Reverse osmosis is a technology that is used to remove much of the pollutants in the water when passing through a very fine semipermeable TFC (Thin Film Composite) membrane with a pore size of 0.0001 µm.
Reverse osmosis is probably one of the best ways to mechanically purify water. Reverse Osmosis Membranes (RO Membranes) are super fine mechanical filters that remove more than 90% of TDS (Total Dissolved Solids), which may include salts, minerals, metals, pathogens, and certain organic substances.
RO Membranes are layers of polymer films that are spirally wound around a core with openings and spacers between each layer. As water passes through the membrane, the openings of each subsequent polymer film become smaller and smaller. Thus, purified water is obtained, without excess salts, solids and microorganisms.
As it ages, the membrane gradually loses its ability to remove contaminants dissolved in water and the value of TDS increases.
The membrane quality rating is evaluated by the percentage of salts discarded (mineral reduction). If the TDS gets too high, it's time to change the diaphragm.
90 - 95% reduction> Maximum quality
At 80 - 90% reduction> Medium quality
At 70 - 80% reduction> Low quality
Below 70% reduction> the membrane must be replaced!
Using a TDS meter, measure and compare the supply water data with that coming out of the membrane and you will get the Salt Discard Percentage value.
Percentage of discarded salts (%) = (1- TDS per RO water / TDS per inlet) x 100