The method of SODIS is based on the principle that exposure of sunlight diarrhea causing organisms in polluted water. The effects of solar radiation can inactivate pathogenic organisms. Scientists separated the various ultraviolet radiation effects that contain in solar radiation:

• UV-A interferes directly with the metabolism and destroys cell structures of bacteria.
• UV-A (wavelength 320-400nm) reacts with oxygen dissolved in the water and produces highly reactive forms of oxygen (oxygen free radicals and hydrogen peroxides), that are believed to also damage pathogens.
• Infrared radiation heats the water. If the water temperatures raises above 50°C, the disinfection process is three times faster.

The steps of SODIS has been explained with diagrams for easy-understanding:

If the weather is sunny, the minimum treatment duration should be at least 6 hours. When the weather is 100% cloudy, the minimum treatment should be 2 days. But when there is continuous rainfall, rainwater is suggested.

Actually this is not our club newest blog as I have decided to move from ussc.blogs.friendster.com to mmstudentclub.wordpress.com . The old information, events, photos and club’s missions can be still found at old blog, again ussc.blogs.friendster.com . I’ll not delete those. As most of our members are using friendster network, the club will still alive at friendster groups. I’ll upload information here and at friendster group simultaneously but not at friendster blog anymore.

As I have titled “upgrading”, some nice posts that will be useful for our myanmar students will be posted. I also warmly welcome the user’s posts. If you want to post, please feel free to mail to me at wphyostar@gmail.com

Best Regards,
Wai Phyo