Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China.
Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China.
Water Res. 2020 Apr 15;173:115530. doi: 10.1016/j.watres.2020.115530. Epub 2020 Jan 23.
The conventional biological nutrients removal process is challenged by insufficient organic carbon in influent. To cross such an organic-dependent barrier, a pilot-scale electrolysis-integrated anaerobic/anoxic/oxic (AAO) process was developed for enhanced removal of nitrogen (N) and phosphorus (P) from low carbon/nitrogen (C/N) municipal wastewater. Average removal efficiencies of total nitrogen (TN) and total phosphorus (TP) in the electrolysis-AAO reached to 77.24% and 95.08% respectively, showing increases of 13.88% and 21.87%, as compared to the control reactor. Spatial variations of N and P showed that NH-N removal rate was promoted in aerobic zone of electrolysis-AAO. The intensified TN elimination, which was mostly reflected by abatement of NO-N with the concomitant slight accumulation of NH-N and NO-N, mainly occurred in anoxic2 compartment as the electrons supplied by electrolysis. Furthermore, minor P contents were measured and remained almost unchanged along the reaction units, indicating that chemical precipitation should be the dominant mechanism of P-removal in electrolysis-AAO. From the metagenomic-based taxonomy, phylum Actinobacteria was dramatically inhibited, and phylum Proteobacteria dominated the electrolysis-AAO. Particularly, nitrifying bacteria and multifarious autotrophic denitrifiers were enriched, meanwhile, a significant evolution of heterotrophic denitrifiers was found in electrolysis-AAO compared to control, which was mostly reflected by the inhibition of genus Candidatus Microthrix. Batch tests further confirmed that autotrophic denitrifiers using H and Fe as essential electron sinks were mainly responsible for the electrolysis-induced denitrification. Differential metabolic capacities were revealed from the perspectives of functional enzymes and genes, and network analysis allowed insight of microbial taxa-functional genes associations and shed light on stronger relevance between autotrophic denitrifiers and denitrification-associated genes in the electrolysis-AAO system.
传统的生物营养物质去除工艺受到进水有机物不足的挑战。为了克服这种依赖有机物的障碍，开发了一种小规模的电解集成厌氧/缺氧/好氧（AAO）工艺，用于增强从低碳/氮（C/N）城市废水中去除氮（N）和磷（P）。在电解-AAO 中，总氮（TN）和总磷（TP）的平均去除效率分别达到 77.24%和 95.08%，分别比对照反应器提高了 13.88%和 21.87%。N 和 P 的空间变化表明，在电解-AAO 的好氧区促进了 NH-N 的去除。强化的 TN 去除主要发生在缺氧 2 区，主要通过电子供体由电解提供，同时消除了 NO-N，伴随 NH-N 和 NO-N 的轻微积累。此外，测量到少量的 P 含量，沿反应单元几乎保持不变，表明化学沉淀应是电解-AAO 中 P 去除的主要机制。基于宏基因组的分类学表明，放线菌门的丰度明显受到抑制，而变形菌门在电解-AAO 中占主导地位。特别是硝化细菌和多种自养反硝化菌得到了富集，同时，与对照相比，在电解-AAO 中发现了异养反硝化菌的显著进化，主要反映在放线菌属的抑制。批处理试验进一步证实，以 H 和 Fe 为必需电子受体的自养反硝化菌是电解诱导反硝化的主要原因。从功能酶和基因的角度揭示了不同的代谢能力，网络分析允许洞察微生物类群-功能基因的关联，并揭示了自养反硝化菌与电解-AAO 系统中反硝化相关基因之间更强的相关性。
