Abstract
Many kinds of volatile organic compounds (VOCs) have been treated in the biofilters based on the degradation of VOCs by the biolayer on the surface of packing media. Such a bed is easily subjected to compaction or clogging due to separation of biolayer and to an increase in pressure drop of gas flow. To overcome the drawbacks, our previous study has proposed the packed column containing the immobilized activated sludge gel beads together with the hollow plastic balls to avoid the bed compaction. In the present study, the biofilter is applied to remove the binary mixture of benzene-ethylbenzene (BE) or benzene-toluene (BT) using the gel beads which have been acclimated during the earlier stage of the respective removal operations. As in the case of the binary acetaldehyde-propionaldehyde mixture in our previous work, the modified Michaelis-Menten type rate equation is determined for the biodegradation of the binary VOCs mixture by the gel beads taking account of the coexistent VOC. The gel beads are efficient for removing both binary mixtures in the biofilter. The design equations similar to those for the binary aldehydes mixture are applicable to predicting the removals of each VOC component. The predictions are successful with the degradation kinetic parameters as well as the Henry's law constants which depend on the VOC concentration and are modified by the partition coefficient of the respective VOC between gel and aqueous phases as opposed to the case of the aldehydes.
