Drinking roof water and showering with sewage water

14 January 2010

"self" is an energy and water independent cell for living and working. The joint project of Empa, Eawag and the Zurich University of Arts will be presented to the public for the first time at the Swissbau in Basel from January 12 to 16, 2010.

"self" is intended to show the possibility of living with the latest building concepts virtually without external energy supply and with an internal water cycle today – without compromising convenience. Hardly anything in "self" meets today's "state of the art". Almost everything is made up of individually designed components, such as the building envelope with sandwich panels made of glass fibre reinforced plastic and the thermal insulation with highly insulating vacuum panels. A heat exchanger preheats the fresh air with exhaust air; filtrating rain water into fresh water only needs gravity. The hydrogen technology will undergo practical testing for cooking and heating. Solar cells on the roof deliver the required electricity for hydrogen synthesis. This is then stored intermediately in containers filled with metal hydrides, a new development of Empa.

Low-pressure membrane technology as a chance

Eawag has developed and implemented the water concept for "self". Because decentralized systems for drinking water processing and sewage water recycling could make a significant contribution to achieving the development goals of the millennium. The chance for this is provided especially by the low-pressure membrane technology that Eawag is researching. The promising results from Dübendorf show that ultra-filtration (filtration through membranes with pore sizes ranging from 0.002 to 0.05 µm) without high-maintenance and energy-intensive pumps can be operated with gravity only. In the field of drinking water processing, the method has been advanced to a stage in which first pilot plants of major manufacturers are already in operation. Field tests of small-scale membrane bioreactors still have to show how rugged such systems are. The membrane bioreactor that is hardly the size of a refrigerator in the narrow installations room of the container is intended to recycle the sewage water from the kitchen and the shower so that it can be reused for the same applications and to flush the toilet. Only the heavily soiled waste water from the water-saving toilet will be removed from the cycle. By separating urine and faeces, it is conceivable to increase the share of recycled water even more in the future.

• Schema [pdf]

Numerous project partners

The concept for "self" was developed by Empa in cooperation with Eawag, students of the Zurich University of Arts ZHdK and of the Energy class at the FHNW. About 20 industrial partners are involved in the conversion. "self", with is very own design, combines a modern living and working concept with practical research and specific information for experts. (Author: Andri Bryner)

Further Information

• The water concept in the independent house [pdf]
• Project flyer [german, pdf]
• Empa project website (currently not updated)
• Empa media info [pdf]
  

Additional images

© Eawag; Free use only in connection with a report on the "self" project  - no archiving.

The ultra membrane filter for processing rainwater into
drinking water.

The narrow installations room in "self". On the left, the metal
hydride storage for the hydrogen, in the middle the micro
sewage plant (with visible membrane module) and the process
tank, the heat accumulator on the right.

Assembly of the membrane bioreactor for process water
recycling.

The membrane filter module for the membrane bioreactor.