Department of Civil and Environmental Engineering, Wayne State University, 5050 Anthony Wayne Dr., Detroit, MI 48202, United States of America.
Department of Civil and Environmental Engineering, Wayne State University, 5050 Anthony Wayne Dr., Detroit, MI 48202, United States of America.
Sci Total Environ. 2020 Jun 10;720:137383. doi: 10.1016/j.scitotenv.2020.137383. Epub 2020 Feb 19.
This study investigated the removal efficiency of micro- and nanoplastics (180 nm-125 μm) during drinking water treatment, particularly coagulation/flocculation combined with sedimentation (CFS) and granular filtration under ordinary working conditions at water treatment plants (WTPs). It also studied the interactions between biofilms and microplastics and the consequential impact on treatment efficiency. Generally, CFS was not sufficient to remove micro- and nanoplastics. The sedimentation rate of clean plastics was lower than 2.0% for all different sizes of plastic particles with coagulant Al(SO). Even with the addition of coagulant aid (PolyDADMAC), the highest removal was only 13.6% for 45-53 μm of particles. In contrast, granular filtration was much more effective at filtering out micro- and nanoplastics, from 86.9% to nearly complete removal (99.9% for particles larger than 100 μm). However, there existed a critical size (10-20 μm) where a significant lower removal (86.9%) was observed. Biofilms were easily formed on microplastics. In addition, biofilm formation significantly increased the removal efficiency of CFS treatment from <2.0% to 16.5%. This work provides new knowledge to better understand the fate and transport of emerging micro- and nanoplastic pollutants during drinking water treatment, which is of increasing concern due to the potential human exposure to micro- and nanoplastics in drinking water.
本研究考察了饮用水处理过程中微塑料和纳米塑料（180nm-125μm）的去除效率，特别是在水厂的常规工作条件下，混凝/絮凝联合沉淀（CFS）和颗粒过滤的去除效率。还研究了生物膜与微塑料之间的相互作用以及对处理效率的影响。一般来说，CFS 不足以去除微塑料和纳米塑料。对于所有不同尺寸的塑料颗粒，在没有添加混凝剂 Al(SO₄)₃的情况下，清洁塑料的沉降率均低于 2.0%。即使添加助凝剂（PolyDADMAC），对于 45-53μm 的颗粒，去除率最高也只有 13.6%。相比之下，颗粒过滤对于过滤微塑料和纳米塑料更为有效，去除率从 86.9%到几乎完全去除（对于大于 100μm 的颗粒为 99.9%）。然而，存在一个临界尺寸（10-20μm），在此尺寸下，去除率显著降低（86.9%）。微塑料上容易形成生物膜。此外，生物膜形成显著提高了 CFS 处理的去除效率，从<2.0%提高到 16.5%。这项工作为更好地理解饮用水处理过程中新兴的微塑料和纳米塑料污染物的归宿和迁移提供了新知识，由于人类可能从饮用水中接触到微塑料和纳米塑料，因此这一问题引起了越来越多的关注。
