Occurrence of microplastic in municipal wastewater sludge

The objectives of this thesis include: following a simple procedure of detecting and identifying microplastic in sludge samples to determine the amount and characteristics of microplastic in Mikkeli municipal wastewater sludge and comparing the results with literature findings. The method implemented would then be concluded if suitable for beginner researchers or not. Two types of sludge were involved: conventional activated sludge (CAS) and membrane bioreactor (MBR). The wet samples were extracted and dried, then inspected under microscope. It was found that there were 14 and 18 microplastic particles per gram dry weight in CAS and MBR, respectively. MBR was found to be more efficient in removing microplastic. Most of these microlitter was fibrous and visually identified to be polyester and polyamide. The results are in agreement with previous studies on the topic. The experimental method followed was found to produce some confusing results and was determined to be more suitable for researchers much more experienced with microplastic rather than beginners who are new to the subject.