Wastewater irrigation: sewage waters a tenth of world’s crops
Updated - Thursday 17 November 2005
Sewage, often untreated, is used to irrigate 10 per cent of the world’s crops, according to the first ever global survey of wastewater irrigation . This is a largely hidden practice and is outlawed in many countries. However, many farmers, especially those in urban areas, use sewage because it is free and abundant, even during droughts, and, being full of nitrates and phosphates, acts as an effective fertiliser. In parts of Mexico, Jordan, Israel and Tunisia, sewage is treated to remove pathogens to make it safe for irrigation. But in India, China and Pakistan, treatment is rare, exposing crops to disease-causing pathogens and toxic industrial waste. Consumers would rather not eat food that has been grown with sewage, but they are often unaware how it has been produced. The study, published in August 2004, concludes that banning the practice is not usually practicable. “We need to recognise that sewage is a valuable resource that grows huge amounts of food. So instead we should help the millions of farmers involved to do it better,” said Chris Scott, co-editor of the study.
Scott is the South Asia regional director of the International Water Management Institute (IWMI), one of three partners that have signed a memorandum of agreement to develop Wastewater Agriculture and Sanitation for Poverty Alleviation (WASPA). The other two are the IRC International Water and Sanitation Centre and the Streams of Knowledge Global Coalition of water and sanitation resource centres. This network brings closer collaboration between the Water for Food and WASH sectors by showing how to integrate wastewater agriculture development into holistic strategies for waste water management and household centred sanitation.
The programme is starting with action research and demonstration projects in Burkina Faso and Mali, and proposals have also been developed for Bangladesh, Sri Lanka, Ghana and Cameroon.
Under right conditions
The key message is that wastewater can be treated and used safely and there is a need to institutionalise the use of waste water under the right sanitary conditions. To achieve medium or long term sustainability, strategies need to take into account dynamic change in local situations, especially demographic growth, urbanisation patterns, economic trends and environmental conditions .
It is also important to develop practical projects so that experience on the ground can contribute to development of practical and applicable international guidelines and feasible technologies. The World Health Organization has welcomed this contribution from IWMI, IRC and the STREAMS coalition, and is undertaking to develop and improve guidelines on the health aspects. Such guidelines need to be reflected in national regulatory frameworks to develop waste water agriculture in the context of sound sanitation policies and local strategic sanitation action plans, based on stakeholder participation.
The programme has the opportunity to create an impact at local, national and international level, and to show how to improve livelihoods and hygiene in small and intermediate sized towns, by bridging the gap between the Water for Food and the WASH sectors.
There are four major challenges to be tackled, to achieve:
- Innovative approaches to link Water for Food and WASH sectors
- Affordable and sustainable technologies
- Effective participatory planning
- Better information sharing and capacity building
Innovative Approaches to link Water for Food and WASH sectors
Local authorities need to recognise the great potential wastewater has for generating livelihoods for the urban poor. Moreover, in the rapidly growing peri-urban areas of the secondary towns, wastewater disposal is a serious problem. Innovative ways of planning sanitation and wastewater management for agricultural end-use particularly in arid and semi-arid environments can help overcome two problems. Town and city planners and health and agriculture authorities will have to link hands with poor farmers and urban dwellers to implement new WASH approaches and improved wastewater agriculture practices.
Affordable and Sustainable Wastewater Technologies
WASPA focuses on decentralised wastewater management approaches, which are environmentally sound and sustainable in terms of investment, operation and maintenance in peri-urban neighbourhoods in secondary cities and towns. WASPA will encourage and link up organisations and projects developing wastewater treatment technologies to reduce health risks from pathogens and other pollutants commonly found in domestic wastewater, while maintaining the maximum level of valuable nutrients for crops.
Effective Participatory Planning for Wastewater and its Utilisation
The use of wastewater by farmers will not go away. It cannot be ignored or dealt with by imposing bans on its use. Municipal policy-makers and planners need to confront reality and face the challenge in innovative ways. WASPA will assist local government to develop, effective and participatory policies, strategies, approaches and regulations for wastewater collection, treatment and use in urban agriculture. WASPA will work in partnership with others, making use of its own and others’ research findings.
Reaching Target Groups through Information Sharing and Capacity Building
WASPA will improve knowledge sharing by packaging information and making it available through multiple media. This information needs to be targeted to meet the needs of different stakeholders, such as municipal policy-makers, planners and practitioners, and farmer associations who need different types of information. Learning Alliances will be another mechanism to build local capacity and to move results from action research and demonstration projects to practical strategies and actions for local governments.
IRC’s WASPA site: http://www.irc.nl/page/13348
Related web site: IWMI - Reuse of Wastewater for Agriculture
 Scott, C. ; Faruqui, N.I. and Raschid, L. (eds) (2004). Wastewater use in irrigated agriculture : confronting the livelihood and environmental realities
Contact:Dr. Chris Scott, Director, IWMI Regional Office (South Asia), India, mailto:email@example.com ; Dr. Liqa Raschid-Sally, Waste Water Specialist, IWMI, Sri Lanka, mailto:firstname.lastname@example.org ; Naser Faruqui, IDRC, Canada,
Source: New Scientist, 18 Aug 2004
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