Im Rahmen dieser Diplomarbeit wurde das Berliner Abwassersystem hinsichtlich einer Abflusssteuerung untersucht. Auf Grundlage des Merkblattes DWA-M 180 wurde zunächst die formale Bewertung des Steuerungspotenzials des Berliner Mischsystems durchgeführt. Weiter wurde für Niederschlagsereignisse des Jahres 2003 eine statische Bilanzierung bezüglich anfallender Wassermengen und vorhandenem Speichervolumen aufgestellt. Anhand von ausgewählten Ereignisse wurden dann für verschiedene Szenarien die Auswirkungen einer geänderten Förderstrategie untersucht. Im Vordergrund standen eine gleichmäßige Nutzung der Systemkapazitäten, die Verringerung von Mischwasserentlastungen und die Reduzierung des Mischwasserabflusses zur Kläranlage.

Since the 1970s, we have known about real-time control of urban drainage systems. However, global real-time control strategies still show a lack of implementation for large drainage systems of high complexity. In Berlin, Germany, a city of 3.5 million inhabitants covering an area of around 900 km2, the demand for enhanced protection of the environment and growing economic pressure have led to an increasing application of control assets and concepts within the sewage system. In the framework of the project "Integrated Sewage Management", the possibilities of a global and integrated control strategy for the Berlin system are examined. The paper is focused on the historical concept and design of the sewerage and the further improvement towards an environment-oriented system that builds the basis for today's considerations. The operational method and functionality of local regulators that have already been implemented are described. Further-more, the model-based methodology for the analysis of the system and the development of global control concepts, as well as the results of system analysis, are stated. On the basis of model simulations, it is shown that a global coordination of pump stations can lead to a reduction of sewer overflows, and consequently to an enhanced water protection.

Real-time control of urban drainage systems allows activating capacities of storm water storage and wastewater treatment that were not used before. The historically developed structure of the Berlin combined sewerage, along with its aforementioned properties, allows per se a systematic management of the sub-systems. In the course of rehabilitation works the implementation of local regulators already opened additional storage reserves. Additionally, the potential of global control concepts for sewerage, pump stations and treatment plants is studied within the framework of the project “Integrated Sewage Management” to increase the systems efficiency. Especially, a coordination of the currently locally controlled pump stations entails a reduction of sewer overflows and hence an enhanced protection of the environment. For the catchment of wwtp Berlin-Ruhleben an integrated model of the collection system, pump stations, pressurised mains and the wwtp itself has been built up in order to evaluate different scenarios of global pump station control in comparison to a local control scenario (reference). Special attention was paid to the discharges from CSOs. Due to the high dynamic of these events and the high fraction of biodegradable organic substrate within the effluents, the impact on the water body over this path plays an important role. Concerning CSOs a maximum reduction of 14 % (COD load) and 20 % (TKN load) could be achieved. In conclusion it can be stated that a reduction of total emissions from the sewage system can be achieved by operating the pump stations in a global control mode. Furthermore, the main improvement can be observed for the discharges from combined sewer overflows.

Simulation tools help develop an integrated approach for Berlin’s combined sewage system in which sewage overflows pose risk to groundwater and surface water quality

The paper introduces an algorithm for a level dependent real-time control of sewage pump stations and states results from its evaluation based on a spectrum of simulations for three different catchments of the Berlin drainage system. The objective of the control function is to smooth the delivery of the pumps towards the wastewater treatment plant during storm weather events by throttling the flow and implicitly activating inline retention capacities of the sewer networks. The article comprises the definition and functioning of the control concept as well as operational constraints and boundary conditions and the derivation of optimal control parameters. The simulation-based evaluation of the concept shows that it is possible to manage available inline storage volume by applying the control function. However, only if an adequate retention volume of around 50.0 m³/ha Aimp or more is available a significant improvement of the flow characteristic towards the wwtp is possible.

Due to the sensitive situation of watercourses in the urban area of Berlin the water authorities have set special conditions for discharge especially from combined sewer overflows. To meet the legal requirements a central task is to reduce the pollutant load discharged into receiving waters and for this purpose the intelligent utilisation of the available capacities of the entire waste water system. Measures of local real-time control have already been implemented in the Berlin drainage system. This paper is focusing on the potential of an additional superior global control concept. Comparative simulations for three interconnected subsystems are carried out to evaluate different operational alternatives.