College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China; Jinyun Forest Ecosystem Research Station, Beijing Forestry University, Beijing 100083, China.
J Environ Sci (China). 2020 May;91:73-84. doi: 10.1016/j.jes.2020.01.009. Epub 2020 Jan 27.
The effects of four conditioning approaches: Acid, Acid-zero-valent iron (ZVI)/peroxydisulfate (PMS), Fe(II)/PMS and ZVI/PMS, on wastewater activated sludge (WAS) dewatering and organics distribution in supernatant and extracellular polymeric substances (EPS) layers were investigated. The highest reduction in bound water and the most WAS destruction was achieved by Acid-ZVI/PMS, and the optimum conditions were pH 3, ZVI dosage 0.15 g/g dry solid (DS), oxone dosage 0.07 g/g DS and reaction time 10.6 min with the reductions in capillary suction time (CST) and water content (Wc) as 19.67% and 8.49%, respectively. Four conditioning approaches could result in TOC increase in EPS layers and supernatant, and protein (PN) content in tightly bound EPS (TB-EPS). After conditioning, organics in EPS layers could migrate to supernatant. Polysaccharide (PS) was easier to migrate to supernatant than PN. In addition, Acid, Acid-ZVI/PMS or Fe(II)/PMS conditioning promoted the release of some polysaccharides containing ring vibrations v PO, v C-O-C, v C-O-P functional groups from TB-EPS. ESR spectra proved that both radicals of SO· and ·OH contributed to dewatering and organics transformation and migration. CST value of WAS positively correlated with the ratios of PN/PS in LB-EPS and total EPS, while it negatively correlated with TOC, PN content and PS content in TB-EPS, as well as PS content in supernatant and LB-EPS. BWC negatively correlated to zeta potential and TOC value, PN content, and HA content in supernatant.
考察了酸、零价铁（ZVI）/过一硫酸盐（PMS）、Fe（II）/PMS 和 ZVI/PMS 四种调理方式对废水活性污泥（WAS）脱水性能及上清液和细胞外聚合物（EPS）层中有机物分布的影响。酸-ZVI/PMS 使结合水减少最多，WAS 破坏最严重，最优条件为 pH 3、ZVI 用量 0.15 g/g 干固体（DS）、过氧单硫酸盐用量 0.07 g/g DS 和反应时间 10.6 min，毛细吸水时间（CST）和含水量（Wc）分别降低 19.67%和 8.49%。四种调理方式均导致 EPS 层和上清液中总有机碳（TOC）和紧密结合 EPS（TB-EPS）中蛋白质（PN）含量增加。调理后，EPS 层中的有机物可迁移到上清液中。与 PN 相比，多糖（PS）更容易迁移到上清液中。此外，酸、酸-ZVI/PMS 或 Fe（II）/PMS 调理促进了含有环振动 v PO、v C-O-C 和 v C-O-P 官能团的某些多糖从 TB-EPS 中的释放。ESR 光谱证明 SO·和·OH 自由基均有助于脱水和有机物转化及迁移。WAS 的 CST 值与 LB-EPS 和总 EPS 中 PN/PS 的比值呈正相关，而与 TB-EPS 中的 TOC、PN 含量和 PS 含量以及上清液和 LB-EPS 中的 PS 含量呈负相关。BWC 与 ζ 电位和 TOC 值、上清液中的 PN 含量和 HA 含量呈负相关。
