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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.

Even if there are no visible electrical installation works on the construction site of Pumping Station Oberhausen yet, the electrotechnical equipment ist making bis steps forward. At the factory acceptance test in Finland, two out of the 10 frequency converters of the "small" and "large" sewage pumps were successfully tested and approved by the manufacturer as the first components of the powerful drivelines. These are frequency converters with a nominal voltage of 690 V and a rated current of 1.180 A, respectively 1.700 A, which corresponds to a rated output of 900, respectively 1.250 kW. The high demand on the network repercussions with limit specifications to the harmonic, inter-harmonic and, for the first time, also to the supra-harmonic currents, required the frequency converters to install active line filters and correspondingly large-sized line reactors. These are, like the actual power electronics of the frequency converter, cooled by water. Each frequency converter consists of 5 control cabinets, with each frequency converter being approx. 3 m wide. Helmut Mangelmann heads the Electrical Engineering Department at DAHLEM and works in the team of the design consortium (Planungs-ARGE) of Pumping Station Oberhausen: "We have planned and built quite a lot in the field of electrical engineering, but these dimensions go far beyond the previous performance levels. In the low voltage sector, they are at the limits of what is technically possible in terms of circuit and transmission technology."

The government grant decision, which the Environment Minister Franz Unterseller (left) handed over to Lord Mayor Fritz Kuhn (middle) and City Director Wolfgang Schanz (right), Head of the Civil Engineering Department, on 3rd September on the spot, was the starting signal for the expansion of the main sewage treatment plant Stuttgart-Mühlhausen with a fourth treatment stage. The main sewage treatment plant Stuttgart-Mühlhausen, built in 1916 as one of the first sewage treatment plants in Germany, is operated by Stadtentwässerung Stuttgart (SES) and should count to the most modern ones in the Federal Republic by 2028. Due to the complexity and the considerable investment, the expansion will take place in three construction phases. In the first phase, powder activated carbon silos and dosing stations will be set up at the Biology North and South as well as an energy control centre will be built. The federal state of Baden-Württemberg supports this project with just under 3 million EUR. With the construction of the treatment stage for the elimination of trace substances, the City of Stuttgart is making a significant contribution to water protection in the federal state. Dipl.-Ing. Mathias Kleffmann, process expert at DAHLEM and project manager of the design consortium, is pleased. "It's great that we can now start with the direct dosing on a large-scale and implement the new process technology on a industrial scale." 

By means of holistic optimization, Waste Water Treatment Plant Aachen-Soers has succeeded in reducing the enormous energy demand of the recovery by around 55 per cent. Together with DAHLEM, the Wasserverband Eifel Rur planned the modernization of the oxygen supply of the aeration tanks. The design was implemented at the beginning of the year, followed by the commissioning of the blower station mid-year. The RWTH Aachen accompanies the project scientifically. DAHLEM supported the process design, which was modeled in a 3D-planning and accompanied the award procedure. The enclosed article about the project provides detailed information about the modernization of the plant. The waste water treatment plant is also referred to as a nationwide model Enterprise.
Article, "Water & Waste Water Technology” magazine, July 2019

There was much enthusiasm at an unusual design meeting on the extension of WWTP Kleve-Salmorth, which is soon to be launched as a thermo-compact plant: plant manager Michael Offenberg and his team from the Kleve-based environmental operations were able to see how it felt in the new buildings of the waste water treatment plant. Is there enough space between the plant parts? Can one move well in between? Are there any missing components, etc. With the help of VR glasses, Torsten Wach, who is in charge of the project coordination, guided the participants through the building model, which was projected directly onto a screen. It made it possible for all involved to point out errors or changes and to rectify them before the start of construction. WWTP Kleve-Salmorth is regarded as a flagship project for innovative sewage sludge treatment and meets the requirements of the new Sewage Sludge Ordinance for Waste Water Treatment Plants to reclaim phosphorus from municipal sewage sludge in the future. Thus in the long run, the supply of this nutrient, which is central to all organism, shall be ensured. DAHLEM provides the design services, from the initial conceptual design to the award, including construction supervision.

Future-oriented flood prevention is a big topic worldwide. How it actually works is what the employees of SIGN, the Chinese-German Water Network, wanted to see for themselves on site in Germany. Dipl.-Ing. Holger Ackermann, employee at DAHLEM in Essen and member of the research project, led the Chinese delegation to various locations such as, for example, the ThyssenKrupp site, the Oberhausen pumping station and the Holtener Feld, designed and supervised by DAHLEM primarily taking into account the rainwater management aspects. As part of a subproject recommended for implementation, namely "Urban Water Management for Future Cities", DAHLEM developed a locally applicable action plan for future-oriented flood prevention in China together with SIGN, the Chinese-German Water Network.

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.

Many municipalities have experienced how massive the damage caused by heavy rain can be in recent years. Targeted flood prevention against are heavy rainfall and flash floods is becoming increasingly important in this context. It represents a major challenge for the municipalities and is closely linked to the municipal adaptation to climate change. The establishment and implementation of coordinated rain risk management is on the one hand a new task. On the other hand, a flood preparedness system coordinated by the various specialist departments increases the complexity of planning and administrative processes and raises questions that are still unanswered. The project "Municipal Flood Prevention - Planners in Dialogue" of the German Institute for Urbanism (DIfU) in cooperation with DAHLEM and numerous experts from the various administrative departments of 15 German cities examined how flood prevention can be achieved within a network of municipalities. The project was funded by the German Federal Environmental Foundation (DBU) in the course of two years. The special feature of the project lies in the fact that the municipalities were represented in each case by the affected department (urban planning, environment, landscaping, roads, municipal water supply and sewerage, disaster control). In eight daily workshops, case studies were developed, where typical obstacles and problems but also possible solutions and success factors lie. Based on the practical experience of the municipalities, recommendations and solutions for administrative work within a municipality were summarized in a brochure. It serves as an aid to municipalities that want to get more involved in heavy rain protection and answers questions (FAQ) on the topics of organization, law, financing, planning/implementation and operation maintenance.

Download the brochure:
Municipal flood prevention - planners in dialogue (4,5 MB)

The Video of the Emschergenossenschaft shows the construction progress of the sewer

It is the last section of the approximately 51-kilometer-long gigantic sewer from Dortmund to the wastewater treatment plant at the Emscher estuary in Dinslaken. The section of the sewer is adjacent to the landscaping of the new Emscher dike in Holtener Bruch in Oberhausen. After almost nine years, the sewer is almost completed. It lacks then only the last three kilometres from the sewer to the last wastewater treatment plant before the Rhine. The serwer is designed as a double frame profile using the cut-and-cover construction method and partially laid to form an arch. The Emscher sewer is completed in the Essen area. In September 2018 it was completely flooded up to Bottrop. A full commissioning is planned for 2020. All services related to the object and specialist planning have been provided for the project. The video of the Emscher Water Management Association shows the construction process of the serwer.

Die Anpassung an den Klimawandel bedeutet für die Städte und insbesondere für die Metropolregionen weltweit eine große Herausforderung. Die Vermeidung von Schäden durch Sturzfluten ist dabei ein wichtiger Aspekt. Gefordert ist ein integrales Starkregenrisikomanagement, das planerische, technische und administrative Maßnahmen umfasst und vorläufige Überflutungsrisikoanalysen beinhaltet. Die Handlungsempfehlung beschreibt die Hauptkomponenten des Risikomanagementansatzes, der sich in Europa mittlerweile als wirksam erwiesen hat. Die Empfehlungen sind weltweit übertragbar unter Berücksichtigung der regionstypischen Randbedingungen. Im Rahmen eines Teilprojektes zur Handlungsempfehlung „Urban Water Management for Future Cities“ entwickelte DAHLEM gemeinsam mit dem Chinesisch-Deutschen Wasser Netzwerk SIGN ein lokal anwendbares Handlungsschema für eine zukunftsgerechte Überflutungsvorsorge in China.

The Video of the Stadtwerke Karlsruhe shows the future project of the watersupply treatment plant Mörscher Wald

In November 2018, the groundbreaking ceremony for the construction of the new Mörscher Wald Waterworks took place. The currently existing waterworks dates back to the 1930s. The facilities are technically outdated and essential parts of the system must be renewed. The new construction will ensure the future vital potable water supply of the city of Karlsruhe and the neighbouring communities. The determination of the potable water requirements by 2040 revealed that in the future, due to climate change and projected population growth, a capacity of 60.000 m³/d, respectively 3000 m³/h, would have to be maintained as maximum output for raw water pumping and treatment. After commissioning of the new plant, the existing one will be completely dismantled. The architectural design of the building provides for a harmonious integration into the forested environment. As a joint venture partner, DAHLEM is entrusted with the building, interior and landscape planning. For the purpose of the construction planning, a BIM-oriented 3D model was set up.

Hemminger Straße in the north of Stuttgart is busy not only at peak times. Approx. 12.000 vehicles drive here on a daily basis - i.a. in the adjacent business park. Due to the traffic load, diverse pollutants that are washed away in the rain collect on the road over time. The polluted rainwater may no longer be discharged directly into the water bodies. It must first go through treatment and retention. On behalf of the urban drainage department of Stuttgart, DAHLEM has designed a cleaning system as a trough-trench system: here, the polluted rainwater is first collected in a shallow, grassy hollow (approx. 500 m²). The accumulated water seeps slowly into the ground. In the process, most of the pollutants contained in the soil layers are filtered out. Under the soil of the trough there is another storage space, which is designed with trenches (250 m³) and ensures that the seeping rainwater can be held back again and introduced as an environmentally friendly inflow into the Lindenbach.

In July 2018, the two new digesters of Wastewater Treatment Plant Würzburg were inaugurated. They are considered an art installation when illuminated. The concrete buildings with the façade insulation have already been implemented since spring-time and now also the membrane shells are on the digesters. Dr.-Ing. Anke Durth is the responsible project manager for the construction of the two new digesters. "They replace the 40-year-old digesters of the wastewater treatment plant, the capacity of which is no longer sufficient to treat the entire amount of sewage sludge. With the new digesters, the amount of sludge to be disposed of is reduced by one-third and power production is tripled", explains Anke Durth, who has been working for 15 years in the expert committee KEK-1 of the DWA-Board Committee for Recycling/Energy/ Sewage Sludge. The water and sewerage company of the city of Würzburg commissioned DAHLEM with the planning for the new construction of the digesters and several operations buildings, in which the facilities for gas treatment, gas utilization, co-substrate acceptance, etc. are housed.The façade design of the digesters and the operations buildings is the result of an architectural competition. The towers are covered with membrane layers of different shapes, so that two similar but not identical sculptures have been created.