State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
Water Res. 2020 May 15;175:115686. doi: 10.1016/j.watres.2020.115686. Epub 2020 Mar 5.
High-solid anaerobic digestion (HAD) can directly treat dewatered sewage sludge (total solid content ≥15%) with superior volume efficiency. Sludge stabilization during HAD is expected to achieve by throughout organic degradation and conversion towards methane-rich biogas release and humic formation. Sewage sludge is the combination of microbial zoogleas and theirs adsorption of organic and inorganic matter, in which the extracellular polymeric substances (EPS) account 60-80% of total sludge organic matter, inevitably participating most extracellular metabolic pathways. The interactions between EPS transformation and genetically annotated metabolic pathways were found in this research. In brief, noticing the highly cross-linked structures in EPS with major active components of humic substances (HS) and protein (PN), as PN hydrolysis and decomposition in EPS were enhanced in the high-solid anaerobic condition, the exposure of aromatic groups and sites in HS were considerable. HS release was the main factor shifting the electron exchange capacity and activity, which aided in energy metabolism of sludge microorganisms involved in redox reactions, especially the methanogenesis, thus in turn facilitating the PN degradation; Then, the screened humic groups and active protein derives might act as the beneficial precursors to regenerate neo-humic structures, whose significant bridging effect and signal role on stimulating amino acid biosynthesis, member transport and metallic complexation could further contribute to proteolytic condensation and EPS reconstruction. Hence, the in-depth sludge stabilization mechanism during HAD process was established for developing enlightening strategies.
高固体厌氧消化（HAD）可以直接处理脱水污水污泥（总固体含量≥15%），具有出色的体积效率。HAD 期间的污泥稳定预计通过彻底的有机降解和转化为富含甲烷的沼气释放和腐殖质形成来实现。污水污泥是微生物菌胶团及其对有机和无机物质的吸附的组合，其中细胞外聚合物物质（EPS）占总污泥有机物的 60-80%，不可避免地参与大多数细胞外代谢途径。在这项研究中发现了 EPS 转化与基因注释代谢途径之间的相互作用。简而言之，注意到 EPS 中具有腐殖质（HS）和蛋白质（PN）主要活性成分的高度交联结构，由于在高固体厌氧条件下 EPS 中的 PN 水解和分解得到增强，HS 中的芳族基团和位点暴露相当可观。HS 释放是改变电子交换能力和活性的主要因素，有助于涉及氧化还原反应的污泥微生物的能量代谢，特别是产甲烷作用，从而反过来促进 PN 降解；然后，筛选出的腐殖质组和活性蛋白可能作为再生新型腐殖质结构的有益前体，其对刺激氨基酸生物合成、成员运输和金属络合的显著桥接作用和信号作用可以进一步有助于蛋白水解缩合和 EPS 重建。因此，为了制定有启发性的策略，建立了 HAD 过程中深入的污泥稳定机制。
