Treatment of volatile organic compounds in a biotrickling filter under thermophilic conditions

The objectives of this research were to investigate the potential to biolog ically treat volatile organic compounds emitted by the forest products indu stry at thermophilic conditions and to examine the microbial community deve loped at high temperatures. Three biotrickling filters were run in parallel at temperatures ranging from 40 degreesC (mesophilic control) to 70 degree sC. The first phase involved treatment of methanol, for a 3-month run, and the second phase involved a 260-day run on the treatment of alpha -pinene. Methanol removal rates over 100 g m(-3) h(-1) where achieved at temperature s up to 70 degreesC. alpha -Pinene removal was achieved at temperatures up to 60 degreesC with optimal treatment occurring at 55 degreesC at rates up to 60 g m(-3) h(-1). The time for acclimation increased with increasing tem perature and was longer for pinene than for methanol. Filter performance wa s also able to quickly recover from a shutdown period of up to 2 weeks due to the robustness of the microbial communities as determined by DNA fingerp rinting analysis. The high-temperature communities treating methanol or pin ene were more similar to each other than the mesophilic communities (i.e., 40 degreesC). The mesophilic methanol community had a high degree of functi onal redundancy, while the mesophilic pinene community was more unique and very distinct from the others. These results show that biofiltration at hig h temperatures is achievable and opens up a range of possibilities for appl ying biofiltration to hot gas streams.