Rapidly expanding cities, escalating water scarcity, food supply and livelihood needs, particularly in low-income regions, are all driving the increasing demand for untreated and treated wastewater and excreta for agriculture. Although much progress has been made in our understanding of these issues since the 'Hyderabad Declaration' of 2002, significant challenges remain to make the use of wastewater and excreta in agriculture safe, economically productive, and sustainable.

We -- an expert group from 30 international, regional, and national research institutes, multilateral and bilateral bodies, and universities based in 17 countries -- emphasize the need to support policy makers around the world to make informed decisions that lead to cost-effective interventions that improve public health, promote sustainable sanitation, protect the environment, and support food security and economic development.

Achieving this goal requires consolidation of information on the science and practice of wastewater and excreta use, and well-targeted research to address gaps in the evidence base needed to support informed decision-making. Therefore, we propose the following multi-disciplinary agenda for action:

1. Integrate health and economic impact assessments to determine the actual contribution of wastewater and excreta use to the burden of disease, particularly in low-income settings, and to prioritize interventions to improve health and livelihood outcomes.
   
   
2. Facilitate the adoption of the 2006 World Health Organization guidelines for the safe use of wastewater, excreta and greywater in low-income settings through the development and application of appropriate local practices and standards that take into account local capacities and resources. Specifically:
   • Fill data gaps on levels, transmission, persistence, and reduction of key pathogens along the environmental pathways from fecal origin to human exposure, and measure disease incidence among those exposed.
     
     
   • Rigorously evaluate -- in multiple geographical contexts -- a range of wastewater and excreta treatment approaches and other risk mitigation strategies for their cost-effectiveness and impacts on health, livelihood, and the environment.
     
     
3. Increase human, institutional, and technical capacities in low-income settings to:
   
   
• Detect important pathogens in human and environmental samples
  
  
• Design and operate wastewater and excreta treatment systems that can be maintained in their ecological and economic context, and thereby support the safe and productive use of wastewater and excreta in agriculture
  
  
• Develop and support effective participatory governance mechanisms for sustainable sanitation design and operation and safe and productive wastewater and excreta use.
  
  
4. Facilitate the exchange of information on best practices, including successful risk assessment and mitigation strategies, among partners around the globe through national and regional knowledge hubs and web-based data banks.

Note: The expert consensus does not necessarily commit the listed institutions to the proposed agenda for action.