Bioscrubbing as a treatment for a complex mixture of volatile organic compounds: influence of the absorption column characteristics on performance

Abstract

A semi-industrial bioscrubber was developed to treat a complex mixture of volatile organic compounds (VOCs), including oxygenated, aromatic, and chlorinated compounds. Packed and atomizing columns were used for the bioscrubber. For an applied inlet load of around 850 – 870 g VOCs·m−3 packing material·h−1, the various performances of the bioscrubber were equivalent (around 50%), regardless of the selected absorption column. Only the removal efficiency of oxygenated compounds was found to be reasonable, close to 80% – 85%. For the bioscrubber equipped with an atomizing column, a doubling of the inlet load involved a decrease in the removal efficiency of the VOC mixture (35%) and oxygenated compounds (from 80% to 55%). As the transferred compounds were biodegraded, the limits could be explained by the hydrodynamic characteristics of the atomizing column. Furthermore, these results demonstrate the necessity of optimizing the gas – liquid mass transfer step. Two-phase partitioning bioreactors seem to represent an attractive option, even though knowledge of the transfer of compounds and biodegradation mechanisms is required prior to scale-up and industrial use.