The effectiveness of traditional drinking water treatment plants for the removal of Microplastics (MPs) in the size range of tens of micrometers is currently uncertain. This study investigated the behavior and removal efficiency of four different sized polystyrene MPs (10−90 μm in diameter) in a simulated cascade of coagulation/sedimentation, sand filtration, and UV-based oxidation over technically relevant time frames. In the coagulation and sand filtration steps, the larger the MP size, the better it was removed. The coagulant type and water characteristics (i.e., pH and the presence of natural organic matter) influenced the coagulation efficiency for MPs. X-ray microcomputed tomography technique and two-site kinetic modeling were used to identify the mechanisms involved in sand filtration. The MPs > 20 μm could be completely retained in sand by straining, while the attachment to the sand surface was likely responsible for the retention of MPs < 20 μm. However, approximately 16% of 10 μm MPs injected passed through the sand, which were further fragmented by UV oxidation. UV/H₂O₂ treatment promoted the MP fragmentation and chemical leaching more significantly than UV treatment, resulting in a higher toxicity for UV/H₂O₂-treated water. Our findings pave the way for deeper understanding of how MPs behave and transform in a sequential drinking water treatment process.

传统饮用水处理厂去除尺寸范围为数十微米的微塑料 (MP) 的有效性目前尚不确定。本研究调查了四种不同尺寸的聚苯乙烯 MP（直径 10-90 μm）在技术相关时间范围内模拟的混凝/沉淀、砂滤和基于紫外线的氧化级联的行为和去除效率。在混凝和砂滤步骤中，MP 尺寸越大，去除效果越好。混凝剂类型和水特性（即 pH 值和天然有机物的存在）影响 MP 的混凝效率。X 射线显微计算机断层扫描技术和双位点动力学模型用于识别砂滤中涉及的机制。国会议员 > 20 μm 可以通过过滤完全保留在沙子中，而附着在沙子表面上可能是导致 MP < 20 μm 保留的原因。然而，注入的 10 μm MP 中约有 16% 通过了沙子，这些沙子被紫外线氧化进一步破碎。紫外线/高温₂ O ₂处理比UV处理更显着地促进MP碎裂和化学浸出，导致UV/H ₂ O ₂处理的水具有更高的毒性。我们的研究结果为更深入地了解 MP 在连续饮用水处理过程中的行为和转变铺平了道路。