Holistic integration of circular economy principles across returnable transport item pooling supply chains for environmental sustainability improvement

Returnable Transport Items (RTIs), including pallets, containers, and crates, are increasingly adopted throughout global supply chains due to their economic, operational, and environmental benefits. Despite their ostensible alignment with the Circular Economy (CE) concept, their reusability and management complexity can generate rebound effects and environmental inefficiencies, including heightened transport emissions, intensive manufacturing, and high landfill disposal, capable of negating their environmental advantages over single-use transport packaging. These challenges are amplified in RTI pooling supply chains, where pooling organisations lease large RTI volumes to multiple customers, forming multi-party networks with multi-directional transport flows. The CE concept involves principles beyond reusability, requiring holistic integration across pooling supply chains to mitigate negative externalities and rebound effects. This integration forms the central focus of this PhD thesis. Three core research themes are developed aiming to examine the RTI pooling Supply Chain Design (SCD), identify the major impact areas responsible for the highest environmental inefficiencies, and investigate CE strategies and their holistic integration across pooling supply chains. A two-phase abductive research is designed. During the first theoretical phase, the theoretical and conceptual foundations are established, and a literature review is conducted. Having adopted a systems thinking theoretical lens, in the second empirical phase, 36 expert semi-structured interviews are conducted in an iterative format to gain in-depth empirical insights. This research significantly contributes to theory and practice. A conceptual framework of the RTI pooling SCD, including the main influencers, design decisions, and building blocks, and their interplay is proposed. Furthermore, the major impact areas are identified, revealing hidden environmental impacts often overlooked in isolated and reductionistic evaluations. Finally, CE strategies regenerating, narrowing, slowing, and closing resource flows and actionable recommendations for their integration across pooling supply chains are provided, offering key insights for addressing the major impact areas and rebound effects of ostensibly circular pooling networks.