e-News November 2013 - Wastewater reuse in agriculture

Toilets, farms and food security: The links, risks and opportunities

On November 19, 2013 the UN Secretary General Ban Ki-Moon launched World Toilet Day. The U.N. General Assembly declared November 19 as World Toilet Day in 2001, and the UN plans to launch an initiative soon to end open defecation. Considering that a third of the population around the world lack toilets (around 2.5 billion!) and that over 800,000 children die each year from preventable diarrheal diseases, this is clearly a global crisis. But the big question is what does this have to do with food security and agriculture? It turns out to be a lot more than most people realize.

Cities in Sub-Saharan Africa are expected to grow faster than in any other region. Already with the rapid pace of urbanization, cities are lagging behind in the provision of sanitation infrastructure and facilities. Commercial sewage trucks commonly dump fecal sludge in open spaces. Individuals without access to toilets openly defecate or dispose waste in open gutters. The fecal material makes its way into water bodies and contaminates both surface and groundwater.

At the same time, the rapid increase in population in the cities of Africa created rising demand for food in urban areas. Farmers have met the demands in the city market for fresh produce by farming on urban and peri-urban lands. However, farmers commonly use the polluted surface water to irrigate the fresh vegetables and other crops, which are then sold to traders to sell in local markets. It is imperative that urban and peri-urban food production continues to provide a critical source of nutrition and job creation, but the risks associated with irrigating with wastewater also need to be reduced for consumers, traders and farmers.

A number of global organizations, in partnership with national governments and local partners, have focused on developing solutions that will minimize risk and also taken advantage of the nutrients and energy available in human waste. The World Health Organisation (WHO) and Food and Agriculture Organisation (FAO) have developed manuals that are useful to those who work along the value chain of waste generation to food consumption – some of which are listed below.

The International Water Management Institute’s (IWMI) research into water quality, health and environment  is showing great potential for safe and cost effective ways to reuse waste in agriculture. IWMI scientists are examining ‘resource recovery’ from waste to transform waste into opportunity to capture nutrients and generate profit.

One critical element is developing business models to recover and safely reuse resources generated from liquid and solid waste to promote food security, cost recovery in the sanitation sector, and livelihood opportunities, while also safeguarding public health and the environment in poor urban and peri-urban communities in developing countries.

IWMI West Africa is using a novel 'Design for Service' approach in Ghana's sanitation sector by demonstrating the economic, social and operational benefits of four resource recovery options from waste: irrigation, land application of composted fecal sludge, aquaculture and biogas. The research may generate a model for turning waste into cash that can then be used to operate and maintain sanitation infrastructure for long-term sustainability through a pilot that is rehabilitating two wastewater treatment plants. This project emphasizes safe resource recovery, where farmers irrigate with treated instead of untreated wastewater. 

Another project that stands out for its innovation with regards to harnessing the nutrients in waste and for which IWMI received a Grand Challenges grant award is the development of Fortifier. The project is enhancing safe use of excreta in agriculture as a means of managing fecal sludge and as revenue source for the sanitation value chain. The project has piloted the production of tons of fecal based fertilizer material Fortifier. IWMI is working with partners to develop market chains, detailed business plans, and a marketing plan for Fortifier in two cities in Ghana. This project will demonstrate that Fortifier technology improves the sustainability of the sanitation value chain by generating a revenue stream, which can measurably improve a city’s fecal sludge management.

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