不同电子受体配比对反硝化除磷特性及内碳源转化利用的影响

Effect of different electron acceptor ratios on removal of nitrogen and phosphorus and conversion and utilization of internal carbon source

以A2/O-生物接触氧化(biological contact oxidation,BCO)系统反硝化除磷活性污泥为研究对象,通过投加不同浓度的N-和NO3-N-(2 NO3-N NO-N--+=30 mg·L-1),考察了反硝化聚磷菌(denitrifying polyphosphate accumulating organisms,DPAOs)在不同电子受体配比(N-:NO3-N-=0,0.2:0.8,0.4:0.6,0.5:0.5,0.6:0.4)条件下的脱氮除磷特性。结果表明:乙酸钠为DPAOs用于反硝化除磷的理想碳源,且其浓度为200 mg·L-1时最佳;仅以NO3-N-为电子受体进行缺氧吸磷反应时,NO3-N-的投加量为30 mg·L-1时较为合适;以NO3-N-作为电子受体,未经N-驯化的DPAOs,短时间内很难利用N-,但低浓度的N-(6 mg·L-1)不会影响DPAOs以NO3-N-作电子受体进行反硝化除磷;同时,N-对于DPAOs吸磷作用的抑制程度明显强于NO3-N-反硝化作用,当N-浓度达到18 mg·L-1时,吸磷反应基本停止;此外,较高浓度的N-不仅会抑制聚羟基脂肪酸酯(poly-β-hydroxyalkanoate,PHA)的分解利用,且会使PHA分解产生的能量较多地用于储存糖原(glycogen,Gly),而所分解利用的PHA中90%以上为聚-β-羟基丁酸酯(poly-β-hydroxybutyrate,PHB)。

The characteristics of removal of nitrogen and phosphorus were investigated by using denitrifying phosphorus activated sludge taken from an anaerobic/anoxic/oxic（A2/O）-biological contact oxidation（BCO） system. Different concentrations of N-and NO3-N-（N ＋-NO3-N-= 30 mg·L-1） were used to evaluate the influence of different electron acceptor ratios（N-：NO3-N-= 0, 0.2：0.8, 0.4：0.6, 0.5：0.5, 0.6：0.4） on nitrogen and phosphorus removal of denitrifying polyphosphate accumulating organisms（DPAOs）. The results showed that sodium acetate was the ideal carbon source for DPAOs to denitrify phosphorus removal and the best concentration was 200 mg·L-1. The more appropriate additive amount of NO3-N-was 30 mg·L-1 when NO3-N-was the electron acceptor in anoxic phosphorus absorption reaction. It was hard for the DPAOs that using NO3-N-as electron acceptor and untamed with NO2-N-to use N-in a short time, but a low N-concentration（6 mg·L-1） did not affected nitrogen and phosphorus removal by DPAOs when NO3-N-was the electron acceptor. Additionally, the effect of N-on phosphorus absorption was more significant than that of denitrification by NO3-N-, and the reaction of phosphorus absorption almost ceased when the concentration of N-achieved 18 mg·L-1. Furthermore, high N-concentration would inhibit the decomposition and utilization of PHA（polyhydroxyalkanoate）, and more energy from PHA decomposition would use for glycogen storage, where PHB（poly-β-hydroxybutyrate） accounted for more than 90% of the PHA decomposition and utilization.