Identification, Quantification, and Evaluation of Microplastics Removal Efficiency in a Water Treatment Plant (A Case Study in Iran)

Abstract

Microplastics (MPs) are among the emerging pollutants that recently attracted the researcher’s attention around the world. These particles can absorb other chemicals, and microbial contaminants and enter them into the food chain, and environment. This study was conducted to investigate the occurrence of MPs in raw and treated drinking water and evaluate the MPs removal efficiency in a drinking water treatment plant (DWTP) in Iran. MPs particles were counted at different stages of DWTP, using a scanning electron microscope after the initial preparation steps include filtration, and chemical digestion, and then examined for the nature of the particles using a micro-Raman spectrometer. The concentration of MPs in influent, clarifier’s effluent, and DWTP’s effluent were 1597.7 ± 270.3, 676.2 ± 69.0, and 260.5 ± 48.9 MPs/L, respectively. The total efficiency of the DWTP in MPs removal was 83.7%, which the clarification and filtration stage removed 57.7%, and 26.0% of total MPs, respectively. The most abundant polymers identified were PP, PE, and PET. Despite the effective removal of MPs in the DWTP, on average 2.25 × 1011 ± 4.23 × 1010 MPs are daily discharged into the water distribution system through the effluent of this DWTP.