TECHNOLOGY > SODIS

SODIS (Solar Water Disinfection)

Introduction

The drinking water situation is precarious in Kibera. Diarrhoeal diseases are transmitted through contaminated drinking water. SODIS can contribute to improve this precarious situation.

SODIS is cheap and practical water treatment method which uses solar energy to improve the microbiological water quality. It is used at household level to treat small quantities fo drinking water. SODIS was developed by the EAWAG Institute in Switzerland and is promoted by SANDEC ( www.sandec.ch).

For detailed information on SODIS please visit www.sodis.ch.

Technique

What is SODIS?

A treatment method to eliminate the pathogens which cause water-borne diseases
Ideal to disinfect small quantities of water used for consumption
A water treatment process depending on solar energy only
An alternative water treatment option for use mainly at household level
An old but so far hardly applied water purification method

A proud grandma showing her SODIS bottle

A grandma with her grandchild
proud to use SODIS in Kibera.

SODIS does not

change the chemical water quality
change the odour nor the taste of the water
increase the water quantity or reduce water shortages

Limitations of SODIS

SODIS is not useful to treat large volumes of water
SODIS requires relativly clear water (turbidity less than 30 NTU)
SODIS needs solar radiation (exposure time 6 hours under bright or up to 50% cloudy sky, or 2 consecutive days unter 100% cloudy sky)

SODIS is ideal to treat small quantities of water. Contaminated water is filled into transparent plastic bottles and exposed to full sunlight for six hours.

Sunlight is treating the contaminated water through two synergetic mechanisms: Radiation in the spectrum of UV-A (wavelength 320-400nm) and increased water temperature. If the water temperatures raises above 50°C, the disinfection process is three times faster.

Description of project areas where SODIS is implemented:

Kibera

Downloads

SODIS promotion leaflets (.ppt, 136kB)
Kibera Sodis Case Study (.pdf, 200kB)