耦合MEC的厌氧EGSB反应器改善甲酸盐厌氧甲烷化性能及其机制
- The Improved Performance and the Mechanisms of Anaerobic Methanogenesis of Formate in an EGSB Reactor Coupled with a MEC
- 基金项目：国家自然科学基金面上项目,国家重点实验室开放基金
- 张代钧
- 重庆大学煤矿灾害动力学与控制全国重点实验室；重庆大学环境与生态学院
- 卢培利
- 重庆大学煤矿灾害动力学与控制全国重点实验室；重庆大学环境与生态学院
- 丁阿强
- 重庆大学煤矿灾害动力学与控制全国重点实验室；重庆大学环境与生态学院
- 摘要：有机化工行业产生了大量甲酸(盐)废水,直接排放到水体环境中存在生态风险,亟待对甲酸(盐)废水进行高值化处理。本研究通过构建微生物电解池(MEC)与厌氧膨胀颗粒污泥床(EGSB)耦合的MEC-EGSB工艺,以甲酸盐废水为厌氧消化底物,通过调控电压同步实现净化废水和产生高质甲烷。研究发现,在单独的EGSB处理中,出水COD去除率和甲酸根去除率均超过90%,甲酸盐废水在厌氧体系下得到有效降解。在MEC-EGSB(施加电压1.8V)处理中,累计甲烷产量(10天)达1096.07 mL、甲烷含量最高达到81.8%,碳转化效率达到67.2%,相比单独的EGSB分别提高了279%、284%、474%,MEC的引入大幅提升了厌氧体系产甲烷性能,最大能量回收效率达到57%。微生物群落结构分析表明,施加电压导致Methanobrevibacter、Lactivibrio的富集,前者是典型的氢营养型产甲烷菌,后者在降解碳水化合物和有机酸上有促进作用；同时氢营养型产甲烷菌Methanobacterium对电压施加更为敏感,在MEC-EGSB 的颗粒污泥和阴极生物膜上大量富集。因此,MEC引入后,阴极发生电化学析氢和生物析氢过程,推动氢营养型产甲烷菌利用氢气作电子供体还原二氧化碳产甲烷,同时选择性富集产甲烷菌群,极大提高了甲酸盐厌氧甲烷化的性能。本研究为甲酸(盐)废水处理提供新方法,并揭示了其厌氧消化生物气提质的生物学电化学机制。
- Abstract：The organic chemical industry generates a large amount of formic wastewater, which poses ecological risks when directly discharged into the water environment. It is urgent to carry out high-value treatment of formic wastewater. This study constructs a MEC-EGSB coupling system, using formic wastewater as the anaerobic digestion substrate, and synchronously purifies the wastewater and produces high-quality methane by regulating the voltage. This work has found that in separated EGSB treatment, the COD removal rate and formic removal rate of effluent both exceed 90%, and formic wastewater is effectively degraded in anaerobic digestion. In the MEC-EGSB (applied voltage 1.8V) treatment process, the cumulative methane production (10 days) reached 1096.07 mL, the methane content reached a maximum of 81.8%, and the carbon conversion efficiency reached 67.2%, which was 279%, 284%, and 474% higher than of EGSB alone. The introduction of MEC significantly improved the methane production performance of the anaerobic system, with a maximum energy recovery efficiency of 57%. The analysis of microbial community structure shows that the application of voltage leads to the enrichment of Methanobrevibacter and Lactivibrio. The former is a typical hydrogenotrophic methanogen, while the latter promotes the degradation of carbohydrates and organic acid. At the same time, the hydrogenotrophic methanogen Methanobacterium is more sensitive to voltage application and accumulates significantly in the granular sludge and cathode biofilm of MEC-EGSB. Therefore, after the introduction of MEC, electrochemical and biological hydrogen evolution processes occur at the cathode, promoting hydrogenotrophic methanogens to use hydrogen as an electron donor to reduce carbon dioxide and produce methane, and meanwhile the cathode selectively enriches methanogenic bacterial communities, greatly improving the performance of formic methanogengesis. This study provided a new alternative for the treatment of formic wastewater, and also revealed the bioelectrochemical mechanisms of biogas upgrading in anaerobic digestion.
