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Extracellular polymeric substance decomposition linked to hydrogen recovery from waste activated sludge: Role of peracetic acid and free nitrous acid co-pretreatment in a prefermentation-bioelectrolysis cascading system.
Water Research ( IF 11.4 ) Pub Date : 2020-03-19 , DOI: 10.1016/j.watres.2020.115724
Zhihong Liu 1 , Aijuan Zhou 2 , Hongyan Liu 1 , Sufang Wang 1 , Wenzong Liu 3 , Aijie Wang 4 , Xiuping Yue 5
Affiliation  

Free nitrous acid (FNA) has been recently reported to be an effective and eco-friendly inactivator for waste activated sludge (WAS), while the limited decomposition of the extracellular polymeric substance (EPS) matrix hampers resource recovery from WAS. This work employed peracetic acid (PAA) to assist FNA and explored the contribution of co-pretreatment to hydrogen recovery in a prefermentation-bioelectrolysis cascading system. The results showed that co-pretreatment led to approximately 8.8% and 20.4% increases in the exfoliation of particulate proteins and carbohydrates, respectively, from tightly bound EPS (TB-EPS) over that of sole FNA pretreatment. Electron paramagnetic resonance analysis verified that the synergistic effect of FNA, PAA and various generated free radicals was the essential process. This effect further promoted the accumulation of volatile fatty acids (VFAs) after 96 h of prefermentation, and the peak concentration in co-pretreated WAS (AD-FPWAS) was approximately 2.5-fold that in sole FNA-pretreated WAS (AD-FWAS). Subsequently, the cascading utilization of organics in the bioelectrolysis step contributed to efficient hydrogen generation. A total of 10.8 ± 0.3 mg H2/g VSS was harvested in microbial electrolysis cells (MECs) fed with AD-FPWAS, while 6.2 ± 0.1 mg H2/g VSS was obtained from AD-FWAS. X-ray photoelectron spectroscopy (XPS) revealed the effective decomposition of the phospholipid bilayer in the cytomembrane and the transformation of macromolecular organics into VFAs and hydrogen in the cascading system. Further microbial community analysis demonstrated that co-pretreatment enhanced the accumulation of functional consortia, including anaerobic fermentative bacteria (AFB, 28.1%), e.g., Macellibacteroides (6.3%) and Sedimentibacter (6.9%), and electrochemically active bacteria (EAB, 57.0%), e.g., Geobacter (39.0%) and Pseudomonas (13.6%), in the prefermentation and MEC steps, respectively. The possible synergetic and competitive relationships among AFB, EAB, homo-acetogens, nitrate-reducing bacteria and methanogens were explored by molecular ecological network analysis. From an environmental and economic perspective, this promising FNA and PAA co-pretreatment approach provides new insight for energy recovery from WAS biorefineries.

中文翻译:

细胞外聚合物质分解与废活性污泥中的氢回收有关:过乙酸和游离亚硝酸共同预处理在优选生物电解级联系统中的作用。

最近有报道称游离亚硝酸(FNA)是一种有效,环保的废物活性污泥(WAS)灭活剂,而细胞外聚合物(EPS)基质的有限分解阻碍了WAS的资源回收。这项工作使用过氧乙酸(PAA)协助FNA,并探索了优选预处理-生物电解级联系统中共预处理对氢回收的贡献。结果表明,与单独的FNA预处理相比,共预处理导致紧密结合的EPS(TB-EPS)分别使颗粒蛋白质和碳水化合物的剥落分别增加约8.8%和20.4%。电子顺磁共振分析证实,FNA,PAA和各种自由基的协同作用是必不可少的过程。在优选96小时后,该效应进一步促进了挥发性脂肪酸(VFA)的积累,并且共同预处理的WAS(AD-FPWAS)中的峰值浓度约为单独FNA预处理的WAS(AD-FWAS)的2.5倍。随后,在生物电解步骤中级联利用有机物有助于有效地产生氢气。在装有AD-FPWAS的微生物电解池(MEC)中收获了总计10.8±0.3 mg H2 / g VSS,而从AD-FWAS获得了6.2±0.1 mg H2 / g VSS。X射线光电子能谱(XPS)揭示了细胞膜中磷脂双层的有效分解以及级联系统中大分子有机物向VFA和氢的转化。进一步的微生物群落分析表明,共预处理可增强功能性财团的积累,包括厌氧性发酵细菌(AFB,28.1%),如Macellibacteroides(6.3%)和Sedimentibacter(6.9%),以及电化学活性细菌(EAB,57.0%)。 ),例如在首选步骤和MEC步骤中,分别是Geobacter(39.0%)和Pseudomonas(13.6%)。通过分子生态网络分析,探讨了AFB,EAB,高产乙酸菌,硝酸盐还原菌和产甲烷菌之间可能的协同竞争关系。从环境和经济角度来看,这种有前途的FNA和PAA共预处理方法为WAS生物精炼厂的能量回收提供了新的见解。在优选步骤和MEC步骤中,分别有9%的细菌和具有电化学活性的细菌(EAB,57.0%),例如,Geobacter(39.0%)和Pseudomonas(13.6%)。通过分子生态网络分析,探讨了AFB,EAB,高产乙酸菌,硝酸盐还原菌和产甲烷菌之间可能的协同竞争关系。从环境和经济角度来看,这种有前途的FNA和PAA共预处理方法为WAS生物精炼厂的能量回收提供了新的见解。在优选步骤和MEC步骤中,分别有9%的细菌和具有电化学活性的细菌(EAB,57.0%),例如,Geobacter(39.0%)和Pseudomonas(13.6%)。通过分子生态网络分析,探讨了AFB,EAB,高产乙酸菌,硝酸盐还原菌和产甲烷菌之间可能的协同竞争关系。从环境和经济角度来看,这种有前途的FNA和PAA共预处理方法为WAS生物精炼厂的能量回收提供了新的见解。
更新日期:2020-03-20
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