In this study, the siderite/PMS conditioning-pressurized vertical electro-osmotic dewatering (PEOD) process was used to reduce the volume of activated sludge (AS). The changes in water content, cell, extracellular polymeric substances (EPS) distribution, protein secondary structures and typical amino acids in EPS fractions of AS along siderite/PMS conditioning-PEOD process were investigated. Results showed that the final water content (WC) of dewatered AS was 58.02% under the RSM optimized conditioning conditions of 0.05 g/g TSS siderite dosage, 0.23 g/g TSS PMS dosage, 600 kPa mechanical pressure and 20 V voltage. At conditioning and PEOD stages, the bound water content(BWC) of AS decreased by 25.23% and 91.76%, respectively. The HO• and ${\text{SO}}_4^{-}·$ generated from siderite activating PMS could lead to the disruption of cells. The ratio of Ala-to Lys (Ala/Lys) showed strong negative correlations with BWC or WC in slime ($R_{\text{BWC}}^2$=$-$0.803, p<0.01; $R_{\text{WC}}^2$=$-$0.771, p<0.01) and TB-EPS ($R_{\text{BWC}}^2$=$-$0.693, p<0.01; $R_{\text{WC}}^2$=$-$0.705, p<0.01), and could be considered as an indicator of AS dewaterability. Compared with raw AS, conditioning led to the occurrence of the denser protein structure in TB-EPS and the looser one in slime. The contact number between Ala-and water decreased in TB-EPS and increased in slime, which indicated that the migration of water adhered in TB-EPS to outer layer. At the DG, MC and EC process, while the looser protein structure in TB-EPS and the denser one in slime occurred, as well as higher contact number between Ala-and water in TB-EPS than that in slime, which indicated that more water flowed outsider of slime than TB-EPS. This implied that the variations of the compactness of protein secondary structures and the contact number between Ala-and water in EPS layers correlated with AS dewaterability.

在本研究中，菱铁矿/PMS 调节加压垂直电渗脱水 (PEOD) 工艺用于减少活性污泥 (AS) 的体积。研究了AS的EPS组分中水分含量、细胞、胞外聚合物(EPS)分布、蛋白质二级结构和典型氨基酸在菱铁矿/PMS调节-PEOD过程中的变化。结果表明，在0.05 g/g TSS菱铁矿添加量、0.23 g/g TSS PMS添加量、600 kPa机械压力和20 V电压的RSM优化条件下，脱水AS的最终含水量（WC）为58.02%。在调理和PEOD阶段，AS的结合水含量(BWC)分别下降了25.23%和91.76%。HO• 和${\text{所以}}_4^{-}·$菱铁矿激活 PMS 产生的 PMS 可能导致细胞破裂。Ala-Lys 的比值（Ala/Lys）与粘液中的 BWC 或 WC 显示出强烈的负相关（${\mathrm{电阻}}_{\text{生物武器公约}}^2$=$-$0.803，p <0.01；${\mathrm{电阻}}_{\text{厕所}}^2$=$-$0.771, p <0.01) 和 TB-EPS (${\mathrm{电阻}}_{\text{生物武器公约}}^2$=$-$0.693，p < 0.01；${\mathrm{电阻}}_{\text{厕所}}^2$=$-$0.705，p < 0.01)，可被视为 AS 脱水性的指标。与原始 AS 相比，调节导致 TB-EPS 中蛋白质结构更致密，而粘液中蛋白质结构更松散。Ala-与水在TB-EPS中的接触数减少，在粘液中增加，表明TB-EPS中附着的水向外层迁移。在 DG、MC 和 EC 过程中，TB-EPS 中蛋白质结构较松散，黏液中蛋白质结构较稠密，TB-EPS 中 Ala-与水的接触次数高于黏液，说明与 TB-EPS 相比，水在粘液之外流动。这意味着EPS层中蛋白质二级结构的致密性和Ala-与水之间的接触数的变化与AS脱水性相关。