Thermodynamically enhancing propionic acid degradation by using sulfate as an external electron acceptor in a thermophilic anaerobic membrane reactor.
Thermodynamically enhancing propionic acid degradation by using sulfate as an external electron acceptor in a thermophilic anaerobic membrane reactor.
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DOI：
10.1016/j.watres.2016.10.013
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发表时间：
2016-12
期刊：
影响因子：
12.8
通讯作者：
W. Qiao;K. Takayanagi;Qian Li;Mohammad Shofie;Fangshu Gao;R. Dong;Yuyou Li
中科院分区：
文献类型：
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作者：
W. Qiao;K. Takayanagi;Qian Li;Mohammad Shofie;Fangshu Gao;R. Dong;Yuyou Li
在高温厌氧膜反应器（AnMBR）中，以硫酸盐作为外部电子受体，研究了其对丙酸盐降解的影响。有机负荷（OLR）由初始的3. 9 kg-COD/m3 d逐渐增加到14. 6 kg-COD/m3 d的抑制性OLR。停止进料98天，但直到向AnMBR中加入500 mg/L的硫酸盐，该过程才恢复。在此之后，实现了增强的丙酸盐降解高达15 kg-COD/m3 d的OLR与减少的硫酸盐添加量为300 mg/L。热力学计算表明，在强化条件下，丙酸降解与产甲烷反应的耦合过程是不利的，△G为+3kJ/mol。相反，硫酸盐还原细菌（SRB）对丙酸的利用将更有利，因为其△G要低得多，为-180 kJ/mol。根据热力学计算结果推测，氢的转化是通过产甲烷途径进行的。丙酸和氢代谢的机制，以及通过比较与硫酸盐添加和不添加的微生物群落支持。因此，硫酸盐促进丙酸降解的作用可以通过结合工艺性能、热力学和微生物学结果来得出。
In this study, sulfate was employed as an external electron acceptor for enhancing the degradation of propionate in a thermophilic anaerobic membrane reactor (AnMBR). The organic loading rate (OLR) was increased gradually from the initial 3.9 kg-COD/m3d to the inhibiting OLR of 14.6 kg-COD/m3d. Feeding was stopped for 98 days but the process did not recover until 500 mg/L of sulfate was added into the AnMBR. After that, the enhanced propionate degradation was achieved up to an OLR of 15 kg-COD/m3d with a reduced sulfate addition of 300 mg/L. However, the thermodynamic calculation indicated that the syntrophic propionic acid degradation, coupled with methanogenesis, was unfavorable with a △G of +3 kJ/mol under the enhanced conditions. Conversely, the utilization of propionic acid by sulfate reduction bacterial (SRB) would be more favourable by having a much lower △G of −180 kJ/mol. The hydrogen conversion was presumed to go through the methanogenesis pathway according to the thermodynamic results. The mechanism of the propionic and hydrogen metabolism was supported as well by comparing the microbial communities with and without sulfate addition. As a result, the role of the sulfate enhancing propionic degradation can be concluded by combining the process performance, thermodynamic, and microbiology results.