Enabling a circular biodegradable plastic flow through a systems-thinking framework
Authors: Kakadellis Sarah 
Published: December 2023

The threat of climate change has accelerated the shift in production and consumption patterns towards more sustainable systems. The proposition of a circular bioeconomy has favoured the development of biodegradable plastics in fast-moving consumer goods, especially in food packaging applications. Since biodegradable plastics can be disposed and treated alongside organic waste, including municipal and commercial food waste, they can contribute towards closed-loop material and product flows. Consumers play a key role as enablers of these flows, provided they accept, understand, use and dispose of biodegradable plastics appropriately. Mapping and facilitating the role of consumer behaviour in tackling post-consumer biodegradable plastic waste is therefore pivotal in designing sustainable systems for these materials and for achieving a circular plastic economy.

To date, literature on pro-environmental behaviour, including recycling, reuse and the adoption of biodegradable plastics has focused on understanding these actions as individual circular behaviours. Adopting a systems approach, we first mapped the consumer behaviour chain that unfolds across stages of acquisition, use and disposal of biodegradable plastics. Informed by a systematic literature review and focus groups, we then developed a stratified framework to identify and structure factors (system elements) that influencing how consumers interact with biodegradable plastics, ultimately enabling or hindering the progression of the behaviour chain. Overall, 18 system elements (further split in 35 system sub-elements) were identified across 6 broad structural categories consisting of resources, intrinsic drivers, data, value, infrastructure and policy. The emerging model acted as a foundation for the design of a survey, as a means of moving from qualitative to quantitative insights. We aimed to explore the dynamic interactions that occur within the system and investigate how system elements interact with each other and how they influence consumer behaviour, focusing on behavioural intentions for circular disposal (which, in the context of this study, was defined as the intention to of dispose biodegradable food packaging waste in food/organic waste bins) and disposal behaviour more broadly.

The survey was conducted at two academic institutions, Imperial College London (United Kingdom) and the University in California, Davis (United States), and formed the basis of a comparative case study and network analysis, in which the role of contextual setting of each case study site on behavioural intentions was also investigated. Results suggested that the presence and consistency of the relevant waste management infrastructure, as well as knowledge of bioplastic terminology and of appropriate disposal routes, play a key role in enhancing circular disposal intentions (and, hypothetically, ultimate circular disposal). The University of California, Davis's unique contextual setting, characterised by comprehensive state and institutional policies on organic waste management, contributed towards a more developed and consistent organic waste management infrastructure (including for food and food packaging waste), which in turn led to a higher proportion of surveyed participants to state having access to a separate food waste collection scheme and to display circular disposal behavioural intentions.

Our approach enabled us to identify leverage points most effectively across the consumption phase of biodegradable plastics to inform design strategies aimed at supporting consumers as they transition towards more pro-environmental behaviour in the context of plastics sustainability and integrated human-physical systems.