Styrene and bioaerosol removal from waste air with a combined biotrickling filter and DBD-plasma system

Abstract

A combined system of a biotrickling filter and a non-thermal plasma (NTP) in a downstream airflow was operated for 1220 days for treatment of emissions of styrene and secondary emissions of germs formed in the biological process. The biotrickling filter was operated at variable inlet concentrations, empty bed residence times (EBRT), type and dosage of fertilizers, irrigation densities, and starvation periods, while dielectric barrier discharge and corona discharge were operated at different specific input energy levels to achieve optimal conditions. Under these conditions, efficiencies in the removal of volatile organic compounds (VOCs), germs and styrene of 96-98%, 1-4 log units and 24.7-50.1 g C m-3 h-1 were achieved, respectively. Fluid simulations of the NTP and a germ emission-based clocking of the discharge reveal further energy saving potentials of more than 90%. The aim of an energy-efficient elimination of VOCs through a biotrickling filter and of secondary germ emissions by a NTP stage in a downstream airflow for potential re-use of purified waste gas as process gas for industrial application was successfully accomplished.