Electroflocculation on Textile Dye Wastewater

Abstract

Textile dye bath dumps are very rich in dyes and chemicals (sodium sulfate or chloride, hydroxides, and carbonates). Mixing of this wastewater with other textile processing wastewaters makes the wastewater treatment very difficult and costly, and compliance with the applicable effluent standards (while conserving water or wastewater minimization) almost impossible. Further, this reduces the recycling and reuses potential of the treated effluents. Segregation and handling of the dye bath dumps separated from the other wastewaters has been considered as an appropriate solution to the problem. The dye bath dump wastewaters can be decolourized and chemical recovery can be tried on the decolourized wastewater. In the present study, decolourization of the dye bath dump wastewaters (sulfate rich and chloride rich wastewaters), collected from the cotton fabric dyeing process, by electro-flocculation have been tried. Of the iron and aluminum electrodes used, iron electrodes were found more effective than aluminum electrodes. 98% colour removal and 84% COD removal were observed at 4, 10 and 9.6 ¬¬volts potential and when treated for 15, 6 and12.6 minutes for sulphate rich wastewater respectively. However, combination electrodes of iron and aluminium (iron as anode and aluminum as cathode) gave still better results. colour removal and COD removal were observed 97 % and 73 % at 8 and 10 volts potential and when treated for 9 and 6 minutes respectively. For chloride rich waste water iron and steel electrodes gave the better results. 91 % COD and 99.4 % color was removed at 12 ¬¬volts potential and when treated for 15 minutes with steel electrodes respectively. 80 % COD and 99 % color was removed at 5.8 and 12 volts potential and when treated for 5.7 and 15 minutes with iron electrodes respectively.