The joint DynaWater4.0 project aims at exploiting the potential of digitisation in industrial wastewater management. Its goal is the digital connection of industrial production plants and wastewater treatment plants in order to action model-based, demand-dependent and dynamic operation of wastewater treatment plants. EnviroChemie is upgrading an existing Split-O-Mat® system into a fully integrated DynaWater4.0 demonstration system. The wastewater treatment plant obtains data in realtime from the production plant. This data, together with online measurement data, is used by a digital twin to model the kinetics of the wastewater treatment and derive the optimum wastewater treatment operation mode. The efficiency of this digital twin is demonstrated in the live operation of the DynaWater 4.0 project.