Environmental interfaces and the intelligent use of resources – raw materials, energy etc. – are often just as much a challenge to modern production facilities as the production process itself. Key factors for success are the efficient handling of raw materials, the optimal integration of WSR®-Subsystems for Water, Sludge and Rejects, the utilization of residual materials and waste water (effluent) for producing energy as well as the recirculation of clarified effluent.