Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-III-42COMPLEX TECHNOLOGY OF TREATMENT OF CHROMIUMCONTAINING WASTE WATERGoshu Yilkal Wassihun, Tsaryov Yuri Valerivich, Kostrov Vladimir Vasilyevich The Ivanovo State University of Chemistry and Technology, Department of IndustrialEcology. Street F. Engels, 7, Ivanovo-centre, 153000, Russia, Tel.: 7-(4932) 30-73-46,Fax: 7-(4932) 41-79-95, 41-77-42, E-mail: yilwass@yahoo.com and tsarev@isuct.ruHexavalent chromium is present in the effluents produced during the electroplating,leather tanning cement, mining dyeing and fertilizer and photography industries and causesenvironmental and public health problems.Hexavalent chromium has been reported to be toxic to animals and human and usually ofanthropogenic origin and rarely occurs naturally [1,2]. Cr (VI) is a skin and mucousmembrane irritant and some of these hexavalent compounds produce an allergic contactdermatitis characterized by eczema [3,4]; it is also recognized as a pulmonary carcinogen[1.2]. Its concentrations in industrial wastewaters range from 0.5 to 270.0 mg.l –1 [5]. Thetolerance limit for Cr (VI) for discharge into inland surface water is 0.1 mg.l –1 and potablewater is 0.05 mg.l –1 [6]. In order to comply with this limit, it is essential that industries treattheir effluents to reduce the Cr (VI) to acceptable levels.The basic purpose of the given work is development of complex technology of treatmentof chromium containing waste water with use of different reagents, reductions, precipitations,and approbation on model waste water. Objects of research had been chose model solutions ofchromic acid, and dichromate salts. The choice of model solutions is based by that the givensalts of chromium use in tanning, textile and other chemical industries. As reducer thesolution of sodium sulphite that is caused by that the given reagent is received as a waste attreatments of off-gases of production of sulfuric acid has been chosen.This study investigated a new treatment process for the removal of Cr (VI) from aqueoussolutions by applying as homogeneous catalysts under the basis of content of chromium fromtannery chemical, metallurgical, machine-building industries wastes.Suggested technology of chromium containing waste water treatment submitted in twoways, that is functional chart with use of sulfuric acid and use of additives of salts of metals.Waste water treatment by using additives of salts of metals presented in figure 1.Thesecond way differs that reduction and precipitation of compounds of chromium carry out inneutral medium 5 %- sodium sulphite at the presence of the additive of 10 % solution of saltCu(NO 3 ) 2 or Fe(NO 3 ) 3 , used as homogeneous catalyst. Process of treatment carry out in onestage, thus the degree of reduction and treatment of a solution of compounds of chromium384