Multi-layer value stream assessment of the reverse logistics network for inert construction waste management

Reverse logistics (RL) concepts have brought sustainable solutions to the problems pertinent to inert construction waste (ICW) management. However, the involvement of different processes and facilities across the RL value chain makes it difficult to visualize and manage the whole process conveniently. Consequently, issues such as inadequate assessment of environmental hazards, unclear cost accrual patterns, misleading information to stakeholders, and other process-related deficiencies arise, thereby questioning the overall sustainability and alike circularity concepts. Despite the prominent role of lean management (LM) concepts in process improvements across various product-oriented sectors, its integration within RL management to solve ICW problems is almost non-existent. This paper presents a unique lean thinking-based multi-layer value stream assessment (MVSA) approach deriving from a conventional value stream mapping (VSM) technique to assess the overall RL network of ICW management. RL network design entails both facility-based and non-facility-based processes, with four different value streams, i.e., time, cost, environmental quality, and process efficiency aspects. A case study of Hong Kong demonstrates the developed MVSA approach. The case study features an assessment of the RL network's current and future states, considering multiple scenarios. Furthermore, a detailed sensitivity analysis is conducted to provide valuable insights and discussions. In the end, an agenda for continuous improvement related to the proposed MVSA approach is expounded. The research findings verify that the proposed MVSA approach can significantly contribute to the overall process improvement, better visualization, and RL network assessment, leading to effective waste management systems.