Prof. Dr.-Ing. Marko Zlokarnik studied chemical technology and obtained his Ph.D. in process engineering from RWTH Aachen University and was active in process engineering R & D at Bayer AG, Leverkusen, for 35 years. His work involved reaction apparatus design for chemical production facilities, which, apart from elucidation of reaction kinetics, also brought fundamental work on mixing technology and modelling with it. In the 70s, he developed an especially efficient biological wastewater treatment (Bayer tower biology with flotative removal of activated sludge). From 1970 to 1990, he taught similarity theory at the Technical University of Clausthal-Zellerfeld, then held the Bayer Foundation Chair of Chemical Technology at the University of Cologne. He served as chairman of the VDI-GVC committee on biological process engineering from 1979 to 1988, and in the course of his career has published 60 books, 20 patents, and 5 books, receiving the Otto Bayer Gold Medal and the VDI Honorary Medal for his work.