The optimal performance of industrial processes often depends on the control over biofilm growth and distribution. Hence, we welcome contributions describing the newest methods for both biofilm monitoring and control at the biofilms 9 conference. Applications can range from drinking water and membrane processes to processes in traditional industries with water reuse (pulp and paper, food, etc.). Especially, advanced examples or cutting-edge research projects combining, for example, on-line monitoring and disinfection/cleaning strategies based on monitoring data are highly appreciated.