Advanced Oxidation and Electrooxidation As Tertiary Treatment Techniques to Improve the Purity of Tannery Wastewater

The option of electro-oxidation and advanced oxidation as tertiary treatment technique for the purification of tannery wastewater was explored. The TOC removal of 85% was achieved by UV/O3/H2O2 process, whereas it is hardly 50% by electr-ooxidation. However the power consumption to remove unit mass of TOC by electro-oxidation process was estimated to be 738 kW h/kg, which is ten times less than that of 7600 kW h/kg, required for advanced oxidation process. The kinetic data indicated that the degradation of organics by electro-oxidation is a current control process. To minimize the power consumption, we attempted a two-stage process involving electro-oxidation in the first stage and advanced oxidation in the second stage. The results indicated that the TOC removal by advanced oxidation became sluggish, when the wastewater was processed initially by electro-oxidation. However, the effluents processed by EO were found to be completely disinfected.