pH对高氨废水限氧半亚硝化过程中N2O释放的影响

Effect of pH values on nitrous oxide emission during partial nitritation of high-ammonium wastewater under oxygen-limited condition

摘要:

为获得半亚硝化系统中强温室气体N₂O减量化释放的控制参数,采用SBR处理人工合成高氨废水(进水氨氮质量浓度约为600 mg·L-1),考察不同进水pH(7.5,8.0和8.5)对N₂O释放特性的影响．结果表明,不同进水pH下均释放N₂O,每个周期内N₂O的释放量随进水pH的升高而减小．pH为7.5,8.0及8.5时,N₂O释放量分别占进水氨氮的3.81％、2.35％和2.00％．当pH为7.5时,曝气初始50 min内,N₂O释放速率先增大后减小,峰值速率为44.5 μg·min-1·g-1,之后维持在16.5 μg·min-1·g-1;当pH为8.0及8.5时,曝气初期N₂O释放峰值速率分别为33.7,2.9 μg·min-1·g-1,之后释放速率随pH降低和NO₂-积累而逐渐增大．

Abstract:

To reduce the emission of the strong greenhouse gas nitrous oxide (N₂O) in partial nitritation system, a lab-scale SBR treating synthetic high-ammonium wastewater (around 600 mg·L-1 of influent ammonia) was investigated for the effect of pH values (7.5,8.0 and 8.5) on N₂O emission. The results showed that, the N₂O emission was observed under different pH values, and the total amount of N₂O emission decreased with pH value increment. At pH 7.5,8.0 and 8.5, the N₂O emission amount accounted for 3.81％, 2.35％ and 2.00％ of the influent ammonium nitrogen, respectively. At pH 7.5, in the initial 50 min the N₂O emission rate firstly increased (maximum value of 44.5 μg·min-1·g-1) and then returned around 26.4 μg·min-1·g-1. At pH 8.0 and 8.5,3.7 and 22.9 μg·min-1·g-1 of maximum N₂O emission rate were achieved in the initial 50 min, respectively, however, they increased slowly with the pH decrease and nitrite accumulation.