A water purifier has become an essential appliance in everyone’s home in order to assure safe and purified drinking water. However, a right choice of purifier is only possible if you are aware of the working of the device. Various technologies are being used in water purifiers and it is necessary to have a basic idea on them. This article aids you to know these different technologies.
Distillation
Distillation is one of the oldest methods of water purification which includes boiling and condensation of water. Initially, water is heated to boiling in this method and the resulting water vapor is sent to a condenser. The cooling water of the condenser decreases the temperature, thereby condensing the vapor back retaining the impurities in the liquid phased condenser.
However, contaminants with a boiling point of less than 100 °C cannot be removed and remain in the output water. Moreover, distillation process is highly energy intensive, expensive and even time consuming.
Carbon adsorption
The technique of carbon adsorption includes adsorption (adhesion) of the water contaminants on to the activated carbon. It is very much effective in removing a wide variety of organic and inorganic adulterants like iron and chlorine. Upon exposure of water to the activated carbon filters, the contaminants get adhered to the carbon surface. They then enter into the large pores of the filter which later get adsorbed into the inner surface of the carbon.
However, carbon adsorption is inefficient in removing certain inorganic elements like salts. In addition, when used in initial stages of purification, the process results in plugging of microscopic adsorption areas, thereby reducing the life of the purifier. It is, therefore, better to use the technology at final stages of purification to remove any dead bacteria, heavy metals, fertilizers, hydrocarbons and other contaminants.
Reverse osmosis
Water purification through reverse osmosis clears a large proportion of contaminants. As the name suggests, the technique acts against the natural osmotic pressure. Generally, in osmosis, the water or a solvent dilutes a concentrated solution. However, when purifying water through reverse osmosis, the water is forced to move through a semi-permeable membrane by application of mechanical pressure. Only pure water is allowed to pass through the membrane with the rejection of adulterants which are too large to pass through the tiny pores of the membrane. The resulted water is free of any salts, inorganic compounds and other contaminants.
One of the disadvantages of this technology is that there is a chance of removal of even certain essential mineral contents. The process even needs a lot of pressure, time and maintenance.
Ultra-filtration
Ultra-filtration ensures efficient water purification removing the contaminants based on their size. Specific ultra filters (semi-permeable membranes) retain macromolecules that are above certain size. Compounds such as colloids, microorganisms and pyrogens get trapped by the filter. The efficiency of this method depends on the size of the filter pores. Certain smaller and ionic contaminants may, however, enter the filtered water.
Ozone purification
Ozone purification is one of the important and new technologies used in water purifiers. It includes passage of oxygen through a UV light. The oxygen, upon oxidation under UV exposure, turns into ozone. Ozone is an effective disinfectant removing various kinds of harmful pathogens. It even removes bad odor of water. The most important advantage of this technology is that no toxic byproducts are remained after purification. However, no chemical components can be cleared by ozone purification. It is, therefore, recommended to use along with any other technology.
UV radiation
It is another advanced water purification technology which is also intended for removal of pathogens from water. Specific UV lamps emit UV radiation which disinfects bacteria, resistant viruses, parasites, etc. Special membranes made of teflon are included in UV water purifiers which allow only 70% of the radiation to water making it safe.
This technology of water purification ensures retaining of water properties like pH, taste and odor even after filtration. However, like ozone water purifiers, they fail to remove inorganic and organic contaminants and hence, needs another assistant purification method.
The above-mentioned technologies have their own important role in water purification. Water purifiers which are designed with a combination of these different technologies are ideal and popularly used these days. Consider various technologies used by a water purifier when purchasing one to ensure safe drinking.