In 2017, the design for the construction of the fully biological wastewater treatment plant Peja in Kosovo started. After more than 2.5 years of construction, the plant has been put into operation. With a treatment plant capacity of 81,000 population equivalents, it is one of the first wastewater treatment plants in Kosovo. An anaerobic-mesophilic digester stabilises the sewage sludge obtained and the plant's own power supply is provided by several CHP units using sewage gas. In addition to domestic wastewater treatment, the connection of a supraregional brewery is planned. Wastewater Treatment Plant Peja is one of the first steps to improve the wastewater infrastructure in Kosovo. Wastewater from residential areas usually ends up untreated in surface waters. While area-wide sewerage systems for wastewater discharge are largely in place in urban areas, the country lacks municipal and industrial wastewater treatment plants. The "Wastewater Management South-West Kosovo IV" programme aims to improve wastewater disposal and treatment in several cities, especially with regard to sustainable protection of natural water resources and improvement of the living conditions of the population. The programme provides for extensive wastewater disposal measures for the city of Peja, financed by KfW, SECO and local own funds from the city administration and the Republic of Kosovo. The total construction costs of the measures in the City of Peja amount to around €20 million. They include the construction of a main collector to transport the wastewater to the treatment plant site 6 km away, another collector to connect the southern city areas, stormwater overflows and a fully biological treatment plant. The municipal waste management company RWC HIDRODRINI JSC commissioned DAHLEM with the design, functional call for tender and construction supervision of the wastewater treatment plant as well as the transport collectors.

It was a historic moment when Pumping Station Oberhausen was commissioned on Friday, 20 August 2021, in the presence of the North Rhine-Westphalian Prime Minister Armin Laschet. For it is only with the start-up of the enormous pumps with a delivery rate of up to 16,000 l/s that the approx. 60 km long Emscher underground sewer (AKE) between Dortmund and Dinslaken also takes on its function of transporting wastewater. Previously, the Emscher served as the "cesspool of the Ruhr" for over 170 years and was long considered the dirtiest river in Germany. The project of the century to renaturalise the Emscher took many years and was completed on time. For the realisation of Pumping Station Oberhausen alone, more than ten years of planning and construction are behind the parties involved, in addition to, for example, Emschergenossenschaft‘s  various planning offices, experts, construction companies and approval authorities. Emschergenossenschaft commissioned DAHLEM with the design of the almost 50-metre deep pumping station of Pumping Station Oberhausen, which also sets architectural standards in the part above ground. In addition to the design, DAHLEM, as part of a joint venture, was responsible also for the construction supervision of the complex process, control, energy and machine technology.

On January 1, 2021, DAHLEM received the ÖKOPROFIT® Company 2021 award. Environment Minister Ursula Heinen-Esser, Mayor Kufen of Essen and around 50 participants met in Zoom as the ÖKOPROFIT® awards were presented virtually for the first time in all of Germany. As a participant in the project, DAHLEM has been implementing numerous in-house measures since 2018 to protect the environment while cutting costs: Reducing electricity and water consumption, introducing e-mobility with cars and bicycles, and much more. The ÖKOPROFIT® Essen-Ruhrgebiet project (Ecological Project for Integrated Environmental Technology) was launched in 2002 by the City of Essen to help companies and institutions establish a feasible environmental management system. "For us, the measures implemented achieved a great record of success. It's good to realize that you can implement many measures for the environment with little effort and at the same time increase the acceptance of environmental protection," says Dipl.-Ing. Markus Küppers enthusiastically.

Our ÖKOPROFIT team, from left to fight: Dr.-Ing. Jan-Gregor Dahlem, Sarah Lukai, M.Sc. and Dipl.-Ing. Markus Küppers