MODELING OF BACKWASHING PROCESS IN SPIRAL RO MEMBRANES
A promising way of back washing of spiral membranes is considered in the article. The principle of backwashing the membranes is to reduce the working pressure of the installation by reducing the speed of the electric motor of the feed pump or turning it off. The product from the reservoir starts to move back from the central part of the membrane to its periphery, washing away the accumulated pollution from the inside. A mathematical model of the process of direct osmosis of the product from the inside of the membrane to its peripheral regions is given. In the first stage, the product dilutes the layer with a high concentration of salts in the near-surface layer of the membranes, while the second reduces the concentration of salts throughout the entire volume of the membrane. The correctness of the proposed model was verified by setting up experiments on a real reverse osmosis membrane of a roll type. After a number of experiments, the hypothesis of a two-stage process of migration of the product from the center of the membrane to its periphery was confirmed. In addition to experimental confirmation of the model, the influence of salt concentration in the initial water during the reverse osmosis process on the parameters of backwashing with the product was also studied.