Removal of dyes from the effluent of textile and dyestuff manufacturing industry: A review of emerging techniques with reference to biological treatment

Biological removal of dyes from effluents of textile and dyestuff manufacturing industry offers some distinct advantages over the commonly used chemicals and physicochemical methods. These include possible mineralization of the dyes to harmless inorganic compounds like carbon dioxide and water, and formation of a lesser quantity of relatively harmless sludge. Removal of dyes from these wastewaters has been reviewed with. respect to biological decolorization as well as complete biodegradation of the dye molecules. Emerging techniques with reference to biological treatment of these wastewaters have been discussed under aerobic, anaerobic, and combined anaerobic-aerobic systems. Advantages and limitations of different biological methods have been highlighted, and future studies to establish these techniques for their applications on industrial scale have been suggested.