SBBR工艺反硝化过程中N_2O和NO的产生情况

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。

Production of N2O and NO during denitrification process in SBBR

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 N₂O-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 NO₂^- 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.