连续流反应器污水硝化过程中的N_2O释放

N_2O emission during nitrification in constant flow biological wastewater treatment systems

污水生物脱氮硝化阶段是温室气体一氧化二氮（N2O）的重要释放源。采用连续流反应器在2种进水氨氮（NH4-N,低氮反应器60 mg/L和高氮反应器180 mg/L）浓度条件下驯化硝化菌,并研究了不同初始NH4-N浓度和不同初始亚硝酸盐（NO2-N）浓度条件下所驯化硝化菌释放N2O的特征。结果表明在反应器运行过程中2个反应器释放N2O较少,均小于去除NH4-N浓度的0.01%;N2O的释放均随着初始NH4-N浓度或初始NO2-N浓度的升高而增加;不同初始NH4-N浓度条件下,低氮反应器驯化硝化菌的N2O释放率在0.51%~1.40%之间,高氮反应器驯化硝化菌在0.29%~1.27%之间;不同初始NO2-N浓度条件下,低氮反应器驯化硝化菌的N2O释放率在1.38%~3.78%之间,高氮反应器驯化硝化菌在1.16-5.81%之间。

Nitrification in biological nitrogen removal from wastewater is a main source of nitrous oxide（ N2O）. Two constant flow reactors were operated to enrich nitrifiers with two influent ammonium（ NH4-N） concentrations of 60 mg/L（ low-N-reactor） and 180 mg/L（ high-N-reactor）,and then effects of different initial NH4-N concentrations and initial nitrite（ NO2-N） concentrations on the N2O emission for the acclimated nitrifiers were examined. There was not much N2O emission during the constant operation of the reactors,with the ratio of N2O emission to the removed NH4-N less than 0. 01%. N2O emission increased with increasing both initial NH4-N and NO2-N concentrations. At different initial NH4-N concentrations,the ratio of N2O emission to the removed NH4-N was in the range from 0. 51% to 1. 40% for activated sludge from the low-N-reactor and from 0. 29% to1. 27% from the high-N-reactor. At different initial NO2-N concentrations,the ratio of N2O emission to the removed NH4-N was in the range from 1. 38% to 3. 78% for activated sludge from the low-N-reactor and from1. 16% to 5. 81% from the high-N-reactor.