The occurrence of microplastics in wastewater and the possibilities of using separation methods to reduce this contamination at the wastewater treatment plant

Microplastics are small pieces of plastic that accumulate in all elements of the. They are created as a result of fragmentation of larger pieces of plastic or they are introduced into the environment as primary microplastics. Due to their small size, microplastics are considered to be bioavailable for organisms at all trophic levels. Their structure makes them susceptible to the adhesion of organic pollutants and the leaching of substances considered to be toxic. In this way, microplastics became a serious threat to the aquatic environment, and thus to the organisms living in it and to the further trophic levels. At present, it is little known to what extent treated and discharged sewage affects the accumulation of microplastics in the environment and how these pollutants behave during transport through wastewater treatment plant (WWTP) facilities. The study showed that the treatment plant contributed to the removal of microgranules. However, the amount of microfoils and microfibers increased in the subsequent stages of the technological process. Although WWTPs use multi-stage wastewater treatment technologies, they are not properly designed to remove microplastics, and WWTPs are reported as an important source of microplastics in water. One of the solutions to change this is the use of specific solutions represented, among others, by separation methods, such as tertiary wastewater treatment in integrated wastewater treatment systems. Therefore, tests were carried out to identify microplastics in wastewater at various locations in the wastewater treatment process at the WWTP. Then, the test results were used to select separation methods that would allow reducing the number of microplastics at individual stages of the technological process, in particular at the outflow from the WWTP. The currently used methods of municipal wastewater treatment are insufficient. Therefore, one of the aims of this publication is to present the possibilities of using other, additional and more effective technologies.