Biomass Control via UV Lamp Application and Nutrient Supply Restriction in the Biofiltration of Gaseous VOCs

Biofiltration may have clogging problems owing to excess biomass growth during the treatment of gaseous pollutants. In this study, we employed an UV (Ultraviolet) lamp and controlled the nutrient supply to conduct a biofiltration process for treating 2-butanone (MEK: Methyl Ethyl Ketone) and toluene in a gas stream. Two methods of UV lamp usage (direct and indirect irradiation) and several nutrient supply methods were tested. However, no clear effect was observed with either UV usage. Under the optimal conditions, 97% of the MEK and 69% of the toluene gases were removed after 29 s of EBRT (Empty Bed Retention Time). The inlet loads were 18 and 19 mg/(m³·h) for MEK and toluene, respectively. Under these conditions, 23 g-N/(m³·day) of nitrate-nitrogen was consumed. Excess biomass growth occurred during simultaneous excess nutrient supply and a persistent irrigation schedule. In this study, we demonstrated the effective use of a dense nitrate solution to deliver an appropriate amount of nutrients and moisture, and the optimal irrigation frequency was four times per week.