Improving wastewater use in agriculture : an emerging priority

Wastewater use in agriculture is a growing practice worldwide. Drivers include increasing water stress, in part due to climate change; increasing urbanization and growing wastewater flows; and more urban households engaged in agricultural activities. The problem with this trend is that in low-income countries, but also in many middle-income countries, it either involves the direct use of untreated wastewater or the indirect use of polluted waters from rivers that receive untreated urban discharges. This poses substantial risks, in particular microbial risks to public health. To address these risks, the World Health Organization in 2006 issued new guidelines for the safe use of wastewater.This paper aims to highlight the growing importance of improving wastewater use in agriculture across the spectrum from lower to high-income countries. It presents an innovative approach linking key issues related to different aspects of wastewater irrigation to a country’s level of economic development. Based on data presented in the World Bank’s World Development Report, it differentiates between four country income levels to create a typology for analyzing current issues, trends, and priorities for improving agricultural wastewater use with a focus on reducing the risks to public health. It also presents the basic principles of the new 2006 World Health Organization Guidelines, and how to apply them. Beyond regulatory aspects, the paper also discusses other aspects that are important for achieving a more integrated approach to agricultural wastewater use, including institutional/planning, technological, economic/financial, and social issues. Finally, the paper provides recommendations for moving the wastewater irrigation agenda forward.