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Abstract

Textile dyeing industries are facing problems to meet the green practices standards for safe discharge of wastewater due to its complex nature. TWWs are a complex mixture of salts, acids, heavy metals, organ-chlorine-based pesticides, pigments and dyes. 5,10 TWWs generated from the different wet processes are characterized by high pH, temperature, BOD, COD, detergents, surfactants, suspended and dissolved solids, dispersants, leveling agents, toxic organics, chlorinated compounds, sulphide and formaldehyde, may be added to improve dye adsorption onto the fibers 9 and more details are mentioned in the Figure 1. Such effluents are also characterized by the presence of heavy metals, such as Cr, Zn, Cu and Al due to metal-based complexes dyes. 10,14 The most common textile operates are desizing, bleaching, mercerizing, dyeing and finishing. 15 Characteristics and the amount of TWWs depend to the process, dyeing is the most one which requires large volumes of water not only in the step of adding color to the fibers, in dye bath, but also during the rinsing step. Mercerizing and finishing are also significant generators of TWWs. In addition, equipment, machines and chemicals, 5 such as detergents and stabilizers, alter significantly the nature of TWWs. Another important factor which contributes to the ecotoxicity and the volume of TWWs is that dyeing and finishing processes, especially, require the imput of a wide range of dyestuffs. The Variety of dyes depends to the fiber used. 16 For example, cellulose fiber requires the application of direct, reactive, vat, azo or sulfide dyes. Acid dyes are used essentially for wool and silk. Azo and disperse dyes are applied to the polyester fiber. A large quantity of these dyes is released in the TWWs due to their degree of fixation to fibers. AbstractThe textile wastewaters (TWWs) are one of the major sources of environmental pollution, due to the presence of various recalcitrant dyes. It is estimated that about 300,000 t of synthetic dyes are discharged in TWWs every year worldwide. Thus, untreated or incompletely treated TWWs cause harm to aquatic and terrestrial life. To avoid the negative impacts associated to the discharge of TWWs into the natural ecosystems, effective dye remediation processes are being developed. Current methods of removing dyes from TWWs are generally regarded to be complex, expensive and energy demanding processes. Therefore, bioremediation of TWWs using microbial consortia has appeared as an emerging alternative for textile dyes removal. This chapter provides an updated literature on the application of microbial consortia in the treatment of TWWs, focusing on the mechanisms involved in dye biodegradation and the main interactions established between the consortia members and how they can influence dye removal efficiencies.