(C) flickr / wastebusters
Research Papers, Publications and Books

Sanitation // Green Opportunities for Urban Sanitation Challenges through Energy, Water and Nutrient Recovery

By Pay Drechsel and Munir A. Hanjra. A Nexus approach means that when governments and industries determine policies in one sector – whether energy, agriculture or water – they take into account the implications in other sectors. Applying this approach within an urbanizing world gives the Nexus a vital justification, since nowhere else are the flows of energy, water and food so stressed as where populations peak within confined spaces. Cities are hungry and thirsty and enormous hubs of consumption of all kind of goods, including food, water and energy. This in turn makes them major centres of solid and liquid waste generation. If this waste remains in the urban area or its landfills, cities will also become vast sinks for valuable resources, like crop nutrients, while rural production areas increasingly face soil fertility degradation.


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.




The Water, Food, Energy and Climate Nexus: Challenges and an agenda for action. Edited by Felix Dodds and Jamie Bartram. London, New York 2016, pp. 204-218

› back

Peace and conflict

Project // Improving Security and Climate Resilience in a fragile Context through the Water-Energy and Food Security Nexus (Frexus)

The Frexus project fosters cross-sectoral and integrated approaches in resource management, within local communities in Mali, Niger and Chad that are faced with the consequences of resource scarcity and climate change. The vicious cycle of resource scarcity, competition, conflict and instability currently challenging many communities, can be turned into a virtuous cycle of resilience, sustainable resources management, cooperation and security. Frexus (Nexus in Fragile contexts) aims at providing...

// more

Pocket Flyer // Water, Energy and Food for All A Nexus Approach

The 2017 BMZ Water Strategy, with its six intersectoral strategies, is a binding basis for German Development Cooperation and integrates cross-sectoral thinking for economically sustainable, integrated and climatefriendly development. The Water, Agriculture and Energy Nexus is one of six intersectoral strategies, highlighting the need to achieve water, energy and food security for well-being.

// more

Publication // What-If: An Open-Source Decision Support Tool for Water Infrastructure Investment Planning within the Water–Energy–Food–Climate Nexus

By Raphaël Payet-Burin, Mikkel Kromann, Silvio Pereira-Cardenal, Kenneth Marc Strzepek and Peter Bauer-Gottwein. This paper presents a new open-source hydro-economic optimization model, incorporating in a holistic framework, representations of the water, agriculture, and power systems. The model represents the joint development of Nexus related infrastructure and policies and evaluates their economic impact, as well as the risks linked to uncertainties in future climate and socio-economic...

// more