The wastewater treatment plant Niedernhausen has two combi tanks which have been equipped with Passavant® scraper technology for circular tanks 20 years ago. The scrapers are made of bent aluminum profiles and have separate, advanced running arms for the floating sludge removal. For winter operation, snow removal units and dosing stations for de-icing agents were installed to enable the scraping operation.
These should be shut down, disassembled and the scraper should be modified, so that a safe winter operation is ensured.
The scraper bridges and, for the first time, the precursor bridges have been installed on rail systems, which guarantee a safe year-round operation via rack-and-pinion drives.
For this purpose, the old, fully-rubberized driving units were dismantled and replaced with new, maintenance-friendly stainless steel units with track rollers and pinions.
The reconstruction was carried out with flooded tanks, in order to keep the failure time as low as possible.
