Catastrophes, fractals and chaos in geoengineering and water treatment systems Igor Yeremeyev, Alina Dychko, Volodymyr Kyselov, Natalya Remez and Ievgen Khlobystov E3S Web Conf., 280 (2021) 02009 Published online: 30 June 2021 DOI: 10.1051/e3sconf/202128002009