Biological elimination of VOCs in biofilter

A laboratory scale biofilter system was used to eliminate toluene and ethanol, the main solvents employed in lacquering, from waste air. A specific micro‐flora (mixture of Bacillus for ethanol and two pseudomonas species for toluene) able to degrade ethanol and toluene, was fixed on a packed bed of particles of commercial peat intermittently humidified by a nutrient solution necessary for the survival of the micro‐organisms. In the experiments, polluted gas was fed upwards through the bed and physcial parameters: moisture content of peat; humidity of air; temperature; pressure drop; inlet/outlet concentration of gas and microbial population were measured regularly in order to check the performance of the biodegradation process. These experiments showed good performance and good stability of the biofilter over time.