RO or reverse Osmosis system is currently one of the best water purification systems. It makes use of a semi permeable membrane through which water is made to pass through. This membrane is effective in removing dissolved salts, impurities and germs from the water. This technology is recommended in areas where quality of water is hard and also the water has a high concentration of total dissolved solids.
Reverse Osmosis process works by making use of a pump which is connected to an electric supply. This pump is effective in increasing the pressure on the salt side of the RO system and forcing water to move across the semi permeable membrane. It is helpful in removing 99% of the dissolved impurities. A reverse osmosis system usually consists of three types of filters or canisters. One of them comprise of the membrane while the other two are nothing but carbon filters.
In the first step of the reverse osmosis process, water passes through the carbon filter where larger sediments, including dissolved solids and chlorine are removed. In the next step, water is forced to pass through a semi permeable membrane under pressure. This membrane is made of a synthetic plastic material which helps in the removal of lead, arsenic, copper, urea, bacteria, glucose etc. In the third step the filtered water goes through a carbon filter which removes any further traces of contaminants.
Multistage filtration systems are easily available in the market and they are cheaper than reverse osmosis systems. These filters usually combine different kinds of water purifiers in a single unit. In the first filter, known as a sediment filter, larger solid particles are removed. This sediment filter gets blocked due to mud or other larger particles and has to be removed and cleaned on a regular basis .After this it passes through a fine filter where large germs like parasites are filtered. In third stage, it passes through a carbon filter which absorbs pesticides. The efficiency of carbon filter also depends on the quality of activated carbon.
Even though both reverse osmosis based water purifier and a multi stage water filter perform the same function of purifying water, the RO system is far more efficient as it is able to filter out more impurities. A multistage filter can filter out only a small amount of contaminants. Also, these multistage filters require huge maintenance.