The simultaneous treatment of N2O-laden air emissions and domestic wastewater was assessed in a novel denitrifying bioscrubber composed of a packed bed absorption column interconnected to a fixed bed reactor (FBR). The influence of liquid recycling velocities (U-L) and gas empty bed residence times (EBRTs) in the absorption column on bioscrubber's performance was evaluated using synthetic wastewater (SW) and a 100 +/- 8 ppm, N2O air emission. Steady state N2O removal efficiencies of 36 +/- 3% concomitant with SW total organic carbon removals of 91 +/- 1% were achieved at an EBRT of 3 min and at the highest U-L tested (8 m h(-1)). The removal of dissolved N2O by heterotrophic denitrification in the FBR constituted the main N2O biodegradation mechanism and limited the abatement of N2O. While the supplementation of SW with Cu2+ (a cofactor of the N2O reductase) did not result in an enhancement in N2O reduction, the increase in FBR volume supported a higher N2O removal. The increase in EBRT up to 40 min supported an enhancement in the gas N2O removal of up to 92%. The DGGE-sequencing analysis of FBR microbial population revealed a high microbial diversity and the abundance of denitrifying bacteria capable of reducing N2O to N-2. (C) 2015 Elsevier B.V. All rights reserved.