Boosting biodegradation and mineralization efficiencies of chlorinated VOCs: The synergy of H2O2 and biotrickling filtration

Abstract

This study explores a new biodegradation process of H₂O₂-stimulated BTFs to remove perchloroethylene (PCE) from the contaminated air stream. BTF stimulated with H₂O₂ significantly boosted PCE biodegradation compared to conventional methods. Optimal parameters for H₂O₂-assisted PCE biodegradation were also identified (nominal inlet concentration = 150 ppm, EBCT = 30 s, H₂O₂/PCE molar ratio = 0.2). Under these optimum conditions, the BTF achieved a maximum PCE removal efficiency of around 95 %, a mineralization rate of 65 %, and an elimination capacity of 117 g/m³.h, demonstrating its effectiveness. The BTF maintained stable performance under various PCE loads, suggesting its applicability for industrial cases. Moreover, the study revealed a positive correlation between increasing H₂O₂/PCE ratios and the activities of key enzymes responsible for biodegradation including dehydrogenase)increased from 1.3 to 26.1 mg-TF/g_biomass), peroxidase (increased from 0 to 251 U/g_biomass), and catalase (increased from 0 to 7.8 U/g_biomass) when the ratio was increased from 0 to 0.2. The H₂O₂-stimulated BTF performed efficiently for biodegradation (>90 %) and mineralization (>60 %) of PCE at empty bed contact times between 20 and 60 s. Finally, the absence of PCE and toxic intermediates in the recycled liquid supports the efficient biodegradation of PCE in the developed system. In conclusion, H₂O₂-stimulated BTF shows promise as a sustainable and cost-effective approach for biodegradation of chlorinated organic compounds in contaminated air streams.