Trus I. Development of low-waste technology of water demineralization to protect water bodies from pollution

Dissertation is devoted to developing efficient processes and technologies of water demineralization. The process of water pre-treatment before its desalination on membrane equipment was studied and the influence of filtering conditions on productivity and selectivity of the membranes was determined. It is shown that deep pre-treatment of water in mechanical filters and stabilizing treatment on weak-acid cationexchange resin in acidic form improves productivity of reverse osmosis and nanofiltration membranes. Membranes selectivity for ions depends on the type of ions and pH. The study of the baromembranes processes allowed to determine the composition of the formed concentrates for various types of water and determine the main directions of their processing. The reagent methods of concentrates processing were developed that allow to remove over 90 % of sulphate and water hardness ions with further disposal of generated sediments into the construction materials (cement, composite cement, clinker). The methods of concentrates demineralization, which contained significant concentrations of chlorides, sulphates and water hardness ions based on the using of high-basic anion exchanger in OH- form were developed. Another method of their processing is chloride and sulfate separation on anionite in a Cl- form that together with the application of electrodialysis allows to obtain the solutions with oxidized chlorine compounds suitable for water disinfection. The processes of concentrates demineralization with high content of water hardness ions in three-chamber electrolyzer with two anionic membranes MA-41 were studied. It is shown that the process is effective at a concentration of alkali in the cathode region not less than 0.1 g-eq/dm3. The methods of alkali and acid concentration up to 40 % in the two-chamber electrolyzers were determined. The fundamental technological schemes of mine and other waste water demineralization, which provides complete processing of generated waste were proposed.