DO浓度对生活污水硝化过程中N2Ｏ产生量的影响

为确定污水脱氮过程中最优的DO浓度和曝气方式，以提高污水处理效率，降低N₂Ｏ产生量，采用实际生活污水应用小试SBR反应器，重点考察了不同DO浓度条件下，硝化效率和硝化过程中N₂Ｏ的产生量.结果表明，当DO浓度恒定为0.4 mg·L^-1时，虽然硝化过程所消耗的能量最低，但其氨氮氧化的速率较低.提高DO浓度，氨氮氧化速率可随之升高.低氨氮生活污水硝化过程中仍有N₂Ｏ产生.DO浓度为0.4 mg·L^-1 和0.9 mg·L^-1时，污水N₂Ｏ产生量(以N计)分别为1.5 mg·L^-1和1.6 mg·L^-1；而DO浓度为1.5 mg·L^-1和2.0 mg·L^-1时，N₂Ｏ产生量则分别降低至0.5 mg·L^-1和0.4 mg·L^-1.当DO浓度高于1.5 mg·L^-1后，继续提高DO浓度，氨氮氧化速率升高的速率变缓，同时N₂Ｏ产生量大幅降低.因此，从提高污水脱氮效率节能降耗和控制N₂Ｏ产生量2个角度考虑，生活污水脱氮过程中控制DO浓度在1.5 mg·L^-1较为适宜.

Effects of DO concentration on N2O production during nitrification for treating domestic wastewater

In order to reduce nitrous oxide (N2O) production from real wastewater and optimize the DO concentration and the aeration mode, nitrification efficiency and N2O production from nitrification treating domestic wastewater under difference DO concentrations were investigated using lab-scale SBR. The obtained results show energy consumption was saved at DO concentration of 0.4 mg L(-1), whereas, ammonia oxidation rate was very low. Ammonia oxidation rate was increased with DO increasing. N2O was produced during the nitrification for treating domestic wastewater with low ammonium concentration. N2O production at the DO concentration of 0.4 mg L(-1) and 0.9 mg L(-1) were 1.5 mg L(-1) and 1.6 mg L(-1), respectively. While N2O production at the DO concentration of 1.5 mg L(-1) and 2.0 mg L(-1) were 0.5 mg L 1)and 0.4 mg L-'(-1)respectively. When DO concentration increased above 1.5 mg L-'(-1)the ammonia oxidation rate increased slightly with N2 0O production sharply decreasing. Therefore, from the aspects of enhancing the efficiency of nitrogen removal with lower energy consumption and reducing N2 Oproduction, the optimal controlled DO concentration was 1.5 mg L-. -1)