(438e) Microbial Dynamics in an Absorber-Bioscrubber System Operating under Sequentially Alternating Feeding Regimens

Industrial biological treatment systems are often exposed to waste streams with fluctuating loads and alternating composition. These dynamic conditions can inhibit microbial activity, and in turn jeopardize treatment performance. To develop more robust biological systems and insure an efficient pollutant removal under such scenarios, it is essential to follow the bacterial communities in more detail to better understand its dynamics, and at the same time develop strategies to prevent treatment disruption.

The performance of a combined absorber-bioscrubber system, degrading a gas stream contaminated with fluorobenzene (FB) and chlorobenzene (CB), was studied under different cyclic feeding regimens, simulating industrial conditions. The absorber was applied as a strategy to buffer pollutant inlet concentrations into the bioscrubber, and as well, to provide a maintenance feed of compounds being desorbed from the oil to the bacterial culture. In order to analyze the performance of the oil-absorber-bioscrubber system (OAB), it was compared to a bioscrubber-only (BO) configuration, operated under the same functional conditions. In both configurations, the bacterial communities were closely monitored by Fluorescence in situ hybridization (FISH) and Denaturing Gradient Gel Electrophoresis (DGGE). FISH allowed a quantification of specific strains involved in the degradation, while DGGE provided a good representation of the community composition and its most active species.

The bioscrubber performance results have shown that the total organic discharged (TOD) was significantly lower in the OAB system when compared to the BO configuration. This result has shown that the oil-absorber had a positive effect on the removal of FB and CB, and that it could be used as a strategy to deal with sequentially alternating polluting and fluctuating loads. The FISH and DGGE results contributed to the understanding of the OAB strategy success, revealing that this configuration sustained a more active community, which responded quickly to pollutant changes.