Published in: 2015
Eawag (Swiss Federal Institute for Aquatic Science and Technology), Switzerland
Swiss Federal Institute for Aquatic Science and Technology
This library entry contains background documents and results for a grant that Kai Udert is leading and which is funded by the Bill and Melinda Gates Foundation. A link to the discussion forum for this project is provided below.
“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. 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.
We are also examining how the same membrane technology functions in systems representing higher and lower organic loading as used in the toilets from other RTTC-partners e.g. RTI International.
Documents available for download (see below):
1 - Poster: On-site treatment - the Autarky Toilet (April 2015)
2 - Poster in French: La Toilette Autonome (April 2015)
Various authors (2015). Blue Diversion Autarky, a self-sustaining grid free toilet - Various documents on results from research grant. Eawag (Swiss Federal Institute for Aquatic Science and Technology), Switzerland
English Fundamental research and engineering
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