Shoji T, Satoh H, Mino T
Department of Urban Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan.
Water Sci Technol. 2003;47(11):23-9.
It has been reported that a proportion of polyphosphate-accumulating organisms (PAOs) can denitrify or utilize nitrate as an electron acceptor. The usage of denitrifying-PAO (DN-PAO) can relieve the competition for COD between denitrification and phosphorus removal because they can treat nitrate and phosphate by using the same carbon source. To effectively use DN-PAO for biological nutrient removal (BNR), a new system was proposed in which an anaerobic phase is placed at the influent end, followed by he anoxic and external nitrification phase. In this study, the lab-scale proposed system (A2N system) was operated with a municipal wastewater 1) to confirm stable settlement of DN-PAO in the proposed system, 2) to quantitatively estimate the fraction of different groups of organisms like denitrifiers without polyphosphate accumulating capability, aerobic-PAO and DN-PAO and 3) to estimate the advantages of DN-PAO's presence in the system. Moreover, batch experiments in which anoxic and aerobic phosphate uptake rates (PUR) were measured were also carried out. The activity of DN-PAO was observed throughout the experimental period by the batch experiment. From the results of the calculation of COD utilized by each group of organisms, it was concluded that the proposed system could accumulate much more PAO (as DN-PAO) than conventional BNR systems. Moreover, they were responsible for both EBPR and denitrification.
据报道，一部分聚磷菌（PAOs）能够进行反硝化作用或利用硝酸盐作为电子受体。反硝化聚磷菌（DN-PAO）的应用可以缓解反硝化和除磷过程中对化学需氧量（COD）的竞争，因为它们可以利用相同的碳源处理硝酸盐和磷酸盐。为了有效利用DN-PAO进行生物脱氮除磷（BNR），提出了一种新系统，该系统在进水端设置厌氧阶段，随后是缺氧和外部硝化阶段。在本研究中，采用城市污水运行实验室规模的该系统（A2N系统），目的如下：1）确认DN-PAO在该系统中的稳定沉降；2）定量估算不同菌群的比例，如无聚磷能力的反硝化菌、好氧聚磷菌和DN-PAO；3）评估系统中DN-PAO存在的优势。此外，还进行了测量缺氧和好氧磷吸收速率（PUR）的批次实验。通过批次实验在整个实验期间观察到了DN-PAO的活性。根据每组生物体利用的COD计算结果得出结论，该系统比传统的BNR系统能够积累更多的聚磷菌（以DN-PAO形式）。此外，它们对强化生物除磷（EBPR）和反硝化作用都有作用。
