Resumen de Biodegradation of BTXS and substrate interactions on a bioactive foam reactor
A bioactive foam reactor (BFR), using surfactant-driven bubbles and suspended microorganisms, has emerged as a potential alternative to packed-bed biofiltration systems for the treatment of volatile organic compounds (VOCs). The study presented herein was designed to investigate the effects of VOC mixtures (benzene, toluene, p-xylene, and styrene) on biodegradation efficiencies and substrate interactions in the BFR. Benzene, toluene p-xylene, and styrene were applied individually to the toluene-acclimated BFR at the same inlet concentration (0.78 g/m3), and then paired BTXS mixtures (BT, BX, BS, TX, TS, XS, and BTXS in the same ratio by volume) were applied but the total inlet concentration were maintained constant. The overall removal rates of each of the four VOCs were in the following order: toluene, styrene, benzene, and p-xylene in the inlet concentration range tested. However, styrene biodegradation was the highest in the presence of other VOC compounds. The removal efficiency for toluene as a single substrate was 82%, but toluene removal efficiencies dropped when the paired mixtures were applied. The removal efficiency for benzene also decreased in the presence of other TXS compounds. In contrast, the removal efficiency for p-xylene as a single substrate was only 21% in the BFR, but p-xylene removal efficiencies ranged 35 � 41% in the presence of other BTS compounds. As a result, the biodegradation of benzene and toluene was inhibited by the other carbon sources, whereas the biodegradation of styrene and p-xylene was enhanced by the others. Consequently, a careful attention needs to be given when BFR performance and biodegradation rates of mixed VOCs are utilized for system design and operational purposes.
