VOC removal and odor abatement by a low-cost plasma enhanced biotrickling filter process

Abstract

A combined three stage waste air treatment system, consisting of a dielectric barrier discharge (non-thermal plasma), a low-cost zeolite adsorber, and a subsequent biotrickling filter, was investigated in respect to industrial practicability. Feasibility was proven by treatment of up to 1000m3*h−1 of emissions during sludge centrifugation in a waste water treatment plant under native conditions with ammonia and methane as the main compounds. In subsequent phases styrene, ethanol, n-butanol, 2-butoxyethanol, and gasoline were added as spiking components. Process parameters were pre-defined by a lab-scale plasma/adsorber system using ammonia, n-butanol, and methane as main compounds, and enhanced gas distribution after computational fluid dynamic simulation of the systeḿs geometry. Lab-scale tests without bioprocess at 300m3*h−1 showed a reduction of 31%, 44%, and 53% of the VOC content in matter of n-butanol feed, forming butyraldehyde as main intermediate, at specific input energy (SIE) levels of 2.8, 4.2, and 5.6kWh*1000m−3. Concentrations dropped by 76%, 98%, and 100% in case of n-butanol, and 41%, 56%, and 73% in case of ammonia at the same SIE levels. With exception of methane, VOCs as well as odor were efficiently eliminated by 50–100% and 60–94% in the pilot-scaled plasma/adsorber system at constant SIE levels of 2.0–2.2kWh*1000m−3. VOC removal and odor abatement were further improved to 95% or higher in combination with the subsequent bioprocess. Conversely, transformation of methane was negligible in both systems under these conditions.