Hans-Peter Schmidt can still remember the stinking Emscher very well. "We didn't feel that way when we were children. But in the summer, the mother often closed the windows at night because there was such an acrid smell," says the 67-year-old, who happened to walk across an Emscher bridge in Castrop-Rauxel on Thursday morning .
Schmidt still lives near the Emscher. But the former sewage river has now become an (almost) normal flowing water. Since the beginning of the year, no sewage has been fed into what was once Germany's dirtiest river. The dirt now flows through a new sewage system that took 30 years to build. The completion of this so-called Emscher conversion was celebrated on Thursday.
Scolz: "Proof of innovative German engineering"
Even Chancellor Olaf Scholz (SPD) came. The conversion is the "world's largest renaturation project," he says, and "a great example of innovative German engineering." The conversion cost more than 5.5 billion euros, for Scholz "a great investment in a better quality of life". The SPD politician emphasizes: "However, success also means that the Emschergenossenschaft has brought this entire huge infrastructure project to a successful conclusion on time and within the framework of the estimated costs. We can see from this: It can be done. In this respect, too, the Emscher -Conversion a real role model."
The Emscher has its source in Holzwickede near Dortmund, crosses the Ruhr area from east to west and flows 83 kilometers into the Rhine in Dinslaken. But how did earlier generations come up with the idea of simply discharging their sewage into the river? This happened mainly because of underground coal mining. Underground sewers were not possible in the region. They would have been damaged by constant subsidence as a result of hard coal mining.
So natural watercourses were converted into open, concrete-bottomed sewers for sewage, which carried suds, dishwater, and worse to the sewage treatment plant. "We played a lot on the Emscher," says Schmidt. "We also watched how oil cakes in iridescent colors came by. Of course, lots of toilet paper and poo - and condoms too."
Only when only a few mines were left did the conversion of the Emscher system, including its 35 tributaries and streams, begin in 1992. The conversion is considered one of the largest infrastructure projects in Europe. Among other things, four large sewage treatment plants, 430 kilometers of sewers and three large pumping stations were built. More than 150 kilometers of river landscapes have been renatured and around 130 kilometers of new cycle paths have been created.
The heart of the conversion is a 51-kilometer sewage tunnel, the "Emscher Waste Canal" (AKE). In recent years, it has been laid along the Emscher to a depth of up to 40 meters. So that the sewage can flow over the entire route with sufficient gradient, the sludge has to be pumped up in three huge pumping stations. The Oberhausen pumping station is Germany's largest sewage pumping station. It can transport 16,500 liters per second.
Project is scheduled for completion in 2027
The renaturation work on the battered river continues. The Emscher has been straightened for around 55 kilometers. A near-natural transformation of the body of water and its tributaries should not be completed until 2027. Wherever possible, the slopes should be flattened. In some places, the Emscher is even allowed to meander through the landscape again in curves.
North Rhine-Westphalia's Building Minister Ina Scharrenbach (CDU) emphasized that the conversion would make new "city and open space qualities on the water" visible and that many natural areas would be created. The CEO of the Emschergenossenschaft, Uli Paetzel, said: "The conversion was worth it, nature is returning to and from the water." More than 1000 different species could already be recorded. "Insects, snails, mussels, crabs and also animals that are threatened with extinction such as lapwings or blue-winged dragonflies."
The next step in terms of renaturation is already pending: before the end of this year, the Emscher is to receive a floodplain landscape at its new confluence with the Rhine. It has been prepared for several years.