Comparison between biological and chemical-physical treatment for colour removal.

The main aim of this research is to compare the efficiency of biological and chemical-physical treatments for the removal of organic azo dyes in the textile wastewater. Regarding the biological reduction of the wastewater colour the anaerobic/aerobic (ANA/AER) sequential step-treatment provides the best reductions in colour and COD. A lab-scale Sequencing Batch Reactor (SBR) fed with synthetic wastewater and mono-azo dye (at the initial concentration of 25 mg/l) was used achieving 84% colour reduction and 82% COD removal. Chemical-physical treatments were performed using the oxidative method with Fenton's reagent and adsorption on the activated carbon achieving respectively colour reduction over 90% (from the initial concentration of 250 mg/l) and 155 mg col/g GAC total adsorption capacity (from the initial concentration of 1 g/l).