Opportunities for preparing urban contaminated land for bio-based production

Conference poster, 2019

Circular economy consists of both technical and biological cycles, the former will typically take place in cities while most of the bio-based production is happening outside the cities’ limits. There are however several strong arguments for also including urban areas in the biological cycles, such as creating awareness in larger parts of the population regarding advantages of the production of food, biomass, biofuel and other bio-based products. Due to urbanization and calls for more compact cities, pressure on urban land resources is high. Here, underused brownfields present opportunities for urban transformation towards a bio-based circular economy. Still, real or perceived soil and/or groundwater contamination is a barrier to redevelopment in terms of investment risks, ownership constraints, risk of future liability claims and public stigma.

The standard solution to remediate those sites for new uses is “dig and dump” as it is quick and easy to communicate with controlling environmental authorities. Even if such remediation is expensive, causes adverse environmental impacts, and consumes non-renewable resources, it is seen as cost-effective and acceptable when the return on investments is high in urban redevelopment projects. Nevertheless, when financial incentives are missing, brownfields risk waiting years for remediation and reuse resulting in underuse of urban land. There is an international consensus on promoting more gentle remediation methods (e.g. phytoremediation) that are low-cost, long-term methods without negative secondary impacts with potential to manage risks and improve soil ecology. While cultivation systems safely can take place on top of remediated soil, bio-based production may also take place directly in contaminated soil. For example, cultivation of bio-energy crops can simultaneously reduce ecological and human health risks, improve soil quality and provide revenue. Brownfields can thus open up cities for a circular economy by facilitating temporary or long-term bio-based production.

This research, stemming from a new Ph.D. project, aims to investigate the possibilities and preconditions for preparing urban brownfields for temporary and long-term urban bio-based production. The specific objectives of the entire PhD work are to: 1) investigate the opportunities in terms of land use functions as well as legal and administrative requirements linked to temporary and long-term land use of former brownfields; 2) develop a method for selecting remediation option, focusing on low-cost and low-impact risk-reducing methods; and 3) investigate involved multi-stakeholder planning and governance processes and disentangle the driving forces that hinder or make such processes possible in practice. This paper addresses objective 1, where the state of the art of remediation and land use options of brownfields are investigated for various type of bio-based production opportunities. A literature review will be the basis for a framework for understanding the potential of brownfields in the urban circular economy. This framework will be tested on selected case study sites in Gothenburg, Sweden and reviewed by a wide range of stakeholders