Colour removal in Sequencing Batch Reactors

The primary objective of this research was to study the biological colour removal from a simulated textile effluent containing an azo reactive dye with a Sequencing Batch Reactor (SBR). Further objectives were to achieve reductions in Ammonia and COD in the effluent wastewater. 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 up in laboratory. At the beginning of the experimentation only the aerobic phase occurred in the reactor in order to acclimate the microorganisms and to study the colour adsorption on the biomass. Later an experimental run with an anoxic/anaerobic phase followed by an aerated phase was carried out in order to study the colour degradation and the nitrification and denitrification processes. Furthermore, the sludge age of the reactor was varied between 10, 20 and 30 days and pH, Temperature, ORP and SST and SSV concentrations were monitored during all experiments. Several samples were also collected within a typical operative cycle during the anaerobic phase to determine the colour removal kinetic.