When the invention of plastic PET bottles for purification of contaminated water hit the news, many believed that there is finally an affordable and easy solution to providing clean drinking water to areas and communities where access to the precious resource is limited.
All it takes is to fill the bottle up, place it in a spot with direct sunlight, and wait for it to do its magic. But for how long? Helioz, an Australian startup, designed the WADI device, which can tell us exactly when the process of decontamination is complete.
The solar water disinfection, a.k.a. the SODIS method, was an initiative of Eawag, whereas the polluted water is placed in a PET-bottle for about 6 hours, turning the water into a bacteria-free liquid. It is true that the method was truly revolutionary, but it has one major flaw. Depending on the amount of UV light that hits the bottle, the duration of the purification process might vary.
Sometimes it can take as little as 45 minutes, but it could also extend up to 2 days, depending on the location, the season and time of the year. This means, that very often people drink only partly disinfected water, exposing themselves to various pathogens without even knowing.
This is where WADI comes into play. It is a small and cheap solar-powered portable device, which measures the amount of UV light with an inbuilt UV sensor and statistically relates the values to scientifically established time periods, in which the bacteria are fully removed. It works just as well at low light conditions, or bad weather, and it gives an accurate estimate of the optimized exposure time. You know that 99.99% of the bacteria in water are removed and it is safe for drinking, once the display of the gadget shows a friendly smiling face.
WADI is equipped with a solar cell, which makes it energy-self-sufficient and Helioz guarantees that the gadget will serve you for at least 2 years. The company is now trying to raise funds to further improve the device by conducting a study on health impact, and make it suitable for specific user needs.
Helioz hopes to be able to release the life-saving device in early 2014, at an affordable price depending on the consumer markets.