International Water Management Institute / Robert B. Daugherty Water for Food Global Institute at the University of Nebraska / Stockholm Environment Institute / Stockholm International Water Institute

Harnessing opportunities for the safe reuse of wastewater in agriculture

Tuesday 29 August | 09.00-10.30 | Room: L7
Photo: Kim Andersson

From Global to Local

Trends of population growth, urbanization and climate change put pressure on sustainable water resources management. Understanding the potential of wastewater reuse can contribute to securing agricultural water availability. This session addresses challenges and opportunities of wastewater reuse and the potential for different regions in the world.  

Achieving food security (SDG 2) is of high priority, increasingly threatened by water scarcity and climate change impacts. The safe reuse of wastewater could play an important role towards increasing agricultural production. A key motivation for increasing wastewater reuse in agriculture is reduced costs, since this waste contains nutrients useful as agricultural fertilizer, along with enough water to irrigate part of all the irrigated farmland in the world. Wastewater reuse also reduces nutrient leaching to lakes, rivers, and groundwater. But how do we harness these opportunities and tap into this largely unused resource from a planning, policy, livelihoods and financial point of view? And what are the pitfalls that should be avoided to ensure safe and sustainable wastewater reuse?

The objective of the seminar is to discuss opportunities and limits for the safe reuse of wastewater and in agriculture.


From Global to Local

09:00 Introduction
Chair: Christopher Neale, Robert B. Daugherty Water for Food Global Institute at the University of Nebraska
Moderator: Pay Drechsel, IWMI

 09:10 Valuing wastewater - Challenges and opportunities of agricultural water reuse
Akissa Bahri, AWF, African Development Bank 

 09:30 Global spatial assessment of indirect wastewater reuse in irrigated croplands
Anne Thebo, University of California, Berkeley

 09:40 Safe use of wastewater in LAC: Status and capacity needs
Javier Mateo-Sagasta, IWMI

 09:50 Connecting Practitioners Across the Asia Pacific: The Kini Initiative
Karen Delfau, International WaterCentre Alumni Network

 10:00 Q&A

 10:20 Poster pitch presentations

 10:25 Conclusions
Guillermo Donoso, Pontificia Universidad Católica de Chile

10:30 Close of session


Wastewater availability is likely to increase in quantity over the coming decades due to population growth and urbanization. In order to combat water scarcity and to improve crop productivity, recent findings show that wastewater is playing an increasingly important role. Current agricultural wastewater use is already a multitude larger than previously estimated; around 10-15% of irrigated croplands indirectly use untreated wastewater globally. This figure is likely to increase markedly over the next few decades in response to rising levels of water stress in inhabited catchments. This raises health concerns and contributes to the negative perception of its use, as treated wastewater is only applied on 0.3% of irrigated croplands.

Different case studies presented during the seminar showed the successes linking the sanitation chain with irrigated agriculture and the advantages of doing so with regards to access to water, nutrients and the improved quality of life through economic gains. Although success stories are present, and can be learned from, there are still major challenges in terms of health security, economic viability, government support and public acceptance. Especially with the increase of anthropogenic pollutants, such as pharmaceuticals, strong regulatory frameworks are needed to secure health safety and promote public acceptance, while identifying solutions that are acceptable and economically feasible for farmers and agricultural workers. In low density rural areas, evidence shows that low cost interventions at the household and community level is an opportunity to increase agricultural wastewater re use.

A limiting factor for further increases of wastewater reuse in agriculture is consumer’s acceptance and risk perceptions. Harnessing the opportunities for agricultural wastewater reuse, however, requires closing the gap between public perception and actual knowledge, which in turn needs taking into consideration the different ways people learn. Consequently, a portfolio of transfer approaches, such as information sharing mechanisms and applications, field visits, and traceability applications, among others, should be considered. Achieving agricultural reuse of wastewater in practice requires long-term cross-sectoral dialogue and engagement processes. Long-term financial viability of wastewater reuse projects requires that externalities, in this case negative impacts on humans and the environment, need to be accounted for in the financial model of the systems.

We advocate for a change of mentality - making resource recovery and reuse central to treatment, while also protecting health. This requires increasing social acceptability and trust along the entire value chain - from waste to food – as we need to be responsive to the diverging interests and needs among the different sector stakeholders. By doing so, wastewater reuse in agriculture can contribute to achieving several 2030 SDG’s, among which are 1 (poverty), 2 (food security) and 6 (water and sanitation).