实时控制序批式膜生物反应器处理养猪废水的短程硝化

Shortcut nitrification in a pilot-scale real-time control sequencing batch membrane bioreactor treating swine wastewater

采用实时控制序批式膜生物反应器(sequencing batch membrane bioreactor,SMBR)工艺处理某种猪场的养殖粪尿污水,通过pH实时曲线上的"氨谷点"对曝气时间进行实时控制实现短程硝化。小试反应器10个月的连续运行结果表明,利用曝气时间实时控制实现了稳定的亚硝态氮累积。短程硝化启动后,SMBR对COD和TN的平均去除率分别达到95.5%和92.4%,亚硝态氮积累率可维持在85%以上。高通量测序与OTU分类的结果表明,实时控制下SMBR内NOB逐渐被淘洗,而AOB得到了富集。从反应器启动初期到获得稳定短程硝化(反应器运行200 d),AOB丰度提高了55倍,而对应的NOB丰度降低了2倍。此外,AOB的绝对数量与DO呈显著负相关(r=-0.846,0.01<p<0.05),而与出水NH+4-N浓度呈显著正相关(r=0.45,0.01<p<0.05),表明较低的DO及NH+4-N的积累有利于AOB的富集。因此,利用曝气时间实时控制实现短程硝化是一种面向群落结构优化的控制方法,有利于短程硝化系统长期稳定的运行,具有实际应用价值和工程意义。

A pilot-scale, real-time control, sequencing batch membrane bioreactor （SMBR） was developed to study the treatment of swine wastewater. Shortcut nitrification was achieved according to the ＂ammonia valley＂ on a pH real-time curve. The result of ten months of operation showed that more nitrogen is oxidized by ammonia oxi- dizing bacteria （AOB） than by nitrite oxidizing bacteria （NOB） in each cycle when using real-time aeration du- ration control. The nitrite accumulation rate increased after long-term application of this method. The mean remov- al rates of COD and TN were 95.5% and 92.4% , and the nitrite accumulation rate was more than 85% after shortcut nitrification was achieved. High-throughput sequencing and OTU classification showed that AOB out- competed NOB gradually after the process started, due to the real-time aeration duration control. The AOB popu- lation was enriched 52 fold （after achieving nitritation for 200 days） , while the NOB population decreased 2 fold. In addition, the absolute number of AOB showed a significant negative correlation with DO （r = -0. 846, p 〈 0.05 ）, and a significant positive correlation with the effluent NH4＋ -N （ r = 0.45, p 〈 0.05 ） , indicating that low DO and ammonia accumulation favor AOB enrichment. Therefore, long-term operation with the use of real- time aeration duration control was not only favorable for AOB community optimization, but also for the achievement of shortcut nitrification in practice.