School of Environmental and Chemical Engineering, Organic Compound Pollution Control Engineering, Ministry of Education, Shanghai University, Shanghai 200444, PR China.
State Key Laboratory of Pollution Control and Resources Reuse, National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
Sci Total Environ. 2024 Apr 20;922:171338. doi: 10.1016/j.scitotenv.2024.171338. Epub 2024 Feb 28.
Wastewater treatment plants (WWTPs) receive large quantities of microplastics (MPs) from raw wastewater, but many MPs are trapped in the sludge. Land application of sludge is a significant source of MP pollution. Existing reviews have summarized the analysis methods of MPs in sludge and the effect of MPs on sludge treatments. However, MP aging and mitigation during sludge treatment processes are not fully reviewed. Treatment processes used to remove water, pathogenic microorganisms, and other pollutants in sewage sludge also cause surface changes and degradation in the sludge MPs, affecting the potential risk of MPs. This study integrates MP abundance and distribution in sludge and their aging and mitigation characteristics during sludge treatment processes. The abundance, composition, and distribution of sludge MPs vary significantly with WWTPs. Furthermore, MPs exhibit variable degrees of aging, including rough surfaces, enhanced adsorption potentials for pollutants, and increased leaching behavior. Various sludge treatment processes further intensify these aging characteristics. Some sludge treatments, such as hydrothermal treatment, have efficiently removed MPs from sewage sludge. It is crucial to understand the potential risk of MP aging in sludge and the degradation properties of the MP-derived products from MP degradation in-depth and develop novel MP mitigation strategies in sludge, such as combining hydrothermal treatment and biological processes.
污水处理厂（WWTP）从原废水中接收大量微塑料（MPs），但许多 MPs 被困在污泥中。污泥的土地应用是 MPs 污染的一个重要来源。现有的综述总结了 MPs 在污泥中的分析方法以及 MPs 对污泥处理的影响。然而，污泥处理过程中 MPs 的老化和缓解并没有得到充分的综述。用于去除污水中的水、致病微生物和其他污染物的处理工艺也会导致污泥 MPs 的表面变化和降解，从而影响 MPs 的潜在风险。本研究综合了污泥中 MPs 的丰度和分布及其在污泥处理过程中的老化和缓解特性。污泥 MPs 的丰度、组成和分布随 WWTP 而有很大差异。此外， MPs 表现出不同程度的老化，包括表面粗糙、增强对污染物的吸附潜力以及增加浸出行为。各种污泥处理工艺进一步加剧了这些老化特性。一些污泥处理方法，如热水解处理，有效地从污水污泥中去除 MPs。深入了解污泥中 MPs 老化的潜在风险以及 MPs 降解产物的降解特性，并开发污泥中新型的 MPs 缓解策略，例如将热水解处理与生物过程相结合，这一点至关重要。
