In your school water cooler, you might have seen a huge, inverted plastic jar saying 'Ozonised water'. Ever wondered why anyone wants to put ozone in drinking water?
What is Ozone?
We've all heard of the ozone layer, and why it is shrinking. But you know there's a lot of ozone right around us, and not just in the sky?
Ozone is a rare form of oxygen. It has three oxygen atoms in it, arranged in a tiny triangle. The three atoms don't get along well in this arrangement, so after sometime ozone breaks up to release an atom. This atom can be quite dangerous, because it will react with almost anything.
Ozone the pollutant
Ozone is formed when sunlight breaks up the nitrogen oxides that come from cars and factories. Since it is reactive, it can cause rusting and corroding of metal things. It is also a greenhouse gas, since it collects the sun's heat and doesn't let go. And if you inhale ozone, it causes irritation and itching of the nose and lungs.
Ozone the purifier
Interestingly, what makes ozone bad also makes it good! Since it releases reactive oxygen atoms, you can use it to kill deadly bacteria in your drinking water. Water contains bacteria that can cause diseases like cholera, dysentery and typhoid. When you bubble ozone through water, the oxygen atoms in it react with the cell walls (which is like their skin) of the bacteria in water. That makes the cell wall weak, and the bacterium bursts open.
Ozone is also used for killing bacteria in fruit juices, cooking oil and other liquid foods. In some warehouses, they release ozone into a sealed room where fruits and vegetables are kept. This way, the bacteria and fungi die, and the fruits don't rot. You can also use ozone to clean swimming pools, and even the municipal water supply.
The nice thing about it is that the reacted oxygen bubbles out, leaving nothing behind. So you are left with a pure and safe glass of drinking water!
Ozone can be made cheaply when you want it. If you pass a very high current through pure oxygen gas, the atoms rearrange into ozone. So you don't have to store ozone, nor carry it around.