60 manholes, 10-year warranty, 0 defects
In 2007, a total of 60 manhole structures in the Eifel municipality of Hellenthal-Hollerath were rehabilitated as part of an extraneous water remediation measure using the KS-ASS technology from Hermes Technologie along with the corresponding Ergelit dry mortars. Ten years later, the results remain thoroughly impressive and without complaint.
Prior to the project, the engineering firm Linscheid Ingenieure GmbH based in Schleiden handled the technical planning. The execution was entrusted to Katec-Kanaltechnik Müller & Wahl GmbH & Co. KG from Junkerath—a company with many years of experience in the trenchless repair and renovation of sewers and structures.
The manholes scheduled for rehabilitation exhibited significant leaks and were exposed to heavily pressing groundwater. Because the damage extended throughout the entire manhole structure, a full-surface mineral coating was chosen. Concerns regarding the adhesion of the coating mortar were taken seriously; consequently, the project was technically supported and monitored by IKT in Gelsenkirchen and Abwasserberatung NRW.
Surface Preparation
The condition of the substrate was the decisive factor in selecting the cleaning system. Due to varying structural conditions and differing concrete qualities, the decision was made to use ultra-high-pressure water cleaning utilizing the TSSR system from Hermes.
This involved fully automated manhole cleaning at pressures of up to 400 bar. The objective was to create a sufficiently rough and load-bearing surface—the fundamental prerequisite for a permanently adhering mineral coating.
To achieve an optimal surface profile, the HDS jet method from Hermes Technologie was additionally deployed. The combination of the ultra-high-pressure water jet and matched abrasive material ensured that the surface preparation met the highest technical requirements and formed the basis for a long-lasting, durable rehabilitation.
Preparatory Measures
Before the final mineral coating could be applied using the KS-ASS technology and the Ergelit-KS1 product, further preparatory work was necessary.
This was carried out manually and included pipe connections for inlets and outlets, sealing against pressing rainwater ingress, and reprofiling the channels. In addition, broken-out areas and defects were partially pre-coated.
Exclusively mineral products from Ergelit were used for all preparatory measures.
Coating using the KS-ASS Method
The final step of the rehabilitation was the fully automated mineral coating of the manholes using the KS-ASS technology from Hermes Technologie.
The Ergelit-KS1 was continuously prepared in a continuous mixer and then applied inside the manhole using a special centrifugal motor unit. Due to the high impact energy combined with numerous lifting movements of the centrifugal motor, a particularly dense and homogeneous coating was created, even on uneven or textured surfaces.
A key advantage of this method, alongside the high coating quality, is occupational safety: no employee needs to be inside the manhole during the coating process. Efficiency, quality, and safety go hand in hand here—one of the reasons why Katec Kanaltechnik Müller & Wahl GmbH has relied on this system for many years.
The Acceptance Inspection
The work was completed in July 2007. Exactly ten years later, in August 2017, a re-inspection of the rehabilitated manholes was conducted.
The result was unequivocal: no defects whatsoever could be found.
For the client, this confirmed the importance of professional planning, the selection of experienced partners, and quality-assured execution. The interplay between the construction company, the process technology from Hermes Technologie, and technical supervision proved to be a sustainable success factor—both technically and economically.
