## 1 Environmental Pollution Due to Textile Wastewater  
The protection of the aquatic environment and life by regulation guidelines of water pollution has become of increasing importance. Although the release of dyes containing coloured water into the environment only contributes a small proportion of water pollution, when compared to other chemical-pollutants, dyes are visible due to their colour even if present in very small quantities. Strict legislation is forcing textile industries to dispose of their waste-effluent after treatment to a required standard. Dyes are used mainly in textile manufacturing to dye fabrics in different colours. The dyes are soluble compounds and are commonly classified under groups of reactive, direct, basic, and acid dyes. The annual production of these dyes is estimated at over \(7\times 10^{5}\) tons worldwide, whereas approximately 10-15% of dye production is wasted in the water bodies during the various processes in dye manufacturing and dyeing in multiple industries. Wastewater generated from the textile industry is a mixture of a variety of polluting materials, including synthetic dyes and other chemicals used in washing and colour-stripping of over or uneven dyed cotton and during the finishing of coloured fabric. These dyes are recalcitrant to microbial degradation because they contain substitutions such as azo, nitro, or sulpho groups. Several types of synthetic dyes as colour-contributing chemicals are being used in textile companies, although in smaller quantities. The synthetic dyes not only affect the aesthetic quality of water sources due to their colour, but also increase biochemical oxygen demand (BOD) and chemical oxygen demand (COD),inhibiting the rate of photosynthesis and plant growth. Dye-contaminated water, if used for irrigation, might enter our food chain, which in the long term will result in recalcitrance and bioaccumulation, and in the development of toxicity, mutagenicity, and carcinogenicity in living systems. The presence of dyes contributes a small fraction of the total organic-load present in wastewater; however, if disposed of as untreated wastewater, their colour in water sources makes them visually unacceptable [1]. Wastewater discharge from textile and dyes manufacturing companies to water bodies and water treatment systems disturbs the ecosystem. It causes health concerns to aquatic life, flora, and fauna; in return, humans are also affected by consuming seafood sourced from such contaminated water. This whole cycle of health concern is alarming to environment-regulatory authorities. Removal of colour from effluents has become of global scientific interest, which is evident from several scientific reports published on this subject [2; 3; 4]. In the last few decades, many physico-chemical techniques for the decolourisation of textile wastewater have been reported, but only a few are practically possible for use by the textile industries. Their implementation is not profitable due to their high cost, less efficiency, and inapplicability of methods to treat a wide range of synthetic dyes present in large volumes of water. Conventionally, the removal of dyes from wastewater has been practiced by physical and chemical methods. Some commonly used methods are adsorption, coagulation, precipitation, filtration, oxidation, and ion-exchange affinity-adsorption [5], which have been used for the remediation of textile effluent. The process of adsorption appears to offer the best prospects over all the other treatments. These systems are mostly expensive, and although the concentration of dyes is either reduced or removed from wastewater, after the treatment process, the resultant sludge creates another problem in terms of their safe and economical disposal. Microbial degradation of several azo and anthraquinone types of dyes has been previously reported.