Abstract：
In this study, Fe2+ activated-PAA was developed as a novel technology to enhance sludge dewatering. The result showed that the filterability (CST0/CST) enhanced by 4.20 ± 0.14 times more than the control, and the SRF and bound water content decreased from 4.58 ± 0.07 × 1013 m/kg and 2.11 ± 0.28 g/g dry sludge to 9.47 ± 0.05 × 1012 m/kg and 1.27 ± 0.18 g/g dry sludge, respectively after the sludge was conditioned by 1.20 mM/g VSS Fe2+ and 1.20 mM/g VSS PAA. The dewatering performance, physicochemical properties, aggregation behaviors, and EPS fractions of sludge were compared before and after Fe2+/PAA and Fe2+/H2O2 conditionings. The results showed that Fe2+/PAA treatment was more competitive in enhancing dewaterability under neutral and alkaline conditions than Fe2+/H2O2 treatment but slightly weaker under acid conditions. Besides, it was found that the oxidation and re-flocculation behaviors were different in those two enhanced dewatering technologies due to the difference in the generated ROS. R-O was the primary radical in the Fe2+/PAA system, while OH was the major one in the Fe2+/H2O2 system. The mechanism analysis found that the Fe2+/PAA process caused harsher disintegration of sludge flocs, meaning more generation of fine particles. However, it exhibited less effect on reducing the energy barrier between sludge particles. Therefore, the Fe2+/PAA treated sludge presented weaker aggregation behaviors. The weaker aggregation was unfavorable for sludge dewatering because the weaker aggregated flocs were more easily fragmented, which hampered the consolidation of sludge cakes and removal of bound water. Moreover, loosely-bound extracellular polymeric substances, particularly tightly-bound extracellular polymeric substances, governed the sludge dewaterability.
摘要：
在这项研究中,Fe2活化PAA是一种新型的污泥脱水技术。结果表明，滤过性（CST0/CST）比对照提高了4.20±0.14倍，SRF和结合水含量从4.58±0.07×1013m/kg和2.11±0.28g/g干污泥下降到9.47±0.05×1012m/kg和1.27±0.18g/g干污泥，污泥后分别用1.20mM/gVSSFe2+和1.20mM/gVSSPAA调理。脱水性能，物理化学性质，聚集行为，比较了Fe2/PAA和Fe2/H2O2条件前后污泥的EPS分数。结果表明，在中性和碱性条件下，Fe2/PAA处理在增强脱水性能方面比Fe2/H2O2处理更具竞争力，但在酸性条件下略弱。此外,发现由于产生的ROS不同，这两种强化脱水技术的氧化和再絮凝行为不同。R-O是Fe2+/PAA体系中的主要自由基,而OH是Fe2+/H2O2体系中的主要分子。机理分析发现,Fe2+/PAA工艺对污泥絮凝物的崩解较为剧烈,意味着更多的细颗粒的产生。然而,它对减少污泥颗粒之间的能量屏障的作用较小。因此,Fe2+/PAA处理污泥表现出较弱的聚集行为。较弱的聚集不利于污泥脱水，因为较弱的聚集絮凝物更容易破碎，这阻碍了污泥饼的固结和结合水的去除。此外，松散结合的细胞外聚合物，特别是紧密结合的细胞外聚合物，治理污泥的脱水能力。
