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SAFE USE OF WASTEWATER IN AGRICULTURE Research priorities. Overview. Situation and Trends The essence of the WHO Risk Assessment and Management Approach The gaps in Knowledge, Evidence and Enabling Environment Current Research
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Overview • Situation and Trends • The essence of the WHO Risk Assessment and Management Approach • The gaps in Knowledge, Evidence and Enabling Environment • Current Research • The Research Agenda for safe wastewater use in agriculture and aquaculture
Situation and trends • Fresh water resources are rapidly becoming scarce. • Rapid urbanization is resulting in increasing outflows of domestic wastewater. • There is a growing market of urban workers looking for fast food with “green” ingredients • Fertilizers are a costly input into the agricultural production system. Result: Farmers in rural and peri-urban areas are turning to the use of wastewater, excreta and greywater in agriculture and aquaculture in increasingly great numbers. Without effective risk assessment and management, such use incurs important health hazards. The associated water-borne disease risks affect farmers and their families, those who market the produce and consumers.
Situation and trends Wastewater use is extensive worldwide, and increasing • Ten percent of the world’s population is thought to consume wastewater irrigated foods. • Twenty million hectares in 50 countries are irrigated with raw or partially treated wastewater. • The use of excreta (faeces, urine) is important worldwide, but the extent has not been quantified. • The use of greywater is growing in both developed and less-developed countries – it is culturally more acceptable in some societies.
Situation and trends Wastewater use is extensive worldwide, and increasing • Ten percent of the world’s population is thought to consume wastewater irrigated foods. • Twenty million hectares in 50 countries are irrigated with raw or partially treated wastewater. • The use of excreta (faeces, urine) is important worldwide, but the extent has not been quantified. • The use of greywater is growing in both developed and less-developed countries – it is culturally more acceptable in some societies. Source: IWMI 2007
Third edition WHO wastewater guidelines: what is new? Health-based targets • Introduction of the concept of Disability-adjusted Life Years (DALYs). • Proposed tolerable disease burden of <10-6 DALY per person per year, equal to the health protection level applied to safe drinking-water. • Flexibility for national authorities to set health-based targets in line with what is realistic in the national socio-economic context.
Third edition WHO wastewater guidelines: what is new? Quantitative microbial Risk Assessment - QMRA A statistical approach to microbial risk assessment and an affordable alternative to conventional epidemiological studies. QMRA has four components: • hazard identification, • exposure assessment, • dose-response assessment, and • risk characterization
Third edition WHO wastewater guidelines: what is new? Preparation of a risk management plan
Third edition WHO wastewater guidelines: what is new? Cumulative risk management A systems approach to risk management. Objectives: • to ensure the most cost-effective implementation of risk reduction measures along the entire chain from waste generation to produce consumption • To recognize the true value of wastewater, excreta and greywater as a water resource and as a source of nutritients in support of agricultural production
Third edition WHO wastewater guidelines: what is new? Monitoring • Validation – to test new systems/processes for their capacity to meet specified targets • Operational monitoring – real-time observations to check whether the system is working as expected • Verification – to ensure the end product meets microbial quality specifications
Third edition WHO wastewater guidelines: what is new? Monitoring Table: Verification monitoring of microbial performance targets for wastewater and excreta use in agriculture Activity/exposure Water quality monitoring parameters (arithmetic mean) E. coli per 100 ml Helminth eggs per litre Unrestricted irrigation Root crops ≤103 ≤1 Leaf crops ≤104 Drip irrigation, high growing crops ≤105 Restricted irrigation Labour intensive, high- contact agriculture ≤104 ≤1 Highly mechanized agriculture ≤105 Septic tank ≤106
Third edition WHO wastewater guidelines: what is new? Policy harmonization and mainstreaming The guidelines propose how to do • Situation analysis and needs assessment • Establish a mechanism for policy dialogue • Obtain political endorsement • Engage in an adequately resourced policy dialogue • Ensure newly formulated policies and adjustments to existing policies are legitimized through Parliament and/or decreed by the Prime Minister’s Office The policy framework should form the basis for effective regulation
? Gaps in knowledge, evidence and enabling environment Technical gaps Concern: epidemiological details (drivers, attribution), statistical approaches of exposure and risk assessment, effectiveness of individual risk management methods in specific settings, combined effectiveness of risk management methods
? Gaps in knowledge, evidence and enabling environment Managerial gaps Concern: Determining optimal management structures at different levels Cost-effectiveness of different risk assesment options Optimizing indicators for monitoring Ways of training farmers and marketeers, and educating the general public
? Gaps in knowledge, evidence and enabling environment Gaps in the enabling environment concern: Policy options, design and test decision making criteria and procedures (public health, agriculture, water management) Balancing combinations of policies, legislation and regulation at different levels What are essential institutional arrangements and how are they sustained? Develop local capacities for interdisciplinary research supported by research policies
Current research:the WHO/FAO/IDRC project on non-treatament options for the safe use of wastewater in low-income communities. • To identify appropriate non-treatment options for health protection • To study the effectiveness of the non-treatment health protection measures in reducing health risks • To increase awareness of the guidelines among national governments • To synthesize research findings into a joint WHO/FAO/IDRC document that will help low- income countries adapt the WHO guidelines
Tamale, Ghana Dakar, Senegal Kumasi, Ghana Jerash, Jordan Current research WHO/IDRC/FAO FAO STAC University of Development Studies Royal Scientific Society ENDA -Tiers Monde KNUST
Research agenda Develop a methodology for and implement integrated health and economic impact assessments to further attribute the burden of disease fraction to specific components in the production and consumption of wastewater- and excreta-fed agriculture, particularly in low-income settings, and to prioritize interventions to improve health and livelihood outcomes. The impact assessments should cover all public health issues, with a focus on communicable diseases and nutrition, as well as livelihood and poverty reduction potential
Research agenda In different settings where wastewater/excreta are used for agriculture or aquaculture, fill data gaps on prevalence, persistence and transmission levels of key pathogens along the environmental pathways from fecal origin to human exposure, measure disease incidence among those exposed and evaluate the impact of individual and combined risk management measures on reducing these levels.
Research agenda 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.
Research agenda Design and test wastewater and excreta treatment systems that can be maintained in their ecological and economic context, and that thereby support the safe and productive use of wastewater and excreta in agriculture
Research agenda Develop and evaluate effective participatory governance mechanisms for sustainable sanitation design and operation and safe and productive wastewater and excreta use.
Research agenda Study the role of current policy, legal and regulatory frameworks with a view to formulating updated version and test these versions for their effectiveness in better regulating the roles and responsibilities of all stakeholders in a concerted effort to reduce health risks associated with wastewater and excreta use in agriculture
