Yuan Feiyi, Sun Yi, Jiang Xiupeng, Liu Tao, Kang Bo, Freguia Stefano, Feng Leiyu, Chen Yinguang
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
Downhole Technical Service Branch, Bohai Drilling Engineering Co., Ltd, National Petroleum Corporation, 8, Second Street, Economic and Technological Development Zone, Tianjin 300450, PR China.
Sci Total Environ. 2023 Feb 10;859(Pt 1):160102. doi: 10.1016/j.scitotenv.2022.160102. Epub 2022 Nov 10.
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.
作为使用最广泛的邻苯二甲酸酯类增塑剂之一，邻苯二甲酸二辛酯（DOP）已在废水中被检测到，并通过废水处理在污泥中积累，这可能会对后续的污泥处理产生不利影响。然而，DOP对污泥厌氧发酵的作用及其机制尚不清楚。因此，本研究聚焦于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的产生有显著贡献，在DOP浓度为500 mg/kg时，VFAs的最大产量达到4769 mg COD/L，是对照组的1.57倍。机理研究表明，DOP主要增强了污泥的水解、酸化及相关酶活性。在DOP作用下，产生VFAs的微生物（如梭菌属和联合杆菌属）也得到了富集。重要的是，DOP的存在使电子传递活性提高了26%，从而促进了有机物的转化和发酵过程。值得注意的是，DOP增强了参与底物代谢和VFAs生物合成的功能基因表达，导致污泥中VFAs产量增加。本研究所得结果为控制污染物及从污泥中回收有价值产品提供了新策略。
