Evaluation of Water Reuse Technologies for the Textile Industry

Treatment technologies were evaluated for application in water reuse for the textile industry. Technologies tested included electrochemical oxidation, hypochlorite oxidation, ozonation, granular activated carbon (GAC) adsorption, bisulfite catalyzed sodium borohydride reduction, Fentonʹs reagent, coagulation, and anaerobic biodegradation. Bench-scale side-by-side tests were conducted using a spent dyebath wastewater from a jigg dyeing operation. The dyebath contained three reactive dyes and auxiliary chemicals (e.g., common salt, soda ash, acetic acid, and caustic). Each technology was evaluated for its effectiveness at removing color and chemical oxygen demand (COD) and anticipated operating costs. Ozone, GAC, and electrochemical oxidation produced high-quality effluent, suitable for reuse. Although hypochlorite oxidation and sodium borohydride reduction resulted in significant color removal, it was not sufficient to meet reuse criteria. Results were either insignificant or inconclusive for coagulation, Fentonʹs reagent, and anaerobic biodegradation. Auxiliary chemicals had great impact on the performance of many of the alternatives evaluated.