Solar disinfection: inventor unveils solar-powered water purifier

Photo: Solvatten

Swedish inventor, Petra Wadström, has unveiled Solvatten, a solar-powered water purifier, that she hopes will be used to provide household drinking water in developing countries.

Developed over a period of eleven years, the device resembles a standard jerrycan. It can be filled with up to 10 litres of water, opened out and left in the sun. A simple indicator uses a red or green face to show users when the temperature has reached 55°C and the water is safe to drink. It uses both thermal energy (heat) and UV radiation from sunlight, a created turbulence and a filter to treat water of up to 200 NTU. Water samples with more than 200.000 E. coli/100 ml have successfully been treated, the Solvatten web site claims.

Serving a family of five, a Solvatten device costs US$ 35 and lasts 5 years or more. The estimated cost per litre of water is 0.002 USD ( based upon 10 litres of water treated, 300 days per year).

The Solvatten company has already tested its device in Kenya and Nepal. In 2009 the first units of Solvatten will reach Nepal for a user study involving a number of families, schools and health centres. The programme is being implemented in collaboration with UN-HABITAT and ENPHO, the Environment and Public Health Organisation.

The Solvatten can also be used a solar water heater to produce hot water.

See videos below on Solvatten trials in Nepal and a product presentation by Petra Wadström.

Source: edie, 12 Jan 2009 : Solvatten web site