## 3 Conclusions  
Research on the use of polymer membranes to counteract the risk of environmental contamination is undergoing constant development due to the possibility of using this technology to purify a whole range of surface and ground waters as well as the soil environment, which is particularly important from the point of view of environmental protection. In addition, the ability to recover valuable natural resources draws attention to important economic aspects. Increased interest in the use of this type of technology is also the result of the growing environmental awareness of societies. Polymer membrane processes do not require dosing of chemicals and do not transform pollutants, saving resources, energy, and human labor. In view of the above facts, there is a continuous and intensive development of research on obtaining more effective methods, allowing the modification of polymer membranes, and at the same time changing their physicochemical properties.  
There are many advantages of using polymer membranes in environmental protection. First of all, compared to many other traditional techniques and processes, e.g., distillation, polymer membranes use less energy, as well as fewer raw materials and operating personnel. It should also be noted that the use of membrane techniques by industry may contribute to increasing resources (mainly water) and the reduction of the amount of solid and liquid waste generated in the production process, and thus allows for obtaining tangible economic benefits. Water purified by membrane processes can return to production and does not remain in the soil and groundwater, poisoning these resources.  
In conclusion, the use of polymer membranes seems to be justified due to many factors, chiefly technical and economic (at least relatively low operating costs), as well as the properties of their easy adaptation in the environment. The introduction of membrane techniques into widespread use is considered to be the right step in the field of environmental protection. It is also assessed that these technologies in water and soil treatment applications are currently among the best available technologies and that they make a beneficial contribution to environmental sustainability. Some of them require relatively high investment outlays. The applicable legal regulations and economic instruments of environmental policy should support the use of these techniques in industry and the economy. For example, the penalties related to the direct introduction of pollutants into the environment are high and it remains necessary to invest in environmental protection, including investments in polymer membrane techniques.  
Conceptualization, A.R., M.Z., K.C., L.P. and L.J.; writing--original draft preparation, A.R., M.Z. and K.C.; writing--review and editing, A.R., M.Z. and K.C.; project administration, L.P. and L.J.; funding acquisition, L.P. and L.J. All authors have read and agreed to the published version of the manuscript.  
This work was supported by a subsidy for the research potential of the Scientific and Research Center for Fire Protection--National Research Institute, project 057/BS/MNiSW ''Research methods of fire vehicles and firefighting tools and equipment''.  
Not applicable.  
The authors declare no conflict of interest.