Study of possibilities of cleaning of mechanical filters of baromembrane plants

Abstract

The appearance of contamination on the membrane and filters, which significantly reduces the efficiency of operation (separation efficiency, water permeate flow, salt rejection) and the service life of a reverse osmosis plant, is one of the most urgent problems that arise during water treatment using this plant. Therefore, the purpose of the work is to find optimal methods for cleaning and regeneration of mechanical filters of reverse osmosis plants. The solution to this problem is carried out by means of an empirical analysis of available scientific information and conducting laboratory studies on cartridge cleaning and infiltrate processing. A cycle of experiments on cleaning of used mechanical filters of reverse osmosis in a specially assembled plant with a gradual increase in the concentration of sulphuric acid has been conducted. According to the observations during laboratory research, effective removal of dissolved iron from the solution used to wash contaminated polystyrene filters begins at pH = 4 and up to pH = 10, but at pH = 4 the settling and filtering take 24 hours, and at pH = 10 this process takes no more than an hour. As a result of further research, the most effective hydrogen indicator for settling and almost complete removal of iron from the solution is 4.5. Further increase of the hydrogen indicator to 10 is ineffective. In addition to the chemical method of neutralising the mother solution, the use of electrodialysis is also advisable, while the use of electrolyser with a lead anode would be the best option. Thus, after cleaning of one mechanical filter, almost 80 g of pure gypsum is obtained. This gypsum can serve as a highquality cement additive or be used for the production of internal cladding plates. Clean water obtained during the process can be used for subsequent cycles of other mechanical filters cleaning