SBBR工艺反硝化过程中N_2O和NO的产生情况

Production of N_2O and NO during denitrification process in SBBR

利用序批式生物膜反应器(SBBR),以葡萄糖为碳源(COD为500 mg/L),考察了不同碳氮比(COD与TN之比)、不同电子受体(NO_2^-或NO_3^-)、不同投加方式(碳源与氮源同步投加或投加碳源60 min后再投加氮源的异步投加)对N_2O产生情况的影响,以及碳氮比为2时NO的产生情况。实验结果表明:不论同步投加还是异步投加,两种电子受体的N_2O-N生成率均随着碳氮比的增大而下降;不同碳氮比下,投加NO2-时的N_2O-N生成率均高于投加NO3-时,异步投加时的N_2O-N生成率均大于同步投加时。说明低碳氮比、高浓度NO2-和胞内贮存物作碳源是反硝化过程中N_2O产生和大量积累的关键因素。此外,NO2-为电子受体时的NO-N生成率高于NO3-为电子受体时。

A laboratory-scale sequencing batch biofilm reactor （SBBR） with glucose as carbon source （COD=500 mg/L） was operated to study the effects of the different C-N ratio （COD ： TN）, electron acceptors （NO2^- or NO3^-） and addition patterns （simultaneous addition as adding nitrogen source and carbon source together or asynchronous addition as adding nitrogen source 60 minutes later than the carbon source） on N2O emission. The situation of NO emission at 2 of C-N ratio was also studied. The experimental results showed that： By both addition patterns, the NzO-N generation rate of the two electron acceptors were all decreased with the increase of C-N ratio; Under different C-N ratio, the N2O-N generation rates with NO2^- addition was higher than that with NO3^- addition, an d the N2O-N generation rates by asynchronous addition was larger than that by simultaneous addition. These results indicated that low C-N ratio, high concentration NO[ and using intracellular stores as carbon source were the key factors for N2O production and accumulation during the denitrification process. And the NO-N conversion rate using NO2^- as electron acceptor was higher than that using NO3^- as electron acceptor.