低碳条件下不同厌氧时长对双PAOs协同EBPR系统效能的影响

Effects of Anaerobic Durations on the Nitrogen and Phosphorus Removal Efficacy of a Dual PAOs Synergistic EBPR System under Low Carbon Condition

为探究低碳条件下不同厌氧时长对双PAOs(聚磷菌)协同强化生物除磷(EBPR)系统脱氮除磷效能的影响,采用厌氧/好氧交替运行的SBR反应器,以混合氨基酸(谷氨酸、天冬氨酸、甘氨酸和脯氨酸)为碳源。结果表明:随着厌氧时长的延长,除磷率总体大幅提高,当厌氧时长为4 h时最高可稳定在80%以上,而氨氮去除性能直至后期逐渐上升至80%以上;16s rRNA高通量测序结果显示,发酵型PAOs如Tetrasphaera偏好利用混合氨基酸这类大分子有机物并与传统型PAOs协同除磷,但厌氧时长为8 h时系统的脱氮和除磷性能均出现了不同程度的波动,且Tetrasphaera和Accumulibacter丰度也随着厌氧时间的延长呈现出先上升后下降的趋势,但硝化细菌丰度整体上升。总体来讲,延长厌氧时间有利于协同除磷脱氮模式的建立,但考虑系统性能的稳定及长期运行效果,4 h厌氧对于低碳条件下双PAOs协同EBPR系统更为合理。

In this study, an alternated anaerobic/oxic sequencing batch reactor(SBR)fed with mixed amino acids(glutamic acid, aspartic acid, glycine, and proline) was employed to explore the impact of anaerobic duration on the nitrogen and phosphorus removal efficacy in a dual PAOs(polyphosphate-accumulating organisms) synergistic enhanced biological phosphorus removal(EBPR) system under low-carbon conditions.The results indicated that with the extension of the anaerobic duration, the phosphorus removal performance has been significantly increased.The phosphorus removal efficiency stability reached above 80% at the 4 h anaerobic duration, while the ammonia nitrogen removal efficiency gradually increased to over 80% till the endof the stage.High-throughput 16S rRNA sequencing results revealed that fermentative PAOs such as Tetrasphaera,which prefer using some complex organic molecules such as mixed amino acids, synergized with conventional PAOs for phosphorus removal.However, both nitrogen and phosphorus removal performance performed a kind of fluctuation at the 8 h anaerobic duration.The abundances of Tetrasphaera and Accumulibacter increased initially and then decreased with the prolonged anaerobic periods, while the abundance of nitrifying bacteria generally increased.Overall, extending the anaerobic durationwas conducive to establishing the synergistic phosphorus and nitrogen removal pattern.Nevertheless, a 4 h anaerobic duration was considered to be more rational for the dual PAOs synergistic EBPR system under low-carbon conditions for the purpose of stability and long-term operation of the system.