Hamburg - Germany
From October 2012 to May 2013, the municipal utility Hamburg Wasser (HW) [urban sewerage and sanitation] had a DN 3000 masonry interceptor in the Hamburg sewerage network repaired. Right from the tendering phase, our ombran unit was able to impress the planning engineers. Its speciality repair products were thus extensively used for the successful implementation of this, the largest single project in ombran’s history.
The origins of the public sewerage system in the Free and Hanseatic city of Hamburg extend back into the middle of the 19th century. A large portion of the sewerage structures were constructed in the form of masonry conduits, most of which have continued to perform well through to today. The only signs of significant wear and tear are in the mortar joints which are frequently found to be crumbling and prone to leakage. And it was this kind of damage that led the Hamburg sewerage and drainage utility Hamburg Wasser (HW) to initiate a full repair of a 400 metre long section of the “Kuhmühlenstammsiel” interceptor sewer in the centre of the city. The difficult conditions surrounding the project presented a number of major challenges, such as the dense transport, cabling and piping infrastructure that had to be negotiated, and also poor accessibility – the manholes were up to 100 metres apart. In two rehabilitation sections totalling 240 metres in length, the main contractor Aarsleff Rohrsanierung GmbH of Röthenbach an der Pegnitz made extensive use of the sophisticated product technologies available from ombran. The unit supported the project from start to finish, additionally providing MC’s extensive repair expertise to keep the work running smoothly.
MC sets the standard
The MC product range impressed the planning engineers of HW right from the initial tendering phase. “In order to ensure that the high demands of the project could be reliably met, our product profiles and quality features were actually cited as the reference requirements,” explains Sebastian Scheffler, ombran sales representative responsible for northern Germany. Especially developed for large-area applications in walk-in sewer structures, ombran MHP-SP – a repair mortar suitable for hand trowelling, spraying and pipe spinning – was selected for reprofiling and coating more than 2,000 m² of sewer and manhole walling. The pre-sealing work was carried out with MC’s low-viscosity Konudur injection resins. These quickly foam on contact with water, reliably halting the flow of even pressurised groundwater. ombran MHP-SP, a mineral-based high-performance coating, offers an optimum combination of good workability and wide application spectrum (reprofiling and coating), while also quickly developing water resistance to allow the early re-commissioning of the rehabilitated interceptor. “Also worthy of note is the exceptional durability of the mortar, with our DySC® technology ensuring that the impermeability of the coating actually increases with service life, enhancing its chemical resistance to the toxins contained in the sewage,” explains ombran product manager Sven Meßmann.
ombran CPS also trialled
A section of the minerally rehabilitated sewer measuring around 30 metres in length was also selected to additionally trial the blue silica-based hybrid coating ombran CPS (see also MC aktiv 3/2012 where we reported on the restoration of the sewer installation at Schwanenplatz in Stuttgart (Germany) with ombran CPS). This application will enable the special coating material, which is resistant even to biogenic sulphuric acid attack, to once again demonstrate its exceptional properties.