event 19 sept. 2011

Nexus Blog // Sanitation and the Nexus

Sustainable and Productive Sanitation is a Perfect Example of the Water, Energy and Food Security Nexus

category Nexus Blog
Tunisia toilet

Sanitation and wastewater treatment are closely interlinked with the given nexus approach of the conference. If the sanitation system is sustainable and productive (see also {www.susana.org}), the benefits not only for public health but for water, energy and food security are enormous. Sustainable and productive sanitation systems save water and energy, contribute to renewable energy security (biogas), and contribute to food security through decentralised and cost-efficient provision of fertiliser, soil conditioner or nutrient rich irrigation water.

Sanitation and Water

Adequate sanitation without water is not thinkable. A toilet might need little or no water to flush but sanitation includes many other water-dependent processes such as the hygiene practice of hand washing with safe drinking water. Insufficient sanitation practices — such as the lack of containment of faecal matter and the inadequate treatment of wastewater — pose direct risks to drinking water sources and to public health.

In many water scarce regions, great amounts of the resource are needed for irrigation in agriculture. Treated domestic wastewater is an excellent source for irrigation because of its constant flow all year round and its contents of various plant nutrients. Wastewater is already re-used worldwide, with a large plant in Milan, Italy, posing a good example. But in most cases re-use is practiced out of necessity and without safe regulations, due to the lack of other water sources. This year's serious e-coli epidemic in Germany also reminds Western countries of the link between sanitation, water supply and food security.

This is why legislators need to both recognise the benefits of using treated wastewater, as well as assure its safety through better regulation and the provision of incentives to ensure adequate treatment and re-use according to the WHO guidelines (2006).

Sanitation and Food Security

The use of treated sanitation products — urine and faeces — as fertilisers can help mitigate poverty and malnutrition, and improve the trade balance of countries importing chemical fertilisers, especially in respect of phosphate fertiliser, a non-renewable resource. Food security can be increased with a fertiliser that is readily available for all at very little cost, regardless of infrastructure and economic resources

Source separation and safe handling of nutrients from the toilet systems is one way to facilitate the recirculation and use of excreta in crop production. Urine contains most of the macronutrients as well as smaller fractions of the micronutrients excreted by human beings. Nitrogen, phosphorus, potassium and sulphur as well as micronutrients are all found in urine in plant available forms. Urine is a well balanced nitrogen-rich fertiliser which can replace and give the same yields as chemical fertiliser in crop production. In addition, treated and sanitised faecal matter contains a number of nutrients and organic matter that improve soil fertility and combat desertification.

Safe handling of urine and faeces including treatment and sanitisation before use according to the WHO guidelines (2006) is a key component of sustainable sanitation as well as sustainable crop production.

Sanitation and Energy

High energy demand is required for conventional sanitation systems, especially for aerobic wastewater treatment targeting nitrogen (N2) removal. A tremendous amount of energy is required to re-capture N2 from the air to produce chemical fertilisers.

On the other hand, sanitation products — wastewater, urine and faecal matter — contain a lot of energy. Firstly, the heat of the wastewater can be re-gained. Secondly, energy in the form of biogas can be gained through anaerobic digestion — a process already applied in large scale plants in industrialized countries, using the sewage sludge at the "end of the pipe". The energy yields would be even higher if anaerobic systems were applied at the source, for example through pour flush biogas toilets, and UASB treatment of wastewater.

It is therefore clear that with enough political will and the creation of adequate incentives for businesses and policy makers alike, sustainable and productive sanitation can be a major contributing factor to the achievement of greener economies, fostering job creation and poverty reduction along the whole sanitation, wastewater treatment and re-use chain.

Please contact jcornforth@stakeholderforum.org for a full list of citations used in this blog.

More information

For more information, case studies and best practices, please contact or visit the WECF website WECF is one of 15 NGOs which make up the German Water Sanitation and Hygiene (WASH) network. WASH will convene a workshop at the Bonn2011 Nexus Conference. For more information on WASH, please contact Claudia or

Dr. Claudia Wendland coordinates the sanitation projects at WECF and promotes re-use oriented sanitation concepts together with local NGOs. The WECF network has implemented more than 900 individual and 50 school toilet facilities based on UDD technology as well as some soil filter based wastewater treatment systems for demonstration in the last years in Eastern Europe, the Caucasus and Central Asia.


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