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/sc ale 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 constituent s. Such high performance could be sustained for at least 4-6 weeks. After t he acclimation phase, the MTBE degrading biotrickling filters were characte rized by their almost full conversion (similar to 97%) of MTBE to carbon di oxide and the absence of any degradation byproducts in either the gas or th e liquid phase. They also exhibited a very high specific degradation activi ty per amount of biomass (5-10 mg of MTBE per gram dry weight of cell per h our), 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 transfe r and on the dynamic behavior of the biotrickling filter are presented in p art 2 of this paper. Overall, the results demonstrate that MTBE can be effe ctively biodegraded under carefully controlled environmental conditions.