Removal efficiencies of microplastics of the three largest drinking water treatment plants in Bangladesh

Muhammad Saiful Islam; Zahidul Islam; A H M Shofiul Islam Molla Jamal; Nasima Momtaz; Sadia Afrin Beauty

doi:10.1016/j.scitotenv.2023.165155

Removal efficiencies of microplastics of the three largest drinking water treatment plants in Bangladesh

Sci Total Environ. 2023 Oct 15:895:165155. doi: 10.1016/j.scitotenv.2023.165155. Epub 2023 Jun 26.

Authors

Muhammad Saiful Islam¹, Zahidul Islam², A H M Shofiul Islam Molla Jamal³, Nasima Momtaz⁴, Sadia Afrin Beauty⁵

Affiliations

¹ Fiber and Polymer Research Division, BCSIR Laboratories Dhaka, Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka 1205, Bangladesh. Electronic address: msaifulislambcsir@gmail.com.
² Fiber and Polymer Research Division, BCSIR Laboratories Dhaka, Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka 1205, Bangladesh.
³ Institute of National Analytical Research & Service (INARS), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka 1205, Bangladesh.
⁴ Biological Research Division, BCSIR Laboratories Dhaka, Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka 1205, Bangladesh.
⁵ Saidabad Water Treatment Plant, Dhaka Water Supply & Sewerage Authority, Dhaka 1204, Bangladesh.

PMID: 37379932
DOI: 10.1016/j.scitotenv.2023.165155

Abstract

Drinking water treatment plants (DWTPs) are intended to provide safe water to the municipality, typically by treating surface waters from rivers, lakes, and streams. Regrettably, all of these water sources for DWTPs have been reported to be contaminated by microplastics (MPs). Hence, there is an urgent need to investigate the removal efficiencies of MPs from raw waters in the conventional DWTPs anticipating public health concerns. In this experiment, MPs in the raw and treated waters of the three major DWTPs of Bangladesh, having different water treatment processes, were evaluated. The concentrations of MPs in the inlet points of Saidabad Water Treatment Plant phase-1 and 2 (SWTP-1 and SWTP-2), which share a similar water source of the Shitalakshya River, were 25.7 ± 9.8 and 26.01 ± 9.8 items L^-1. The third plant, Padma Water Treatment Plant (PWTP) utilizes water from the Padma River and had an initial MP concentration of 6.2 ± 1.6 items L^-1. The studied DWTPs, with their existing treatment processes, were found to reduce the MP loads substantially. The final MP concentrations in treated waters of SWTP-1, SWTP-2, and PWTP were 0.3 ± 0.03, 0.4 ± 0.01, and 0.05 ± 0.02 items L^-1 with the removal efficiencies of 98.8, 98.5, and 99.2 %, respectively. The considered size range of MP was 20 μm to <5000. Fragments and fibers were the two predominant MP shapes. In terms of polymer, the MPs were polypropylene (PP, 48 %), polyethylene (PE, 35 %), polyethylene terephthalate (PET, 11 %), and polystyrene (PS, 6 %). The field emission scanning electron microscopy-energy dispersive X-ray spectroscopy (FESEM-EDX) revealed the fractured and rough surfaces of the remaining MPs, which were also found to be contaminated with heavy metals, like lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), copper (Cu), and zinc (Zn). Hence, additional initiatives are required to remove the residual MPs from the treated waters to safeguard the city dwellers from potential hazards.

Keywords: Drinking water treatment plant; Microplastics; Public health; Removal efficiency; Surface water.

MeSH terms

Bangladesh
Drinking Water*
Environmental Monitoring / methods
Microplastics
Plastics
Water Pollutants, Chemical* / analysis
Water Purification*

Substances

Microplastics
Plastics
Drinking Water
Water Pollutants, Chemical