Impact of ammonium and salinity concentrations on Nitrous Oxide emission in partial nitrification system

This study attempted to elucidate the effects of ammonium and salinity concentrations on Nitrous Oxide (N2O) emission in a partial nitrification system producing an influent suitable for the anammox process. 1.2%, 1.3% and 1.0% of the incoming nitrogen load was emitted as N2O-N during the batch partial nitrification with 200, 300 and 400 mg L−1 NH4+-N, respectively. N2O emission increased with the increase of ammonium concentration and the load in the wastewater due to the high values of the nitrite and ammonium. 1.5%, 1.6%, 1.8% and 1.9% of the incoming nitrogen load was emitted as N2O-N during the batch partial nitrification with 2, 4, 6 and 8 wt% NaCl, respectively. N2O emission increased with the increase of salinity concentration in the wastewater as the result of inhibition of nitrous oxide reductase activity. The dynamic behavior of N2O emission (quantity (y) varying with time (x)) in the partial nitrification process can be fit to the line where y = ax + b under different ammonium and salinity concentrations.