Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
Water Res. 2019 Jun 15;157:8-18. doi: 10.1016/j.watres.2019.03.054. Epub 2019 Mar 29.
Due to highly recalcitrant and toxicological nature of halogenated organic compounds, conventional anaerobic dehalogenation is often limited by low removal rate and poor process stability. Besides, the reduction intermediates or products formed during dehalogenation process, which are still toxic, required further energy-intensive aerobic post-treatment. In this study, an up-flow electricity-stimulated anaerobic system (ESAS) was developed by installing cathode underneath and anode above to realize simultaneous anaerobic debromination and mineralization of 4-bromophenol (4-BP). When cathode potential was -600 mV, high TOC removal efficiency (98.78 ± 0.96%), complete removal of 4-BP and phenol could be achieved at 4-BP loading rate of 0.58 mol m d, suggesting debrominated product of 4-BP from cathode (i.e., phenol) would be utilized as the fuel by the bioanode of ESAS. Under high 4-BP loading rate (2.32 mol m d) and low electron donor dosage (4.88 mM), 4-BP could be completely removed at acetate usage ratio as low as 4.21 ± 1.42 mol acetate mol 4-BP removal in ESAS, whereas only 13.45 ± 1.38% of 4-BP could be removed at acetate usage ratio as high as 31.28 ± 3.38 mol acetate mol 4-BP removal in control reactor. Besides, electrical stimulation distinctly facilitated the growth of various autotrophic dehalogenation species, phenol degradation related species, fermentative species, homoacetogens and electrochemically active species in ESAS. Moreover, based on the identified intermediates and the bacterial taxonomic analysis, possible metabolism mechanism involved in enhanced anaerobic debromination and mineralization of 4-BP in ESAS was proposed.
由于卤代有机化合物具有很强的抗降解性和毒性，传统的厌氧脱卤往往受到去除率低和工艺稳定性差的限制。此外，脱卤过程中形成的还原中间产物或产物仍然具有毒性，需要进一步进行能量密集型的好氧后处理。在本研究中，通过在底部安装阴极和顶部安装阳极，开发了一种上流式电流刺激厌氧系统（ESAS），以实现 4-溴苯酚（4-BP）的同时厌氧脱溴和矿化。当阴极电位为-600 mV 时，在 4-BP 负荷为 0.58 mol m d 时，可以实现高 TOC 去除效率（98.78±0.96%）和 4-BP 的完全去除，表明 4-BP 的脱溴产物从阴极（即苯酚）将被 ESAS 的生物阳极用作燃料。在高 4-BP 负荷（2.32 mol m d）和低电子供体剂量（4.88 mM）下，在 ESAS 中，乙酸盐的使用比低至 4.21±1.42 mol 乙酸盐 mol 4-BP 去除时，可以完全去除 4-BP，而在控制反应器中，乙酸盐的使用比高达 31.28±3.38 mol 乙酸盐 mol 4-BP 去除时，只有 13.45±1.38%的 4-BP 可以去除。此外，电刺激明显促进了 ESAS 中各种自养脱卤物种、苯酚降解相关物种、发酵物种、同型乙酰菌和电化学活性物种的生长。此外，根据鉴定的中间产物和细菌分类分析，提出了 ESAS 中增强 4-BP 厌氧脱溴和矿化的可能代谢机制。
