Wastewater treatment plants are considered to be one of the largest sources of microplastics in the natural environment. The problem of microplastics has been widely studied in many environments. It remains a subject of the growing interest for researchers. By definition, microplastic is plastic that does not exceed 5 mm in size. There are three stages in the study of microplastics in wastewater: sampling, treatment, and the identification of microplastics. This paper aims to review the strategies for sampling microplastics in wastewater treatment plants and their laboratory treatment to isolate microplastics. The collection of samples from the wastewater treatment plant is based on two mechanisms, namely a continuous filtering and pumping system and instantaneous sampling (steel bucket, glass jar, telescopic sampling). The removal of organic and inorganic matter is carried out with the use of physical and chemical analyses. The subject of this article is the compilation of the generally available research methods on microplastics. Based on the literature analysis, conclusions were drawn regarding the recommended methods of microplastic detection.

Due to the widespread occurrence and the potential threat to the environment, plastic materials are currently a growing problem of environmental protection in the world. Plastics whit dimensions not exceeding 5 mm are called microplastics. One of the main sources of microplastics in the aquatic environment are municipal wastewater treatment plants. The paper presents the results of research on the presence of microplastics in leachate from sludge processing at a large municipal wastewater treatment plant. The leachate was divided into the leachate produced in the processes of sludge thickening and dewatering. The analysis of the isolated microplastics included a physical analysis, which focuses on determining size, shape, and color of the isolated material. The next step was the chemical identification of the microplastic, where the type of polymer of the tested material was confirmed by means of Attenuated Total Reflection Fourier Transform Infrared. Among the isolated microplastic particles, almost a half was identified as fragments, and a smaller amount was confirmed for the presence of foil, fibers, foams and granules. The identified particles were plastic materials, including polypropylene, polyethylene, polystyrene or poly(terephthalate). Based on the results of the conducted research, the mass of microplastics in leachate was characterized and determined.