ABSTRACT

Biochar as a soil remediation method has great potential to reduce landfilling of soil and save virgin materials, leading to more sustainable use of land and waste resources. However, to enable large-scale use, there is an urgent need for good examples and a framework to assess potential benefits and risks of this remediation technique. The overall goal of the BALANCE-project is to develop such a framework, including methods for assessing 1) detoxification, 2) soil quality improvement and 3) environmental impact of various alternatives in a life cycle perspective. In 2019, a field trial was initiated where multi-contaminated soil was treated with 0, 3 or 6% (w/w) biochar. So far, the study has shown that 1) addition of biochar can decrease contaminant mobility and uptake to biota, making the soil less toxic and 2) the remediation technique can save fuel and backfill materials, bringing large reductions of CO₂-emissions compared to traditional remediation (excavation and landfilling of soil).  The mobility of the contaminants, measured as soil porewater concentrations, was monitored during 2020-2022. This monitoring will continue in 2023-2024 together with analysis of ecological effects and ecotoxicity. In addition, a new pilot scale trial will assess the potential of biochar to decrease the risk for vapor intrusion of volatile contaminants into buildings. Compiled data will be used to gain knowledge about long term effects and provide guidance on how to assess risk reduction for humans and the environment in multi-contaminated soils treated with biochar. BALANCE will also cover circular resource and environmental effects using life cycle assessment and a new framework for urban circularity.

Biography:

Ludvig has an M.Sc in geology from Lund University, Sweden, and a solid background in soil and groundwater management. Ludvig has been the head of Environment and Innovation at NSR, a public waste management company where the trials of this study are held. Ludvig has contributed to several projects on how biochar can be used for soil remediation, designing large-scale production plants with biochar from park and garden waste, and is the founder of a biochar competence center sponsored by Bloomberg Philanthropies and affiliated with a national Swedish biochar association.

Keywords: soil remediation, risk assessment, toxicity, resource use