School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, China.
School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, China; Key Laboratory of Intelligent Health Perception and Ecological Restoration of Rivers and Lakes, Ministry of Education, Hubei University of Technology, Wuhan, 430068, China.
Environ Pollut. 2024 Oct 1;358:124498. doi: 10.1016/j.envpol.2024.124498. Epub 2024 Jul 6.
Activated persulfate and hydrothermal treatment (HTT) are often employed to treat waste activated sludge, which can improve the efficiency of subsequent sludge treatment and change the distribution of pollutants in the sludge. However, the impact of sludge solid content and temperature on the occurrence and aging of microplastics (MPs) during HTT remains poorly understood. This study investigated the effects of persulfate-HTT (SPS-HTT) co-treatment on the migration, occurrence, and aging of MPs in sludge with different solid contents (2% and 5% solid content). The results indicated that SPS-HTT co-treatment triggers both the disruption of sludge flocs and the melting deformation of MPs at high temperatures, leading to variations in the increasing trend of MP concentration in the solid-liquid phase at different solid contents. 5% solid content sludge showed a weak release of MPs from the solid phase. The proportion of fiber MPs first increased and then decreased with increasing temperature, while no significant changes were observed in the color and type of MPs. Higher temperature and solid content induced the melting deformation of MPs, exacerbated the aging of polypropylene MPs, and resulted in rough surfaces, higher carbonyl index, and variations in crystallinity. Moreover, the correlation between the carbonyl index and aging indicators increased with increasing solid content. The MP-derived dissolved organic matter under HTT primarily comprised soluble microbial by-products and humic acid-like substances. These findings underscore the significance of sludge solid content in affecting the migration and aging of MPs during HTT, and offer novel insights into the application of HTT to MP management in sludge treatment.
过硫酸盐-热水解（SPS-HTT）联合处理通常用于处理废活性污泥，可以提高后续污泥处理效率并改变污泥中污染物的分布。然而，污泥固含量和温度对 HTT 过程中微塑料（MPs）的产生和老化的影响仍不清楚。本研究考察了过硫酸盐-热水解（SPS-HTT）联合处理对不同固含量（2%和 5%固含量）污泥中 MPs 的迁移、产生和老化的影响。结果表明，SPS-HTT 联合处理会引发高温下污泥絮体的破坏和 MPs 的熔融变形，导致不同固含量下固液相间 MPs 浓度增加趋势的变化。5%固含量污泥中 MPs 从固相中较弱地释放。纤维 MPs 的比例随温度升高先增加后减少，而 MPs 的颜色和类型没有明显变化。较高的温度和固含量会导致 MPs 的熔融变形，加剧聚丙烯 MPs 的老化，使表面变得粗糙，羰基指数增加，结晶度发生变化。此外，随着固含量的增加，羰基指数与老化指标之间的相关性增加。HTT 下 MP 衍生的溶解有机物质主要由可溶性微生物副产物和腐殖酸样物质组成。这些发现强调了污泥固含量在影响 HTT 过程中 MPs 迁移和老化方面的重要性，并为将 HTT 应用于污泥处理中 MPs 管理提供了新的思路。
