Now and for the first time in 170 years, the Emscher, the primary river in Germany’s largest conurbation, is entirely free of wastewater. As such, the main objective of the intergenerational Emscher Conversion project in the heart of the Ruhr region has been achieved. This development is attributable to Emschergenossenschaft as the responsible water board and to wide-ranging engineering services, many of which had to be rethought, researched and developed and which go far beyond merely water conservation.
Emschergenossenschaft was founded in 1899 as Germany’s first water board. It subsequently served as a model for an array of other water boards including Lippeverband, which was founded in 1926. From the outset, Emschergenossenschaft and Lippeverband have worked together under a joint umbrella (EGLV). As a self-governed public-sector entity, the organisation is supported and funded by its members – towns and cities, business and mining. It currently has a workforce of 1,800 working on a total of 782 km of waterways across an area of 4,145 km2.
More than a century ago, a sparsely populated agricultural landscape evolved into an industrial conurbation and the naturally flowing Emscher was turned into a man-made system of open wastewater canals. As mining dwindled, structural change set in and traditional heavy industry yielded, allowing wastewater to be carried away in enclosed underground sewers and the river with its tributaries to be turned back into near-natural waterways on the basis of innumerable carefully considered steps.
One of the world’s biggest restoration projects
The Emscher Conversion is playing its part in bringing water management experience together with the current requirements regarding the development of a sustainable region. Managing such a mammoth task calls for countless partners from all kinds of different fields who are often moving into new territory, who have the necessary expertise and who must merge these skills.
Johannes Siepenkötter and Reiner Tatus are project managers at Emschergenossenschaft and they are anything but out of their depth when it comes to structural, mechanical and electrical engineering. ‘Be it climate change, a changing energy market or wastewater treatment, modern-day water management has to come up with innovative solutions to a large number of challenges. There’s more to it than the obvious aspects all along the waterways – it’s also about wastewater heat utilisation, sewage sludge and ash management, phosphorus recycling, offsetting the fluctuations in other renewable energies with methane and hydrogen production, flood control and much more besides. Across the entire complex, the three major pumping stations along the Emscher wastewater canal in Gelsenkirchen, Bottrop and Oberhausen undoubtedly stand out – there were no models or experience reports on which to base them, but without them the primary objective of freeing the Emscher of wastewater could not have been achieved,’ explains Tatus, summarising his responsibilities.
Wastewater elimination for Dortmund, Castrop-Rauxel, Recklinghausen, Herne, Herten, Bochum, Gelsenkirchen, Gladbeck, Bottrop, Essen, Oberhausen, Duisburg and Dinslaken
The latter of the three pumping stations represented the greatest milestone along the road to achieving this objective. Wastewater arrives at the Oberhausen pumping station at a depth of approximately 38 metres and can be pumped around 42 metres up by as many as ten pumps simultaneously. All the incoming wastewater is pumped into overground pressure relief shafts, from where it flows a further 3.2 kilometres along the final stretch of the Emscher Wastewater Canal (AKE) to the Emscher estuary sewage treatment plant in Dinslaken. Without the technical excellence of the three major pumping stations, the canal would be far too low upon arrival there – approximately 75 metres below the surface.
The history of the Oberhausen pumping station’s construction began in 2016 with what was probably the largest hole in the Ruhr region – or at least the deepest earthwork site required for the Emscher Conversion. Below the surface, the facility is an impressive multi-level network consisting of 30,000 m3 of concrete, 3,500 m3 of reinforced concrete, a great deal of steel and seemingly never-ending stairways. All the way down at a depth of 40 metres is the facility’s centrepiece – ten huge centrifugal pumps, each with a maximum pumping volume of approximately 2,000 litres a second. These offset the wastewater’s natural gradient, enabling it to travel the distance from its source in the east of the Ruhr region via various sewage treatment plants and pumping stations, all the way to its final station – it will henceforth flow into the Rhine as clean water via the new Emscher estuary near Dinslaken and Voerde.
Surprisingly important – fire protection in the context of water conservation
The achievement behind these impressive figures becomes apparent if we take a closer look at a single element within the pumping station complex that is often initially somewhat overlooked, namely fire protection.
You could be forgiven for jocularly suggesting that, with so much water present, a fire would be extinguished in next to no time. But if given greater consideration and, moreover, if we take the strict structural engineering and building permission requirements that apply in Germany (and Europe) into account, we soon see that a lack of expertise here would be misguided. What’s more, incorporating a fire protection concept into construction planning early on allows for high time and cost savings as well as assured planning application and approval from the competent authorities and acceptance by the fire brigade, which has the ultimate say.
With projects on the scale of and as significant as the Emscher Conversion, unusual legal aspects can soon arise too, as planning approval procedures are selected which are unprecedented in law. With the project in question, a single application was required incorporating all the building regulation aspects of various building authorities, meaning the application consisted of several hundred folders. Here, a single planning error could soon result in considerable delays to the entire project. Finding a technical planner for fire protection at this point who has such a broad range of expertise that they can cover all the areas and disciplines of a technically sophisticated building complex is the first major hurdle to be overcome. Few specialist service providers know how to get all the requirements translated, transferred, checked and subsequently accepted following a cumulative approval. DMT is one of these rare companies and was therefore entrusted with the task of fire protection site management, providing general fire protection technical advice during the entire construction phase.