Abstract:

Waste activated sludge with high moisture content challenges the harmless treatment and resource utilization of sludge. In this study, low temperature hydrothermal coupling Fe²⁺-activated persulfate was used to improve the dewatering performance of waste activated sludge. The results showed that when 0.75mmol/g DS Fe²⁺ and 0.6mmol/g DS S₂O₈^2- were added at 80℃, the molar ratio of Fe²⁺/S₂O₈^2- was 1.25, capillary suction time (CST) of sludge decreased from 397.4s±7.9s to 18.9s±0.4s. It was found that in the process of activating persulfate with hydrothermal coupling Fe²⁺ at low temperature to enhance the dewatering performance of sludge, the particle size of sludge first decreased and then increased, the extracellular polymer substance (EPS) was degraded, and the floc structure was damaged. The combination of heat and Fe²⁺ accelerated the decomposition of persulfates to generate sulfate radicals (SO₄^•-) and hydroxyl radicals (^•OH) for oxidizing EPS, promoted the conversion of bound water into free water, and facilitated the solid-liquid separation of sludge. These studies provided a theoretical basis for dewatering sludge with low temperature hydrothermal coupling Fe²⁺-activated persulfate.

Key words: waste activated sludge, dewaterability, persulfate, hydrothermal, activation, advanced oxidation process

摘要：

含水率高的剩余污泥给污泥的无害化处理和资源化利用带来了挑战。本文采用低温水热耦合Fe²⁺活化过硫酸盐提高剩余污泥的脱水性能。结果表明，在80℃、Fe²⁺/S₂O₈^2-的摩尔比为1.25的条件下，加入0.75mmol/g DS的Fe²⁺和0.6mmol/g DS的S₂O₈^2-，污泥的毛细吸水时间（CST）由397.4s±7.9s下降到18.9s±0.4s。研究发现在低温水热耦合Fe²⁺活化过硫酸盐提高污泥脱水性能的过程中，污泥的粒径先减小后增大，胞外聚合物（EPS）被降解和絮体结构遭到破坏。在热和Fe²⁺的共同作用下加速了过硫酸盐的分解，生成的硫酸根自由基（SO₄^•-）和羟基自由基（^•OH）降解了EPS，促进结合水转化为自由水，有利于污泥的固液分离。这些研究可为低温水热耦合Fe²⁺活化过硫酸盐对污泥进行脱水处理提供了理论基础。

关键词: 剩余污泥, 脱水能力, 过硫酸盐, 水热, 活化, 高级氧化工艺