Understanding how cities can transform organic waste into a valuable resource is critical to urban sustainability. The capture and recycling of phosphorus (P), and other essential nutrients, from human excreta is particularly important as an alternative organic fertilizer source for agriculture. However, the complex set of socio-environmental factors influencing urban human excreta management is not yet sufficiently integrated into sustainable P research. Here, we synthesize information about the pathways P can take through urban sanitation systems along with barriers and facilitators to P recycling across cities. We examine five case study cities by using a sanitation chains approach: Accra, Ghana; Buenos Aires, Argentina; Beijing, China; Baltimore, USA; and London, England. Our cross-city comparison shows that London and Baltimore recycle a larger percentage of P from human excreta back to agricultural lands than other cities, and that there is a large diversity in socio-environmental factors that affect the patterns of recycling observed across cities. Our research highlights conditions that may be “necessary but not sufficient” for P recycling, including access to capital resources. Path dependencies of large sanitation infrastructure investments in the Global North contrast with rapidly urbanizing cities in the Global South, which present opportunities for alternative sanitation development pathways. Understanding such city-specific social and environmental barriers to P recycling options could help address multiple interacting societal objectives related to sanitation and provide options for satisfying global agricultural nutrient demand.
Socio-Environmental Consideration of Phosphorus Flows in the Urban Sanitation Chain of Contrasting Cities
Journal Article by Geneviève Metson, Steve Powers, Rebecca Hale, Jesse Sayles, Gunilla Öberg, Graham MacDonald, Yusuke Kuwayama, Nathaniel Springer, Anthony Weatherley, Kelly Hondula, Kristal Jones, Rubel Chowdhury, Arthur Beusen, and Alexander Bouwman — Dec. 19, 2017View Journal Article
Fellow and VALUABLES Consortium Director
The Future of Carbon Pricing
Opportunities and challenges facing carbon pricing during the next few years, and lessons learned from carbon pricing around the world.
Workshops & Seminars
The Confidence Trap and Dysfunctional Dialogues about Climate Change: ETH Zurich
Stepping on the Gas: The Evolving Climate Impacts of the US Shale Boom