Circular Food Systems in Cities
– seminar by Cameron Kennett
How can residual materials, nutrients and waste streams be recirculated into regenerative production cycles in cities? Cameron Kennett's research examines how cities produce and provision food, combining systems analysis with experiments in practice.
Currently, 55% of the world’s population lives in urban areas, and will continue to increase significantly by 2050. Urban growth is stabilizing in the West but is increasing at a staggering pace in the global south. While more people are moving into urban areas, modern cities generally follow a linear in- and output model. This generates high amounts of underutilized waste and leaves cities heavily reliant on food imports. Crucial frontiers now strive to balance urban growth pressures by developing domestic systems that transition the linear model into an Urban Industrial Symbiosis (UIS) ecosystem.
Focusing on Stockholm’s food systems, Cameron and his team has been working on the FOCUSE project at IVL Swedish Environmental Research Institute. The project initially focused on identifying streams, identifying that a large proportion of waste were not being captured or recirculated back into productive streams. Although the 2030 Action Plan aims for regenerating food waste and sewage sludge to biogas, the group underscores redesigning the food system to a connected, closed-loop network is a far more efficient approach, for example by reimagining food production byproducts as alternative growing media. Furthermore, they also investigate how these circular designs can be integrated into unused urban spaces, such as brownfields and rooftops, by experimenting with vertical farming technologies.
By combining Material Flow Analysis with GIS mapping, product throughputs and quantities can be pinned to different geographic hotspots, creating a clear framework to track resources and their residuals. This strategy revealed that Stockholm has an abundance of local urban side-streams that could substitute imports and be used for urban farming, such as mushroom cultivation. Spent brewer’s grain from microbreweries, wood shreds from forestry, and coffee grounds from local cafes are just a few examples of accessible urban byproducts that can be repurposed as substrate for nutrient supplementation and soil enrichment. Integrating these industries into the urban supply chain creates substantial cultivation substrate substitutions, while allowing academia, businesses, and policymakers to identify where streams intersect.
Urban food circular and provisioning modules, such as vertical farming recirculation systems, are still operated on an experimental scale. Many barriers remain before these model strategies can be applied to wider societies. These barriers include intermediate processing challenges –biological systems are tricky to work with, and requires strict processing that prevent degradation of bio-based materials. A clear economic framework is also required to determine who will fund and take operational responsibility, both of which need institutional support and regulatory policies that actively promote circular actions.
Ultimately, Cameron predicts that the UIS approach is moving in the right direction towards circular and resilient food systems, highlighting that many tools may work for the Stockholm city. By directing legislative policies towards circular and resilience practices, we can shift our semantics to recognize the novel value of the products that would otherwise be discarded.
Contact Cameron Kennett and read more about the FOCUSE project.
Text by: Catherine Shi