A DEMONSTRATION OF REUSE OF SPENT DYEBATH WATER FOLLOWING COLOR REMOVAL WITH OZONE

Results of a project to evaluate the technical and economic feasibilit y of renovating spent reactive dyebath wastewater with ozone has been reported. A pilot scale study of dyebath reuse was conducted using ten commercial dye shades. Dyeings were performed in a tumbler type dye m achine equipped to automatically collect the spent dyebath. Color repr oducibility of the dark shades was good in water in which 50-90% of co lor was removed by ozonation. Dyeings of pastel colors and very bright shades required 95% or greater color removal for good shade reproduct ion. Ozonation was done in a continuous ozone contactor with ozone gen erated from oxygen. The effects of temperature and pH on decolorizatio n of spent dyebath water with ozone were studied. Kinetics of color re moval by ozone were studied. Ozone requirements to decolorize spent re active dyebath water were measured. Decolorization of spent reactive d yebath water using ultraviolet light and hydrogen peroxide was also st udied briefly.