Water recycling from desalination and purification process of reactive dye manufacturing industry by combined membrane filtration

In this study, nanofiltration membrane and reverse osmosis membrane were tested to investigate the optimal operating conditions for COD, color, salt rejection and permeate flux and evaluate the feasibility of nanofiltration and reverse osmosis membrane combined process to improve the permeate flux and separation efficiencies in reactive dye manufacturing process wastewater. Effects of pressure, types of membrane and dye solution on flux and rejections were investigated. Experiments showed that the type of membrane had a significant effect on both permeate flux and rejection efficiencies. Variations in the applied pressure also affected the COD, color and salt rejections, which increased with increasing pressure. Finally, the nanofiltration and reverse osmosis membrane combined process was found to be suitable for the removal of residual organics, color, salt and the water recycling from waste stream arising from reactive dye manufacturing process. The permeate can be recycled back into the process, thus offering economical benefits by reducing the water consumption and wastewater treatment cost. (c) 2004 Elsevier Ltd. All rights reserved.