ASSESSMENT OF PFAS CONTAMINATION AND REMOVAL EFFICIENCY ACROSS WASTEWATER TREATMENT STAGES: A QUANTITATIVE ENVIRONMENTAL STUDY

Abstract

In this study, a quantitative evaluation of microplastic (MP) contamination, antibiotic resistance gene (ARG) loads and physicochemical parameters was demonstrated through the various stages of municipal wastewater treatment plants (WWTPs). Based on the complete dataset of 100 matched influent and effluent samples from 5 treatment facilities, we investigated removal performance, morphological transformations and co-occurrence of MP and ARG. The mean number of microplastic particles found in influent wastewater was 234.43 ± 82.57 particles/L, whereas the effluent number of microplastic particles was 50.58 ± 26.28 particles/L, indicating that the removal efficiency of the total microplastic particles was 78.42% (t = 15.00, p < 0.001). Total ARG abundance demonstrated a higher mean reduction of 95.93%, falling from 620,879.90 ± 822,954.64 copies/mL in influent to 25,267.86 ± 14,997.97 copies/mL in effluent (t = 5.12, p < 0.001). The abundance of the relative ARG was 455.19% copies of 16S rRNA and reduced by 94.45% to 25.27% copies of 16S rRNA. The removal of integron class 1 integrase gene (intI1), sul1, tetA, and blaTEM was consistently high from the specific resistance targets. In the influent, the dominant morphotypes were fragments (48.0%) and fibers (32.0%), while the dominant polymer compositions were polyethylene (32.0%) and polypropylene (26.0%) and in the effluent were polyethylene (36.0%) and polypropylene (24.0%) and fragments (42.0%). Correlation testing showed a strong overall association between the log₁₀ transformed abundance of MPs and the log₁₀ total ARG copies (r = 0.851, p < 0.001). These empirical results not only quantify the combined effectiveness of standard treatment but also identify loads discharged to the environment.