Rhamnolipid‐Enhanced Biotrickling Filter for Styrene Removal and Microbial Community Analysis

ABSTRACT Styrene is a typical hydrophobic volatile organic compound (VOC) that poses potential risks to both the environment and human health, making its efficient removal of great significance. Adding surfactants is an effective method to enhance efficiency of biotrickling filter (BTF) in removing hydrophobic VOCs. This study conducted experiments with and without adding rhamnolipid (RL, concentration 150 mg/L) as a control to investigate its impact on BTF's performance in removing styrene. Results showed that during BTF's initiation phase, compared with BTF1, which required 9 days for the removal efficiency (RE) to reach 100%, BTF2 achieved 100% RE in only 6 days. After initiation, as the styrene concentration at the inlet increased and the empty bed residence time decreased, the RE of BTF2 was on average 5% higher than that of BTF1 during the same period. Ultimately, BTF2 achieved a maximum elimination capacity (EC) of 186.27 g/m 3 /h, whereas BTF1's maximum EC was 149.51 g/m 3 /h. Following a starvation period, BTF2 restarted within 32 h, whereas BTF1 required 44 h. Finally, microbial community analysis revealed that the genera Psedomonas , Gordonia , and Comamonadaceae played major roles in styrene removal, while BTF2 supplemented with RL exhibited a higher abundance of dominant populations. In conclusion, adding RL to the nutrient solution positively affected BTF's styrene removal performance. It serves as an effective method to enhance BTF's removal of hydrophobic VOCs.