Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore.
Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore.
Water Res. 2017 Mar 15;111:393-403. doi: 10.1016/j.watres.2017.01.006. Epub 2017 Jan 3.
Enhanced biological phosphorus removal (EBPR) is a widely used process in wastewater treatment that requires anaerobic/aerobic or anaerobic/anoxic cycling. Surprisingly, phosphorus (P) release was observed in the presence of nitrate in the anoxic compartment of the activated sludge tank in a full-scale treatment plant with the Modified Ludzack Ettinger configuration. We therefore studied the potential of this full-scale activated sludge community to perform EBPR under anoxic/aerobic cycling. The polyphosphate accumulating organism (PAO) Candidatus Accumulibacter represented 3.3% of total bacteria based on 16S rRNA gene amplicon sequencing, and metagenome analysis suggested it was likely to be dominated by Clade IIC. Using acetate as the carbon source in batch experiments, active denitrifying organisms (DPAOs) were estimated to comprise 39-44% of the total PAO population in the sludge, with the remaining 56-61% unable to utilize nitrate. When propionate was provided as the organic carbon source, 95% of the PAO population was unable to denitrify. EBPR occurred under defined anoxic/aerobic conditions, despite the presence of DPAOs, when synthetic wastewater was supplemented with either acetate or propionate or when primary effluent was supplied. In addition, the P release and subsequent uptake rates under anoxic/aerobic conditions were comparable to those observed under anaerobic/aerobic conditions. In contrast, a significant reduction in P release rate was observed when acetate was provided under oxic conditions. We postulate that non-DPAOs that recognize the anoxic condition as pseudo-anaerobic were the key players in anoxic/aerobic EBPR.
强化生物除磷（EBPR）是一种广泛应用于废水处理的工艺，需要在厌氧/好氧或厌氧/缺氧循环中进行。令人惊讶的是，在具有改良 Ludzack Ettinger 构型的全尺寸处理厂的活性污泥罐缺氧区中存在硝酸盐的情况下，观察到了磷（P）的释放。因此，我们研究了这种全尺寸活性污泥群落在缺氧/好氧循环下进行 EBPR 的潜力。聚磷酸盐积累菌（PAO）Candidatus Accumulibacter 根据 16S rRNA 基因扩增子测序代表了总细菌的 3.3%，并且宏基因组分析表明它可能主要由 Clade IIC 主导。在批处理实验中使用乙酸盐作为碳源，活性反硝化菌（DPAO）估计占污泥中总 PAO 种群的 39-44%，其余 56-61%的菌无法利用硝酸盐。当提供丙酸盐作为有机碳源时，95%的 PAO 种群无法反硝化。尽管存在 DPAO，但当合成废水补充乙酸盐或丙酸盐或供应原废水时，在定义的缺氧/好氧条件下仍会发生 EBPR。此外，在缺氧/好氧条件下的 P 释放和随后的摄取率与在厌氧/好氧条件下观察到的相当。相比之下，当在好氧条件下提供乙酸盐时，P 释放率显著降低。我们推测，将缺氧条件识别为假厌氧的非 DPAO 是缺氧/好氧 EBPR 的关键因素。
