTs recommended in the Behaviour Change Wheel guide as most commonly used to deliver each intervention type. The use of APEASE criteria, along with consideration of intervention context, assisted in narrowing down potentially appropriate BCTs (
Identification of the possible BCTs that could be used in the intervention.
Psychological Capability (i.e., attention and knowledge) | Education |
• Instruction on how to perform the behavior |
Reflective motivation |
Education | • Instruction on how to perform the behavior |
List of included/excluded BCTs with reasons for inclusion/exclusion.
Instruction on how to perform the behavior | Considered |
Included |
Information about social and environmental consequences | Considered |
Included |
Information about health consequences | Not considered applicable for the present context | Excluded |
Feedback on behavior | Not considered |
Excluded |
Feedback on outcome of the behavior | Not considered |
Excluded |
Prompts/cues | Considered |
Included |
Self-monitoring of behavior | Considered |
Included |
Adding objects to the environment | Considered |
Included |
Restructuring the physical environment | Considered |
Included |
The outputs of Section Select intervention options and Section Content (illustrated in
Consensus that a label designed to communicate end-of-life disposal instructions for compostable plastic packaging was the most suitable implementation option for this intervention.
Consensus that the prototype labels tested on packaging formats as outlined in WRAP's Considerations for Compostable Packaging report, as they represent likely applications for compostable packaging in the future (WRAP,
Additional packaging formats requested to be tested were sauce sachets and takeaway food and drinks containers.
There is a need to test how the wording “compost with food waste” and “recycle with food waste” are understood by citizens.
Importance of testing different combinations of logos (WRAP “Recycle Now” logo), disposal instructions and packaging formats to see if this impacts citizen understanding of label messaging.
The importance of testing potential alternative compostable logos to understand if this impacts citizen understanding and subsequent disposal behavior of compostable waste materials.
Importance of testing labels alongside representative examples of packaging formats to understand if the presence of other mandatory and non-mandatory labeling impacts citizen understanding and behavior.
Consensus regarding the utility of an online task-based experiment to test the impact of different labels on disposal behavior.
Owing to industry support and UK Government's proposed Extended Producer Responsibility binary labeling system the OPRL label system was chosen to form the basis for prototype intervention labeling formats.
Once a label had been agreed on as the implementation option, our selection of BCTs were further refined (see
Narrowing down selection of BCTs.
Instruction on how to perform the behavior | Included | Prioritized as lack of disposal instructions identified as key barrier to correct disposal |
Information about social and environmental consequences | Excluded | Limitation of space to provide information on a label |
Prompts/cues | Included | A new label on packaging delivers this |
Self-monitoring of behavior | Excluded | Not practical to deliver |
Adding objects to the environment | Included | A new label on packaging delivers this |
Restructuring the physical environment | Included | A new label on packaging delivers this |
Other considerations were the limitation of space to display an intervention prototype label due to mandatory product labeling requirements under Regulations 2005 (Government,
Examples of the disposal instruction labels developed.
This study aimed to report the multi-method process involved in designing an intervention to promote disposal of compostable plastics. A secondary aim was to do this using a theoretical behavior change framework – the Behaviour Change Wheel. Our proposed intervention involved a rigorous and structured design process built on a foundation of primary research and evidence synthesis by a team of multi-disciplinary researchers with expertise in behavioral science, implementation science, health psychology, design, architecture and material science. This was supported by input at each stage from industry and policy experts.
The resulting intervention is a disposal instruction label for compostable plastics, comprising of instructions and a logo. In this paper, we report on influencing disposal to local food waste collections in the UK. However, the method is general and could easily be applied to a local authority, region or country that wants to use labeling to influence behavior to direct compostable plastics to a different destination other than food waste collection. Our step-by-step documentation of the intervention development process, including our systematic mapping exercises, has demonstrated a transferrable methodology and created a series of useful research outputs (i.e., tables) which can be used as guiding templates by others.
Our work has important practical applications. Unless citizens are able to dispose of compostable plastic waste materials in the correct bin, these materials will continue to contaminate other waste streams or sent to landfill and incineration. We have designed an intervention that, when evaluated, has the potential to provide important answers relating to how best to get citizens to dispose of compostable plastic waste appropriately. This, in turn, has key policy implications for product and package labeling. In addition, applying behavioral science can aid in the designing of theory and evidence-based strategies that are more likely to be effective at achieving sustainable behavior change. The UK Medical Research Council framework for designing and evaluating “complex” interventions has advocated systematic intervention development, using evidence base and theory (Craig et al.,
Our work also has important theoretical implications. There are few published examples of the Behaviour Change Wheel applied to developing interventions sustaining environmental health e.g., (Gainforth et al.,
In line with the UK Medical Research Council's guidance for developing complex interventions, the next stage of this project is to pilot the prototype labels developed (Craig et al.,
At the conclusion of the intervention development process, we were able to describe the rationale, theoretical basis, content and delivery of the intervention. However, we were not able to investigate in detail the potential impacts of other aspects of product packaging e.g., branding, color, imagery, material texture, packaging/product format. These are very likely to influence the delivery of our disposal instruction labels and so their potential impacts in the specific context of our developed disposal instruction labels should be explored in any user testing. Existing rules and regulations (or lack, thereof) relating to package labeling and imagery are also important contextual factors to take into consideration. There is much “greenwashing” and false advertising in the area of biodegradable and compostable plastic products (Aparsi et al.,
The original contributions presented in the study are included in the article/
AA, DP, SM, and MM: conceptualization, methodology, and validation. AA: data curation, formal analysis, investigation, project administration, and writing–original draft. MM and DP: funding acquisition. AA and DP: resources and visualization. SM, MM, and FL: supervision. AA, DP, MM, SM, and FL: writing–review and editing. All authors contributed to the article and approved the submitted version.
This study was supported by the EPSRC and UKRI, under grant EP/S024883/1 and NE/V010735/1.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.
We would like to thank all past and present members of the UCL Plastic Waste Innovation Hub for their help contributing to this research.
The Supplementary Material for this article can be found online at:
Affordability-Practicability-Effectiveness-Acceptability-Side-effects-Equity Framework
Behavior change technique
Capability-Opportunity-Motivation-Behavior Model.