Microplastic Contamination in Landfill Leachate and Surface Water: Assessment of Wastewater Treatment Efficiency at the Nonthaburi Waste Management Center, Thailand

Microplastics (MPs), plastic particles smaller than 5 mm, have emerged as a significant environmental concern, particularly as contaminants originating from landfills. Landfills can serve as a major source of MPs, potentially releasing them into surface water through leachate. This study aims to investigate the contamination of MPs in leachate and surface water, as well as to evaluate the efficiency of landfill wastewater treatment in removing these particles. The research was conducted at the Waste Management Center of the Nonthaburi Provincial Administrative Organization, Thailand, with samples collected in June 2023. Sampling included two leachate sources, influent and effluent from the treatment system and surface water. The abundance and characteristics of MPs in each sample were analyzed. Results indicated a significant presence of MPs in leachate, with an average concentration of 173.98 pieces/L, while concentrations in influent, effluent and surface water were 38.40 pieces/L, 10.80 pieces/L and 11.33 pieces/L, respectively. MPs in all samples were predominantly in the size range of 16-100 µm, corresponding to 71.28-93.75% of the total particles. Polypropylene was the dominant polymer in leachate (69.66%) and effluent (48.94%), whereas acrylate copolymer (96.53%) and polytetrafluoroethylene (44.12%) were the major types found in influent and surface water, respectively. The wastewater treatment system of the landfill demonstrated an overall removal efficiency of 71.88% for MPs in leachate. These findings highlight the extent of MP contamination in landfill environments and the importance of improving treatment processes to mitigate their release into surrounding ecosystems.