Due to its good characteristics and low price, the production of plastic materials has increased significantly in the last few decades. The vast majority of these materials are made for single use only, which leads to large amounts of waste. Unfortunately, most of the plastic waste is not disposed of in the right way so it ends up in the environment where it starts to disintegrate, lose its properties and break down into smaller pieces called microplastic. These tiny particles can be found in fish and underground water. In this thesis advanced oxidation, UV-C/H2O2, UV-C/S2O82-, Fenton and photo-Fenton processes are discussed as the methods of polyethylene and polypropylene microplastic removal. During decomposition of these polymers by advanced oxidation processes, the influence of oxidant concentration (H2O2 and Na2S2O8), the mass of microplastic, pH value and time of exposure to UV-C light was monitored. Photo-Fenton process was performed similarly, but in addition to monitoring the effect of H2O2, the effect of Fe2+ ion concentration was also monitored while the length of radiation exposure and mass of microplastic did not change. The Fenton process was carried out as a photo-Fenton process but without exposure to UV-C radiation. After the implementation of UV-C/H2O2 and UV-C/S2O82- advanced oxidation processes and the analysis of the obtained results, Na2S2O8 proved to be a better oxidant. proved to be a better oxidant as a higher degree of decomposition in both types of plastic polymers occurred. Also, the maximum decomposition was achieved at the maximum exposure time to radiation (90 min) with a minimum concentration of oxidant (1 mM) and vice versa, at a minimum exposure time (30 min) and maximum concentration (20 mM) due to the presence of the „Scavenger effect“. Comparing the results obtained after the Fenton and photo-Fenton processes, the photo-Fenton process in most cases proved to be more efficient, which was to be expected because UV-C radiation contributes to the formation of more radicals.