Operational factors affecting the bioregeneration of mono-amine modified silica loaded with Acid Orange 7

In this study, the operational factors affecting the bioregeneration of AO7-loaded MAMS particles in batch system, namely redox condition, initial acclimated biomass concentration, shaking speed and type of acclimated biomass were investigated. The results revealed that with the use of mixed culture acclimated to AO7 under anoxic/aerobic conditions, enhancement of the bioregeneration efficiency of AO7-loaded MAMS and the total removal efficiency of COD could be achieved when the bio-decolorization and bio-mineralization stages were fully aerated with dissolved oxygen above 7 mg/L. Shorter duration of bioregeneration was achieved by using relatively higher initial biomass concentration and lower shaking speed, respectively, whereas variations of biomass concentration and shaking speed did not have a pronounced effect on the bioregeneration efficiency. The duration and efficiency of bioregeneration process were greatly affected by the chemical structures of mono-azo dyes to which the biomasses were acclimated.

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► Operational factors investigated for bioregeneration of AO7-loaded MAMS.
► Complete bio-decolorization and bio-mineralization in bioregeneration.
► Shorter bioregeneration duration in increasing initial biomass concentration.
► Longer bioregeneration duration in increasing shaking speed.
► Use of AO7-acclimated biomass essential for bioregeneration.