Impact of Different Nitrogen Concentrations on the N2 O Production in the Denitrification Process of Granular Sludge
不同氮浓度冲击对颗粒污泥脱氮过程中N2 O产生量的影响

The aerobic-anoxic SBR biological wastewater treatment systems were used to examine the impact of different influent NH4+-N concentrations on the release of N2 O and nitrogen removal in the simultaneous nitrification and denitrification of granular sludge. The results showed that when the influent NH4+-N concentration suddenly increased from the stable concentrations of 30 mg·L-1 to 40 mg·L-1,60 mg·L-1 and 80 mg·L-1, the ammonia removal rate decreased from 80.04% to 61.40%,39.65% and 31.02%, respectively, however, the ammonia nitrogen removal amount underwent little change, being about 25 mg·L-1 in all cases; in addition, there was little influence of influent NH4+-N on the N2 O production, under the four different influent NH4+-N concentrations, the N2 O production in a typical cycle was 3.019 mg·m-3, 3.489 mg·m-3, 3.271 mg·m-3, and 3.490 mg·m-3, respectively, and the N2 O emission rates were all around 0.0045 mg·(m3·min)-1. N2 O was produced in both the aerobic stage and anoxic stage of the granular sludge simultaneous nitrification and denitrification system. Under different influent NH4+-N concentrations, the amount of NH4+-N removal by the granular sludge simultaneous nitrification and denitrification system was not changed, but significant decrease in nitrogen removal rate was observed with the increase in the influent NH4+-N concentration.