Microplastics Removal Efficiencies by Non-Sewered and Sewered Wastewater Treatment Systems and Potentials of the Algal-Bacterial System

Document Type : Original Research Paper

Authors

1 Department of Civil Engineering, Thammasat school of Engineering, Thammasat University, P.O.Box 22, Klong Luang, Pathum thani, 12121, Thailand

2 Department of Water Resources and Environmental Engineering, School of Engineering and Technology, Asian Institute of Technology, P.O.Box 4 , Klong Luang, Pathum thani, 12120, Thailand

10.22059/poll.2025.388116.2726

Abstract

Wastewater treatment systems (WWTSs) are a major source of microplastics (MPs) in the environment. In this study, the influent, effluent, and sludge samples from three non-sewered and two sewered WWTSs were analyzed. The samples were collected and filtered through two sized mesh sieves (5.6 and 0.3 mm). The retained residues were pretreated and observed under a digital microscope for their abundance and characteristics. Results showed that MPs concentrations in the influent of the non-sewered and sewered WWTSs were 3 – 6 and 1.6 – 2.0 particles/L, respectively, with the removal efficiencies ranging from 83 – 94 and 74 – 78 %. Due to their higher MPs loading rates and shorter HRT, the sewered WWTSs had less efficient in MPs removal than the non-sewered WWTSs. Polyethylene terephthalate (PET) was the most polymer type found in all samples, while fiber accounted for about 70-95% of all samples. The results indicated that the MPs in wastewater could be partially removed and accumulated with the sludge in both non-sewered and sewered WWTSs. To minimize the impacts of MPs contained in the treated effluents, the results of the biosorption experiments showed the potential of the algal-bacterial system in which the operation time of 96 h had the highest biomass production of 220 mg/L and the MP removal efficiency and capacity of 88-90% and 587 mg/g, respectively. Because the algal-bacterial system operating at 96 h was effective in COD, TN and TP removal, it is strongly recommended for use in both MP removal and wastewater treatment. 

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Main Subjects


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