Huang Ji-Lin, Cui You-Wei
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing, 100124, China; State Environmental Protection Key Laboratory of Urban Ecological Environment Simulation and Protection, South China Institute of Environmental Sciences, MEE, Guangzhou, 510535, China.
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing, 100124, China.
J Environ Manage. 2025 Aug;389:126039. doi: 10.1016/j.jenvman.2025.126039. Epub 2025 Jun 9.
Heterotrophic nitrification-aerobic denitrification (HN-AD) microorganisms enable simultaneous removal of inorganic nitrogen and organic pollutants in a single reactor. Sludge retention time (SRT) is a critical operational parameter shaping microbial community dynamics and functional competition. However, the ecological mechanisms underlying the succession of HN-AD bacteria under different SRT regimes remain poorly understood. This study evaluates how the HN-AD bacteria compete with autotrophic ammonium oxidizing bacteria under different SRTs in a halophilic aerobic granular sludge (HAGS) system. When the SRT increased from 10 to 20 days, the total inorganic nitrogen removal efficiency decreased from 100 % to 51.3 %, with the proportion of heterotrophic bacterial biomass reduced from 80.1 % to 47.7 %. Paracoccus was the main HN-AD bacteria, and its relative abundance decreased from 65.8 % to 55.5 %. A significant reduction of napA gene was also found in this study. Results showed that short SRT conditions ensure that HN-AD bacteria an advantage in niche competition, assisting the maintenance of HN-AD function during long-term operation. By unraveling the SRT-dependent dominance of HN-AD bacteria in HAGS, this work offers a cost-effective approach to improve nitrogen and organic matter removal efficiency in saline wastewater, which holds significant potential for scaling up in industrial saline wastewater treatment.
异养硝化-好氧反硝化（HN-AD）微生物能够在单个反应器中同时去除无机氮和有机污染物。污泥停留时间（SRT）是塑造微生物群落动态和功能竞争的关键运行参数。然而，不同SRT条件下HN-AD细菌演替的生态机制仍知之甚少。本研究评估了在嗜盐好氧颗粒污泥（HAGS）系统中，不同SRT条件下HN-AD细菌如何与自养氨氧化细菌竞争。当SRT从10天增加到20天时，总无机氮去除效率从100%降至51.3%，异养细菌生物量比例从80.1%降至47.7%。副球菌是主要的HN-AD细菌，其相对丰度从65.8%降至55.5%。本研究还发现napA基因显著减少。结果表明，短SRT条件确保了HN-AD细菌在生态位竞争中具有优势，有助于在长期运行中维持HN-AD功能。通过揭示HAGS中HN-AD细菌依赖SRT的优势地位，本研究提供了一种经济有效的方法来提高含盐废水的氮和有机物去除效率，在工业含盐废水处理中具有巨大的扩大规模潜力。
