After 25 years of operation: efficient HUBER Rotary Drum Fine Screen ROTAMAT® Ro2 replaces the STEP SCREEN at the Schnaittachtal sewage treatment plant
The Schnaittachtal sewage treatment plant has been in operation for almost 50 years and currently employs six male and one female sewage treatment operators. For many years, the plant has relied on HUBER machines for mechanical wastewater treatment, such as the HUBER Screenings Wash Press WAP® Ro4-OS, HUBER Screw Conveyor Ro8 and HUBER STEP SCREEN. These have now been replaced by a new HUBER Rotary Drum Fine Screen ROTAMAT® Ro2 size 1600 with a 3 mm bar spacing, a HUBER Screw Conveyor Ro8 T and HUBER Screenings Wash Press WAP® SL.
A quarter of a century in service
In service since 1999, the STEP SCREEN, which was well known at the time for its mechanical efficiency, was taken out of service in August 2024. After this long operating period of around a quarter of a century, the separation performance declined, partly due to age and partly due to changes in the wastewater inflow conditions, such as flushing loads and changes in screenings, so that the downstream processes could no longer run optimally.
Increased efficiency thanks to modern screening technology
The new screening system is a more efficient solution. It is also easier to maintain. Consequently, the STEP SCREEN offered a low financial return. Due to the load it was subjected to, the STEP SCREEN was estimated to have a service life of 15 to 20 years. The regional characteristics near Neunkirchen am Sand already provide an indication of what has also contributed significantly to the wear and tear of the screen.
Significant relief for the entire plant
The entire plant has been significantly relieved thanks to the new HUBER Rotary Drum Fine Screen ROTAMAT® Ro2, which has decreased the loads in the other areas of the wastewater treatment plant. This is because the new screen's high efficiency makes it much easier to retain and safely remove even the smallest residues from the wastewater stream. This is also reflected in the amount of screenings now being produced. It has doubled compared to the old STEP SCREEN.
Structural challenges successfully overcome
Initially, there were space-related challenges involved in replacing the system. This was due to the space required for the new screen, which is twice the size of the STEP SCREEN. Instead of 80 cm, 1.6 m was now required, as a wider channel was needed for the system. The conversion, including the removal of the main screen, the installation of the new channel and the reinstallation, was carried out quickly in just four weeks.
Precise planning and project management are the keys to success
The fact that this challenging conversion, involving the redesign of the entire inlet area and the replacement of the sewage lifting screws, could be completed within this time frame was also made possible by the perfect planning and project management by the commissioned engineering firm Miller from Nuremberg.
We would like to thank everyone involved in the project, especially the employees of the Schnaittachtal sewage treatment plant, for the trust they placed in us and for the excellent cooperation.
