The German project transforming an open sewer to a nature paradise

The German project transforming an open sewer to a nature paradise
13 July 2015
By Andrea Loebbecke

German project transforming an open sewer to a nature paradise - © Roland Weihrauch, dpa

Bottrop, Germany (dpa) - It's a daunting project: hundreds of kilometres of reeking open sewers in Germany's Ruhr region are to be turned back into the river Emscher and its tributaries.

Building work on the main, 50-kilometre-long sewage pipe began four years ago. In total, 423 kilometres of underground pipes will eventually carry the region's sewage instead of it being dumped into the river. By 2020, "Crap Creek", as it is known locally, will be a thing of the past and the people will get their river back.

The Muehlenbach (Mill Brook) in Essen is one of those tributaries which has already been cleaned up. "It used to absolutely stink here," says one dog-walker. "But now it's a little paradise."

The Emscher Cooperative has invested 4.5 billion euros (5 billion dollars) into the project, of which 18 per cent comes from the state and the European Union. "We're on budget and on schedule," says Jochen Stemplewski, chairman of the board of management - an achievement that can't be taken for granted on big projects like this. "We did this by costing everything honestly and precisely, and we took our time with it," says Stemplewski. Contracts with the building companies include clauses which state that if they finish on time, they get a bonus. The Cooperative also has its own project managers who are always on site. "And last but not least we include the people in the surrounding area," says Stemplewski. On the "Day of Open Canals" the public is free to take a look at the building sites.

Work began on the project in the 1990s, with the building of several sewage treatment plants. But the undisputed heart of the project is the canal which reaches from the city of Dortmund to where the Emscher meets the River Rhine, at Dinslaken. Drilling is continuing at several places in parallel, including in the city of Essen. Pipes with a diameter of 2.8 metres are being built by the course of the river 20 metres underground, local project manager Wulf Himmel explains. "The drill, named Isabel, manages about 13 to 14 metres a day," he adds.

It's powered by hydraulic presses. When 4 metres have been drilled, a crane lowers a new section of pipe into the pit. The underground sewer "highway" is to continue for 1.2 kilometres until Isabel resurfaces in Gelsenkirchen. Around 130 kilometres of the Emscher and its tributaries have already been transformed back into a river with babbling brooks. Along many of the banks run cycle and footpaths, at Phoenix Lake in Dortmund for example. All of the pipes are scheduled to be laid by 2017 and work on the banks completed three years later.

Germany's Ruhr region should be perhaps be more accurately known as the Emscher region - the Emscher runs directly through the middle of the mining area rather than along its southern border like the River Ruhr. The ecological death of the river began when the population of the towns in the Emscher Valley exploded between 1850 and 1900, from 300,000 to around 3 million. The residents and the factories continued to let their waste flow into the Emscher, which soon became a stinking slurry.

With its many curves and low gradient the river also often flooded its banks, leaving whole areas of towns under water. "With the floods came the hygiene issues," says Stemplewski. But underground canals had always been unthinkable in the region because of its many mines. So the Emscher Cooperative, founded in 1899 turned the 350 kilometres of the river into an open sewer. "In the mining region it was just accepted as the price you paid for a flourishing industrial sector, even when the sewer ran right past your house and stank enormously," says Stemplewski.

But since the middle of the 1980s the "Black Emscher" increasingly came in for criticism and soon a plan came into being to clean it up. As the mining industry moved further north, underground pipes became an increasing possibility. The first step was to invest around 1 billion deutschmarks (558 million dollars) in sewage treatment works - in Duisburg, Dortmund, Bottrop and Dinslaken. Of the planned pipe network, which runs between 10 and 40 metres under the earth, around 300 kilometres is now complete. There are also three major pumping stations on the main artery, which ensure a continuous gradient.

You can still enter the pipe and Emscher clay displaced by the drills is transported away on trollies. When it's finished the pipes will always be at least a third full with sewerage, says Himmel. And only rain and spring water will flow into the Emscher.

Source: dpa.