Redirecting nutrients in urban waste to urban agriculture

Until the nineteenth century, ‘nightsoil’ and organic waste were recycled to agriculture to replenish farmland with nutrients and organic matter in (peri-)urban areas. However, with the onset of cheap chemical fertilizer production, nightsoil use was abandoned. This development facilitated the geographic disconnection between food production and consumption, leading to the expansion of agriculture on distant soils. This chapter introduces new approaches to food production and ‘waste’ management, including the opportunity to partially close nutrient cycles on the urban scale. Moreover, this chapter provides an overview of wastewater sources, scales and systems and discusses the opportunities and constraints of recycling human excreta to urban agriculture as a means to restore the nutrient cycle in the food system. Finally, the chapter looks ahead to future research trends in this area.