Group of Environmental Physical Chemistry, Department F.-A. Forel for environmental and aquatic sciences, University of Geneva, Uni Carl Vogt, 66, boulevard Carl-Vogt, CH-1211 Geneva 4, Switzerland.
SIG, Industrial Boards of Geneva, Ch. du Château-Bloch, Le Lignon, 1211 Genève 2, Switzerland.
Sci Total Environ. 2022 Mar 20;813:152623. doi: 10.1016/j.scitotenv.2021.152623. Epub 2021 Dec 25.
Occurrence of microplastics and nanoplastics in aquatic systems, as well as in water compartments used to produce drinking water have become a major concern due to their impact on the environment and public health. Nanoplastics in particular, in regard to their fate and removal efficiency in drinking water treatment plants (DWTP), which ensure water quality and supply drinking water for human consumption have been, by far, rarely investigated. This study investigates the removal efficiency of polystyrene (PS) nanoplastics in a conventional water treatment plant providing drinking water for 500'000 consumers. For that purpose, a pilot-scale DWTP, located within the main treatment plant station, reproducing at a reduced scale the different processes and conditions of the main treatment plant is used. The results show that filtration process through sand and granular activated carbon (GAC) filters in the absence of coagulation achieves an overall nanoplastic removal of 88.1%. The removal efficiency of filtration processes is mainly attributed to physical retention and adsorption mechanisms. On the other hand, it is found that coagulation process greatly improves the removal efficiency of nanoplastics with a global removal efficiency equal to 99.4%. The effective removal efficiency of sand filtration increases considerably from 54.3% to 99.2% in the presence of coagulant, indicating that most of PS nanoplastics are removed during sand filtration process. The higher removal efficiency with the addition of coagulant is related to nanoplastics surface charge reduction and aggregation thus significantly increasing their retention in the filter media.
微塑料和纳米塑料在水生系统中的出现，以及在用于生产饮用水的水隔室中的出现，由于它们对环境和公共健康的影响，已成为一个主要关注点。特别是纳米塑料，就其在饮用水处理厂 (DWTP) 中的命运和去除效率而言，这些处理厂确保了水质并为人类消费提供饮用水，迄今为止，很少有研究对其进行调查。本研究调查了在为 50 万消费者提供饮用水的常规水处理厂中去除聚苯乙烯 (PS) 纳米塑料的效率。为此，使用位于主处理厂站内的中试规模 DWTP，以降低的规模复制主处理厂的不同工艺和条件。结果表明，在没有混凝的情况下，通过砂和颗粒活性炭 (GAC) 过滤器的过滤过程可实现总体纳米塑料去除率为 88.1%。过滤过程的去除效率主要归因于物理保留和吸附机制。另一方面，发现混凝过程大大提高了纳米塑料的去除效率，总去除效率等于 99.4%。在存在混凝剂的情况下，砂滤过程的有效去除效率从 54.3%大幅增加到 99.2%，表明大多数 PS 纳米塑料在砂滤过程中被去除。添加混凝剂时去除效率更高，与纳米塑料表面电荷减少和聚集有关，从而大大增加了它们在过滤介质中的保留。
