The problem of the release of microplastic particles from polyester textiles is a topic that attracts the attention of researchers from various fields of science. This work was done in field of textile technology, where the modification of polyester fabric with alkaline hydrolysis and coating of chitosan was investigated in order to evaulate the effects of treatments on composition of effluents that originate from washing process. Treatment with chitosan was preceded by alkaline hydrolysis in two variations, without and with addition of cationic surfactant. An analysis of mechanical and physico-chemical properties was carried out on untreated, alkaline hydrolyzed and chitosan-treated fabrics in order to assess the degree of surface modification. On polyester fabrics before and after modification and cyclic washing with a standard detergent at 60°C, analysis of the surface, peeling, tensile properties, staining test on chitosan, moisture transfer and touch properties were performed. Collected effluents after 5 and 10 washing cycles were characterized by parameters: pH, conductivity, turbidity, total solid matter, total dissolved matter, total suspended matter, chemical oxygen demand and biochemical oxygen demand. After membrane filtration of the thus collected effluents, the resulting filtrates were analyzed by measuring pH, conductivity, turbidity, chemical and biochemical oxygen demand. The filter cake was characterized by gravimetry and microscopy coupled with Fourier transform infrared spectroscopy (FTIR). Almost all implemented methods and measurement parameters showed that alkaline hydrolysis of polyester fabric is a sufficient preparatory phase for chitosan coating and it is not necessary to add cationic surfactant as promoter in the pretreatment process. On the basis of the obtained indicators of the degree of loading of effluent and filtrate, it can be concluded that alkaline hydrolyzed polyester fabric chemically and biochemically burdens them more than pristine and chitosan treated sample as well. The chemical and biochemical degree of loading of effluents and filtrates from chitosan treated alkaline hydrolyzed polyester fabric is higher compared to alkaline hydrolyzed polyester fabric with cationic surfactant. The biochemical loading of these effluents confirms the fact that chitosan is gradually released and the release dynamics depends on the degree of pretreatment. The glass fiber filter surface of filter cake obtained from chitosan treated polyester samples has a less fibrillar character, which can be attributed to the chitosan particles released from the surface of the polyester fabrics in the washing process, rather than the polyester fabric particles. Chitosan coated on alkaline hydrolyzed polyester fabrics can protect the fabric and reduce the release of fibrils, oligomers and other forms of textile origin in the washing process. The microscopy coupled with FTIR has a good potential for identifying the chemical composition of released particles compared to other physico-chemical methods applied in this research.