Sewage sludge is one of the sinks for PAHs accumulation and concerns are growing regarding the environmental risk of the discharge of PAHs in waste activated sludge (WAS) as a major byproduct of sewage treatment. Here, we evaluated the effectiveness of ozone treatment to eliminate the 16 priority PAHs in WAS. The PAHs removal efficiency increased with ozone dosage and was strongly pH dependent. Even at ozone dosage of 40 mg O₃·g⁻¹, the PAHs removal efficiency at pH 9.0 (44.5%) was significantly higher than that observed at pH 5.0 and 200 mg O₃·g⁻¹ (41.7%). The pH-dependent elimination behavior of PAHs was attributed to the varying yield of hydroxyl radicals (OH) and degree of sludge disintegration (R² = 0.88–0.92). Over 96% of the PAHs were in the particulate flocs (PF) phase, while the fraction bound to the freely dissolved (FS) and dissolved and colloidal (DC) matters was negligible, indicating the need of WAS disintegration during ozonation to make PAHs more accessible to O₃ molecules and OH to initiate oxidation reactions. Failure of the three-compartment model to describe the PAHs sorption behavior in sludge matrix during ozonation implied that oxidation reaction occurred simultaneously with the partitioning of PAHs from PS to DC/FS fraction. Lastly, the results of the intermittent ozonation experiment demonstrated the interference of soluble organic compounds during PAHs degradation, particularly proteins and humic substances, as O₃ and OH scavengers. At ozone dosage of 120 mg O₃·g⁻¹ (pH 9.0), the PAHs removal efficiency was improved by 19.5% by intermittent ozonation, as compared to continuous ozonation under the same conditions.

污水污泥是多环芳烃积累的汇之一，人们越来越关注作为污水处理的主要副产品的废活性污泥（WAS）中多环芳烃排放的环境风险。在这里，我们评估了臭氧处理消除WAS中16种优先PAH的有效性。PAHs的去除效率随臭氧剂量的增加而增加，并且与pH值密切相关。即使在40 mg O ₃ ·g ^-1的臭氧剂量下，pH 9.0（44.5％）下的PAHs去除效率也明显高于pH 5.0和200 mg O ₃ ·g ^-1（41.7％）下的去除率。PAHs的pH依赖性消除行为归因于羟基自由基（OH）的收率和污泥分解程度（R ² = 0.88–0.92）。超过96％的PAH处于颗粒絮凝（PF）相，而与自由溶解（FS）以及溶解和胶体（DC）物质结合的部分微不足道，这表明在臭氧化过程中需要WAS分解以使PAH更多可被O ₃分子和OH引发氧化反应。三室模型未能描述在臭氧化过程中污泥基质中PAHs的吸附行为，这意味着氧化反应与PAHs从PS分配到DC / FS馏分同时发生。最后，间歇臭氧氧化实验的结果表明，可溶性有机化合物在PAHs降解过程中会干扰，特别是蛋白质和腐殖质，如O ₃和OH清道夫。与相同条件下的连续臭氧化相比，在臭氧剂量为120 mg O ₃ ·g ^-1（pH 9.0）时，通过间歇性臭氧化，PAHs去除效率提高了19.5％。