Effects of ozone treatment on performance and microbial community composition in biofiltration systems treating ethyl acetate vapours

Ozone (O3) treatment has been suggested as an effective strategy in maintaining high efficiency and control of biomass accumulation in gas phase biofiltration. However, little is known about the long-term impact of O3 on the microbial communities present in biofiltration systems. In the present study, two biofilters treating gaseous ethyl acetate were operated continuously for 230 days under three different inlet loads (60, 120 and 180 g·m-3·h-1). One biofilter was operated under continuous O3 addition (90 ppbv). The ozonated reactor continuously showed a higher removal efficiency (RE) and elimination capacity (EC) compared to the control system. After 120 days of operation a change in pH to 1.5 and 4 was observed in the ozonated and control reactors, respectively. Both reactors developed a distinct microbial community composition over the course of 230 days. The bacterial community was dominated in both biofilters by Beijerinckia and Gluconacetobacter, while Rhinocladiella similis, Trichosporon veenhuissi and Exophilia oligosperma were represented abundantly in the fungal community.