Laboratory of Aquatic Systems: Marine and Continental Environments (AQUAMAR), Faculty of Sciences, Ibn Zohr University, Agadir, Morocco.
Universidad San Ignacio de Loyola, Av. La Fontana 501, Lima 12, Lima, Peru.
Chemosphere. 2023 Oct;339:139743. doi: 10.1016/j.chemosphere.2023.139743. Epub 2023 Aug 9.
Wastewater treatment plants (WWTPs) have been identified as high-load receptors of microplastics (MPs) from different sources. However, the influence of specific treatment stanges requires further research. The main objective of this research was to evaluate the abundance and chemical characteristics of MPs in the sludge of two major wastewater treatment plants in the Agadir metropolis (Central Atlantic of Morocco). The Aourir plant receives urban influents and the inputs of the M'zar facility were urban and industrial. Samples were collected from the sludge matrices after primary settling, clarifying, dewatering, and drying systems. In addition, the effect of seasonality on MP load was assessed. The results showed that a higher abundance was noticed in raw sludge than in dewatered one in Aourir WWTP, while in M'zar WWTP, a very low decrease is noticed in dried sludge compared to raw sludge. The concentration of MPs in the summer season was significantly higher compared to other seasons for Aourir WWTP, while the winter season was higher for M'zar WWTP. Moreover, the most abundant shapes were fibers and the fraction 100-500 μm was the most preponderant. Eleven polymers were identified by ATR-FTIR, being polyester, polyethylene, polypropylene, and polystyrene the most abundant ones. Scanning Electron Microscopy coupled with Energy Dispersive X-ray revealed the visible degradation and fragmentation of MPs from sewage sludge and their ability to adsorb inorganic elements. It was estimated that between 2.2 × 10 and 7.4 × 10 MPs were evacuated with the sludge per day. The obtained findings confirmed that WWTP sludge acts as a vector of MPs with a high level of hazard to various matrices, such as landfills, agricultural soils, and groundwater. Overall, consideration must be given to the regulatory system managing the fate of sewage sludge to mitigate the collateral effects and provide solutions.
污水处理厂（WWTP）已被确定为来自不同来源的微塑料（MPs）的高负荷受体。然而，特定处理阶段的影响需要进一步研究。本研究的主要目的是评估阿加迪尔大都市（摩洛哥中大西洋）的两个主要污水处理厂的污泥中 MPs 的丰度和化学特征。Aourir 工厂接收城市污水，而 M'zar 工厂的污水则来自城市和工业。样品是从初级沉降、澄清、脱水和干燥系统后的污泥基质中收集的。此外，还评估了季节性对 MP 负荷的影响。结果表明，Aourir WWTP 的原始污泥中 MPs 的丰度高于脱水污泥，而 M'zar WWTP 的干燥污泥中 MPs 的丰度与原始污泥相比下降非常小。与其他季节相比，Aourir WWTP 夏季 MPs 的浓度明显更高，而 M'zar WWTP 冬季的浓度更高。此外，最丰富的形状是纤维，而 100-500 μm 的分数是最主要的。ATR-FTIR 鉴定出 11 种聚合物，其中聚酯、聚乙烯、聚丙烯和聚苯乙烯最为丰富。扫描电子显微镜结合能量色散 X 射线揭示了污水污泥中 MPs 的可见降解和碎片化及其吸附无机元素的能力。据估计，每天有 2.2×10 到 7.4×10 MPs 随污泥一起被排出。研究结果证实，WWTP 污泥是 MPs 的载体，对垃圾填埋场、农业土壤和地下水等各种基质具有很高的危害。总体而言，必须考虑管理污水污泥命运的监管系统，以减轻附带影响并提供解决方案。
