Decolorization of textile industry effluent using immobilized consortium cells in upflow fixed bed reactor

Abstract

Textile dyes are xenobiotic contaminants which pose a potential risk on the ecosystem upon their disposal to the water bodies. This study evaluated the efficiencies of different immobilization matrices for its utilization in a reactor with continuous mode operation for decolorization of textile effluent. An effective consortium of bacteria (Brevibacillus laterosporus) and yeast (Galactomyces geotrichum) were immobilized in different support matrices including calcium alginate, polyvinyl alcohol, stainless steel sponge and polyurethane foam to investigate the decolorization of a model azo dye, Remazol red and textile industry effluent. The microbial consortia immobilized in stainless steel sponge and polyurethane foam exhibited 100% decolorization of 50 mg L-1 Remazol red in 11 and 15 h, respectively; however, calcium alginate and polyvinyl alcohol required considerably more time (20 and 24h, respectively) for complete decolorization. Among all the matrices, The calcium alginate, stainless steel sponge and polyurethane foam showed >95% decolorization of textile industry effluent within 48 h. The calcium alginate and polyvinyl alcohol exhibited stable performance of decolorization with its repeated use for 5 cycles with >76% decolorization. An upflow fixed bed reactor (total volume- 215 mL) packed with the immobilized cells of consortium onto stainless steel sponge attained similar to 90% decolorization of textile industry effluent in continuous operation at 10 mL h(-1). The decolorization efficiency of the reactor was well maintained (>90%) when the reactor was used repeatedly for three cycles. The overall results indicated that immobilized mixed consortium cells can be considered as an effective tool for its potential application in removal of xenobiotic textile dyes from the textile industry wastewater with >90% of decolorization efficiency.