A water purification system

Abstract

The invention relates to a device and method for purification of water using Reverse Osmosis (RO) membrane. There is a need to maintain uniform TDS (Total Dissolved Solid) level in the output water that has been purified using a reverse osmosis process where there is significant variation in the TDS (Total Dissolved Solid) levels of the input water. This is important considering the fact that there may be significant variation in the TDS (Total Dissolved Solid) levels from various sources of water. It is thus an object of the present invention to design a filter cartridge to ensure that the TDS(Total Dissolved Solid) level in the water purified by a reverse osmosis membrane is maintained within a range of 25 to 200 ppm (parts per million) irrespective of the TDS(Total Dissolved Solid) levels in the input water. It is another object of the present invention to provide a filter cartridge that provides sustained release of TDS (Total Dissolved Solid) over a typical lifetime of an RO membrane which is generally about 8,000 to 10,000 litres. We have determined that a certain combination of calcium carbonate and magnesium carbonate provides controlled increase in TDS (Total Dissolved Solid) irrespective of the TDS (Total Dissolved Solid) levels in the input water, thereby making the water palatable.