The paper investigates the use of cress (Zabava and Krupnolistovoi varieties) and wheat (Salavat Yulaev and Omskaya varieties) as phytoecological indicators. The object for testing was still waste liquid, the main waste of soda ash production. The toxicity was assessed by three parameters (seed germination, length and dry weight of the seedlings). It is shown that the still waste liquid has an acute toxic effect on all phytoecological indicators used. It has been found that the regression equations for seed germination and dry weight of seedlings in contrast to their average length for all plants do not adequately describe the experimental results and can not be used to evaluate the safe dilution factor. The safe dilution factor, determined by the average length of the seedlings, for cress Zabava is 34.7 and cress Krupnolistovoi is 34.4, and for wheat Salavat Yulaev is 73.0 and for wheat Omskaya is 81.8. It was established that the safe dilution factor determined with the use of different plant species varies quite strongly.

In the production of metal coating by electroplating, wastewater containing the metal ions is used. The paper presents the study results of cleaning waste water of nickel after electroplating. Wastewater treatment was implemented in an electrodialysis plant. The initial wastewater contained from 20 to 80 mg/l of nickel II. Experimental results obtained by studying the electrodialysis extraction of nickel from wastewater of electroplating plants, indicate that the cleaning process is influenced by such factors as the effluent treatment time, the current load on the electrodialyzer, the initial metal concentration in the effluent. The increase in voltage in the electrodialysis plant leads to an increase in the treatment efficiency. So after six hours of processing, the processing rate during nickel extraction increases from 39 to 66.5% with an increase in voltage from 40 to 100V. Along with cleaning wastewater of nickel electrolyte, the electrodialysis method allows obtaining concentrates of this electrolyte containing from 260 to 1230 mg/dm3 of nickel and suitable for use in the electroplating process.

The paper presents the study results for the treatment of sulfide wastewater generated by tanneries. Wastewater treatment was carried out by electrolysis with a sacrificial ferrous anode. It is shown that during the treatment process, the ferrous anode dissolves and deposition of iron sulfide is formed. The process of effluent treatment is determined by the anode current density. The most efficient effluent treatment is carried out at a current density of 133 A/m2. In this case, the purification efficiency reaches 99.2%, and the cost per unit of electricity makes 169.2 kW·h/kg.

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