Closing the nutrient loop

Wednesday, 11 August 2010 15:46

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See video on SEI's work through the Ecological Sanitation Research programme.

Success stories from China and Africa show how ecological sanitation can help mitigate poverty and replace chemical fertilizers in crop production.

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Poor sanitation and hunger have disastrous effects in the developing world, however, human urine and dried faeces are well suited as fertilizers and can help close the nutrient loop.

Only minute amounts of the plant nutrients are absorbed by and retained in a growing human body, the remainder leaves the body as excreta. As a consequence, nutrients from human excreta can be returned to the soil to fertilize crops.

SEI’s Ecological Sanitation Research (EcoSanRes) programme provides and promotes pro-poor sustainable sanitation by building local capacity in areas of Asia, Africa and Latin America. It has helped implement nationwide policy changes in India as well as leading a number of groundbreaking projects elsewhere.

The yellow revolution in Niger
In the Aguié province in southern Niger, more than 700 households collect and use urine as a liquid fertilizer. This ‘’yellow revolution’’ was triggered in 2009 when eight villages in southern Niger were given a demonstration of the effects of using urine as a fertilizer on cereals and vegetables.

Chemical fertilizers are costly and often of poor quality. Looking for alternatives, it was estimated that the annual quantity of plant nutrients in human urine and faeces produced by an average family in Aguié (nine persons) is roughly equivalent to one bag of urea (50 kg) and one bag of NPK (50 kg). Two such bags cost around USD 80 on the local market, which is more than most families can afford.

On this basis, the International Fund for Agriculture Development (IFAD) granted SEI and partners a pilot project to test the use of urine as a fertilizer and develop a strategy to facilitate an upscaling of productive sanitation.

For fertilizer collection, the eco-lilly urinal, a 25-litre plastic jerry can and a funnel, was promoted together with low-cost versions of urine-diverting dehydration and composting toilets.

Thanks to good yields and good-looking vegetables, the demand has been high for urinals and toilets that make the collection of the ‘’new fertilizer’’ possible.

Read more about the Niger projet here (external website)

Read more on productive sanitation initiatives in Burkina Faso and Niger here



Urine-diverting dry toilets in China
Although batch composting of manure is common throughout China, there is little experience with composting of human waste in urban centres. In a high-density urban setting in Dongsheng, in Inner Mongolia, a project has managed to do just that.

Urine-diverting dry toilets were installed and the faeces collected in basement bins from about 3000 inhabitants in a new housing project in Dongsheng. The toilets were transferred periodically to an onsite composting facility with six individual compartments, each with forced air supplied through small openings beneath the floor heating.

The result was a pure faeces compost with lower nitrogen levels and higher content of stable organic carbon compared to animal manure.

- Our work in Dongsheng shows that its possible to compost human faeces in an urban setting and that the compost along with urine provides a competitive alternative to chemical fertilizers, says Arno Rosemarin, Research and Communications Manager for the EcoSanRes Programme.

Read more about the project in Dongsheng here (external link)

Developing a human excreta fertilizer market in Burkina Faso
Since March 2009, human urine and dried faeces have been collected and ultimately sold on a ‘’human excreta fertilizer market’’ in Ouagadougou, the capital of Burkina Faso. The project has been implemented by CREPA , GTZ and ONEA, with contributions from SEI researchers.

Since 2006 the project partners have worked on ways to raise awareness on sustainable sanitation in four out of Ouagadougou’s 30 urban sectors. The challenge has been to provide an attractive sanitation system for peri-uraban households which at the same time provide valuable and safe fertilizers for Ouagadougou’s urban farmers.

More funding is needed, but the project has succeeded in raising awareness on urban excreta and nutrient management in Ouagadougou and the opportunities for urban agriculture.


Transport of urine to the fields, storage of urine and urine application in Ouagadougou. Photo: Linus Dagerskog

Read more about the Burkina Faso project here (external link)