This page was designed to be viewed with a browser that supports Cascading Style Sheets [CSS] and if you are using earlier versions [pre- ver.5.0] of Internet Explorer or Netscape Navigator,you are missing out on a pleasant viewing experience. It is best that you upgrade your browser soon as most of the sites will increasingly make use of CSS.

 gniLogo GoodNewsIndia ::Supplement

Care for India? Then *be* the good news! ©

Prev: The import of EDUSAT  |  Next: Children's own bank

Page: 1 2 >
Ideas For India

Dec 01, 2004
Safe water from SODIS and SPOWTS

Two environmentally-soulful, low-cost technologies —SODIS and SPOWTS—are capable of producing safe drinking water from polluted water sources in remote areas. Both deliver sharp slaps on the notion of safe water having to come in priced bottles that are thrown away as litter.

For those of us, now made forgetful by electric UV-treated water units in our homes, here’s a quick primer on ultra violet rays [UV] and Ozone. The sun constantly radiates UV light, which if it enters the atmosphere unrestrained, is harmful to life. But luckily we have the ozone layer in the stratosphere. Ozone is a highly reactive form of oxygen and is equally destructive to life forms in large quantities. However, when UV meets the ozone layer, most of the former is blocked and absorbed. Which by the way, is the reason why we need an intact ozone layer. The purpose of this primer is to remind ourselves that diffused UV is everywhere around us in nature. When polluted water is exposed to UV or made to interact with ozone, harmful micro life forms are destroyed.

The Solar Water Disinfection Process [SODIS], a Swiss innovation, is simplicity itself. Polluted water is prepared for treatment by nominal filtering for sediments. Discarded plastic bottles are cleaned, partially filled with water that is to be treated and shaken vigorously, in order to oxygenate it. The bottles are then filled fully, closed and placed in full sunlight for between 6 and 8 hours. The combination of heat and oxygen-UV interaction kills all pathogens, rendering water safe for drinking.

Obviously SODIS works best in sunny climes— which are also places where safe drinking water is a concern. The process is helped by placement of a black sheet under the bottle to enhance heating. Also, PET bottles are better than PVC ones. It must be remembered chemical, toxic pollutants are not removed by this process.

SODIS is becoming popular in South America, Thailand and Kenya. In Kenya for example, people took quickly to the idea because their tradition was to wash and sun-dry utensils. Goes to show that when we go close to ‘native-ways’, a lot of good sense is revealed.

Page: 1 2 >

HOME
Directories:: MagazineSupplementsBackstage
Print:: Text & ImagesText only

Send This Story To Friends

Print




GNI Mailing List
Sign UpLeave

Articles by category: ALL  Appeal  Activism  Economy  Elsewhere  Energy  Enthusiast  Environment  Governance  Ideas For India  Initiative  Innovation  Memory Speaks  Newsclip  Profile  Reforms  Resources  Sciences  Springs  Trend  Update  Water 

Write to GoodNewsIndia


 Shop at Amazon::Support GNI 

Internet Explorer distorts many of the styling features of this site. Switch to Firefox