As we’ve already pointed it out earlier, water purifiers are used mainly in removing biological water contaminants such as Bacteria and Viruses. Water purifiers are usually used in conjunction with water filters to achieve the maximum possible quality of water. Let’s proceed by looking at the common types of water purifiers.


Water purifiers occur in three main types and these are Ultraviolet, Ultra-filtration and Reverse Osmosis air purifiers. Each type harbors its advantages and disadvantages and some air purifiers combine the elements of each type to exploit the advantages of each type. Let’s look at the types in a little more detail.

Reverse Osmosis purifiers

RO purifiers function by means of a semipermeable membrane that’s designed to allow passage of water molecules only. The membrane has ultra-fine pores which are estimated to be about 0.0005 micron in diameter which is considered to be slightly larger than a water molecule. In this case, all the associated contaminants which include bacteria and several types of salts are left behind and are collectively known as Reject Stream. The resulting water is known as Desalined water and is considered to be free from any impurities.

UF water purifiers

Ultra-filtration water purifiers also employ a semipermeable membrane. The only difference with Reverse Osmosis purifiers is that UF purifiers have much larger pores. This difference translates into a smaller spectrum in terms of which particles are filtered or not. UF purifiers remove pathogens or germs along with colloidal substances and are not able to get rid of salts and dissolved solids like the Reverse Osmosis water purifiers.

UV purifiers

As the name suggests, UV purifiers utilize Ultra Violet rays to kill pathogens such as bacteria, some viruses and other biological agents. The water purifiers are equipped with a mercury lamp which emits UV rays aimed at irradiating the pathogens in the water leading to a high level of sterility. These filters require additional filtration to ensure that the killed germs are removed from the purifiers and they are often used together with other types of purification.