A new technology for reducing and disposing of concentrates from reverse osmosis plants by creating conditions for the crystallization of insoluble salts in the channels of the devices

Precipitation of poorly soluble salts on membranes and discharge of concentrate have always been problems for the development and improvement of reverse osmosis plants. Deposits are also the main reason that prevents increased extraction and reduced discharge of concentrate, since the formation of insoluble salts due to supersaturation negatively affects the membrane performance. The article presents the results of research based on the study of the theory of sedimentation and crystallization, which make it possible to ensure effective control over the formation and growth of crystals. As a result, a new technology has been developed that makes it possible to reduce concentrate consumption by 20-100 times without the formation of deposits of insoluble salts on membranes and without the use of reagents. Calcium carbonate and calcium sulfate are precipitated without the use of a softening reagent due to the creation of supersaturation due to the concentration of source water in the channels of the apparatus. This non-reactive technology has been developed using nanofiltration membranes with low selectivity. The results of experiments are presented, which demonstrate the conditions necessary for the start of the nucleation process in the concentrate stream, and allow us to determine the rates of nucleation and crystal growth. The application of a new technology for desalination of groundwater and marine waters is presented. The technology allows not only to reduce the discharge of concentrate, but also to divide it into a number of concentrated solutions. An economic comparison of the newly developed technology used in groundwater treatment is given.