Enhanced nitrogen removal from high-strength ammonium wastewater by improving heterotrophic nitrification-aerobic denitrification process: Insight into the influence of dissolved oxygen in the outer layer of the biofilm. (15th May 2021)

• Record Type: Journal Article
• Authors: Xiao, PengYing; Zhou, Jing; Luo, Xiaojing; Kang, Baowen; Guo, Lei; Yuan, Gang; Zhang, Lei; Zhao, Tiantao
• Is Part Of: Journal of cleaner production. Volume 297(2021)
• Publication Date: 2021-05-15
• Subjects: High-strength NH4+-N wastewater -- DO concentration -- HN-AD process -- The outer layer biofilm -- Microbial community structure; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2021.126658
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: 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. Graphical abstract: Image 1 Highlights: A novel strategy of increasing DO in the outer layer biofilm was applied in the MABR. DO increasing strategy relieved DO limitation of the outer layer biofilm. A superior nitrogen removal efficiency of MABR was achieved via the novel strategy. DO increasing in the outer layer biofilm was conducive to HN-AD process.