Site layout and waste management system design for on-site construction waste sorting: Danish practitioners' insights into challenges, mitigation practices, and future approaches

The unprecedented rate of construction waste and its improper handling pose environmental risks and contribute to project cost overruns. Together with stricter regulatory requirements, tighter certification boundaries, and comprehensive Life Cycle Assessment (LCA), this highlights the importance of on-site construction waste sorting (CWS) and systematic documentation. This study investigates challenges, mitigation practices, and future approaches related to CWS focusing on site layout and waste management system design from practitioners’ perspectives under new Danish regulations. A workshop with 25 participants was conducted using a non-probability sampling method, with participants divided into three focus groups, each comprising different stakeholder roles. Statements were first deductively grouped into challenges, existing practices, and future approaches. Subsequently, inductive thematic analysis refined the statements into descriptive sub-themes, resulting in 39 challenges, 17 mitigation practices, and 9 future approaches grouped into categories. Most challenges fell under operational constraints (9), while most mitigation practices related to communication, training, and documentation (7). Future approaches were more evenly distributed, with container design and choice, standardization, and regulatory framework each containing two approaches. Challenge-solution mappings revealed that some challenges are addressed, whereas others rely on normative practices that overlook practical implementation or lack mitigation measures. The interconnected nature of the identified challenges highlights the need for adaptive and combined practices. The findings suggest that current practices require development to bridge the gap between new regulations and practical implementation. Improved CWS can support recycling and reuse, reduce waste transport and treatment emissions (A5), and lower material, landfill, and sorting errors costs.