Temporal and longitudinal biofilm matrix analysis of a biofilter treating ethyl acetate during ozonation

The present paper focuses on the biofilm composition and pattern of biomass in gas biofiltration of ethyl acetate working under continuous addition of ozone (O₃). Two biofilters were operated for 230 days, one under continuous addition of O₃ (90 ppb_v) and another one without. Throughout the operation time, the extracellular polymeric substances (EPS), the main components in the extracellular matrix (ECM), were extracted from the biofilm and characterized qualitatively using Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) and quantitatively by analyzing its main constituents: carbohydrates, proteins, and glucuronic acid. To date, EPS characterization has been attempted mainly with biofilm aggregates related to water treatment, not air biofiltration. The results of this study may be helpful and provide more information about EPS structure when O₃ was added. O₃ addition only affected the amount of EPS and not its composition. The greater effect was observed on carbohydrate content since it is the main component in EPS. The EPS/biomass ratio measured was twice lower with O₃ addition. Higher removal efficiency (RE) and mineralization rates were obtained with the biofilter subjected to O₃ addition, and a smaller volume of a reactor would be necessary to treat all contaminant under this condition. EPS content is only quantitatively reduced by O₃ addition, and at the low O₃ concentration applied_, no structural alteration is noted regarding the composition of the EPS.