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After 40 years of operation, the old circular grit chamber with circular scrapers at Düsseldorf-Süd Wastewater Treatment Plant was replaced by a new grit chamber with two stainless steel longitudinal scrapers. The new scrapers, each weighing 4,5 tons, with a span of 13 meters, run over two parallel sand-trap basins. In January 2017, the demolition works of the old plant began, as the previous plant components were no longer economically feasible to overhaul. The renovation and renewal of the mechanical treatment stage is carried out while maintaining the treatment plant in operation. DAHLEM provides the project and technical design planning (construction technology, structural design, technical equipment) through to the construction supervision.

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.

At the wastewater treatment plant Paderborn, a research project for the tertiary wastewater treatment with a fourth treatment stage was currently being set up. Biologically activated carbon filtration (BAC) is a novel process combination of ozone and activated carbon filtration designed to significantly reduce the total annual costs and increase the amount of eliminable substances. On behalf of STEB Paderborn, DAHLEM implemented the large-scale research project on the wastewater treatment plant, which is funded by the state of NRW. The Institute for Urban Water Management (ISA) of RWTH Aachen advised DAHLEM scientifically during its implementation. At the beginning of 2018 the plant went into operation.

The project "MURIEL - Multifunctional Urban Retention Spaces: From Idea to Realization", funded by the German Federal Environmental Foundation, was successfully completed. The German Federal Environmental Foundation in Osnabrück commissioned DAHLEM as part of a joint venture with the research project, which aims to show ways in which existing inner-city open spaces can be used as emergency flooding areas during heavy rainfall events. The use of public open spaces as temporary retention areas is an important and necessary contribution to municipal flooding prevention - especially with regard to climate change. The three-part documentation summarizing how such retention rooms can be implemented and what needs to be considered in the concept and design is available for download here. 

Teil 1 – Wissenschaftliche Grundlagen (ca. 20 MB)
Teil 2 – Fallstudien (ca. 78 MB) 
Teil 3 – Arbeitshilfe für Planung, Umsetzung und Betrieb (ca. 52 MB) 

In 2018, RAG Aktiengesellschaft is going to suspend coal mining. Mining aftereffects need to be taken care of. Mine water discharge, polder measures and groundwater management are the “eternity tasks” of the post-mining era. Mine water conservation protected the mines from watercourses which had to be pumped out and discharged via streams and rivers. The future water retention should avoid environmental damage. The long-term mine water concept developed by RAG for the Ruhr region provides for a partial increase in mine water without affecting potable water. Through the use of subterranean waterways, the number of pumping stations is to be reduced, and the mine water still there is to be discharged without damage. The necessary pressure pipelines were planned for two locations: the Zeche Zollverein colliery and the Lohberg mine. A total of approx. 16 km of pipeline from DN 500 to DN 1.200 has been laid. A specially developed, novel monitoring system detects leakages at the pipes - also with regard to the pipeline route in the nature and landscape conservation areas.