Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070, China.
Environ Int. 2019 Feb;123:10-19. doi: 10.1016/j.envint.2018.11.039. Epub 2018 Nov 24.
Free ammonia (FA) can pose inhibitory and/or biocidal effects on a variety of microorganisms involved in different biological wastewater treatment process, which is widely presented in wastewater treatment plants (WWTPs) due to the high levels of ammonium in the systems. This review article gives the up-to-date status on several essential roles of FA in biological wastewater treatment processes: the impacts of FA, mechanisms of FA roles, modeling of FA impacts, and implications of FA for wastewater treatment. Specifically, the impacts of FA on both wastewater and sludge treatment lines were firstly summarized, including nitrification, denitrification, anaerobic ammonium oxidation (Anammox), enhanced biological phosphorus removal and anaerobic processes. The involved mechanisms were then analyzed, which indicated FA inhibition can slow specific microbial activities or even reconfigure the microbial community structure, likely due to negative impacts of FA on intracellular pH, specific enzymes and extracellular polymeric substances (EPS), thus causing cell inactivation/lysis. Mathematical models describing the impact of FA on both wastewater and sludge treatment processes were also explored to facilitate process optimization. Finally, the key implications of FA were identified, that is FA can be leveraged to substantially enhance the biodegradability of secondary sludge, which would further improve biological nutrient removal and enhance renewable energy production.
游离氨（FA）会对参与不同生物污水处理过程的各种微生物产生抑制和/或杀菌作用，由于系统中氨氮水平较高，因此在污水处理厂（WWTP）中广泛存在。本文综述了 FA 在生物污水处理过程中的几个重要作用：FA 的影响、FA 作用机制、FA 影响模型以及 FA 对污水处理的意义。具体而言，首先总结了 FA 对废水和污泥处理线的影响，包括硝化、反硝化、厌氧氨氧化（Anammox）、强化生物除磷和厌氧过程。然后分析了涉及的机制，表明 FA 抑制可能会减缓特定微生物的活性，甚至重新配置微生物群落结构，这可能是由于 FA 对细胞内 pH 值、特定酶和胞外聚合物物质（EPS）的负面影响，从而导致细胞失活/裂解。还探索了描述 FA 对废水和污泥处理过程影响的数学模型，以促进工艺优化。最后，确定了 FA 的关键意义，即 FA 可以被利用来显著提高二级污泥的生物降解性，这将进一步改善生物营养素去除并提高可再生能源的生产。
