There has been a lot of talk about solar technology in the press in recent years as the world starts to realize that we cannot continue to abuse the world in the way we have been. Although we tend to think of solar power being used to generate electricity for our homes, there are actually other uses that you might not have heard of before. One of these other uses is to treat water.



The problem is that water around the world often isn't as pure as we are used to in Western countries. People who drink dirty water can end up with all sorts of medical conditions such as typhus and diarrhoea. Even in developed countries there can be problems with the water. There are small devices that can easily be built to help with these problems.

Solar disinfection (SODIS) is very similar to the method of pasteurizing milk. The microorganisms that are found in water which give us the health problems, can't survive in temperatures that are too high. So this is an ideal method of either killing the germs or deactivating it.

You might think that creating a solar water treatment system is very difficult to set up however it's a lot more simple than you might have ever imagined. All that you need is to place the water in a plastic water bottle with a black background so that the light from the sun is absorbed. On sunny days it might on take a few hours for the water to become purified. This knowledge can come in very useful if you need drinking water whilst hiking in the countryside.

However it's important that you know that you shouldn't use just any plastic bottle. It needs to be the PET type rather than PVC. This is simply because they block the sun's UV light more than PET plastic, thus reducing the efficiency.

If you need to treat more than just a bottle or two of water then you can build a larger version for only a few hundred dollars. What you need to build is a container that is rectangular in shape and is just a few inches deep, there will be glass sides along with a siphon hose.

Basically when the water is heated by the sunlight the water evaporates and condenses on the glass. The siphon hose is then used to draw off a portion of this water and you will find that it will contain much less bacteria and also chemicals such as chlorine.