The removal of colour from textile wastewater using whole bacterial cells: a review

The delivery of colour in the form of dyes onto textile fibres is not an efficient process. The degree of efficiency varies, depending on the method of delivery. As a result, most of the wastewater produced by the textile industry is coloured. It is likely that coloured wastewater was a feature of the first practices of textile dyeing. However, treatment to remove this colour was not considered until the early natural dyestuffs were replaced by synthetic dyes, and the persistence of such synthetic dyes in the environment was recognised (Willmott NJ. The use of bacteria-polymer composites for the removal of colour from reactive dye effluents. PhD thesis, UK: University of Leeds; 1997.). Colour pollution in aquatic environments is an escalating problem, despite the fact that there has been substantial research into the modification of the dyeing process to improve the level of affinity/fixation of the dyestuffs onto the substrate. The recalcitrant nature of modern synthetic dyes has led to the imposition of strict environmental regulations. The need for a cost-effective process to remove the colour from wastewater produced by the textile industry has been recognised (Willmott NJ, Guthrie JT, Nelson G. The biotechnology approach to colour removal from textile effluent. JSDC 1998; 1 14(February):38-41.). Several strategies have been investigated. However, the review presented here concerns the use of whole bacterial cells for the reduction of water-soluble dyes present in textile dyeing wastewater. (C) 2003 Elsevier Ltd. All rights reserved.