Effectiveness of a multi-stage biofilter approach at pilot scale to remove odor and VOCs

This paper describes an experience conducted to evaluate the performances of a multi-stage approach using a biofiltration process applied to treat exhaust air. In particular, the experimentation was carried out using a pilot plant for the biofiltration of exhaust air from a solid recovered fuel drying process treating the dry fraction of municipal solid waste. Such exhaust streams are characterized by low concentrations of volatile organic compounds and high presence of odorous compounds, such as H2S and NH3. The adopted layout for the experimentation was a multi-stage plant. Each of the two stages (biotrickling filters) used seashells as packing material. In particular, the choice of seashell was defined after the evaluation of the hydrodynamic behavior of different packing materials at the same running conditions. Moreover, some velocity measurements were conducted with the aim at improving the geometry of the reactors and the fan sizing. The multi-stage biofiltration performances indicate that the solutions are suitable as well as applicable for use in industrial plants.