The Salierweg sewage treatment plant is the largest of Bonn's sewage treatment plants.
It is equipped with a biogas power plant and processes the resulting sewage sludge into renewable energy.
The Salierweg wastewater treatment plant is located in the middle of a residential area and must therefore meet the highest requirements for avoiding noise and odour emissions.
The sewage treatment plant Salierweg serves the sewage disposal from the following districts of the federal city Bonn and Alfter (partly): Bonn Castell, Endenich, Ückesdorf, Dottendorf, Buschdorf, Südstadt, Lessenich, Röttgen, Venusberg, Graurheindorf, Weststadt, Hardtberg, Lengsdorf (partly), Ippendorf, Auerberg, Dransdorf, Poppelsdorf, Gronau, Tannenbusch, Messdorf, Brüser Berg and Kessenich.
Not an easy task when you consider that on a day without rain every second approx. 410 litres of wastewater get here via the sewer system. That is 35,500,000 litres per day. It's much more when it rains.
The wastewater first enters the mechanical treatment stage via an inlet pumping station.
Dissolved substances are removed in the biological treatment stage. During revitalisation, microorganisms remove dissolved substances from the wastewater and convert them into body substance. The nutrient nitrogen is also removed by further biochemical reactions. The activated sludge, which is heavier than water, settles in the final clarification. A constantly running scraper pushes it into a funnel in the middle of the pool. There it is available for further processes. The now treated wastewater continues to flow into the filtration system.
Chemical purification takes place by binding the phosphorus in the form of flakes by adding salts and removing it together with the activated sludge from the wastewater in the four final sedimentation tanks. Drain pipes below the water surface conduct the water almost silently into the final cleaning stage, the filtration. In it the last still contained fine suspended particles are held in different filter layers. The laboratory examines the quality of the treated wastewater before it is finally discharged into the Rhine.
The sludge from the clarification process remains. Water is extracted from it using various techniques to reduce its volume before it disappears for approx. 30 days at 37°C in the digester. There, microorganisms convert the sludge into water, digester gas, carbon dioxide and stabilized sludge.
After 30 days of digestion, the sludge enters the post-drainage system. There, a centrifuge ensures a further reduction in volume. The remaining sludge is thermally recycled in the fluidized bed furnace and converted into ash.
Very complex cleaning systems remove ash, dust and pollutants from the resulting flue gases. The digester gas is used as a renewable energy source in the wastewater treatment plant.
From the Friedrich-Ebert bridge you have a good overview of the grounds and the facilities.
(Source: LINK)