Abstract
The profile of nitrous oxide (N2O) production was examined for aerated lagoon (AL) and intermittent aeration sequencing batch reactor (IASBR) treating swine wastewater. N2O production rate was 1.07×101～2.03×103(mgN2O－N/head/day) in AL and 2.83×102～1.12×103 (mgN2O－N/head/day) in IASBR. The emission of N2O in aeration phase accounted for over 80％ of all N2O emission in AL, and almost 100％ in IASBR. In AL, the N2O emission rate increased in the last aeration phase due to the simultaneous occurrence of nitrification and aerobic denitrification. In IASBR, the N2O emission was promoted by the accumulation of dissolved N2O caused by stagnation of denitrificatoin in anaerobic phase and the occurrence of aerobic denitrificatoin caused by high concentration of organic matter carried over from anaerobic phase. It was suggested that the risk of N2O emission in AL was higher than that in IASBR, because aerobic denitrification was promoted easily in aerobic phase, and the accumulation of dissolved N2O lead to the gasification in the anaerobic phase in AL.
