氧对膜生物反应器短程硝化的影响

Effect of oxygen on partial nitrification in a membrane bioreactor

摘要:

为了研究膜生物反应器的短程硝化性能以及氧对短程硝化的影响，通过对比耗氧率和供氧率，提出了膜生物反应器短程硝化的控制优化建议。在膜生物反应器硝化过程中，DO小于1 mg/L开始出现亚硝氮积累；DO降到0.5 mg/L，出水氨氮浓度与亚硝氮浓度之比接近1∶1；DO调控在0.5?1 mg/L范围内，有利于前置硝化反应器与后续厌氧氨氧化反应器衔接。膜生物反应器中污泥浓度可达20 g/L，耗氧能力可达19.86 mg O2/(L·s)，但最大供氧能力仅为0.369 mg O2/(L·s)，供氧成为反应器运行的制约瓶颈，“低DO高流量”曝气是继续提高短程硝化效能的控制策略。

Abstract:

We studied the effects of the oxygen on partial nitrification in a membrane bioreactor (MBR), to find out critical dissolved oxygen (DO) concentrations for the optimal partial nitrification by monitoring the oxygen uptake rate (OUR) and oxygen supply rate (OSR). The nitrite accumulation occurred at a DO concentration of 1 mg/L, while the ratio of nitrite to ammonia in effluent was close to 1 at a DO concentration of 0.5 mg/L which was suitable to serve as the feed of an ANNAMOX system. When the mixed liquid suspended?solids(MLSS) was 20 g/L in MBR, OUR and OSR were 19.86 mg O2/(L·s) and 0.369 mg O2/(L·s) respectively, indicating that the oxygen supply was the bottleneck of partial nitrification. “Low DO and high aeration rate” were suggested as a control strategy to further improve the efficiency of partial nitrification.