Department of Landscape of Architecture, Center for Ecophronetic Practice Research, College of Architecture and Urban Planning, Tongji University, Shanghai, 200092, China.
Key Laboratory of Yangtze River Water Environment of the Ministry of Education, Tongji University, Shanghai, 200092, China.
Environ Sci Pollut Res Int. 2019 Apr;26(10):10292-10305. doi: 10.1007/s11356-019-04479-6. Epub 2019 Feb 13.
Anaerobic digestion (AD) is an attractive technology for sludge treatment as it stabilizes sludge and produce renewable energy. However, problems such as low organic matter content and high heavy metals level are often encountered which severely limits the effectiveness of AD. In this study, the biochar-supported nanoscale zerovalent iron (nZVI-BC) was synthesized and used as additives during AD of sewage sludge to investigate the enhancement effects for methane production and its impacts on microbial structure at mesophilic temperature. nZVI-BC addition enhanced process stability by improving the generation and degradation of intermediate organic acids, but inhibitory effects were observed at high dosage. The methane content and cumulative methane yields were increased by 29.56% and 115.39%, respectively. Compared with AD without nZVI-BC, the application of nZVI-BC showed positive effect on improvement of metals (Cu, Cd, Ni, Cr, and Zn) stabilization in the digestate. Microbial community analysis illustrated that nZVI-BC addition could significantly increase the Shannon diversity index and Chao1 richness index of archaea, and meanwhile archaea were more diverse in nZVI-BC amended digesters than in control. It was notable that Methanosaeta dominated in all the digesters at genera level, while the relative abundance of hydrogenotrophic methanogens (Methanobacterium and methanospirillum) increased 35.39% in nZVI-BC amended digesters compared to the control, resulting in higher methane production. The results will guide development of microbial management methods to enhance the stability of AD process.
厌氧消化（AD）是一种有吸引力的污泥处理技术，因为它可以稳定污泥并产生可再生能源。然而，通常会遇到有机物含量低和重金属水平高的问题，这严重限制了 AD 的效果。在这项研究中，合成了负载纳米零价铁的生物炭（nZVI-BC），并将其作为添加剂用于污水污泥的 AD 中，以研究其对甲烷生产的增强效果及其对中温微生物结构的影响。nZVI-BC 的添加通过改善中间有机酸的产生和降解来提高过程稳定性，但在高剂量下会观察到抑制作用。甲烷含量和累积甲烷产率分别提高了 29.56%和 115.39%。与没有 nZVI-BC 的 AD 相比，nZVI-BC 的应用对改善消化物中金属（Cu、Cd、Ni、Cr 和 Zn）的稳定性表现出积极的效果。微生物群落分析表明，nZVI-BC 的添加可以显著增加古菌的 Shannon 多样性指数和 Chao1 丰富度指数，同时 nZVI-BC 处理的古菌比对照处理的古菌更加多样化。值得注意的是，在属水平上，Methanosaeta 是所有消化器中占主导地位的，而与氢气营养型产甲烷菌（Methanobacterium 和 Methanospirillum）相比，nZVI-BC 处理的消化器中相对丰度增加了 35.39%，导致甲烷产量更高。这些结果将指导开发微生物管理方法，以增强 AD 过程的稳定性。
