On Thursday, April 12, 2018, the Eifel-Rur Water Association and the mayor of Aachen, Mrs. Margarethe Schmeer, commissioned Europe's largest ozonation plant at the Aachen-Soers wastewater treatment plant. The treatment plant has been equipped with an additional treatment stage to remove trace substances from wastewater and implemented in the existing wastewater treatment. The wastewater treatment plant has been cleaning the sewage of the city of Aachen since 1913 and is dimensioned for 458,300 population equivalents. The large-scale ozonation plant belongs to the NRW state-funded project "DemO3AC" (Demonstration project for ozonation of wastewater to the Aachen-Soers treatment plant) and should contribute to a considerable reduction of anthropogenic trace substances and a significantly improved water quality of the Wurm river. An accompanying research in situ investigates how the ozonation of the wastewater treatment plant effluent affects the water in particular. A joint venture with DAHLEM as the lead company is responsible for the object and technical planning. The state of North Rhine-Westphalia supports both the large-scale realization and the accompanying research. In October 2017, after only eight months’ construction time, the topping-out ceremony was celebrated.
After 26 years of operation, one of the two parallel-fed disc dryers of the sludge drying plant was replaced by a new one at Waste Water Treatment Plant Düsseldorf-Süd. In order to ensure a constant operation of the facilities, the exchange of the other rotor took place already in 2005. Before the replacement of the second rotor, a study showed that the drying of sludge by means of a new disc dryer represented the most favorable solution in terms of operating costs. With a pipe length of 8.6 metres and a heating surface of 400 m², the new disc dryer 2, partly made of stainless steel, provides a throughput of 5.2 tonnes per hour. As the previous plant part was no longer economically viable, the rotor replacement took place in March 2019. For the replacement of the disc dryer, DAHLEM provides the technical equipment planning, from establishing the basis of the project to the award, including construction supervision.