College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, P R China.
College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, P R China.
Water Res. 2022 Aug 1;221:118780. doi: 10.1016/j.watres.2022.118780. Epub 2022 Jun 19.
Microplastics (MPs) have been frequently detected in effluent wastewater and sludge in wastewater treatment plants (WWTPs), the discharge and agricultural application of which represent a primary source of environmental MPs contamination. As important as quantitative removal is, changes of physicochemical characteristics of MPs (e.g., shapes, sizes, density, crystallinity) in WWTPs are crucial to their environmental behaviors and risks and have not been put enough attention yet. This review is therefore to provide a current overview on the changes of physicochemical characteristics of MPs in WWTPs and their corresponding environmental risks. The changes of physicochemical characteristics as well as the underlying mechanisms of MPs in different successional wastewater and sludge treatment stages that mainly driven by mechanical (e.g., mixing, pumping, filtering), chemical (e.g., flocculation, advanced oxidation, ultraviolet radiation, thermal hydrolysis, incineration and lime stabilization), biological (e.g., activated sludge process, anaerobic digestion, composition) and their combination effects were first recapitulated. Then, the inevitable correlations between physicochemical characteristics of MPs and their environmental behaviors (e.g., migration, adsorption) and risks (e.g., animals, plants, microbes), are comprehensively discussed with particular emphasis on the leaching of additives and physicochemical characteristics that affect the co-exist pollutants behavior of MPs in WWTPs on environmental risks. Finally, knowing the summarized above, some relating unanswered questions and concerns that need to be unveiled in the future are prospected. The physicochemical properties of MPs change after passing through WWTP, leading to subsequent changes in co-contaminant adsorption, migration, and toxicity. This could threaten our ecosystems and human health and must be worth investigating.
微塑料（MPs）经常在废水处理厂（WWTP）的污水和污泥中被检测到，这些污水和污泥的排放和农业应用是环境中 MPs 污染的主要来源。定量去除固然重要，但 WWTP 中 MPs 物理化学特性的变化（例如形状、大小、密度、结晶度）对于它们的环境行为和风险至关重要，但目前还没有得到足够的重视。因此，本综述旨在提供 WWTP 中 MPs 物理化学特性变化及其相应环境风险的最新概述。综述了 MPs 在不同连续废水和污泥处理阶段的物理化学特性变化及其潜在机制，这些变化主要由机械（如混合、泵送、过滤）、化学（如絮凝、高级氧化、紫外线辐射、热水解、焚烧和石灰稳定）、生物（如活性污泥法、厌氧消化、组成）及其组合效应驱动。然后，综合讨论了 MPs 的物理化学特性与环境行为（如迁移、吸附）和风险（如动物、植物、微生物）之间的必然联系，特别强调了 WWTP 中 MPs 共存污染物行为的浸出添加剂和影响 MPs 物理化学特性对环境风险的影响。最后，了解以上内容后，展望了未来需要揭示的一些相关未解决的问题和关注点。MPs 通过 WWTP 后，其物理化学性质发生变化，导致共污染物吸附、迁移和毒性的后续变化。这可能会威胁到我们的生态系统和人类健康，值得研究。
