MONITORING CIRCULARITY IN DOWNSTREAM MANAGEMENT OF EXCAVATION MASSES An assessment of End Use and Management Practices for Masses Generated by Göteborg Energi

Sammanfattning

Excavation masses constitute the largest waste category within the Swedish construction sector. Despite the potential for reuse, large volumes are removed from project sites for disposal, while virgin materials are extracted and used for backfilling. This contributes to greenhouse gas emissions, mainly through transport of generated masses and the extraction and transport of virgin materials. The aim of this thesis was to improve the understanding of the downstream management of excavation masses removed from project sites and assess their end use, including circular pathways such as reuse and recycling compared to landfill disposal. The study was conducted in collaboration with Göteborg Energi, a municipal energy company in Gothenburg, Sweden. The company generates excavation masses from groundwork associated with the distribution of district heating, district cooling, gas, electricity, and city fiber. The study combined quantitative mapping of material flows with qualitative interviews. Waste statistics from contractors and waste receiving facilities were used to estimate downstream end use, while interviews with these actors were conducted to identify factors affecting current management, monitoring possibilities, and environmental impacts. The results indicate that a substantial share of the generated excavation masses were managed through downstream pathways replacing virgin materials rather than being landfilled. The largest identified end-use category was other recycling, primarily involving use for construction purposes. The findings further suggest an indicator measuring the proportion of excavation masses replacing virgin materials downstream may represent a relevant approach for monitoring circularity of generated excavation masses. However, the study identified significant challenges related to traceability and access to data, which need to be improved to enable such monitoring. The study concludes that monitoring of downstream excavation mass management requires increased organizational control and traceability. Furthermore, increased circular management of excavation masses requires improved collaboration and data availability among involved actors.