Advanced technological solutions for enhanced biological decolourization of textile wastewater

In this study, the biological decolourization of a real textile wastewater was investigated under different reaction environments and operation modes. Colour load was mainly constituted by reactive azo-dyes. Single aerobic and anaerobic, and sequential anaerobic-aerobic conditions were applied and the last one has been also tested in a two-phase partitioning bioreactor (TPPB). Bioreactors were operated in sequencing batch mode with a reaction time of 24 h and the decolourization process was kinetically characterized in all tested conditions. From the influent characterization a dominant wavelength (?=536 nm) was determined as representative of the colour load components. With reference to ?=536 nm, and to an applied dye load of 0.01 kgCOD/(m3d), the aerobic system showed a limited colour removal efficiency of ~30%, better performance was obtained with the anaerobic (~65%) and the sequential anaerobic-aerobic processes, with efficiencies of ~70%. A further improvement was achieved with the sequential process in a TPPB, with colour removal efficiencies of 84%.