Microfiltration membrane with a pore size of 0.1-1.0 microns detain small particulate matter and colloidal particles, defined as the turbidity. As a rule, they are used when there is a need in the rough water purification or pretreatment of water before a deep cleaning. Ultrafiltration membranes with a pore size of 0.01 to 0.1 microns are removed large organic molecules (molecular weight greater than 10, 000), colloidal particles, bacteria and viruses, rather than delaying when it dissolved salts. Such membranes are used in industrial and residential applications and provide consistently high quality cleaning of these impurities, without changing the mineral composition of water. Nanofiltration membranes are characterized by a pore size from 0.001 to 0.01 microns. They retain organic compounds having a molecular weight above 300 and passed 15-90% of salts, depending on the structure of the membrane. Reverse osmosis membranes contain very narrow pores and are therefore the most selective.
They retain all bacteria and viruses, bolshuyu of dissolved salts and organic substances (including iron and humic compounds that give the water color and pathogens), missing only the water molecules are small organic compounds and light minerals. The average RO membranes retain 97-99% of total dissolved solids. In fact reverse-osmosis systems make the water distillate, ie, there is nothing: no harmful substances or bacteria or viruses, there is no essential trace element for humans, the importance of which we discussed above! Few people know that this water washes away the salt from the body, thereby disrupting the water and salt balance.