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

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。

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.