Treatment of metal finishing effluents by the electroflotation technique

Metal finishing plants in the vicinity of the Mazafran River continuously discharge a substantial amount of wastewater. This water disposal contains an appreciable quantity of heavy metals such as nickel, copper, zinc, cobalt, etc. The river, located west of Algiers Bay, ends at the Mediteranean Sea. The techniques used to depress the pollution caused by the effluents of the metal finishing industry are costly and not easily controllable. Electroflotation (EF) serves as an efficient and promising alternative due to its simplicity and cost-effectiveness. In the present work EF was used to reduce the concentrations of copper and nickel found in real wastewater. The effects of the following parameters were examined: current density, pH, heavy metal concentration, supporting electrolyte concentration, and the nature of the electrodes. By optimizing the operation, heavy metal removal reached 98-99%, and maintained final and global concentration to a value lower than the World Health Organization standard, which is 1 mg/L for nickel and copper.