Publication Date:
2014-12-31
Description:
The potential of a bioscrubber composed of a packed bed absorption column coupled to a stirred tank denitrification bioreactor (STR) was assessed for 95 days for the continuous abatement of a diluted air emission of N 2 O at different liquid recycling velocities. N 2 O removal efficiencies of up to 40 ± 1 % were achieved at the highest recirculation velocity (8 m h −1 ) at an empty bed residence time of 3 min using a synthetic air emission containing N 2 O at 104 ± 12 ppm v . N 2 O was absorbed in the packed bed column and further reduced in the STR at efficiencies 〉80 % using methanol as electron donor. The long-term operation of the bioscrubber suggested that the specialized N 2 O degrading community established was not able to use N 2 O as nitrogen source. Additional nitrification assays showed that the activated sludge used as inoculum was not capable of aerobically oxidizing N 2 O to nitrate or nitrite, regardless of the inorganic carbon concentration tested. Denitrification assays confirmed the ability of non-acclimated activated sludge to readily denitrify N 2 O at a specific rate of 3.9 mg N 2 O g VSS h -1 using methanol as electron donor. This study constitutes, to the best of our knowledge, the first systematic assessment of the continuous abatement of N 2 O in air emission. A characterization of the structure of the microbial population in the absorption column by DGGE-sequencing revealed a high microbial diversity and the presence of heterotrophic denitrifying methylotrophs.
Print ISSN:
0175-7598
Electronic ISSN:
1432-0614
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
