Effect of Ammonium Concentration on the Emission of N2O Under Oxygen-Limited Autotrophic Wastewater Nitrification = Effect of Ammonium Concentration on the Emission of N2O Under Oxygen-Limited Autotrophic Wastewater Nitrification

다국어 초록 (Multilingual Abstract)

A significant amount of nitrous oxide (N2O), which is one of the serious greenhouse gases, is emitted from nitrification and denitrification of wastewater. Batch wastewater nitrifications with enriched nitrifiers were carried out under oxygen-limited condition with synthetic (without organic carbon) and real wastewater (with organic carbon) in order to find out the effect of ammonium concentration on N2O emission. Cumulated N2O-N emission reached 3.0, 5.7, 6.2, and 13.5 mg from 0.4 l of the synthetic wastewater with 50, 100, 200, and 500 mg/l NH4 +-N, respectively, and 1.0 mg from the real wastewater with 125 mg/l NH4 +-N. The results indicate that N2O emission increased with ammonium concentration and the load. The ammonium removal rate and nitrite concentration also increased N2O emission. Comparative analysis of N2O emission from synthetic and real wastewaters revealed that wastewater nitrification under oxygen-limited condition emitted more N2O than that of heterotrophic denitrification. Summarizing the results, it can be concluded that denitrification by autotrophic nitrifiers contributes significantly to the N2O emission from wastewater nitrification.