Reactive dye house wastewater treatment. Use of hybrid technology: Membrane, sonication followed by wet oxidation

To address problems associated with treatment of an aqueous waste stream from a reactive dye house, a model dye, turquoise blue CI25, was studied. A hybrid technology, membrane separation followed by sonication and wet oxidation, has been demonstrated to treat the wastewater for reuse and discharge. Experiments were first performed with the reactive dye solution in water. A nanofiltration membrane (MPT 30) was found to be suitable to concentrate the dye. The concentrate was then treated with a wet oxidation process. Kinetics studies were performed with and without catalyst, in the temperature range of 170-215 degrees C. The color destruction achieved was >99%. After process parameters were fixed, studies were conducted with the actual dye waste stream. The actual waste stream was found to be refractory for wet oxidation under the above conditions. Sonication of the concentrate obtained after membrane filtration, in the presence of CuSO4, made the waste stream amenable to wet oxidation. Sonication followed by wet oxidation was found to be more effective at near neutral conditions as compared to basic conditions.