Abstract:

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 NO₂^--N and NO₃^--N(NO₂^--N+NO₃^--N=30 mg·L^-1) were used to evaluate the influence of different electron acceptor ratios (NO₂^--N:NO₃^--N0, 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 NO₂^--N in a short time, but a low NO₂^--N concentration (6 mg·L^-1) did not affected nitrogen and phosphorus removal by DPAOs when NO₂^--N was the electron acceptor. Additionally, the effect of NO₂^--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 NO₂^--N achieved 18 mg·L^-1. Furthermore, high 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.

Key words: denitrifying phosphorus removal, specific uptake phosphorus rate, specific denitrification rate, PHA

摘要：

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NO₂^--N和NO₃^--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(NO₂^--N:NO₃^--N0, 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NO₂^--N作为电子受体,未经 驯化的DPAOs,短时间内很难利用NO₂^--N,但低浓度的 (6 mg·L^-1)不会影响DPAOs以 作电子受体进行反硝化除磷;同时,NO₂^--N对于DPAOs吸磷作用的抑制程度明显强于 反硝化作用,当NO₂^--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NO₂^--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)。

关键词: 反硝化除磷, NO₂^--N, 比吸磷速率, 比反硝化速率, PHA