A simple and efficient disinfection method using natural (solar) or artificial (lamp) ultraviolet radiation. Artificial designs include mercury-filled UV-lamps placed next to the water flow. These have a limited applicability in middle- to low-income settlements. SODIS is a natural radiation using technology, but is limited to daytime use. A good removal of bacteria, protozoa and most viruses is achievable.
SODIS is inexpensive and offers a reasonable protection against pathogens. Utilizing used PET flasks requires no hardware purchase. Purchase of UV lamps for one household may be prohibitive (USD2-300), but power use is lower than that of boiling/pasteurization.
UV lamps are suitable for (small-)community, possibly shared household application. The treatment requires no specific skills. When other treatments are coupled, professional organization may be necessary. SODIS is a simple, household-level application, where organizational needs include public education only.
Environment related issues are estimated to be minimal. Only mercury lamps itself might represent serious health hazard when not properly disposed. The efficiency of UV treatment might be reduced in case of increased water flow (like with heavy rainfall events) because of high turbidity water.
Sunlight or sufficient UV-C (100-280 nm) radiation required. Works better if water becomes >45oC and >6 hours of sun. Both sub-methods easy in operation and maintenance. UV lamps: regular checking for scaling on protective sleeve. Pre-treatment required with straining or settling.
Treatment leaves no aesthetic marks in water. SODIS is a popular method with >2 million users worldwide. Insufficient functioning may allow reactivation of microorganisms, posing health risk to users. UV lamp to be used with caution (exposure hazard: skin/eye damage).
No relevant remarks for UV treatment.