Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Water Res. 2017 May 15;115:266-277. doi: 10.1016/j.watres.2017.02.067. Epub 2017 Mar 1.
Conductive materials have been widely investigated to accelerate and stabilize the conversion of organic wastes to methane. However, the potential mechanisms involved with different types of conductive materials are still unclear. In this study, magnetite (FeO) and granular activated carbon (GAC), as the two typical conductive materials, were respectively supplemented to acidogenesis and methanogenesis of a two-phase anaerobic digestion (AD) system in an attempt to explore their different mechanisms. The results showed that, magnetite supplemented to the acidogenic phase could enhance the decomposition of complex organics into simples, but significantly raise the hydrogen partial pressure as well as enrich the hydrogen-utilizing methanogens, which were not expected for aceticlastic methanogenesis known as a mainstream of methanogenesis in most of traditional digesters. GAC supplemented to the methanogenic phase had less influences on syntrophic metabolism of alcohols and fatty acids when acidogenesis was ineffective or out of work. Microbial community analysis suggested that direct interspecies electron transfer (DIET) had been established on the GAC, though the insignificant improvement of performances. Once magnetite was supplemented to the acidogenesis to improve the acidification efficiency, the syntrophic conversion of alcohols and fatty acids to methane in the GAC-supplemented methanogenic phase was significantly improved. These results suggested that, DIET was unlikely to participate in the direct decomposition of complex organics, even in the presence of GAC, but it could work effectively once acidogenesis functioned well.
导电材料已被广泛研究以加速和稳定有机废物向甲烷的转化。然而，不同类型导电材料所涉及的潜在机制仍不清楚。在这项研究中，磁铁矿 (FeO) 和颗粒活性炭 (GAC) 作为两种典型的导电材料，分别被补充到两相厌氧消化 (AD) 系统的产酸相和产甲烷相，以试图探索它们的不同机制。结果表明，磁铁矿补充到产酸相可以促进复杂有机物分解为简单有机物，但会显著提高氢气分压并富集利用氢气的产甲烷菌，这与大多数传统消化器中乙酸营养型产甲烷作用作为主流的产甲烷作用预期不符。GAC 补充到产甲烷相时，在产酸相无效或停止工作时，对醇和脂肪酸的共代谢影响较小。微生物群落分析表明，尽管性能改善不明显，但在 GAC 上已经建立了直接种间电子转移 (DIET)。一旦磁铁矿被补充到产酸相以提高酸化效率，GAC 补充的产甲烷相中的醇和脂肪酸向甲烷的共代谢转化就会得到显著改善。这些结果表明，DIET 不太可能参与复杂有机物的直接分解，即使存在 GAC，也只有在产酸作用良好时才能有效发挥作用。
