Development and application of innovative technologies for toxicological and hygienic security of treated wastewaters using materials releasing hydroxyl radicals, or zerovalent iron nanoparticles (NZVI). The proposed solutions will aim to replace currently used chlorinating technologies, which produce substances harmful to the environment (e.g. AOX). The project will be focused on removal of endocrine disruptors, microbial contamination of water and phosphorous, with subsequent research of ecotoxicity of secured water. Hygienically and toxicologically secured effluents from municipal WWTPs of the size between 500 - 10 000 PE (on which the project is focused) can also guarantee quality assurance standards and quality of discharge into receiving waters, and to serve as a valuable source of water that can be recycled in a wide range of other applications.