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Nitrous oxide emission depending on the type of electron acceptor by a denitrifying phosphorus removal sludge

Paper Topic: 
Wastewater treatment

Pages :
251 - 258

Corresponing Author: 
Wu G.
Tang B., Wu G., Wang H. and Guan Y.
Paper ID: 
Paper Status: 
Date Paper Accepted: 
Paper online: 

Denitrifying polyphosphate accumulating organisms (DNPAOs) are very promising for simultaneous nitrogen and phosphorus removal. While during denitrification, emission of a greenhouse gas, nitrous oxide (N2O), may occur. In this study, DNPAOs were enriched in a lab-scale reactor, and N2O emission was examined under different electron acceptor conditions. During the anoxic phase, with the uptake of phosphorus, denitrification of nitrate nitrogen (NO3-N) was observed without the accumulation of nitrite nitrogen (NO2-N). In general, a very low amount of N2O was produced with nitrate as the electron acceptor, independent of the applied different nitrate concentrations. However, with nitrite as the electron acceptor, a much higher N2O emission occurred. The N2O emission factor to the denitrified NO2-N was 6.2%, 5.3% and 4.9% at the initial NO2-N concentration of 10, 20 and 40 mg l-1, respectively. In addition, a much higher N2O emission occurred with the co-existence of NO3-N and NO2-N. The initial organic carbon concentration had no significant effect on N2O emission with NO3-N as the electron acceptor. When stored organic carbon by DNPAOs was used as the electron donor, N2O emission was mainly dependent on the electron acceptor. 


nitrous oxide, denitrifying polyphosphate accumulating organisms, nitrite, intracellular stored organic carbon