Electrocoagulation treatment of metallurgical industry wastewater – A laboratory scale batch and pilot scale continuous study

Abstract

Laboratory scale batch EC experiments were performed on real metallurgical industry wastewater (MIWW). The most suitable process conditions were found to be: Al anode, a current of 1.05 A (150 A/m2) and a treatment time of 5 min (175 C/L). Operating costs and electrical energy consumption values were very low, 0.065 €/m3 and 0.44 kWh/m3, respectively. In the most suitable process conditions, 96% of turbidity, 92% of TSS, 87% of Altot, 99.9% of Cr, 99.6% of Zn, and 96% of COD could be removed from MIWW. Filtration tests showed that filter size had a significant effect on the residual metal content, and less than 10% of the Al, was in a dissolved form. Similar results were obtained for both Fe and Al anodes. Test runs with a novel pilot-scale continuous EC system were also conducted. These results were well in line with the batch experiments. To obtain the best possible results in the treatment of MIWW, the continuous EC treatment system needs to be followed by a settling or filtration step. The results obtained in this work were repeatable. To conclude, EC was shown to be a feasible technology for the treatment of real MIWW.