Solar water disinfection (SODIS) relies on the freely available ultraviolet and infrared rays of the sun, which can disinfect by killing pathogens that contaminate water. The process is as easy as leaving a clear plastic bottle of water out in the sun for six hours.
If clean water is that easy, why are so many people, especially young children, dying from diseases contracted by drinking unclean water? There is a major obstacle to effective use of SODIS: if the water is muddy or murky, pathogens can hide in the shadows of the particulates, avoiding the death-rays of the sun. Read more
Access to drinking water is a major issue in the developing world, especially in Africa, where dirty water kills more people than violence. Solar water purification is a tried and true method of using UV rays to kill harmful bacteria and viruses in water, and we’ve featured a good number of designs that harness the process (see a few at the left). The Solar Bag, created by Ryan Lynch and Marcus Triest is another in the genre that stands out.
The idea is pretty simple: fill the bag with 2.5 gallons of water, sling it over your shoulder, and let the sun do its work while you walk. Lynch and Triest say the idea takes into account how far some people need to walk to access even dirty water. Within six hours, the water in the bag is safe to drink. Read more