Gas-phase toluene biodegradation by Burkholderia vietnamiensis G4 in a biofilm membrane reactor

[Abstract] A laboratory-scale biofilm membrane bioreactor inoculated with Burkholderia Vietnamiensis G4 was examined to treat toluene vapors from a synthetic waste gas stream. The gas feed side and nutrient solution were separated by a composite membrane consisting of a porous polyacrylonitrile (PAN) support layer coated with a very thin (0.3 µm) dense polydimethylsiloxane (PDMS) top layer. After inoculation, a biofilm developed on the dense layer. The biofilm membrane bioreactor was operated continuously at different residence times (28-5 sec) and loading rates (1.2-17.7 kg m-3 d-1), with an inlet toluene concentrations ranging from 0.21-4.1 g m-3. The overall performance of the membrane bioreactor was evaluated over a period of 151 days. Removal efficiencies ranging from 78-99% and elimination capacities ranging from 4.2-14.4 kg m-3 d-1 were observed depending on the mode of operations. A maximum elimination capacity of 14.4 kg m-3 d-1 was observed at a loading rate of 17.4 kg m-3 d-1. Overall, the results illustrate that biofilm membrane reactors can potentially be more effective than conventional biofilters and biotrickling filters for the treatment of air pollutants such as toluen

Thermophilic biotrickling filtration of a mixture of isobutyraldehyde and 2-pentanone

In this study, the possibility of the removal of isobutyraldehyde and 2-pentanone was investigated in biotrickling filters (BTFs) at higher temperature (52-65 °Q. First, the biodegradation of isobutyraldehyde and 2-pentanone in activated sludge was proven by batch experiments at 52 and 62°C. In batch experiments isobutyraldehyde was also degraded up to a temperature of 72°C. Thereafter two bioreactors were operated in parallel, one at ambient temperature (BTF25), and one at 52°C (BTF52). Maximum elimination capacities of 97 and 139 g m-3h-1 were observed in BTF25 and BTF52, respectively, for isobutyraldehyde. Maximum elimination capacities of 53 and 63 g m-3 h-1 were obtained for 2-pentanone in BTF25 and BTF52, respectively. A significant difference was observed in the operational stability of the two reactors. In the reactor at ambient temperature, operational problems such as foam formation, higher biomass accumulation and organic acid production were observed. In the thermophilic reactor these problems did not occur or were less severe. © 2007 Society of Chemical Industry