SoWaDis – thermal water disinfection

Solar Water Disinfection

On behalf of the waterkiosk foundation, the Swiss Institute for Solar Technology (SPF) in Rapperswil sought a solution that would be both robust and inexpensive to implement, but also easy to understand and maintain.

They came up with a solution called SoWaDis, which stands for “solar water disinfection”. This water treatment technology is based on thermal disinfection (similar to boiling of water).

All SoWaDis water systems installed in Tanzania since 2011 still work faultlessly and require minimal maintenance. The SoWaDis system is our preferred technology for “safe water schools “, “safe water hospitals ” and “safe water villages “. More than 100 plants are now in operation.

The SoWaDis systems offer the following advantages:

The system is very easy to operate and maintain. These advantages make SoWaDis the most suitable technology for developing countries.

SoWaDis is 100% solar powered and works without conventional electricity and operating materials. In contrast to other technologies, the system does not require pumps, chlorine addition, replacement of UV lamps and elaborate cleaning of filters.

One SoWaDis unit produces up to 600 liters of clean drinking water per day, depending on location and use. A modular concept can also be used to achieve a higher daily output. The system is very cost-effective compared to other common water treatment technologies. This is mainly due to its extremely low maintenance and operating costs.

Through the simple combination of several SoWaDis units, it is possible to supply even large quantities of clean drinking water without substantial efforts.

SoWaDis applies heat to disinfect the microbiologically contaminated water. This is one of the safest and most effective methods to disinfect water. The system’s thermally controlled valve and its design ensure sufficient hot water dwell time for cleaning and treatment.

Broadly accepted
As the process is similar to boiling water, local users understand and accept the concept from the very beginning and trust its effectiveness in producing clean drinking water.


Operating principles and specifications for a SoWaDis system are available as PDF.

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