This work aims to optimize the process of heterotrophic nitrification-aerobic denitrification (HN-AD) in the membrane-aerated biofilm reactor (MABR) by way of increasing the dissolved oxygen (DO) concentration in the outer layer biofilm to treat high-strength ammonium-nitrogen (NH₄⁺-N) wastewater. The results show that the removal efficiencies of NH₄⁺-N, total nitrogen (TN) and chemical oxygen demand (COD) increased by 42.4%, 65.7%, and 15.2%, respectively, in MABR-1 with high-DO concentrations than in MABR-2 with low-DO concentrations in the outer layer biofilm. High-DO concentrations in the outer layer biofilm increased the thickness of the aerobic layer to encourage HN-AD bacteria enrichment, which paved the way for nitrogen removal enhancement in MABR-1. Moreover, based on the analysis of functional gene expressions predicted by PICRUSt2, the relative abundances of seven key genes (hao, nirK, napA, napB, norB, norC and nosZ) relating to HN-AD bacteria in the MABR-1 significantly increased, indicating that DO increasing in the outer layer biofilm remarkably promoted the occurrence of HN-AD process. From the viewpoint of economic efficiency, the advantage of the novel strategy of increasing DO concentrations in the outer layer biofilm is that this optimized alternative for the MABR provides a superior nitrogen removal process in the high-strength NH₄⁺-N wastewater treatment.

这项工作旨在通过增加外层生物膜中的溶解氧（DO）浓度来处理高强度铵，从而优化膜曝气生物膜反应器（MABR）中的异养硝化-好氧反硝化（HN-AD）工艺。 -氮（NH ₄ ⁺ -N）废水。结果表明，NH ₄ ⁺的去除率高。-高氮浓度的MABR-1中的氮素，总氮（TN）和化学需氧量（COD）分别比低氮浓度的MABR-2中的42.4％，65.7％和15.2％升高。外层生物膜。外层生物膜中的高溶解氧浓度增加了好氧层的厚度，以促进HN-AD细菌的富集，这为提高MABR-1中的氮去除量铺平了道路。此外，根据PICRUSt2预测的功能基因表达分析，MABR-1中与HN-AD细菌有关的七个关键基因（hao，nirK，napA，napB，norB，norC和nosZ）的相对丰度显着增加，表明外层生物膜中溶解氧的增加显着促进了HN-AD过程的发生。从经济效率的角度来看，₄ ⁺ -N废水处理。