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The increased emphasis on non- or post-treatment measures in the 2006 edition of the World Health Organization Guidelines on the safe use of wastewater in agriculture will require behaviour change along the food chain. Low health risk awareness likely limits adoption of safe food practices in many areas. Based on experiences from Ghana, where informal wastewater irrigation occurs around all cities, the necessary steps for increasing adoption probability are outlined under a generic framework, which is based on the four pillars of social marketing, incentive systems, awareness creation/education and application of regulations. Any of these approaches requires research of the target groups. Cost effectiveness can be improved by linking related efforts with other hygiene and food safety interventions.

This paper sets out the trends and challenges of wastewater use in agriculture; identifies the risks and benefits of wastewater irrigation; describes the risk-assessment and management framework adopted by the World Health Organization, the Food and Agriculture Organization of the United Nations and other international and national organizations; and proposes measures for applying the framework to reduce health risks by moving from unplanned to a planned, integrated, approach to wastewater use for irrigation.

In this article the authors draw from a comparative assessment of different interventions, examining their costs, risk-reduction potential and cost-effectiveness. They consider a case study in Ghana, using an approach that integrates quantitative microbial risk assessment (QMRA), disability-adjusted life years (DALYs) and cost-effectiveness analysis. Most practices appear highly cost-effective, although only a few are likely to avert more than 80% of the DALY burden. As compliance will always be a challenge, the results support the need for a multi-barrier risk-management approach that, where possible, combines treatment and non-treatment interventions.

Opportunities for public–private partnerships based on cost recovery from the reuse of human waste remain unexplored. In this paper, the authors present four potential business models involving aquaculture, biogas recovery, compost production and the use of faecal sludge as an industrial fuel, and describe their associated financial flows. The business models are based on efficiency indicators that can provide decision support to local authorities and entrepreneurs in choosing options that are best suited to local conditions and needs. The ultimate target should be that a portion of revenues from reuse can help finance less-profitable sections of the sanitation service chain.

Many farmers in developing countries use treated or untreated wastewater to irrigate crops, partly in designated irrigation schemes, but mostly on large areas of small farms located along streams passing through or near cities. Much of the wastewater use is informal and unplanned, as farmers divert water from streams that carry untreated or partially treated effluent from cities and towns. The farmers generate good revenue by selling fresh produce that, otherwise, might not be available in urban markets. However, wastewater irrigation also creates health risks for farmers, their families, and consumers. Public officials must consider those risks and the values generated through wastewater irrigation, as they implement policies to protect farmers and consumers from the negative health impacts. Given the increasing scarcity of fresh water in many urban and peri-urban areas of developing countries, the increasing demand for food, and the persistent desire to improve the livelihoods of small-scale farmers, th...