Evaluation of Membrane Filtration and Ozonation Processes for Treatment of Reactive-Dye Wastewater

Membrane filtration coupled with ozonation of the retentate was used for the treatment of colored textile wastewater. The textile wastewater examined was simulated from a commercial batch formula and contained organic dyes, sodium chloride, and copper among its components. A selected membrane filtration process generated a permeate with over 99 of the color and copper removed, while 85 of salt by mass and 85 of the original water were reusable. The effect of pressure, cross-flow velocity, feed concentration, and membrane fouling on permeate flux also was investigated. Subsequent ozonation of several different concentrated retentates each followed first-order reaction kinetics and removed color effectively. However, the decolorization rate constant decreased with increasing initial dye color. An empirical correlation was established for the apparent first-order rate constant of ozonation and the initial dye concentration. The relationship between the apparent rate constant and the dosage of ozone input also was investigated.