A1 Journal article (refereed)
Optical Monitoring of Microplastics Filtrated from Wastewater Sludge and Suspended in Ethanol (2021)

Asamoah, B. O., Salmi, P., Räty, J., Ryymin, K., Talvitie, J., Karjalainen, A. K., Kukkonen, J. V. K., Roussey, M., & Peiponen, K.-E. (2021). Optical Monitoring of Microplastics Filtrated from Wastewater Sludge and Suspended in Ethanol. Polymers, 13(6), Article 871. https://doi.org/10.3390/polym13060871

JYU authors or editors

Publication details

All authors or editors: Asamoah, Benjamin O.; Salmi, Pauliina; Räty, Jukka; Ryymin, Kalle; Talvitie, Julia; Karjalainen, Anna K.; Kukkonen, Jussi V. K.; Roussey, Matthieu; Peiponen, Kai-Erik

Journal or series: Polymers

eISSN: 2073-4360

Publication year: 2021

Volume: 13

Issue number: 6

Article number: 871

Publisher: MDPI

Publication country: Switzerland

Publication language: English

DOI: https://doi.org/10.3390/polym13060871

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/75025


The abundance of microplastics (MPs) in the atmosphere, on land, and especially in water bodies is well acknowledged. In this study, we establish an optical method based on three different techniques, namely, specular reflection to probe the medium, transmission spectroscopy measurements for the detection and identification, and a speckle pattern for monitoring the sedimentation of MPs filtrated from wastewater sludge and suspended in ethanol. We used first Raman measurements to estimate the presence and types of different MPs in wastewater sludge samples. We also used microscopy to identify the shapes of the main MPs. This allowed us to create a teaching set of samples to be characterized with our optical method. With the developed method, we clearly show that MPs from common plastics, such as polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), and polyethylene (PE), are present in wastewater sludge and can be identified. Additionally, the results also indicate that the density of the plastics, which influences the sedimentation, is an essential parameter to consider in optical detection of microplastics in complex natural environments. All of the methods are in good agreement, thus validating the optics-based solution.

Keywords: microplastics; plastic waste; monitoring; sewage; detectors; optical instruments

Free keywords: microplastics; sludge; wastewater; Raman spectroscopy; laser speckle pattern; transmittance; sedimentation

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2021

JUFO rating: 1

Last updated on 2022-20-09 at 15:25