Relationships between biomass, pressure drop, and performance in a polyurethane biofilter

In biofilters for controlling volatile organic compounds (VOCs), clogging in the filter bed due to overgrowth of biomass causes the deterioration of biofilter performance. In this study, the relationships between biofilter performance, biomass concentration (X), and pressure drop (ΔP) was qualitatively and quantitatively evaluated in a polyurethane (PU) biofilter. Benzene was used as a model VOC. The relationship between ΔP and X at a moisture content of 80–90% was expressed as log ΔP (mm H2O m−1) = 0.315 + 3.87 log X (g-dry cell weight (DCW) g-PU−1), 0.8 < X < 2.5. Maximum removal rate (Vm) for benzene declined with increasing biomass concentration at more than 0.8 g-DCW g-PU−1, and the following equation was obtained: Vm (g m−3 h−1) = 811 − 261 X (g-DCW g-PU−1), 0.8 < X < 2.5. The quantitative relationships obtained in this study can be applied to assess and optimize PU biofilter performance for long-term operation.