Sewage treatment plant
Bottrop

The Emscher sewage treatment plant in Bottrop, one of the largest and most modern sewage treatment plants in Europe, is a showcase project for sustainable water management and energy self-sufficiency. With a capacity for 1.3 million population equivalents and a total annual electricity requirement of 35 million kilowatt hours - comparable to that of a small town of 25,000 inhabitants - this plant sets standards in climate-friendly energy generation. Thanks to the innovative combination of sewage sludge and sewage gas utilization with the generation of renewable energy from solar, wind and hydropower, the sewage treatment plant can almost cover its own energy requirements and save 70,000 tons of CO2 every year.
The plant, which is known for its impressive, world's largest digestion towers, covers an area of 147,000 square meters. It purifies 8,500 liters of water per second and produces 190,000 tons of sewage sludge annually. Sewage gas containing methane is extracted from this sewage sludge, which is not only used to generate electricity for the plant's own needs, but also to produce bio natural gas. The latter in turn serves as fuel for the company's own natural gas-powered vehicles.
The Emschergenossenschaft, which operates the sewage treatment plant, built the first plant at the site back in 1929 and took a significant step in the modernization of water purification and energy generation with the current plant between 1991 and 2003 at a cost of 230 million euros. The Emscher sewage treatment plant in Bottrop is not only a key player in the conversion of the Emscher system from a cesspool to the "blue Emscher", but also a model project for sustainable sewage treatment plants worldwide, recognized by an innovation award from the International Water Association (IWA) in 2008.