Blue Diversion Autarky, a self-sustaining grid free toilet

2015 - 2017 • Eawag/Sandec (Swiss Federal Institute for Aquatic Science and Technology)


Development of technologies and prototype reactors for the on-site treatment of source-separated urine, feces and polluted water from anal cleansing and handwashing.


“Blue Diversion AUTARKY” is the continuation of Eawag's RTTC project "Blue Diversion". In this new phase we will develop technologies and prototype reactors for the on-site treatment of source-separated urine, feces and polluted water from anal cleansing and handwashing.

The urine treatment reactor will consist of a first process step, in which calcium hydroxide is dosed to the fresh urine to increase the pH to above 12 to stabilize the nitrogen content, to precipitate phosphorus and to inactivate pathogens. In the second step the water is removed by passive evaporation techniques driven by atmospheric energy to avoid further energy requirements. The final products of the urine treatment are two solids; one containing all phosphorus, another containing all other nutrients and salts.

The feces treatment will be based on hydrothermal oxidation (HTO, also known as supercritical water oxidation SCWO). Its final products are water and precipitated solids. The latter contains all the phosphorus from feces. To heat up the process energy is needed once, it can be provided by a generator or a simple 220V power plug. Further energy demand is covered by a solar panel.

The water treatment reactor is based on gravity driven membrane technology (GDM) developed during the previous phases of the "Blue Diversion" project (see also in the SuSanA project database). The goal is to better understand and verify the safety of the system with respect to the user, and to explore alternative technologies such as activated carbon, ozone and UV light which may reduce capital and energy costs.


Image: Blue Diversion Autarky, a self-sustaining grid free toilet

Countries of activity

Location of main activity


Development of prototype reactors for the on-site treatment of source-separated urine, feces and polluted water.

Further information

Research or implementation partners:
- Eawag (Swiss Federal Institute of Aquatic Science and Technology)
- PSI (Paul Scherrer Institute)
- FHNW (University of Applied Sciences and Arts Northwestern Switzerland)
- EPFL (Swiss Federal Institute of Technology in Lausanne)
- SLU (Swedish University of Agriculture)
- EOOS (Austrian Design Office)

Filter tags

Bill & Melinda Gates Foundation Europe, Caucasus & Central Asia Faeces or faecal sludge Fundamental research and engineering Global Greywater or wastewater Other Product design and engineering Resource recovery Switzerland Toilets or urinals (user interface) Treatment of wastewater or greywater University, education or research institution Urine


Eawag (Swiss Federal Institute for Aquatic Science and Technology)

Eawag is a world-leading aquatic research institute. Its research, which is driven by the needs of society, provides the basis for innovative approaches and technologies in the water sector. Through close collaboration with experts from industry, government and professional associations, Eawag plays an important bridging role between theory and practice, allowing new scientific insights to be rapidly implemented.

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