Water purifiers have become an essential requirement for the people of the current world. It is the only easy source that can afford pure water whenever required. There are different types of water filtration processes such as Reverse Osmosis Water Filtration (RO), Ultra Filtration (UF) and Ultra Violet disinfection (UV). While most of us are given a good orientation at the time of installation of such devices, it is always wise to know how these systems function.
The Reverse Osmosis system involves a simple water filtration mechanism. Osmosis is the passage or diffusion of water or other solvents through an extremely semi permeable membrane that blocks the passage of dissolved solutes. It can filter all sorts of contaminants from ions, pesticides, microorganisms and other chemicals. This technology is one among the effective processes that makes desalination possible. Desalination is the process of removal of salt from sea water. Many water treatment plants now started using this Reverse Osmosis technique to deal with many water-related issues.
There are various components involved in a Reverse Osmosis system. The functions of the components that play an integral part in the Reverse Osmosis system are as follows.
Pre-filters | Water flowing through the cold water line valve enters into the Reverse Osmosis Pre-Filters. Sediment and carbon filters are the commonly used filters. The major role of these filters is to protect the membranes of the Reverse Osmosis system by removing dirt, chlorine content and other sedimentations which might damage the Reverse Osmosis system.
Reverse Osmosis Membrane | The Reverse Osmosis Membrane is an important component in the system. The membrane serves the purpose of removing all sorts of contaminants in water. The water then enters the storage tank.
Storage tank | The storage tank is the one in which the treated water is stored. The tank is designed in such a way that it accumulates about 2-4 gallons of water.
Post-filters| Before the water stored in the storage tank runs out of the Reverse Osmosis faucet, it enters through the final post-filters. It is actually a carbon filter. The purpose of these filters is to give a final touch up by removing bad odors and adding sweetness to the water.
Drain line | The drain line is used to drain out the waste water which consists of dirt and other contaminants. (Source: How Stuff Works)
Ultra Violet disinfection
Ultra Violet disinfection usually involves a UV lamp. The UV lamp is used to provide pure and safe drinking water. The UV light used in this process is a high powered UV termed as UV-C or germicidal UV. UV-C rays attack the pathogens and penetrate into their body. The DNA of the pathogenic organisms is modified in such a way that they cannot multiply and are killed and cannot cause diseases. These rays have the ability to kill 99.9% of the microorganisms. Unlike chemical disinfection, the organisms are unable to develop any immune mechanism against UV light (Source: Water Tiger). Pre-treatment can be carried out to maximize the efficiency of the treatment. Sediment filters, carbon filters, and water softeners are the pre-treatment methods. Sediment filters are used to remove silt while organic materials are removed with the help of carbon filters. Water softener is used to remove the minerals present.
Ultra Filtration is a type of membrane filtration in which hydrostatic pressure forces a liquid against a semi permeable membrane. This semi permeable membrane used in this process has the ability to remove bacteria and other sorts of microorganisms and bad odor in the water. Ultra Filtration is not fundamentally different from reverse osmosis, microfiltration or Nano Filtration, except in terms of the size of the molecules it retains. As far as the ultrafiltration method is concerned, it is better in the case of removal of colloids, bacteria and other pathogens and other molecules that are larger than the size of the pores in the semi-permeable membrane.