Copenhagen is one of the few cities in the world where you can safely bathe in the harbour. This is largely owing to the extension and upgrading of the sewer system that has taken place in the recent years. Among other things realized through closing of many of the outlets where combined sewer overflow was previously discharged in connection with heavy rain. Instead, large tanks have been set up for collection and delay of the wastewater, and control of sewer system and wastewater treatment plants has been introduced.
Krüger has been involved in many of the projects executed in Copenhagen, and similar projects all over Denmark.
In Copenhagen, Krüger has executed hydraulic model predictions to determine the necessary pipe dimensions and tank sizes, and subsequently designed many of the plants.
When designing the tanks, Krüger has focused on:
- Creating a modern working environment through implementation of automated flushing systems to ensure that the operators do not get in contact with wastewater
- Avoiding nuisances for the surrounding environment, neighbours, etc. which makes heavy demands with regard to aesthetics, odour and noise
- Ensuring proper treatment of the water that – in rare cases – still may need to be discharged directly to waters, which among other things takes place by means of drum sieves.
The STAR SewerControl is currently being implemented for the integrated control of sewer systems and wastewater treatment plants. STAR SewerControl ensures an optimum use of the total tank volume through control of gates, pumps, etc., so that the total discharge of untreated stormwater and wastewater is minimised. Furthermore, the system ensures that the discharge of untreated stormwater and wastewater that cannot be avoided is directed to areas where the environmental damage is minor.
The control system also comprises a radar-based prediction of inlet flow to the wastewater treatment plant, and on this basis, the wastewater treatment plant’s rain control is able to start up in good time before the critical water volumes reach the treatment plant.