In this article the authors summarize findings from West Africa which analyzed the metabolism of four cities, visualizing the challenges of linear resource flows for system sustainability, followed by a discussion of options for transforming the urbanization challenge into an opportunity for a circular economy.
Pay Drechsel has twenty-five years of working experience as an environmental scientist aiming at the safe recovery of irrigation water, nutrients, and carbon from domestic waste streams, integrated natural resources management, and sustainable agricultural production in developing countries. Pay worked extensively on urban and peri-urban agriculture, safe wastewater irrigation in low-income countries, as well as economic opportunities for resource recovery and reuse. Pay joined the International Water Management Institute (IWMI) and for the last ten years has been coordinating different IWMI research programmes and divisions in the agriculture–sanitation interface, supporting impact-oriented and multi-disciplinary teams.
Munir A. Hanjra is currently working as an economist at the International Water Management Institute (IWMI). Previously he worked as a senior research fellow at the Charles Sturt University Institute for Land, Water and Society, and CSIRO Land and Water, Australia. He is a development economist with over twenty years of professional experience on issues related to sustainable water management.