METHOD FOR COMPLEX DEMINERALISATION OF NATURAL AND WASTE WATER BY SEPARATING SEPARATE GROUPS OF SALTS IN FORM OF COMMERCIAL PRODUCTS Russian patent published in 2024 - IPC C02F1/44 

FIELD: water treatment.

SUBSTANCE: invention relates to the field of water treatment and water treatment of highly concentrated on salt content of natural or (and) waste water and can be used for water treatment of drinking or industrial water or treatment of industrial or household waste water to obtain commercial products. Initial water is supplied to pretreatment facilities, then initial water after pretreatment is directed to ultrafiltration unit, obtained filtrate is discharged into ultrafiltrate tank, from which part of water is used for washing ultrafiltration membranes with backflow of water. Ultrafiltrate from ultrafiltrate tank is directed to first stage reverse osmosis unit (ROU-1), to prevent biofouling of reverse osmosis membranes, biocide solution is dosed, permeate is discharged via pipeline into demineralised water tank and used as process water for station needs or for supply to consumer. Concentrate is discharged via the pipeline into the first stage reverse osmosis concentrate tank, from which it is directed to the second stage reverse osmosis units (ROU-2), permeate from ROU-2 is supplied to the demineralised water tank, with further supply to the consumer or for production needs, and the concentrate is discharged via the pipeline into the ROU-2 concentrate tank. Further, the concentrate is sent to the salt concentrate evaporation plant, during the evaporation plant operation the salt concentrate is evaporated to the salt saturation limit, after which the saturated salt concentrate is supplied to the crystallisation plant No. 1, due to the difference in crystallisation temperatures of various salts at crystallisation plant No. 1, sulphate salts are first formed, for example Na₂SO₄, Na₂K₃SO₄, CaSO₄, which are removed from crystallizer No. 1 and sent for dehydration to a decanter, then to obtain end product is sent for drying, wherein residual salt centrate with reduced concentration of sulphates is fed to evaporator to produce chloride salts while distillate is fed into desalinated water tank.

EFFECT: invention enables to perform complex processing of salt solutions with production of certain types of salts as commercial products with simultaneous achievement of stability of operation and reliability of production of commercial products, namely mineral salts, as well as saving water used at an industrial enterprise, including treatment plants, an important factor is the improvement of the environmental situation as a result of the termination of the discharge of reverse osmosis concentrates into water bodies or sewers; implementation of technological scheme of water treatment or water treatment with production of commercial products from treated water is economic and ecological advantage.

4 cl, 2 dwg, 2 tbl