Removal of toluene in a fungal vapor-phase bioreactor

Toluene is a volatile organic compound (VOC) that is listed as a hazardous air pollutant (HAP). As stricter regulations on VOCs and HAPs have been promulgated, the demand for more cost effective and efficient abatement-technologies has increased. One promising new technology for removing VOCs from polluted gas streams is biofiltration, a process in which contaminated air is passed through a biologically active bed. Although bioreactors that contain bacteria have been successfully employed to treat VOCs in waste gas streams, bacterial systems are generally most applicable for removing low concentrations of VOCs. In this study, a fungal vapor-phase bioreactor, operated under aerobic conditions and a 39-second residence time, was used to treat a gas stream contaminated with varying concentrations of toluene. The fungal bioreactor achieved a maximum toluene elimination capacity of 285 g/m(3)-hr, which is three to seven times greater than toluene elimination capacities typically reported for bacterial systems. In addition, harsh operating conditions such as low moisture content and low pH did not adversely affect the performance of the fungal bioreactor. These results indicate that fungal bioreactors may be an effective alternative to traditional abatement technologies for treating high concentrations of VOCs in waste gas streams.