Solar Water Disinfection: A Guide for the Application of SODIS
Regula Meierhofer & Martin Wegelin
Solar Water Disinfection (SODIS) is a simple, environmentally sustainable, low-cost solution for drinking water treatment at household level for people consuming microbiologically contaminated raw water. SODIS uses solar energy to destroy pathogenic microorganisms causing water borne diseases and therewith it improves the quality of drinking water. Pathogenic microorganisms are vulnerable to two effects of the sunlight: radiation in the spectrum of UV-A light (wavelength 320-400nm) and heat (increased water temperature).
A synergy of these two effects occurs, as their combined effect is much greater than the sum of the single effects. This means that the mortality of the microorganisms increases when they are exposed to both temperature and UV-A light at the same time.
SODIS is ideal to disinfect small quantities of water of low turbidity. Contaminated water is filled into transparent plastic bottles and exposed to full sunlight for six hours. During the exposure to the sun the pathogens are destroyed. If cloudyness is greater than 50% , the plastic bottles need to be exposed for 2 consecutive days in order to produce water safe for consumption. However, if water temperatures exceed 50°C, one hour of exposure is sufficient to obtain safe drinking water. The treatment efficiency can be improved if the plastic bottles are exposed on sunlight reflecting surfaces such as aluminium- or corrugated iron sheets.
88 Pages
Publication Details
- Published: 2002
- Publisher: EAWAG
- ISBN-10: 3906484246
- ISBN-13: 9783906484242
- Dewey Decimal: 621.
- ECHO Library: 621. MEI