Assessment of sustainable mass management strategies in infrastructure projects - Application of the SCORE method in a case study of Lundbyleden

Abstract

Large infrastructure projects often result in large amounts of excavated material. This raises important questions about handling, transport and opportunities for reuse. This thesis applies the SCORE (Sustainable Choice of Remediation) tool to the Lundbyleden project in Gothenburg to help guide sustainable management of these materials. Three mass management alternatives were compared: i) sending all the material to landfill, ii) sieving to allow for some reuse of masses, and iii) a combination of sieving and washing, increasing the reuse rate even more. Each alternative was assessed for its environmental, social and economic impacts to identify which best balanced the different aspects of sustainability. Further, three scenarios were developed to investigate the impact of different perspectives (sustainability vs. circular economy) and different references (“no action” or “landfill disposal”). The results, which were supported by Monte Carlo simulations, showed that treating the material to allow for reuse of masses generally gave better sustainability results than sending it directly to landfill. The results indicate that the most preferred alternative depends on the evaluation approach. From an environmental standpoint, sieving combined with washing had the best environmental performance, due to reduced landfill use, lower transportation impacts and greater reuse potential. On the other hand, from a circular economy perspective that considers both environmental and economic factors, sieving alone was more favourable, as it delivered environmental benefits at lower cost compared to washing. Including all sustainability dimensions resulted in considerable uncertainty, especially since the social dimension could only be assessed with limited data. The findings should therefore be interpreted as an assessment of circular mass management, rather than a full sustainability assessment. Although SCORE effectively structured the comparison, for infrastructure projects, referring to landfill disposal provides a more practical reference than ‘no action,’ as it mirrors actual decision making.