高氨废水自养半亚硝化过程N2O释放特性

接种普通活性污泥,以人工配制高氨废水为基质。在SBR中通过逐步提高进水氨氮浓度并控制低溶解氧的方法,经过58 d连续运行使出水NO2--N/NH4+-N维持在0.88~1.25,成功实现了半亚硝化的启动。通过对典型周期内氮素转化及N2O释放特性的考察表明:周期内DO浓度基本维持在0.4 mg/L以下,NH4+-N浓度由410.46 mg/L下降至257.26 mg/L。NO2--N浓度由162.90 mg/L升高至295.80 mg/L,NO3--N浓度由27.01 mg/L逐渐升高至50.16 mg/L。pH先由7.94升高到8.01后缓慢降至7.96,溶解性N2O浓度基本维持在0.07 mg/L。初期(0~20 min)气态N2O浓度由0.13 mg/L迅速升至1.13 mg/L后急剧下降到0.34 mg/L,随后缓慢升至0.54 mg/L。初期N2O的平均释放速率高达0.84 mg/min,这主要是上周期沉淀阶段产生并附着在污泥中的N2O受曝气吹脱所致。

Nitrous oxide emission in partial nitritation process for treating high ammonia wastewater

A lab-scale SBR fed with synthetic high ammonia wastewater was operated under oxygen limited condition for partial nitritation. After 58 days' operation, the ratio of nitrite to ammonia in effluent maintained between 0.88-1.25 and the partial nitritation has been successfully started up by increasing the influent ammonia concentration. Conversion of nitrogen and N2O emission in single cycle was investigated. During a single cycle, DO concentration maintained below 0.4 mg/L. NH4+-N concentration decreased from 410.46 mg/L to 257.26 mg/L, NO2--N concentration increased from 162.90 mg/L to 295.80 mg/L, NO3--N concentration increased gradually from 27.01 mg/L to 50.16 mg/L. The pH value increased from 7.94 to 8.01 and then returned to 7.96. Dissolved N2O generally maintain around 0.07 mg/L. The emission of gaseous N2O increased from 0.13 mg/L to 1.13 mg/L and returned to 0.54 mg/L when aeration finished. The average of N2O emission rate was 0.84 mg/min in the initial stage, and the main source was identified as air stripping of accumulation N2O in last settling phase.