不同电子受体驯化聚糖菌反硝化过程及N2O释放特性

利用序批式（sequencing batch reactor，SBR）生物反应器，采用厌氧-好氧运行方式，以乙酸钠为碳源，在控制进水P/COD<2/100条件下，成功实现了聚糖菌（glycogen accumulating organisms，GAOs）富集。缺氧初始阶段ρ（NO_x--N）为30.0 mg/L，经厌氧-缺氧驯化后，反硝化聚糖菌（denitrifuing GAOs，DGAOs）可利用聚-β-羟基脂肪酸酯（poly-β-hydroxyalkanoate，PHA）为内碳源进行反硝化，且分解利用的PHA中80%以上为聚-β-羟基丁酸酯（poly-β-hydroxybutyrate，PHB）。高浓度NO₂-抑制DGAOs活性，厌氧PHA合成降低，且缺氧段PHA分解产生的能量较多地用于储存糖原（glycogen，Gly）。NO₃-和NO₂-还原过程中，PHA降解速率分别为19.28，10.02 mg/（g·h），内源反硝化速率分别为3.32，2.29 mg/（g·h），TN去除率达95%以上。随NO₂-/NO_x-增加，N₂O平均产率由29.1%增至59.0%。高浓度NO₂-对氧化亚氮还原酶（Nos）活性抑制作用以及Nos和亚硝态氮还原酶（Nir）之间的电子竞争过程，是导致NO₂-内源反硝化过程中N₂O大量释放的主要原因。

CHARACTERICS OF DENITRIFICATION AND N2O EMISSION OF ACCLIMATED GLYCOGEN ACCUMULATING ORGANISMS USING DIFERENT ELECTRON ACCEPTOR

Using an anaerobic-aerobic sequencing batch reactor (AO-SBR), the glycogen accumulating organisms (GAOs) had been enriched with sodium acetate as the carbon source and the P/C ratio lower than 2/100. Cultured in anaerobic-anoxic operation mode, the acclimated GAOs could perform endogenous denitrification reaction with NO_x--N as electron acceptor and poly-β-hydroxyalkanoate(PHA) as electron donor, where PHB (poly-β-hydro-xybutyrate) accounted for more than 80% of the PHA decomposition and utilization. The higher NO₂- concentration inhibited the activity of DGAOs, which led to the decrease of PHA synthesis. More energy from PHA decomposition would be used for glycogen storage. During the reduction process of NO₃- and NO₂-, the PHA degradation rate was 19.28 mg/(g·h) and 10.02 mg/(g·h) respectively, which resulted in the related endogenous denitrification rates were 3.32 mg/(g·h) and 2.29 mg/(g·h). The TN removal efficiency reached more than 95% in the end. With the increase of NO₂-/NO_x-, the N₂O yield during the endogenous denitrification process increased from 29.1% to 59.0%. The higher NO₂- inhibition on the activity of Nos, as well as the electron competition between Nir and Nos, resulted in the higher N₂O production during PHA-driven denitrification by DGAOs.