Toluene degradation in a polyurethane biofilter at high loading

In the present study, toluene elimination in the polyurethane (PU) biofilter during long-term (145 day) operation was characterized, and assessed the effects of changing the inlet loading and space velocity (SV). A very high elimination capacity of 3.7 kg·m^-3·h^-1 was obtained at an inlet loading of 4.0 kg·m^-3·h^-1 (inlet toluene concentration of 900 ppmv at a SV of 1,040 h^-1). Backwashing with irrigation and compressed air allowed maintenance of a pressure drop of < 80 mm H₂O·m^-1-filter at an SV of 830 h^-1 and an elimination efficiency of > 90% during the 145 day of operation. In conclusion, the PU biofilter can overcome the problems of clogging caused by excess biomass growth and of low treatment capacities of conventional biofilters.