UDC 628.161:66.081.63
DOI 10.35776/VST.2024.01.02
Pervov Aleksei, Spitsov Dmitrii, Tet Zo Aung, Medved’ko Viktoriia
Use of the reverse osmosis method for the preparation of concentrated sodium chloride solutions for the production of sodium hypochlorite
Summary
The use of membrane reverse osmosis and nanofiltration plants for the production of drinking water is described. It is noted that using hypochlorite obtained by the electrolysis of concentrated solutions of table salt is an effective method of disinfection in drinking water supply systems. A new area of application of reverse osmosis systems is considered, i. e., the preparation, in addition to clean water, of concentrated solutions of sodium chloride used for the production of sodium hypochlorite to reduce the operating costs of a drinking water treatment plant eliminating the purchase of the chemical, i. e., table salt. A process flow scheme of the proposed technology is presented, that involves cascade processing of the source water using nanofiltration membranes of low selectivity to provide for separating the concentrate into the solutions of monovalent and divalent ions. The experimental procedure is described and experimental dependencies are presented to determine the efficiency of the concentrate separation. Based on the results of the experiments, an economic calculation of the costs of designing an additional system for producing concentrated solutions was performed proving the economic efficiency of the proposed process compared to the use of table salt.
Key words
disinfection , sodium hypochlorite , reverse osmosis , reverse osmosis unit , nanofiltration , concentrate utilization , water treatment , electrolysis method
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UDC 628.162:62-278
Pervov Aleksei, Efremov R. V.
The Use of Nanofiltration Membrane OPMN-K for Production of Potable Water and Calculation of Operation Characteristics
Summary
Recommendation on the use of nanofiltration membranes OPMN-K manufactured by the Vladipor OJSC for natural water treatment and production of potable water of high quality are presented. It is shown that at the high efficiency of removal of iron, hardness, fluorine and ammonium ions from water the OPMN membranes are exposed considerably less to the danger of generation of calcium carbonate cake on them than the low pressure reverse osmosis membranes. Depending on quality of influent water and types of membranes these recommendations make it possible to determine the reagent consumptions for operation of plants. Calculations presented show that the use of OPMN-K membranes instead of reverse osmosis membranes ESPA makes it possible to reduce significantly expenditures for operation of the ground water treatment unit.
Key words
nanofiltration membrane , inhibitor , selectivity , operation expenditures , reverse osmosis unit
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UDC 628.32.66.081.63
DOI 10.35776/VST.2025.03.06
Shirkova T. N.
Reducing the flow of reverse osmosis concentrate in the process of solid waste landfill leachate treatment
Summary
Leachate of the municipal solid waste landfills is a major environmental hazard. Reverse osmosis technology is used for leachate treatment. The disadvantage of using reverse osmosis is generation of a large amount of concentrate because its disposal involves high costs. A technology is presented that provides for reducing concentrate flow to values that ensure the economic feasibility of its evaporation or removal by trucks. Reducing concentrate flow is achieved by changing the ratio of salt ion concentrations and organic substances. The separation of the concentrate solution is effected owing to the difference in the retention capacity of low-pressure nanofiltration membranes in relation to organic substances and monovalent salt ions. The separation of the concentrate solution provides for reducing not only its flow, but also the costs of its disposal, that is to process and reduce the volume of each solution separately at lower costs. A method for conducting experiments is presented, the results of the separation of the concentrate solution are given, as well as technical and economic calculations that allow comparing the effectiveness of the proposed approach with the traditional solution based on the use of high-pressure membranes.
Key words
filtrate , concentrate , reverse osmosis , reverse osmosis unit , nanofiltration , membrane selectivity , low-selectivity membranes , solid municipal waste landfill
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