It is one of the most significant wastewater infrastructure projects that has ever existed in Cologne. The new Rhine tunnel is not only a special feature because of its size, but the local conditions during its construction were also extremely challenging.
Tunnel boring machine goes for a dive
The StEB Cologne celebrated the start of tunnel construction for the new Rheindüker between Stammheim and Niehl on May 21, 2025, with a symbolic machine baptism.
Enercity is digging a 300-meter long underpass for district heating, water, and electricity
This tunnel construction project is even unusual for the experts. The energy company Enercity-Netz is digging a 300-meter long pipe tunnel under the Mittelland Canal next to the Messe Schnellweg in Groß-Buchholz.
see press report, Hannoversche Allgemeine Zeitung and Neue Presse Hannover, Feb. 2025
In Ludwigshafen am Rhein, a decommissioned subway tunnel has been repurposed.
Rust
The new wastewater relief channel will be built in the coming weeks from the Ruster Rheinweg towards Kappel.
Demanding large pipe jacking in the city center
In Wuppertal, a relief collector from the 1990s is being expanded. The location of the collector with an inner diameter of 2 m and the technical framework conditions were major challenges.
Hamburg has Trude, Henstedt-Ulzburg has Pina: Since Tuesday, the earth drill with this name has been in operation, drilling two earth tubes, each nearly one kilometer long, through which the earth cables of the 380 kV East Coast Pipeline will be laid.
As part of the conversion of the German power grid to renewable energies, the grid operator TenneT chooses underground power lines in sections to take advantage of this construction method.
Safety and quality for water protection
In Solingen, Sonntag Baugesellschaft mbH & Co. KG, Dörth, is currently constructing the collector Untenitter with a length of approximately 1,800 meters and a nominal width diameter DN 1800 in pipe jacking.
Entry into HDD technology
It is currently observed that companies traditionally at home in pipe jacking are engaging with the horizontal directional drilling method. Now the company Sunday has also invested in an HDD drilling rig. We spoke with the managing director of Sunday, Robert Himmel.
Herrenknecht technology has been used in Kehl for the crossing of the federal highway and the Kinzig with a gas pipeline.
Visible since Monday while passing by Kraftsdorf. When the shafts will be dug and how the cable will be laid under the highway.
Solingen - A new, holistic water protection concept is being implemented in the Ittertal. In order for the new collector to fulfill its task in the long term, emphasis is placed on the triad of quality, qualification, and occupational safety.
Three trenchless methods in one project
As part of the relocation of the natural gas high-pressure pipeline "Zollvereinring", the engineering office De la Motte & Partner was entrusted with the planning and the specialist construction supervision of three special structures. In addition to a mammoth find, there were several other special challenges to overcome.
Special proposals reduce the burden for people and nature
The major project Riederwaldtunnel creates a gap closure between the A 66 and the A 661 in Frankfurt over a length of 2.2 km.
Renewal in the upper Baybach Valley is progressing - Third construction phase recently started
SONNTAG Bau is celebrating its 90th anniversary this year. From a regional construction company, it has developed over the decades into a complete provider of civil engineering with a focus on microtunnelling ...
The ecological conversion of the Emscher system is one of the largest infrastructure projects in Europe, lasting several decades. SONNTAG has already realized many different construction projects for the Emscher cooperative in recent years, contributing to the wastewater freedom of the Emscher. Now the construction company was again involved in a very large, demanding construction measure.
Model project from planning to construction
At an S-Bahn station in Hamburg-Altona, a cable protection pipe system is being relocated over a length of 120 meters under the tracks. During the planning...
Pipe jacking DN 1000 - In itself, the pipe jacking in Datteln was routine for the SONNTAG construction company. Nevertheless, the measure was something special for the experienced thrust company: The installation of the thrust pipes Perfect Jacking Pipe Plus was a premiere for SONNTAG.
Infrastructure: Second construction phase of the future Newtonstraße completed / Construction work ahead of schedule
see press article: Heidelberg and metropolitan region, 20.12.2021
In Goddelau, the new canal is being laid underground with consideration for the railway line / 2.5 million euros in costs.
Construction of a canal in the protected area, conveyance work at over 30 m depth, 580 large pipes - "Wolfsbachtal collector" is a true mammoth project.
The trenchless construction of a sewage pipeline under the Enz and the Nagold on behalf of the Pforzheim city drainage (ESP) was awarded two prestigious prizes at the national and international level.
The executing construction company for the 16-million-euro project was the SONNTAG Baugesellschaft. The branch in Bingen was responsible for the underground pipe jacking in diameters of 1400, 1600, and 2200 and provided the engineering work. The Enz siphon received the “Big Project and BGreen Award” in the category of water protection.
The award is presented annually in Dubai and honors special construction measures in the fields of “construction” and “sustainability.”
The second award was the GSTT Award in Gold, which recognizes outstanding projects in trenchless construction. For the Bingen company, this was already the third GSTT award as a project partner. “A remarkable record, with which we have given ourselves a nice Christmas gift,” said the credo of the corporate group.
The GSTT Award is presented by the “German Society for Trenchless Construction and Maintenance of Pipelines.” With this, the institution aims to emphasize the versatility of the innovative technology and raise awareness of the savings compared to open construction methods. Last but not least, it is also about the environmental aspect, as the underground pipe jacking allows for a more gentle handling of nature's resources.
Source: Rhein-Zeitung, December 2011
The proud winners at the award ceremony in Dortmund: 1st from right, branch manager Bingen Alfons Bongard, 5th from right, senior construction manager Bingen Bernd Seis, and representatives of the city of Pforzheim and the engineering office.
Project Enzdüker:
36 tons heavy drill head carved 485 meters through the rock beneath the Enz.
“We are very satisfied with the progress of the work so far,” explains site manager Becker, who celebrated the 485-meter breakthrough yesterday with around 25 construction workers and engineers involved in the project at the starting point Theaterstraße.
Source: Pforzheimer Kurier, August 2011
Until the opening of the modern visitor center, there is a lot of "underlying work" to be done. These highly demanding stabilization, foundation, and concrete works are carried out by the Hunsrück-based specialized deep construction company SONNTAG headquartered in Dörth on the A 61. In addition to the actual fish exchange system above and below the weir, the team is constructing a structure for an additional water turbine.
Source: Rhein-Zeitung, August 2011
Environment Minister Margit Conrad, Dagmar Barzen, President of the Structural and Approval Directorate North, Felix Stenschke, Head of the Shipping Subdepartment, Mayor Dr. Eberhard Schulte-Wissermann, and Professor Dr. Hofmann-Göttig perform the first groundbreaking for the new fish ladder.
The construction costs for the overall project at the Mosel dam Koblenz amount to around 5.5 million euros. This also includes a visitor center and facilities for fish monitoring, which are to be completed by the Federal Garden Show 2011.
Source: Blick aktuell, April 2010
Very satisfied with the progress of the most extensive civil engineering measures of recent decades is "First City Councilor" Martin Ringhof. "So far, we have been able to achieve the set goals without any problems and also adhere to the time and especially the cost framework…
The contracted company has done a good job.
Source: Mannheimer Morgen, April 2010
Specialists are constructing a new railway overpass at night under floodlights. A drilling rig, about 22 meters high, which is being used in the Urft Valley, is operated by a tough 28-year-old construction assistant.
Source: Kölner Stadt-Anzeiger, October 2009
Sonntag Bau takes over the renovation of the walls at Konrad-Adenauer-Ufer.
...the first step is the renovation of the riverbank walls. This includes lowering the existing wall between Stresemannstraße and Rheinkavalier by one meter. This will make it easier for wheelchair users or families with strollers to access the Rhine shipping fleet without stairs. However, between Rheinkavalier and Deutsches Eck, the existing wall must be preserved from slipping. A technically demanding task. Below the water surface, a pile wall with a 1,600-ton heavy head beam must be constructed - just the right thing for the Sonntags.
Source: Rhein-Zeitung, February 2009
Praise for the company - Jopp, members of the local council, and citizens are full of praise for the company commissioned by the city this time. It is working quickly. "If we had had this company from the beginning, we would be much further along today," said the local mayor.
Source: Rhein-Main-Presse, May 2014
Precisely to the millimeter: With a sense of touch, the four-ton steel structure is installed in the underground dam structure. It went well: Danny Thom, project manager of SONNTAG Baugesellschaft mbH, Hönow, and Udo Salzwedel from the planning and construction department of Berliner Wasserbetriebe are satisfied with the installation.
Source: Wasserspiegel Magazine, Berlinwasser, September 2013
Saarlouis. For a new main collector, about 200 pipes are being laid underground in Saarlouis.
Saarlouis. The Saar Waste Management Association (EVS) is preparing the construction of a new main collector in Saarlouis with sewer construction work.
Traditional company from the Hunsrück employs 400 employees
Koblenz. The old dam will be renovated and reinforced, the pumping station revitalized: Around 3.7 million euros are to be invested in the eighth and final section of flood protection for Lützel, Neuendorf, and Wallersheim within 24 months...
Marienfels. In April, the renovation work at the wastewater treatment plant Mühlbachtal in Marienfels is set to begin. During a site visit, VG Works Manager Ralf Solinski discussed the planning with the contracted companies this week ...
At Bogenstraße, water pipes are being laid in advance. City councilors have visited the construction site ...
The municipal utilities are laying new sewage pipes in Bogenstraße - in an unusual way.
SONNTAG can lift its tunneling machine AVND 2500 from the target pit after crossing 36 railway tracks on August 24, 2016, during a press event with the client MAINOVA.
Residents praise the progress of the construction work on Villiper Main Street. The company aims to be finished by March 2017.
City: Everything fit! ... that it went more than half a year faster now has several reasons according to Peter Esch, head of the civil engineering office: "We had a particularly efficient construction company, the best site manager available to the civil engineering office for sewer construction, and optimal conditions for execution. With a less efficient company or unfavorable conditions encountered underground, it could look very different."
Example Bingen-Rhine crossing in the trade journal "bi-Umweltbau".
Article (PDF)
Construction site Cologne-Rheindüker in the trade magazine "bi-Umweltbau".
Article (PDF)
The head of the Kreuznach wastewater management praises in particular the company Sonntag in Bingen, which has been entrusted with the sewer renewal. With the increased use of the company Sonntag, the planned completion date - namely before the fair - can certainly be met, provided nothing unforeseen happens.
Source: Rhein Main Presse, July 2015
From a lofty height under the water
As part of a nationwide maintenance offensive, the Hans-Martin-Schleyer Bridge built in 1964 in Esslingen will be replaced. Since the structure also serves as a pipeline bridge for district heating, an alternative route had to be created before the planned demolition starting in 2021. EnBW opted for a siphon under the Neckar to ensure a permanently safe connection between the banks, and commissioned the SONNTAG Baugesellschaft.
The Dortmund-Ems Canal (DEK) is being expanded. Among other things, five culverts are being newly constructed.
see press article trade magazine "Road and Underground Construction", October 2020
Esslingen: Before the demolition of the Hanns-Martin-Schleyer Bridge, EnBW is laying a new district heating pipeline.
Retention basin is making progress - work on Hasenstraße is advancing rapidly.
In Triniusstraße in Bernkastel-Kues, the existing drainage pipes are being replaced with more efficient lines. The work marks the beginning of the three-year expansion of Cusanusstraße.
Consistent soil protection during pipe jacking measure
Mannheim. The connection of the Friesenheimer Island to the Mannheim district heating network is entering the next phase: ...
Pipeline - A large milling machine is creating a tunnel that connects the drinking water network on the right and left banks of the Rhine.
Tunnel construction for the first drinking water pipeline - The pioneers from the Rhine
Untertürkheim: 180 meter long relief channel from AWO-Waldheim to TBU pushed forward in advance
Since September, the drilling head Isabelle has been digging from the Aabach roundabout in Zug towards Lake Zug for the construction of the energy network Circulago. Yesterday, it reached the target shaft Schützenmatt at the lakeshore.
