温度对滴滤池硝化过程氧化亚氮释放的影响

Impact of temperature on nitrous oxide emission in a tricking filter

研究了某大学污水处理厂的一个滴滤池（生物膜系统）随季节变化N2O的释放特征.结果表明,滴滤池中N2O的释放浓度范围为0～18.21×10^-6,释放量为20.5～554g N2O/（m^3·a）,其释放因子（N2O-N/进水NH3-N）为0.1%～0.8%.N2O释放量与季节变化有关,夏季产生量较高而春季较少,空气和进水的温差是影响滴滤池中硝化作用和N2O释放的主要因素,7月份时气温和水温温差较小,导致空气中的氧气无法充入水中,水中溶解氧的不足使得滴滤池硝化不完全,N2O释放量最高.另外,N2O释放量的昼夜变化规律表明,滴滤池的N2O释放、硝化作用和温度变化相关,通过在线监测N2O释放和水温/气温温度变化可以间接反映滴滤池的生物硝化效果.

As a powerful greenhouse gas,nitrous oxide （N2O） is found in wastewater treatment plants. The factors influencing N2O emission from a natural-draft trickling filter （TF） was investigated in situ by treating domestic wastewater. The concentration of N2O released from TF varied between 0-18.21 × 10^6 and the amount of N2O emission was estimated to be 20.5-554g N2O/（m^3·a）, representing 0.1%-0.8% of oxidized ammonia. Variations of N2O emission followed the seasonal weather pattern, with more N2O emission in the summer period and less in the spring. Temperature differences between air and water were the most influential environmental factors governing the nitrification and the N2O emission patterns in TF. The highest N2O emission occurred in July when temperature differences between air and water were minimal, causing insufficient oxygen availability and incomplete nitrification. The daily patterns indicated that N2O emission was closely correlated with the variations of nitrification and temperature differences, which made it possible for using on-line temperature or N2O monitor to identify the nitrification failures.