Microplastics occurrence in a municipal wastewater treatment plant: a case study using Raman spectroscopy and morphological analysis

ABSTRACT

Microplastics (MPs) in wastewater treatment plants (WWTPs) are a significant route for plastic pollution of aquatic environments. This work employed multidisciplinary analytical methods to investigate the presence, type, and seasonal variation of MPs in a WWTP. Influent and effluent samples at a WWTP during the winter and spring seasons were analyzed for MPs using Raman spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy analysis. Results demonstrated the presence of polypropylene, polyethylene, and accompanying materials of polystyrene, polyamide, and polyvinyl chloride. Additionally, morphological analysis confirmed the presence of fibers with some random-shaped fragments and film-shaped particles. There was marked seasonal variation, with a concentration of 7,532 ± 429 MPs/m3 during the spring season, compared with 3,158 ± 214 MPs/m3 during the winter season (p < 0.001). Removal rates of 87.7 and 85.3% during the spring and winter seasons could be achieved. This study provides essential baseline data to develop targeted approaches and inform environmental policy on managing MP pollution in urban water systems.