The managing operators in Germany considered several suppliers – only Evoqua Water Technologies UV systems with an integrated control unit and from a single source met theier requirements. Thus, in Echthausen five Barrier® M UV systems were installed. This unit encloses medium pressure lamps and is DVGW certified, which is approved for the disinfection of potable water in Germany.
The UV systems, installed in May 2010, are operated in parallel, at the end of the water treatment. This means high safety for the disinfection – even if one unit fails. They have an average of 2,200 (9,700 US gpm) and a maximum throughput of 4,000 cubic meters of water per hour (17,600 US gpm). Each plant can be separately controlled to match requirements. The continuously variable control of the intensity of irradiation delivers exactly the required “dose”. Electronic control ballasts ensure high efficiency: combining the safest possible disinfection with energy-saving operation.
The Simatic® PCS7 process control system is used to control the plants. This enables the UV disinfection stage to be seamlessly integrated into Wasserwerke Westfalen‘s overall control concept, which is also based on PCS7. The peripheral equipment is connected by ET200 signal modules and communications via Profibus® protocol are also integrated. The UV plants can be operated the WinCC® HMI system from the local Echthausen works control center or from the control center in Hengsen.
The Wasserwerke Westfalen anticipate they will reduce their annual consumption of chlorine dioxide by 20 tons. In the following years the other water works facilities will be upgraded and rebuilt in the same way.