In-situ Decolorization of Residual Dye Effluent in Textile Jet Dyeing Machine by Ozone

In this study, a new idea of decolourization was investigated in which residual dyeing effluent from textile dyeing process was treated using O3 in the same machine where it was generated. The novelty comes from the idea of doing dyeing and treatment simultaneously. At the completion of dyeing process, O3 gas was injected directly into the machine to remove colour and COD from the wastewater. To evaluate the effectiveness of new method, pilot-scale studies were performed, and decolourization of residual dyeing effluents containing C.I. Reactive Orange 7, C.I. Reactive Blue 19, and C.I. Reactive Black 5 was carried out in specially built textile jet dyeing machine. The results showed that almost 100% colour removal and 90% COD reduction were achieved when process conditions such as pH, dye concentration (mg/L), ozone production rate (g/hr), and temperature were optimized. The study concludes that new method has a great potential to eliminate the need of a separate end-of-the-pipe wastewater treatment system, thus offering an on-site and cost-effective solution.