Response of syntrophic aggregates to the magnetite loss in continuous anaerobic bioreactor
Response of syntrophic aggregates to the magnetite loss in continuous anaerobic bioreactor
复制标题
连续厌氧生物反应器中互养聚集体对磁铁矿损失的响应
DOI：
10.1016/j.watres.2019.114925
复制
发表时间：
2019
期刊：
影响因子：
12.8
通讯作者：
Zhu Liang
中科院分区：
文献类型：
--
作者：
Wang Caiqin;Wang Chen;Jin Luonan;Lu Donghui;Chen Hui;Zhu Weitang;Xu Xiangyang;Zhu Liang
越来越多的研究表明，磁铁矿的添加可以通过增强直接种间电子传递（DIET）为基础的厌氧合成营养来促进甲烷的生成。然而，磁铁矿在连续生物反应器中被发现流失，磁铁矿流失对互养聚集体的影响仍然报道不足。在这项研究中，两个EGSB反应器（RM与磁铁矿强化污泥，RB作为对照）运行，以探讨磁铁矿的行为在连续生物反应器和相应的响应的互养聚集体。结果表明，磁铁矿以铁离子的形式逐渐被冲洗掉，微酸性环境可能是主要原因。然而，候选的饮食伙伴，如吉西他滨和甲硫醇以及互养挥发性脂肪酸（VFA）降解微生物在RM中富集。此外，污泥胞外聚合物（EPS）氧化还原活性的提高、污泥电导率的提高和电子传递活性的增强表明，RM中污泥的DIET能力仍在增强，有利于VFAs的互养代谢。有趣的是，在高有机负荷（OLR）条件下，在磁铁矿存在下，互养伙伴的结合较为松散，但随着磁铁矿的逐渐流失，RM中形成了致密而活跃的厌氧颗粒污泥（AGS）。本研究提供了一个全面的了解磁铁矿在连续生物反应器中的行为和互养聚集体的响应。磁铁矿投加后，以DIET为基础的强合成营养作用有利于未来高效厌氧污水处理和资源回收，建议进一步研究磁铁矿的再补给和磁铁矿富集候选DIET伴侣的机理。
Increasing studies indicate that magnetite addition could accelerate the methanogenesis via enhancing direct interspecies electron transfer (DIET)-based anaerobic syntrophy. However, magnetite is found to run off in continuous bioreactor, and the effect of magnetite loss on syntrophic aggregates is still underreported. In this study, two EGSB reactors (RM with magnetite-enhanced sludge, and RB as a control) were operated to investigate the magnetite behavior in continuous bioreactor and the corresponding response of syntrophic aggregates. Results showed that magnetite in RM was washed out gradually in form of iron ions, and a slightly acidic niche was supposed to be the major cause. Nevertheless, candidate DIET partners like Geobacter andMethanothrixalong with syntrophic volatile fatty acids (VFAs)-degrading microbes were enriched in RM. In addition, the improved redox activity of extracellular polymeric substance (EPS), higher sludge conductivity and electron transport activity suggested that the DIET ability of sludge in RM was still enhanced, which favors the syntrophic metabolism of VFAs. Interestingly, syntrophic partners were loosely combined under the condition of high organic loading rate (OLR) in the presence of magnetite, but with gradual loss of magnetite, dense and active anaerobic granular sludge (AGS) was formed in RM. This study provided a comprehensive understanding of magnetite behavior in continuous bioreactor and the response of syntrophic aggregates. The robust DIET-based syntrophy after magnetite adding could favor the high-efficient anaerobic wastewater treatment and resource recovery in the future, and further investigations on magnetite resupply and the mechanism of magnetite enriching candidate DIET partners are recommended.