The article presents results of researches on treatment of spent acid etching solution (SAES) formed during etching of titanium products by hydrochloric acid. The process includes neutralization of SAES with alkali, filtering, drying and calcinations of titanium hydroxide precipitate and electrochemical processing of the filtrate containing sodium chloride in a cell with ion exchange membranes. During electrolysis, sodium hydroxide and hydrochloric acid are produced. The proposed process scheme of SAES treatment allows to obtain titanium dioxide, sodium hydroxide and acid. Titanium dioxide can be used in paint and coatings industry. Alkali can be used in SAES neutralization process. The acid is suitable for use in etching process of titanium products.

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This paper discusses occurrence of toxic wastewater from the production of ethylenediamine by aminating 1,2-dichloroethane with ammonia. It is shown that wastewater from ethylenediamine production is formed at the stages of evaporation of ethylenediamine dihydrochloride and rectification of a mixture of amines obtained as a result of evaporation. In the first case, the wastewater contains a saturated NaCl solution with a content of 1 2% polyethylene polyamines, and in the second case, the drain contains a solution containing about 1% of ethylenediamine and about 2% of ammonia. To study the toxicity of these wastewater, watercress of Zabava and Krupnolistovoy varieties were used. The assessment of toxic properties of wastewater was carried out according to such values as seed germination, the average length of seedlings and the dry weight of seedlings. It is revealed that the studied drains have an acute toxic effect on the watercress of both varieties. It is shown that the regression equations obtained for the dry weight of seedlings and seed germination, in contrast to the length of the seedlings, do not adequately describe the experimental results and cannot be used to determine the safe multiplicity of breeding. The safe multiplicity of breeding, calculated using the average length of seedlings, ranges from 489,1 to 892,9 for various drains and watercress varieties. It is shown that the most toxic is the runoff containing a saturated NaCl solution with a content of 1 2% of polyethylene polyamines Zabava is the most sensitive to the degree of toxicity of runoff.