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The Køge-Egnens Renseanlæg is the wastewater treatment plant responsible for treating the wastewater generated in the Koege region south of Copenhagen, Denmark. The region numbers approximately 64,000 residents, which account for roughly half of the 20,000 cubic meters of wastewater that flow into the treatment plant each day. The region’s business community generates the other half of the wastewater. The plant is operated jointly by three municipalities, as the region extends beyond the geographical borders of the Koege municipality itself. The plant uses the best modern technology to treat the wastewater to high standards before leading it into the nearby Koege Bay.
The Koege treatment plant uses dosing pumps in their sedimentation process, where equipment is used in the chemical purification process to add an aluminium compound in order to remove phosphorus in the wastewater. This precipitant is added just prior to the secondary sedimentation process. In addition to removing phosphorus, the precipitant also has a positive effect on sludge sedimentation.
When the plant management wished to replace their existing dosing equipment, they cooperated with an independent contractor who introduced them to Grundfos Digital Dosing pumps. At the time, the smaller models in the range were already well-established successes due to their combination of smooth, accurate dosing and remarkable user-friendliness, but Grundfos was still in the process of extending the range to suit large-scale applications. So the larger pumps in the Digital Dosing series—the DME60 and DME150 models—were still under development. Even so, the plant and operation managers decided to give the larger Digital Dosing pumps a chance in their new facilities.
The Grundfos Solution
The first DME60 pumps installed were test versions intended for reference and fine-tuning. “After a few teething problems with the first versions, Grundfos supplied new, final versions of the dosing pumps—and they have worked just fine,” said Kim Tietze, operation assistant at the Koege Region. “I was already familiar with a dosing pump from another manufacturer and might well simply have reordered from them, but I have to say that the Grundfos pumps seem very reliable and accurate. So I’m pleased!”
The Digital Dosing pump range can be equipped with a fieldbus communication module, allowing for many types of information sharing. For example, the pumps can supply performance data and status information that can be used for quality control, preventive maintenance and future reference. At the Koege treatment plant, the pumps communicate with the central monitoring and operation system via Profibus.
“The pumps offer a wealth of information options, and in fact we don’t use them all here—but we derive great benefits from the ones we do use,” Tietze said. “As yet, we have mainly employed their alarm functions, as the Digital Dosing pumps haven’t had a malfunction yet! But we know from experience that Profibus communication is a great help when looking for malfunctions, and I can certainly see how the many additional functions offered would be useful for others.”
The DME60 pumps now function as integrated parts of the treatment plant’s processes, which are continually monitored to maintain high quality and efficiency. Grundfos is very happy that the DME60 and DME150 series now makes it possible to supply efficient largescale dosing solutions for processes that demand higher flows, such as in wastewater treatment plants.