Liu Tao, Hu Shihu, Yuan Zhiguo, Guo Jianhua
Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia.
School of Energy and Environment, City University of Hong Kong, Hong Kong SAR, China.
Water Res. 2023 Aug 15;242:120194. doi: 10.1016/j.watres.2023.120194. Epub 2023 Jun 8.
Anaerobic treatment of mainstream wastewater has been proposed as a promising solution to enhance bioenergy recovery for wastewater treatment plants (WWTPs). However, the limited organics for downstream nitrogen removal and emissions of dissolved methane into the atmosphere are two major barriers to the broad application of anaerobic wastewater treatment. This study aims to develop a novel technology to overcome these two challenges by achieving simultaneous removal of dissolved methane and nitrogen, and unravel the microbial competitions underpinning the process from the microbial and kinetic perspectives. To this end, a laboratory granule-based sequencing batch reactor (GSBR) coupling anammox and nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) microorganisms was developed to treat wastewater mimicking effluent from mainstream anaerobic treatment. The GSBR achieved high-level nitrogen and dissolved methane removal rates (> 250 mg N/L/d and > 65 mg CH/L/d) and efficiencies (> 99% total nitrogen removal and > 90% total methane removal) during the long-term demonstration. The availability of different electron acceptors (nitrite or nitrate) imposed significant effects on the removal of ammonium and dissolved methane, as well as on the microbial communities, and the abundance and expression of functional genes. The analysis of apparent microbial kinetics showed that anammox bacteria had a higher nitrite affinity than n-DAMO bacteria, while n-DAMO bacteria had a higher methane affinity than n-DAMO archaea. These kinetics underpin the observation that nitrite is a preferred electron acceptor for removing ammonium and dissolved methane than nitrate. The findings not only extend the applications of novel n-DAMO microorganisms in nitrogen and dissolved methane removal, but also provide insights into microbial cooperation and competition in granular systems.
主流废水的厌氧处理已被提议作为一种有前景的解决方案，以提高污水处理厂（WWTPs）的生物能源回收。然而，下游脱氮可用有机物有限以及溶解甲烷排放到大气中是厌氧废水处理广泛应用的两个主要障碍。本研究旨在开发一种新技术，通过同时去除溶解甲烷和氮来克服这两个挑战，并从微生物和动力学角度揭示该过程背后的微生物竞争。为此，开发了一种基于实验室颗粒的序批式反应器（GSBR），耦合厌氧氨氧化和亚硝酸盐/硝酸盐依赖型厌氧甲烷氧化（n-DAMO）微生物，用于处理模拟主流厌氧处理出水的废水。在长期示范过程中，GSBR实现了高水平的氮和溶解甲烷去除率（>250 mg N/L/d和>65 mg CH/L/d）以及效率（总氮去除率>99%和总甲烷去除率>90%）。不同电子受体（亚硝酸盐或硝酸盐）的可用性对铵和溶解甲烷的去除以及微生物群落、功能基因的丰度和表达产生了显著影响。表观微生物动力学分析表明，厌氧氨氧化细菌比亚硝酸盐依赖型厌氧甲烷氧化细菌对亚硝酸盐具有更高的亲和力，而亚硝酸盐依赖型厌氧甲烷氧化细菌比古菌对甲烷具有更高的亲和力。这些动力学支持了以下观察结果：与硝酸盐相比，亚硝酸盐是去除铵和溶解甲烷的首选电子受体。这些发现不仅扩展了新型亚硝酸盐依赖型厌氧甲烷氧化微生物在氮和溶解甲烷去除方面的应用，还为颗粒系统中的微生物合作与竞争提供了见解。
