A biofilter for treating toluene vapors: performance evaluation and microbial counts behavior

A lab-scale biofilter packed with mixed packing materials was used for degradation of the toluene. Three gas flow rates, i.e. 0.1, 0.2 and 0.4 m 3 /h, were tested for inlet concentration ranging from 0.2 to 1.2 g/m 3 . Removal efficiencies ranging from 45.6 to 97.3% and elimination capacities ranging from 4.95 to 61.07 g/(m 3 h) were observed depending on the inlet loading rates. Maximum elimination capacity of 35.95 g/(m 3 h) occurred at inlet loading rate of 45.87 g/(m 3 h). The lowest layer always had highest elimination capacity. Carbon dioxide concentrations and the microbial cell counts for bio-degraders followed toluene elimination capacities. Results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m), for treating air streams containing VOCs.