The production of purified sodium bicarbonate is accompanied by the formation of wastewater containing sodium carbonate and bicarbonate. Up to 1.5 m3 of sewage is formed per 1 ton of filtered sodium bicarbonate density. Wastewater contains about 23.5 g/l sodium carbonate and about 40.4 g/l sodium bicarbonate. The article presents the results of studies related to the processing of wastewater generated in the production of purified sodium bicarbonate in a membrane electrolyzer with a cation exchange membrane. The wastewater treatment process was carried out at a membrane current density of 30 mA/cm2 to 60 mA/cm2. The research shows that in the process of electrochemical processing of wastewater, sodium carbonate is obtained first, and only then sodium bicarbonate is extracted. At the same time, during the electrolysis, sodium hydroxide is formed. The maximum achieved concentration of sodium hydroxide was 362 g/l. The current efficiency of electrolysis process calculated by changing sodium hydroxide concentration depends on the membrane current density.

Sodium bicarbonate is used in various areas of the national economy. It is used in medicine to prepare different medications that neutralize excessive acidity in the body and softens tissue. In the baking industry, sodium bicarbonate density is used as an additive to the dough, contributing to its raising and loosening, which increases the porosity of bread products. In microporous rubber products, sodium bicarbonate is used to impart a porous structure to rubber. Sodium bicarbonate is used for charging the liquid and foam extinguishers.
For these purposes, an aqueous solution, containing about 285 g/l sodium carbonate, is saturated with carbon dioxide. Sodium bicarbonate is formed in this process. The solubility of sodium bicarbonate density in water under these conditions is almost five times less than sodium carbonate; therefore, sodium
bicarbonate forms a solid phase. After the separation of the sodium bicarbonate precipitate, the mother liquor is returned to the beginning of the process to obtain the initial sodium carbonate solution. As a result of the mother liquor’s repeated circulation, impurities accumulate in the mother liquor (mostly sodium chloride). This can lead to their appearance in pure bicarbonate. Therefore, part of the mother liquor is removed from the process. Production effluents containing sodium carbonate and sodium bicarbonate form the carbon columns’ washing waters and filter washing waters. An analysis of the effluents from the purified sodium bicarbonate production showed that, per 1 ton of sodium bicarbonate, up to 1.5 m3 of wastewater is generated containing about 23.5 g/l sodium carbonate and about 40.4 g/l sodium bicarbonate. Such a drain must be diluted before discharge. Also, there is a loss of substances that can be used to produce products.