Water is a precious commodity on earth, but nowadays it is very bad exploited: the developed countries consume it over the top and do not recycle it at all, and above all they almost never drink the tap water. While other countries which are less developed do not have any access to drinking water and have to be satisfied with the polluted water of the rivers and the lakes. Moreover, people are usually worried about reusing the soiled waters for their daily consumption, even if the wastewater is obviously treated and totally purified before reutilization.
Water treatment in water treatment plant
The classic water treatment consists in purifying it in a water treatment plant: firstly the water is filtered through a big sieve to eliminate the biggest sediments and other solid impurities. Once filtered, the water is the subject of a physicochemical treatment to aggregate the suspended particles to remove them easier. Then the water is filtered one more time, and disinfected with chlorine and ozone to remove the germs and the pathogens. Once treated, the water becomes again perfectly drinkable. This solution is the most used all over the world, although only the two percent of the used waters are recycled this way.
Solar disinfection, a good option for the poor countries
The water treatment plants are a luxury than many developing countries cannot afford: the access to drinking water is a major problem in these countries. However there is a very simple option to disinfect the water and make it drinkable again: the solar disinfection. It consists in exposing water bottles in full sunshine during at least six hours, to kill the germs into which are responsible for diseases. Yet it is necessary to use only ethylene polyterephtalate bottles to guarantee the success of the process. Obviously this solution cannot be used on a large scale, but it is a perfect secondary solution.