Treatment of textile effluents through bio-composite column: decolorization and COD reduction

Textile is one of the most important sectors generating large volume of liquid pollutants. Hence, one of the great challenges is to design effective adsorbent to treat wastewaters prior to their discharge in water streams. This study emphasizes the use of microorganisms for the treatment of recalcitrant and toxic dyes being caused by textile industries. For this aim, the azo dyes of Reactive Red 3, Reactive Yellow 42, Reactive Black 5, Reactive Blue 4 and Acid Orange 74, which are extensively used in textile industry, were treated by dispersed Aspergillus niger. Decolorizing of basic dyes was successful at higher pH values, while acid dyes’ removal was possible only at low pH values. Removal efficiency after 24 h incubation for R. Red, R. Black and R. Blue reached to 95% in batch process. FTIR analysis of 24-h treatment showed change in peaks when compared to control dye spectra indicating biodegradation of dyes after treatment. Then, the fungi were embedded in polyhydroxyethyl methacrylate-glycidyl methacrylate [poly (HEMA-co-GMA)] to fabricate bio-composite columns. Removal of color and reduction of chemical oxygen demand (COD), biological oxygen demand, total dissolved solids, total solids and total organic carbon of industrial textile effluent were studied through the bio-composite column. COD reduction and color removal of textile effluents were 77.5% and 99.2%, respectively.