Microplastics in Wastewater: A Case Study of Embu WWTP, Kenya

Wastewater treatment plants (WWTPs) can function simultaneously as a barrier and also as an entrance pathway for microplastics into aquatic ecosystem. The present study investigates the occurrence and characteristics of microplastics in the Embu, Kenya WWTP. Wastewater physicochemical parameters were measured in situ. Water samples were collected using grab sampling, filtered through a stack of sieves, and treated with H 2 O 2 catalyzed by Fe 2+ to digest organic matter. MPs were classified by visual identification and attenuated total reflection–Fourier transform infrared spectroscopy. Microplastics abundance reduced from 12.900 ± 1.296 MPs/L in the influent to 0.371 ± 0.04 MPs/L in the effluent, corresponding to an average removal efficiency of 84.1 ± 2.5%. MPs were mainly white/transparent (39.7%), with yellow‐colored MPs being rare (0.06%). The dominant morphotype was fibers (90.11%), while films were the least common (0.87%). Polymer types included polyacrylamide, ethylene vinyl alcohol, polyamide, and polyvinyl alcohol. Correlational analysis revealed a moderate positive relationship between MPs abundance, total nitrogen, and pH, suggesting a limited impact of wastewater physicochemical parameters on MPs abundances. These findings reveal that Embu WWTP substantially reduces MPs pollution and highlight the dual role of stabilization ponds as sinks and potential source of MPs to the environment.