ABSTRACT
The recalcitrant volatile organic compounds with low biodegradability pose challenges for biofiltration technology. To investigate the effect of adding ozone on biofiltration process, a biofilter was operated continuously for more than 160 days under different inlet ozone concentrations. The experimental results showed that the chlorobenzene removal capacity of the biofilter with 10-50 mg ⋅ m−3 ozone was obviously higher than those with no ozone. Furthermore, a higher chlorobenzene removal capacity was achieved when the ozone concentration was increased. The mechanism of ozone on biofilter performance was also investigated. The average biofilm thickness and extra-cellular polymers content (EPS) were both reduced when the inlet ozone concentration was increased. The specific surface areas of the filter bed increased from 784 m2 ⋅ m−3 (no ozone) to 820 m2 ⋅ m−3 (10-30 mg m−3 ozone) and 880 m2 ⋅ m−3 (30-50 mg ⋅ m−3 ozone). The microbial activity estimated by Biolog plate analysis was found to increase with higher ozone concentration. All the experimental results proved that ozone can promote the chlorobenzene removal capacity of the biofilter by optimizing the physical structure and microbial property of the filter bed.
