Simultaneous nitrification–denitrification (SND) is a promising nitrogen removal process. However, total nitrogen (TN) removal is limited due to unsatisfactory denitrification. This study demonstrated that short-time (1 h) pre-anoxic electro-stimulation significantly enhanced SND efficiency in the aerobic phase by promoting the proliferation of mixotrophic and heterotrophic denitrifiers. SND and TN removal efficiencies at the optimal electric current (EC) (0.02 A) were 85.6 % and 93.9 %, which were 39.1 % and 17.2 % higher than control. Microbial community analysis indicated that the abundance of mixotrophic and heterotrophic denitrifiers significantly increased. H2 generated in the electro-stimulation process induced the proliferation of mixotrophic denitrifiers. The weak EC (0.02 A) promoted the activity and growth of heterotrophic denitrifiers by accelerating electron transfer. They concurrently mediated heterotrophic denitrification to enhance SND efficiency. PICRUSt2 analysis revealed that the abundance of denitrifying genes dramatically surged. This study provides new insights into applying electrolysis to achieve advanced SND while minimizing electricity consumption.

中文翻译：

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预缺氧电刺激在单级电解集成序列间歇式生物膜反应器中增强同步硝化-反硝化


同步硝化-反硝化 （SND） 是一种很有前途的脱氮工艺。然而，由于反硝化效果不佳，总氮 （TN） 去除受到限制。本研究表明，短时 （1 h） 缺氧前电刺激通过促进混合营养和异养反硝化剂的增殖，显著提高了好氧阶段的 SND 效率。最佳电流 （EC） （0.02 A） 下的 SND 和 TN 去除效率分别为 85.6 % 和 93.9 %，分别比对照高 39.1 % 和 17.2 %。微生物群落分析表明，混合营养和异养反硝化剂的丰度显著增加。电刺激过程中产生的 H2 诱导混合营养反硝化剂的增殖。弱 EC （0.02 A） 通过加速电子转移促进异养反氮化剂的活性和生长。他们同时介导异养反硝化以提高 SND 效率。PICRUSt2 分析显示，反硝化基因的丰度急剧增加。这项研究为应用电解实现高级 SND 同时最大限度地减少电力消耗提供了新的见解。