RO is a system that uses the principle of reverse osmosis to compare with conventional osmosis. The system is designed with pore size of membranes from 0.0001 to 0,001 µm, working in conditions of normal pressure from 850 - 7000kPa; able to remove 95 - 99% of all minerals and chemicals (dissolved solids in water). Reverse osmosis membrane is made of special materials, operating under a specific principle not only to remove very small particles, but also all kinds of hazardous substances causing cancer and taste of water.
The RO membrane consists of several thin films or filter sheets which are bonded, rolled together in a spiral configuration around a plastic tub (this is also known as a thin-film composite or TFC). The material of the membrane is the structure of "semi-permeable" that allows water molecules pass through while acting as a barrier to prevent dissolved solids (for example: contaminated mineral chemicals). When the water supplier passes across water stream on the surface of the membrane (sufficient pressure to maintain membrane filtration), water molecules penetrate horizontally to the membrane surface, ambient the spiral surface. Simultaneously accumulating the contaminants and washing the surface of the membrane itself to push the contaminants down to the drain and going out to the supply lines.