title: Electroplating wastewater treatment by the combined electrochemical and ozonation methods.
abstract: This article presents a pilot-plant study of the electroplating wastewater treatment by the processes of electroreduction with iron electrode plates, and electrocoagulation/ozonation with aluminum electrode set, followed by the process of ozonation. The initial effluent was found to be highly enriched in heavy metals and to possess the elevated levels of organic contaminants. The values of Cr(VI), Fe, Ni, Cu, Zn, Pb, TOC, and COD exceeded the upper permissible limits of 63, 220.2, 1.1, 7, 131.3, 1.7, 12.3, and 11.4 times, respectively. The heavy metal removal was forced either by the coagulation/flocculation using Fe(II), Fe(III), and Al(III) ions released into the treated solution by the electrochemical corrosion of the sacrificial iron and aluminum electrodes, or the precipitation of the metal hydroxides as well as co-precipitation with iron and aluminum hydroxides. The principle organic matter destruction mechanisms were ozone oxidation and the indirect oxidation with chlorine/hypochlorite formed by the anodic oxidation of chloride already present in the wastewater. Following the combined treatment, the removal efficiencies of Cr(VI), Fe, Ni, Cu, Zn, Pb, TOC, and COD were 99.94%, 100.00%, 95.86%, 98.66%, 99.97%, 96.81%, 93.24%, and 93.43%, respectively, thus complying with the regulated values.
authors.affiliation: Advanced Energy Ltd., Zagreb, Croatia. vorescan@gmail.com
authors.forename: Visnja
authors.initials: V
authors.lastname: Orescanin
authors.forename: Robert
authors.initials: R
authors.lastname: Kollar
authors.forename: Ivanka Lovrencic
authors.initials: IL
authors.lastname: Mikelic
authors.forename: Karlo
authors.initials: K
authors.lastname: Nad
mesh_terms: D004563:Electrochemistry / Q000379:methods*; D004595:Electroplating / Q000379:methods*; D010126:Ozone; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D010126:Ozone