Contamination and Removal Efficiency of Microplastics and Synthetic Fibres in a Conventional Drinking Water Treatment Plant

Abstract

Microplastics have been detected all around the globe in freshwaters which are frequently used to produce drinking water. Therefore, the contamination of raw water with microplastics that supplies drinking water treatment plants, and their removal efficiency is raising more concern and interest. In the present study, we evaluated the microplastic contamination in a conventional drinking water treatment plant (Geneva, Switzerland) and the contribution of coagulation on the efficiency of the filtration systems (sand and activated carbon filtrations) in the removal efficiency of microplastics (MPs) and synthetic fibres. This work was performed in a pilot station that replicates the main drinking water treatment process. Raw water and effluents of each filtering processes were analysed for the presence of MPs and synthetic fibres with sizes ≥ 63 μm using infrared spectroscopy. The contamination of MPs in raw water and in drinking water ranged from 19.5 to 143.5 MPs/m3 and from 0 to 8 MPs/m3 (in presence and absence of coagulant), respectively. On the other hand, concentration of synthetic fibres ranged from 7.7 to 23.8 synthetic fibres/m3 in raw water and from 0 to 3 synthetic fibres/m3 in drinking water. Results show that on average 89% of microplastics and 81% of synthetic fibres (≥63 μm) are retained in water treatment in absence of coagulant. Better final removal efficiency of microplastics (97%) and synthetic fibres (96%) was observed in drinking water with coagulation treatment. The chemical composition of microplastics and synthetic fibres is found more heterogeneous in raw water than after sand filtration and activated carbon filtration.

Chemical and microbiological safety of drinking water in distribution networks made of plastic pipes

“…The main sources of primary MPs in drinking water sources are industrial plants, especially those producing plastics, the decomposition of plastic litter and associated surface runoff and leachate from landfills, abrasion from vehicle tyres during driving, and discharges of untreated and treated wastewater (Boucher & Friot, 2017;da Costa et al, 2016;Eerkes-Medrano et al, 2015;Mason et al, 2016;Mintenig et al, 2017Mintenig et al, , 2019. From domestic and industrial wastewater, MP can be partially removed in wastewater treatment plants (WWTPs), but only the largest fragments are effectively eliminated, while smaller particles freely pass through all treatment stages, representing an undesirable admixture of treated wastewater (up to several thousand particles per m 3 of treated wastewater) (da Costa et al, 2016;Fortin et al, 2019;Leslie et al, 2017;Mason et al, 2016;Mintenig et al, 2017Mintenig et al, , 2019Novotna et al, 2019;Talvitie et al, 2017;Velasco et al, 2022).…”

“…Studies conducted at treatment plants have shown that the key to reducing the content of primary plastics in drinking water is the appropriate choice of process line (Novotna et al, 2019;Pivokonsky et al, 2018;Pivokonský et al, 2020;Velasco et al, 2022). The degree of microplastic removal achieved during water treatment ranged from 70% to 83%, with the highest degree of reduction achieved in multi-stage process trains including, for example, coagulation/flocculation, flotation and filtration, and GAC filtration (Chae & An, 2017;Mintenig et al, 2017Mintenig et al, , 2019Novotna et al, 2019;Pivokonsky et al, 2018;Pivokonský et al, 2020;Velasco et al, 2022;Zhao et al, 2014). Unfortunately, in addition to the so-called primary MP, derived from raw water, the presence of secondary MP has also been reported in drinking water.…”

A Path to a Reduction in Micro and Nanoplastics Pollution

“…Most MP are consumed via drinking water and food. Since most water treatment plants are unable to remove NP and most of the finer MP, they are found in drinking water, a significant exposure pathway [ 45 , 46 , 47 , 48 , 49 , 50 ]. Zuccarello [ 51 ] showed MP (<10 μm) associated to plastic water bottles, another source of drinking water.…”

Analysis of bamboo fibres and their associated dye in the parasite-host dynamics of freshwater fish

“…A drop of each bre water was then viewed under a compound microscope at 40x magni cation, and the number of bres counted on days 1, 3, 5 and 7 of soaking. This was repeated 10 times per bre treatment to calculate the average number per 1 mL, which were then all diluted to 700 bres/L, equivalent to levels found in some natural systems (Carr, 2017;Velasco et al, 2022). The reactive black dye, obtained from Sigma-Aldrich (Merck), is analogous to the setazol black SDN dye previously con rmed by BAM Bamboo to be used during manufacture of bamboo clothing products.…”