METHOD OF OBTAINING DEEPLY DESALINATED WATER FROM FRESH WATER Russian patent published in 2011 - IPC C02F1/44 B01D61/02 C02F103/04 

FIELD: chemistry.

SUBSTANCE: invention can be used in obtaining deeply desalinated water for microelectronics, medicine, pharmaceutics and cosmetics. Fresh water undergoes two-step reverse-osmosis desalination to obtain a concentrate and permeate at each step. A membrane for fresh water is used at the first reverse osmosis step and a membrane for sea water is used at the second step. Concentrate from the first and second steps is merged and taken for mixing with initial water fed at the input of the first step. Permeate obtained from the first step is taken to the second reverse osmosis step. Permeate from the second step is the end product. When desalinating water from natural sources, the water undergoes pre-settling and mechanical impurities are removed.

EFFECT: invention enables to obtain deeply desalinated water with salt content less than 1,5 mg/l without additional desalination steps, simplifies the process, enables to get rid of secondary effluent and additional chemical agents.

2 cl, 4 ex