The Emscher region transforms her face - again. More than a hundred years ago, it changed from a sparsely populated agricultural landscape into an industrial agglomeration. The Emscher River was transformed into a drainage system of open sewers. It has nowadays a drainage basin of 865 km2 with 2.2 million inhabitants.
With the decline of mining in the second half of the last century, structural change has begun, in which the traditional heavy industry gives way to high-tech and service sectors. The end of the land subsidence, caused by mining makes it possible to discharge wastewater in closed underground channels and convert the river with its tributaries, step by step in natural waters - a long-term project.
Four large sewage treatment plants were built to decentralize the waste water treatment. One of it, the plant Bottrop, was visited at the excursion. It was built from 1991 to 1996 for 230 million Euros and cleans up to 8.5 cubic meter waste water per second.
From Dortmund-Deusen to the Rhine estuary at Dinslaken is the Emscher sewer built, a gigantic structure on a length of 51 kilometers in up to 40 meters depth: the most modern sewage system in the world. Three large pumping stations with capacities up to 1 million cubic meters per day transports the waste water along the sewer. One of it, the pumping station Bottrop with a diameter of 50 m and a depth of 40 m was visited.
The last station at this excursion gave an impression about the benefits of the new Emscher River for the region. We visited the Lake Phoenix, a man-made lake which is located at a former ground of steelworks in the city of Dortmund. It became a landmark for the social and ecological rehabilitation of the region