Plastic bottles may offer cheap solution

Scientists at Switzerland’s Federal Institute for Environmental Science and Technology have been promoting solar water disinfection using an inexpensive plastic bottle as one way to combat the spread of waterborne diseases for over a decade.

Waterborne diseases are the biggest threats to the lives of the recent tsunami survivors, according to the World Health Organisation (WHO), based in Geneva, Switzerland. It estimated that up to 150,000 people could face outbreaks of cholera, typhoid and dysentery, along with diarrhoea. Every year, some 1.6 million diarrhoeal deaths related to unsafe water, most of them children under the age of five.

Solar water disinfection or Sodis, is already in use in 20 countries, and is a cheap alternative to expensive water purification systems. People can clean water in clear plastic bottles by filling them, shaking them and then leaving them in the sun for at least six hours, if possible on a sheet of corrugated iron or a roof. Radiation from sunlight and the increased temperature of the water are enough to kill many forms of bacteria and viruses.

The Swiss Agency for Development and Cooperation (SDC) recommended the use of the system in the areas affected by the tsunami where no proper water treatment system were in operation before. Sodis projects are underway in other Asian countries, including India, Sri Lanka and Thailand, not in any areas struck by the tsunami, but some are close to the disaster zones.