DNN projectional observer for advanced ozonation systems of complex contaminants mixtures⁎This work is partially supported by CPeR DATA "ControlHub", ANR DIGITSLID 18-Ce40-0008, the Government of Russian Federation (Grant 08-08), the Ministry of education and Science of Russian Federation (Project 14.Z50.31.0031), and Russian Foundation for Basic Research (Project No. 19-08-00535). Issue 2 (2020)