Combined Treatment of Sugar and Dye Industrial Wastewaters Using an UASB Process

Application of anaerobic treatment to the biodegradation of reactive dyes using sucrose as a co-substrate was evaluated for five Sumifix Supra dyes (Blue; Scarlet; Navy; Red and Yellow) in batch and continuous-flow UASB assays. Results of the batch tests showed that with an initial TOC concentration of 500 mg/l high dye removal efficiencies of 97% and 98.6%were obtained for the Sumifix Supra Blue and Yellow, respectively, after 24 hours of incubation. It was shown that increasing sucrose concentrations enhanced the mte of dye reduction. At an initial TOC concentration of 1500mg/l the slowly decolourizing Sumifix Supra Scarlet, Navy and Red dyes were effectively decolourized with dye removal efficiencies of 91.7, 95.6 and 97.3%, respectively. The decolouization processes of all the examined dyes proceeded without a lag phase and followed first-order kinetics. Results obtained from continuous-flow UASB treatment showed that a sludge concentration of about 16 g-VSS/l was most effective, at which high TOC and dye removal efficiencies of greater than 95% and 82%, respectively, were obtained. Results of this study provide further insight into the combined treatment of sugar and dye industrial wastewaters using an UASB process.