Treatment of methyl tert-butyl ether vapors in biotrickling filters.: 1.: Reactor startup, steady state performance, and culture characteristics

An aerobic microbial consortium able to biodegrade methyl tert-butyl ether (MTBE) was enriched in two waste air biotrickling filters after continuous operation for 6 months. After this acclimation phase, the two laboratory/scale biotrickling filters were able to degrade up to 50 g of MTBE per cubic meter of reactor per hour, a value comparable to other gasoline constituents. Such high performance could be sustained for at least 4-6 weeks. After the acclimation phase, the MTBE degrading biotrickling filters were characterized by their almost full conversion (similar to 97%) of MTBE to carbon dioxide and the absence of any degradation byproducts in either the gas or the liquid phase. They also exhibited a very high specific degradation activity per amount of biomass (5-10 mg of MTBE per gram dry weight of cell per hour), and a low rate of biomass accumulation. An observed biomass yield of 0.1 g g(-1) and a specific growth rate of 0.025 day(-1) were determined for the biotrickling filter process culture. Further data on MTBE mass transfer and on the dynamic behavior of the biotrickling filter are presented in part 2 of this paper. Overall, the results demonstrate that MTBE can be effectively biodegraded under carefully controlled environmental conditions.