Repurposing brownfields as urban greenspace with gentle remediation options: A circular outlook

Doctoral thesis, 2022

Circular Economy (CE) is regarded as an efficient strategy to address the challenges arising from the linear ‘take-make-use-dispose’ system of exploitation of resources. Urban land and soil are among the most exploited resources wherein brownfields, the potentially contaminated and currently obsolete land, can be considered the waste of the linear land use system. Recent CE policies and action plans acknowledge soil as a finite resource and set out clear directives for circular management of both soil and land. Brownfields pose possibility to integrate Urban Greenspaces (UGS) in increasingly denser cities to provide a range of Ecosystem Services (ES) and are instrumental in ensuring the liveability of cities. To manage risks posed by contaminants present at these brownfields, UGS can be combined with Gentle Remediation Options (GRO). Gentle remediation options are remediation strategies involving plants, fungi, bacteria, and soil amendments for managing contamination risks and simultaneously improve or at least maintain the soil quality. The overall aim of this PhD project is to develop adequate tools and methods to facilitate bringing brownfields back in use by combining UGS and GRO. This thesis presents four studies: i) a framework for identification of different UGS at a brownfield, ii) a framework for identification of potential GRO strategies for a site, iii) a working process for stakeholder analysis to explore their interests, resources, and challenges related to different UGS at a site, and finally iv) a framework to support the exploration of combining UGS and GRO on a brownfield and which integrates the tools and methods in the aforementioned studies.. The final framework is demonstrated in the case study site Polstjärnegatan in Gothenburg, Sweden, and challenged in a workshop with relevant stakeholders. The necessity of such an approach is validated as it can potentially increase the value derived from the depreciated brownfields progressively and it can support the formulation of long-term goals for sites.  Some additional needs are also identified to support the practical application of the framework and they are: procedures to monetise the value generation over time, tools for estimating the time required for risk reduction with GRO (and thus the cost), and tools for selecting suitable plants, bacteria, fungi and soil amendments for more detailed site design