Novel Insights into the Mechanisms of Periodate-Based Pretreatment in Enhancing Short-Chain Fatty Acids from Waste Activated Sludge

作者：Haixiao Guo, Lixin Tian, Yufen Wang, Jiaqi Hou, Tingting Zhu, Yiwen Liu · 发表于：ACS ES&T Engineering · 年份：2023 · DOI：10.1021/acsestengg.2c00279 · 被引用次数：16 · 研究领域：Anaerobic Digestion and Biogas Production、Wastewater Treatment and Nitrogen Removal、Biofuel production and bioconversion

Resource recovery in the form of short-chain fatty acids (SCFAs) from waste activated sludge (WAS) is usually limited due to the quantity and quality of SCFAs. To mitigate these restrictions, this study provides a novel method by using periodate (PI) pretreatment. With an increase in the PI concentration from 0 to 50 mg/g total solids (TS), the SCFA yield increased from 1486 to 3109 mg COD/L and acetic acid production was enhanced by more than twice. Further increase of PI had an adverse effect on SCFA production. Electron spin resonance analysis confirmed that hydroxyl radicals ( • OH) and superoxide radicals ( • O 2 – ) might play crucial roles in the pretreatment process. Further mechanism studies revealed that PI pretreatment improved the disintegration of WAS and decomposition of humus as well as lignocellulose, thereby providing more substrates for SCFA production. The model-based synthetic wastewater tests combined with enzymatic analyses revealed that the stronger suppression of SCFA consumers compared to SCFA generators causes SCFA accumulation; specifically, the inhibitory order was methanogenesis > hydrolysis > acetogenesis > acidogenesis. The suppressed gene expression of acetate-dependent (such as cdh [EC: 2.1.1.245]) and CO 2 -type methanogenesis (such as fwd [EC: 2.3.1.101] and mch [EC: 1.5.98.1]) further triggered SCFA accumulation with PI addition. Moreover, PI pretreatment caused the microbial community to shift toward the favorable hydrolytic and acidificat...