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Practicing the safe use of wastewater for food production

Compelling discussion, commentary, stories on agriculture within thriving ecosystems.

René van Veenhuizen from RUAF reviews two new guides on the safe use of wastewater in agriculture:

Safer Irrigation Practices for Reducing Vegetable Contamination in Urban Sub-Saharan Africa.  An illustrated guide for farmers and extension officers.  IWMI-KNUST 2012

On Farm Practices for the Safe Use of Wastewater in Urban and Peri-Urban Horticulture.  A training handbook for farmers field schools.  FAO 2012, ISBN 978-92-5-107330-8

Wastewater is a resource which can, when used safely, alleviate the pressure on (fresh)water resources and improve food security, particularly in urban and peri-urban areas. Wastewater is often heavily contaminated with disease-causing organisms and chemical agents that can seriously harm the health of the farmers, the traders who handle crops and the people who consume them. It is therefore very important for urban and peri-urban vegetable farmers to be aware of the health-risks associated with using wastewater for crop irrigation and to know how to use wastewater safely at the farm level to reduce those health risks. The competition for water and the growing importance of food supply from urban and peri-urban agriculture makes the "safe use of wastewater in agriculture" an urgent and important issue to address and promote.

Wastewater use for food production has been investigated for several years now, especially by the International Water Management Institute (IWMI) under the CGIAR Challenge Program on Water and Food (CPWF), in collaboration with RUAF, FAO, WHO, IDRC and others, and has led to many publications. Its importance increasingly is being recognised. In addition to on farm research, this safe reuse needs involvement of all stakeholders to develop appropriate legislation and guidelines for safe reuse. The WHO guidelines for safe reuse were adapted in 2006, but require local specification and adaptation to the needs and ways of learning of local partners.

Based on its work in Ghana with the Kwame Nkrumah University of Science and Technology (KNUST), IWMI developed an illustrated guide for farmers and extension officers. IWMI successfully collaborated with several local organisations in understanding the complicated issue of reuse and each other’s stakes. Through a series of meetings with famers, vendors, consumers and extension staff safety measures can be analysed and accepted. The 14 illustrations of the guide can be used for sessions in the field or classroom.

A way of systematically working with farmers in improving their farming systems is the Farmers Field Schools approach. First developed by FAO on Integrated Pest Management, Field Schools exist nowadays on a wide variety of topics. Recently RUAF developed the Urban Farmer Field School approach as part micro-enterprise development with small-scale urban farmers, working on the most important technical and organisational changes that were identified.

The training handbook for farmer field schools (FFS) on safe use of wastewater in urban and peri-urban horticulture by FAO uses the same material developed in Ghana by FAO, IWMI and KNUST. It can be used in all kinds of specific or broader field school approaches, or stand alone in working with farmers and others along the farm to fork chain, in reducing the risk of using wastewater.

The training handbook is aimed at working with farmers using wastewater and focuses on low-cost and low-tech on-farm wastewater treatment and safe irrigation practices. The handbook has five main so-called “units”, which can be used for separate FFS sessions:

  • Contamination of irrigation water and vegetables.
  • Five easy ways to reduce health risks
  • Monitoring and evaluating performance
  • Farmer to Farmer Training
  • Dissemination and Communication Strategies.

Each unit has an introductory text and one exercise to guide farmers through the session. The first three sessions are focused on improving own practices, while the latter two deal with spreading the knowledge and supporting other farmers to do the same.

Both documents are concise and provide a good basis for developing local sessions. We recommend making ample use of information and visuals of the local situation and applying it to local farming practices.

Both documents are available free online. Comments for improvement and experiences with its use are highly appreciated by the authors.

Additional Resources:

IWMI's work in Wastewater

Related Videos: 

Recycling Realities in African Cities. Towards safe wastewater use in agriculture.

Health risk reduction in a wastewater irrigation system in urban Accra, Ghana. 


It's stunning to see that while urban agriculture is a middle class pastime in the West, if carefully managed, it can actually prove to be a very important tool in a developing world. Sometimes I feel that we should almost obligatorily read guides on use of wastewater and generally more efficient upkeep of our oh-so-eco-friendly little gardens.

Thanks for the the valuable suggestions…keep writing on this topic. "Practicing the safe use of wastewater for food production" - interesting title René. Very valuable information René.