Thermophilic biotrickling filtration of ethanol vapors

The treatment of ethanol vapors in biotrickling filters for air pollution c ontrol was investigated. Two reactors were operated in parallel, one at amb ient temperature (22 degreesC) a nd one at high temperature (53 degreesC). After a short adaptation phase, the removal of ethanol was similar in both reactors. At a bed contact time of 57 s, the elimination capacity exceeded 220 g m(-3) h(-1) at both temperatures. The experiments performed revealed that the process was most likely limited by biodegradation in the biofilm. The high-temperature biotrickling filter exhibited a higher degree of ethan ol mineralization to CO2 (60 vs 46% at ambient temperature); hence, a lower rate of biomass accumulation was observed. Plating and cultivation of biof ilm samples revealed that the high-temperature biotrickling filter hosted a process culture composed of both mesophilic and thermotolerant or thermoph ilic microorganisms, whereas the ambient-temperature reactor lacked microor ganisms capable of growing at high temperature. Consequently, the performan ce of the control biotrickling filter was significantly affected by a short incursion at 53 degreesC. The upper temperature limit for treatment was 62 degreesC. Overall, the results of this study open new possibilities for bi otrickling filtration of hot gases.