As one of the most widely used phthalate plasticizers, dioctyl phthalate (DOP) has been detected in wastewater and accumulates in sludge through wastewater treatment, which may adversely affect further sludge treatment. However, the role of DOP on sludge anaerobic fermentation and its mechanism are not yet clear. Therefore, this study focused on the effect of DOP on the volatile fatty acids (VFAs) generation via the anaerobic fermentation of sludge. The results demonstrated that the presence of DOP had a considerable contribution to the generation of VFAs, and the maximum production of VFAs reached 4769 mg COD/L at 500 mg/kg DOP, which was 1.57 folds that of the control. Mechanistic investigation showed that DOP mainly enhanced the hydrolysis, acidification and related enzymes activities of sludge. VFAs-producing microorganisms (e.g., Clostridium and Conexibacter) were also enriched under DOP exposure. Importantly, the presence of DOP increased the electron transfer activity by 26 %, consequently facilitating the organics conversion and fermentation process. Notably, the functional gene expressions involved in substrate metabolism and VFAs biosynthesis were enhanced with DOP, resulting in increased VFAs production from sludge. The results obtained in this study offered a new strategy for the control of pollutants and the recycling of valuable products from sludge.

作为最广泛使用的邻苯二甲酸酯增塑剂之一，邻苯二甲酸二辛酯（DOP）已在废水中被检测到，并在废水处理过程中积累在污泥中，这可能会对进一步的污泥处理产生不利影响。但DOP对污泥厌氧发酵的作用及其作用机制尚不明确。因此，本研究的重点是 DOP 对污泥厌氧发酵产生挥发性脂肪酸 (VFAs) 的影响。结果表明，DOP的存在对VFAs的产生有相当大的贡献，500 mg/kg DOP时VFAs的最大产量达到4769 mg COD/L，是对照的1.57倍。机理研究表明，DOP主要增强了污泥的水解、酸化和相关酶的活性。产生 VFA 的微生物（例如, 梭状芽胞杆菌和Conexibacter ) 在 DOP 暴露下也被富集。重要的是，DOP 的存在使电子转移活性提高了 26%，从而促进了有机物转化和发酵过程。值得注意的是，DOP 增强了参与底物代谢和 VFA 生物合成的功能基因表达，从而增加了污泥中 VFA 的产量。本研究获得的结果为控制污染物和从污泥中回收有价值的产品提供了新的策略。