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.
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.