Achieving stable biological oxidation of erraticwaste gas streams by utilizing cyclic adsorption/desorption beds

Off-gas treatment streams for volatile organic compounds (VOCs) that originate in industrial processes have variable flow rates, transient loadings and VOC composition. These fluctuations in loadings limit achieving stable removal efficiency for a biological oxidation process because they are very sensitive to changes in type or quantity of food. In order to overcome these ambiguities a cyclic adsorption/desorption system was installed in series before the biological oxidation process. Basically, the system consists of two fixed beds of granular activated carbon in series where the cyclic operation of adsorption and desorption was achieved by switching the flow direction within the two bed adsorber unit. The system worked as a buffering unit to flatten and reduce the VOC concentration in the treated air which allowed long-term stable performance of the biological oxidation process.