Enhanced aerobic granular sludge by static magnetic field to treat saline wastewater via simultaneous partial nitrification and denitrification (SPND) process

• Published in: Bioresource technology 2022-04, Vol.350, p.126891-126891, Article 126891
• Main Authors: Wang, Hutao, Guo, Liang, Ren, Xiaomin, Gao, Mengchun, Jin, Chunji, Zhao, Yangguo, Ji, Junyuan, She, Zonglian
• Format: Article
• Language: English
• Subjects: Aerobiosis; Bioreactors - microbiology; Denitrification; Extracellular polymeric substance; Magnetic Fields; Microbial community; Nitrification; Nitrogen - metabolism; Salt-tolerance; Sewage - microbiology; Simultaneous partial nitrification and denitrification granular sludge; Static magnetic field; Waste Disposal, Fluid - methods; Waste Water
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.126891

[Display omitted] •SMF enhanced AGS salt-tolerance to improve nitrogen removal of saline wastewater.•SMF shortened granulation by promoting EPS secretion with high protein contents.•Obvious sludge bulking occurred at 2.0% salinity without SMF.•Better SPND performance was in SMF with TN removal recovering to 72.9% finally.•SMF improved the activity of predominant halotolerant genus. Saline wastewater poses a threat to biological nitrogen removal. This study investigated whether and how static magnetic field (SMF) can improve the salt-tolerance of aerobic granular sludge (AGS) in two simultaneous partial nitrification and denitrification (SPND) reactors. Results confirmed that the SMF improved the mean size and settleability of granules, stimulated secretion of extracellular polymeric substances with high protein content, in turn enhancing the aerobic granulation. Although high salt stress inhibited functional microorganisms, the SMF maintained better SPND performance with average COD removal, TN removal and nitrite accumulation ratio finally recovering to 100%, 72.9% and 91.1% respectively. High throughput sequencing revealed that functional bacteria evolved from Paracoccus to halotolerant genera Xanthomarina, Thauera, Pseudofulvimonas and Azoarcus with stepwise increasing salinity. The enhanced salt-tolerance may be because the SMF promoted the activity of these halotolerant bacteria. Therefore, this study proposes an economic, effective and environmental biotechnology for saline wastewater treatment.