Biological colour removal in Sequencing Batch Reactors

The primary objective of this research was to study the biological removal of organic azo dyes by using a Sequencing Batch Reactor (SBR). Further objectives were to achieve reductions in Ammonia and COD in the effluent wastewater. Anaerobic and aerobic treatment systems could be both effective in reducing the wastewater colour; however, anaerobic treatment generally produced the greatest colour removal. Anaerobic/aerobic (ANA/AER) sequential step-treatment could provide the best reductions in colour, ammonia and COD. A lab-scale SBR fed with synthetic wastewater and mono-azo dye was set in laboratory in order to perform some experimental runs. A first experimental run was performed with only aerobic phase, to acclimate the microorganisms and to study the colour adsorption on the biomass. Other runs will be performed with an anoxic/anaerobic phase followed by an aerated phase to study the colour degradation and to obtain the nitrification and denitrification removal rates (results here not presented)