An approach to identify options for reuse of nutrients under different development scenarios
The majority of the world population is living in cities, and population and urbanization rates are expected to grow further, raising challenges for food production. At present, cities do not use resources efficiently. Unsustainable resource management is a key driver for resource depletion. One of the key challenges for future food production is to increase the sustainability of land and resource management, and to make a shift from a linear toward a circular metabolism. In particular, the reuse of nutrients such as N and P from urban areas is regarded essential, because the energy needed for production of N‐fertilizer requires approximately 1‐2% of the global energy production, and Pfertilizer is obtained from mining phosphate rock, which is a finite and non‐renewable resource. However, the assessment of options for reuse of nutrients from cities in agriculture requires a holistic approach, where urban and rural areas are analyzed together, as highly inter‐linked systems. This presentation aims to describe an innovative approach to assess the options to reuse nutrients
under different future development scenarios. The approach integrates concepts from the domains of land use planning, urban and agricultural systems analysis and new sanitation technology. The island of St Eustatius in the Dutch Caribbean was used as a case study. The methodology includes three parts. First, the design of four external scenarios for the future urban and agricultural land use at St Eustatius based on an analysis of global and regional trends. Second, the assessment of the consequences of these scenarios on the N and P balance using a substance flow analysis model, and third the assessment of the applicability of different sanitation concepts for recovery and reuse of nutrients in agriculture. The results show that the approach is a promising tool to identify options for closing nutrient cycles and supporting the planning and decision making of a more sustainable food system.