Herford, a town with approximately 70,000 inhabitants in North Rhine- Westphalia, Germany, is located at the confluence of the Aa and Werre rivers. It has a sewer network of about 500 kilometers which is about 50% separated, with the rest operating as combined.
The challenge
Inconsistent behavior and utilization of control structures was observed for past rainfall events. The municipality decided that an optimized network control system should be implemented to better utilize existing retention volumes, coordinate them effectively and reduce water pollution.
The solution
In 2021, Herford utility joined forces with Xylem to conduct a pilot study in a drainage area containing six combined sewer structures. A model-based analysis by Xylem proved that a Real-Time Decision Support System (RT-DSS) could help the utility significantly reduce combined sewer overflows during rainfall events, without modifying the existing infrastructure.
Following these promising results, the utility decided to implement the Xylem Vue application Unified Network Management in the subcatchment area initially optimizing the operation of four sewers. The application continuously processes sensor data, monitors dynamic conditions in the individual basins in real time, and optimizes the management of the network’s available storage capacity.
This solution provides and displays status and control recommendations for the entire system from a single location. These recommendations are automatically forwarded to the control system as target values, while still enabling operators to manually intervene and control individual systems at any time.
The results
Since implementing Xylem Vue in January 2024, Herford has reduced combined sewer overflows in the target drainage area by approximately 15% without modifying their existing infrastructure.
The municipality has already initiated the integration of three additional basins, encouraged by these positive results and the system’s easy scalability.