Solar Disinfection

ENTRY DATE: 03.05.2015 | LAST UPDATE: 03.05.2015

CATEGORIES:

  • Water Resources
  • Securement of quality of drinking water

TECHNOLOGIES MATURITY:

Applicable immediately

Technology Owners:

  • SODIS – Solar water disinfection
  • Private implementing agencies, NGOs
  • Households

Needs Address

Supply of safe water for domestic use

Adaptation effects

  • Diversity of safe water supply when alternative sources become unusable – less time spent on water collection enables more time to be allocated to agriculture and other livelihood activities
  • Increases water security

Overview and Features

Solar water disinfection is a type of portable water purification that uses solar energy to make biologically-contaminated (e.g. bacteria, viruses, protozoa and worms) water safe to drink. Water contaminated with non-biological agents such as toxic chemicals or heavy metals require additional steps to make the water safe to drink.

Solar disinfection involves the removal of bacteria, protozoa and other viruses from water. Bacteria and virus are removed when water is kept above 62.8°C for 30 minutes or above 71.7°C for 15 seconds. Water is put in PET bottles or other transparent water containers and left in a place highly exposed to sunlight for 6 hours.


Figure: Batch and continuous solar disinfection (Source: Smet and van Wijk, 2002)

Cost

SODIS requires only PET bottles or other transparent containers and access to sunlight

Energy source

Solar water requires solar energy only

Ease of maintenance

Transparent containers need cleaning and replacing from time to time

Technology performance

The technology provides a viable alternative for safe water where none/ few options for safe drinking water are available. 

Considerations

  • Appropriate storage is needed post-treatment to stop the water becoming re-contaminated
  • Can be conducted by unskilled personnel, however training and education in the need for employing safe water sources should accompany introduction of this technology
  • Ineffective operation of the solar treatment can lead to reactivation of microorganisms therefore training should be provided as art of the introduction of the technology

Co-benefit, suitability for developing countries

  • Provides health and sanitation benefits, reducing disease and mortality
  • Environmentally friendly method of disinfecting water
  • SODIS is affordable, requiring minimal inputs
  • Has been found to be acceptable to communities with no resistance
  • Adoption encouraged by NGO and CBO representatives

Information Resources

Smet, J. and van Wijk, C (eds.) 2002. Small Community Water Supplies: Technology, People and Partnership. Delft, the Netherlands. IRC International Water and Sanitation Centre. (Technical paper Series 40). Available from: http://www.ircwash.org/sites/default/files/Smet-2002-Small_TP40.pdf [20 January 2015]

SODIS, 2011. SODIS Method. Webpage. Available from: http://www.sodis.ch/methode/index_EN [20 January 2015]