Towards a qualitative understanding of urban metabolism: The metabolic pathways of plastic waste in Cairo (Egypt)

Urban metabolism is a biological metaphor often used in urban studies according to a homeostatic lens centring analysis on an equilibrium of stocks and flows of materials and energy of particular cities. This approach is nevertheless limited by this understanding of the concept as well as by the prevalence of quantitative methodologies like MFA (Mass Flow Analysis) which seek to quantify the exchanges between cities and their environments. This article offers an alternative and complementary reading of urban metabolism in line with works associated with Urban Political Ecology (UPE) and centred on the processes of transformation and exchange of materials taking place in cities. It seeks to reactivate the biological metaphor through an analysis of the “metabolic pathways” which reflect the diversity of sociotechnical apparatuses that constitute the underlying framework for urban flows (infrastructures) as a result of power struggles. These apparatuses are studied through a wide definition of infrastructures including actors whose practices connect different spaces and actors, allowing the circulation and transformation of materials. The article studies the metabolic pathways of plastic waste (circulation and recycling) in Cairo through an analysis of social and technical infrastructures deployed by the Zabbaleen community as a way to stabilise a social field of interactions allowing the community to canalise and control flows of waste through the city.