Nitrous emission from a SBR wastewater treatment system under different NH4+ concentration

Nitrous emission in SBR denitrification process and the microbial community impact on it were studied. Result showed that the relationship between the N₂O emission and conversion efficiency of nitrogen in system during the wastewater nitrogen removal process is negatively correlated. Under the experimental conditions, with NH₄⁺ concentration increased, the efficiency of nitrogen transformation is decreased in this SBR system, meantime the N₂O-N ratio is rapidly increase. Using PCR-DGGE technique analysis characteristics of microbial communities in SBR system under the different concentrations of NH₄⁺ Showed that in high NH₄⁺ concentration (60 mg · L^-1)the microbial community is quite different when compared to medium (40 mg ·L^-1)and low (20 mg ·L^-1)concentrations. N₂O emission in high NH₄⁺ concentration was effected by the nitrogen conversion efficiency and the changes in microbial community. In this study, the proportion of N₂O-N is 0.25%~6.35% in the wastewater nitrogen removal process under different NH₄⁺ concentrations.