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 N
₂
O emission and conversion efficiency of nitrogen in system during the wastewater nitrogen removal process is negatively correlated. Under the experimental conditions, with NH
₄
⁺
concentration increased, the efficiency of nitrogen transformation is decreased in this SBR system, meantime the N
₂
O-N ratio is rapidly increase. Using PCR-DGGE technique analysis characteristics of microbial communities in SBR system under the different concentrations of NH
₄
⁺
Showed that in high NH
₄
⁺
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. N
₂
O emission in high NH
₄
⁺
concentration was effected by the nitrogen conversion efficiency and the changes in microbial community. In this study, the proportion of N
₂
O-N is 0.25%~6.35% in the wastewater nitrogen removal process under different NH
₄
⁺
concentrations.